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Home My WebLink About20173516.tiffEXHIBIT INVENTORY CONTROL SHEET Case USR17-0043 - CACTUS HILL RANCH COMPANY, C/O SIMON CONTRACTORS, INC. Tyler Exhibit Page # Submitted By (Cont'd from 2017-3515) Description Email of Opposition Research Articles and Links, dated CA. 1-289 Greg and Laura Doyle 11/7/2017 (Cont'd to 2017-3886) 2017-3516 Tisa Juanicorena From: Sent: To: Cc: Subject: Kim Ogle Tuesday, November 07, 2017 7:28 AM doylegreg5@aol.com Esther Gesick; Tisa Juanicorena RE: landowner rights Simon Contractors 11/8 presentation Hello and Good morning The articles and publications provided to this office are now a part of the case file for the Simon Contractors land use application. Thank you for sending this information Kind regards, Kim From: doylegreg5@aol.com[mailto:doylegreg5@aol.com] Sent: Tuesday, November 7, 2017 5:39 AM To: Kim Ogle <kogle@weldgov.com> Subject: landowner rights Simon Contractors 11/8 presentation Land Ownership Rights EXHIBIT CAD R 1 -•• b There are a number of rights that are inseparable from land ownership_ Once you purchase a piece of land. you will most likely have the following rights: Surface Rights A landowner has a right to occupy the surface of his/her land Subterranean Rights A landowner has a right to valuable things (such as oil. minerals. and any other substances) found beneath the land's surface. Air Rights A landowner has a right to the air above and below his/her to a reasonable extent. See air space rights for a more detailed discussion Vegetation Rights A landowner has a right to plant treescrops. and other vegetation on his/her land. Improvement Rights A landowner has a right to improve and place fixtures on his/her land (such as a shed or a patio) Right to Lateral and Subjacent Support 1 A landowner has a right to stop his/her neighbors from excavating or otherwise changing their land such that it would damage his/her land and/or building. See lateral and subjacent support for a more detailed discussion. Right to Be Free Of Public Or Private Nuisances A landowner has a right to request a court order to stop non -consented interferences with his/her enjoyment of the land. Examples of nuisances include pollution. noxious odors. and excessive noise. Riparian Rights A landowner has a right to use the natural waterway within his/her land. See riparian ownership for a more detailed discussion. Are There Limits to How a Landowner May Exercise These Rights? Yes. For one. a landowner usually may not exercise his/her rights in a way that will interfere with another landowner's rights_ Furthermore. government may impose zoning law and special building law that will limit how a landowner may use his/her land. The government may even exercise the power of eminent domain and take away a landowner's land. There may also be private restrictions place on the deed of the land between the buyer and the seller. and these restrictions will usually be valid unless they contradict public policy_ Do I Need an Attorney? Real estate and property law can be very complex and frustrating. Laws not only vary from state to state. but from city to city. An attorney can make sure that your property transaction conforms to all local laws. Whether you are a homeowner or just renting. a lawyer can help resolve your real estate and property law problem 2 Tisa Juanicorena From: Sent: To: Cc: Subject: Kim Ogle Tuesday, November 07, 2017 7:25 AM Tisa Juanicorena; Esther Gesick Johnson, Anne FW: colorado nuisance laws- Simon Contractors 11/8 presentation Internet article on Nuisance Suits -- Environmental Law One page From: doylegreg5@aol.com[mailto:doylegreg5@aol.com] Sent: Tuesday, November 7, 2017 5:18 AM To: Kim Ogle <kogle@weldgov.com> Subject: colorado nuisance laws- Simon Contractors 11/8 presentation Nuisance suits. in environmental law. pertain mostly to practices and property uses that encroach upon a neighbors right to enjoy their own property. The nuisance must constitute an unreasonable and objectionable public or private use of one's land to the detriment of another's. In environmental law, many public nuisances are considered crimes. Private nuisances make similar allegations: however, they more often involve civil court actions. In application to environmental law. Two parallel scenarios will illustrate the concepts of private nuisance versus public nuisance. Environmental violators that are guilty of public nuisance in a civil court proceeding conduct lawful business in accordance with local zoning, health board, and environmental statutes. For example, many cities have a butcher district. The area is specifically zoned for that type of business. However, many people live near that district but outside of that urban district. A slaughterhouse dumps its scraps lawfully in the dumpster outside but fails to keep the dumpster lid closed. The entire neighborhood smells of rotting meat scraps. Residential neighbors complain about the awful stench. The slaughterhouse refuses to close the lid on the dumpster. The residential neighbors can sue the slaughterhouse for failure to make a reasonable request to curb the stench by closing the dumpster lid. This is an example of a private nuisance. The slaughterhouse is not guilty of violating public environmental law. However, the slaughterhouse still guilty of impeding on the residential neighbors' right to be free from an unreasonably bad smell. Therefore. this example fall under private nuisance. Keeping with the theme of slaughterhouses. an example of a private nuisance in violation of environmental law willed be forged. A slaughterhouse conducts its business in a lawfully zoned area. It has all its credentials and acts in accordance with the law. However. its business practices violate public environmental law by dumping meat scraps and blood in the canal near the back lot of the facility. Part of that canal lies on the facility's property. The canal empties out to a beach resort on the coast. Beach goers have noticed an unusually high amount of sharks in the waters. Fortunately. no one has been injured: However. word travels and shark infested waters are bad for business. The beach resort has reason to suspect that it may be the blood that is attracting the sharks to the waters. threatening the livelihood of the private beach goers. The violation of environmental law is first reported as a private nuisance. Upon investigation. it becomes a public nuisance because the state has a statute against dumping food scraps into the canal, especially blood. The beach resort can still bring civil action However, the owner of the slaughterhouse is criminally liable for his violation of environmental law because it violates the public safety. 1 Tisa Juanicorena From: Sent: To: Cc: Subject: Kim Ogle Tuesday, November 07, 2017 7:23 AM Esther Gesick; Tisa Juanicorena Johnson, Anne FW: eminent domain issue/ landowner rights- Simon Contractors 11/8 presentation Internet article on Eminent domain and land owner rights From: doylegreg5@aol.com[mailto:doylegreg5@aol.com] Sent: Tuesday, November 7, 2017 5:10 AM To: Kim Ogle <kogle@weldgov.com> Subject: eminent domain issue/ landowner rights- Simon Contractors 11/8 presentation Landowner Rights • Print HTML • Send via email • Overview • Team • The taking of private property by a governmental entity or public utility for public use — commonly referred to as eminent domain or condemnation — is a unique legal proceeding which often pits the power and prowess of state and federal agencies, public authorities, cities and utilities against landowners in a battle that often seems difficult to win. McAfee & Taft lawyers have a proven track record - both at the negotiation table and in the courtroom - of protecting the rights of commercial landowners and maximizing the "just compensation" due to them under the law. Attorneys Joe Bocock and Jeff Todd have both been honored for their work in the field of eminent domain and condemnation law by the publishers of The Best Lawyers in America, and Joe holds the distinction of being selected by Best Lawyers as the "Oklahoma City Eminent Domain and Condemnation Lawyer of the Year" for 2014. Click here to watch this complimentary webinar in its entirety on our dedicated landowner rights website, LandownerLlNC.com Our role in maximizing 'just compensation' Our commercial clients are typically businesses, large groups of landowners, individuals and families who own raw land being held for development, farm and ranch land, manufacturing facilities, office buildings and shopping centers and who face condemnation proceedings by such entities as departments of transportation, turnpike authorities. state and municipal governments. utility companies. rural water districts. and schools and universities. 1. We also assist landowners in obtaining compensation for damages to the value of their commercial land or other property caused by the actions of a governmental entity or utility through the process of inverse condemnation. While some threats of condemnation can be challenged on the basis of valid public use or necessity. the vast majority of condemnation cases focus on the issue of just compensation due the landowner Our attorneys work closely with clients. landowner groups. appraisers, real estate agents, engineers, location and development professionals, and other experts to thoroughly assess the value of the property taken as well as injury or damages to the remaining property. We are well - versed in the various techniques used by condemning authorities to get landowners to settle for a lower amount, and we know how to successfully anticipate and counter those moves. Our approach involves counseling clients throughout every possible phase of the condemnation process. advising them of their options and opportunities for maximizing their monetary recovery and non -monetary benefits every step of the way. We will first attempt to reach an agreement with the acquisition service that makes initial contact with the landowner to purchase the land and access rights. Few landowners are familiar with the dynamics of that process and understand what can and what cannot be realistically accomplished depending on the kind of "take- that is required. If early negotiations fail and a condemnation action is filed. we then guide clients through the complex Commissioners' Award process whereby three commissioners are appointed to inspect the property. assess the just compensation for the taking based on instructions from the court. and then render an award. The amount of that award is important for two and only two reasons. First. the landowner is entitled to immediately be paid the award even if he decides to contest the amount at a later jury trial. Second, if the subsequent jury verdict exceeds the award by 10%, the landowner is also entitled to be paid a reasonable attorney's fee. expert appraisal fee and expert engineering fee. The jury will never know the amount of the commissioners' award under any circumstances. and it is irrelevant in the determination of value. There are strict rules about communications with the commissioners and sometimes complicated issues concerning the instructions given to them. At the conclusion of this stage in the process, landowners may demand a jury trial if they believe the commissioners' award to be unjust compensation. Prior to a jury trial to determine the fair value of loss, extensive discovery is often needed in conjunction with the careful. thorough preparation of a case. This process typically employs engineers and leading Members of the Appraisal Institute to carefully and cogently explain to a jury the true value of the land taken and how the taking adversely impacts the use of the remaining land not taken. Often this explanation involves adverse impacts to an operating business and employs state-of-the-art graphics and photographic technology to hammer home the truth_ Our team has an undefeated track record in securing decisive verdicts well in excess of commissioners' awards. The representation of landowners in eminent domain proceedings requires us to battle powerful governmental entities and utilities with seemingly limitless resources for lawyers and experts. Subject opponents such as the Oklahoma Department of Transportation. Oklahoma Turnpike Authority, and public utility companies are worthy adversaries often fighting you with your tax dollars, turnpike fees or utility payments. Navigating the condemnation process Throughout this process. our highly knowledgeable and experienced attorneys help guide landowners and business owners through an ever-changing maze of legal issues as the niche area of condemnation law continues to evolve. We are often asked such questions as: 1. Do they have a right to take my land? 2. Who should be my first contact in the condemnation process? 3. What kinds of property are threatened by eminent domain? 4. Should I settle my condemnation dispute? 5. Can I be compensated for damage caused to the remaining part of my land? 6. What is the role of the commissioners? 7. Who will pay my legal and other expenses? 8 Do I have a right to a trial? 9. What creative solutions can avoid a trial and maximize my compensation? 10. What resources are available to protect my rights? 11. Am I entitled to relocation benefits? Additional resources for landowners 2 Tisa Juanicorena From: Sent: To: Cc: Subject: Attachments: One Article, please add to file Kim Ogle Tuesday, November 07, 2017 7:22 AM Esther Gesick; Tisa Juanicorena Johnson, Anne FW: COMPATABILITY OF ZONING AG/RESIDENTIAL WITH INDUSTRIAL --for Simon Contractors 11/8 presentation. A_Review_of_Industrial_Land_Use_Studies_Dempwolf.doc Research paper An Evaluation of Recent Industrial Land use Studies: Do Theory and History Matter in Practice? March 19, 2009 35 pages From: doylegreg5@aol.com[mailto:doylegreg5@aol.com] Sent: Tuesday, November 7, 2017 5:00 AM To: Kim Ogle <kogle@weldgov.com> Subject: Fwd: COMPATABILITY OF ZONING AG/RESIDENTIAL WITH INDUSTRIAL --for Simon Contractors 11/8 presentation. Original Message From: doylegreg5 <doylegreg5Aaol.com> To: DOYLEGREG5 <DOYLEGREG5(c aol.com> Sent: Tue, Nov 7, 2017 4:46 am Subject: COMPATABILITY OF ZONING AG/RESIDENTIAL WITH INDUSTRIAL. NICE TABLES AND DOES THIS LINK TO AREA GOALS AND OTHER BUSINESS IN AREA 1 Tisa Juanicorena From: Sent: To: Cc: Subject: Attachments: One article, please add to file Kim Ogle Tuesday, November 07, 2017 7:05 AM Esther Gesick; Tisa Juanicorena Johnson, Anne FW: study for Simon Contractors 11/8 presentation asphaltstudy199.pdf Centers for Disease Control and Prevention The National Institute for Occupational Safety and Health Benzene -Soluble Fraction and Total Particulate (Asphalt Fume) Partial Evaluation Issue 1, January 15, 1998 7 pages From: doylegreg5@aol.com [mailto:doylegreg5@aol.com] Sent: Tuesday, November 7, 2017 4:59 AM To: Kim Ogle <kogle@weldgov.com> Subject: Fwd: study for Simon Contractors 11/8 presentation Original Message From: doylegreg5 <doylegreg5@aol.com> To: DOYLEGREG5 <DOYLEGREG5(c�aol.com> Sent: Tue, Nov 7, 2017 4:00 am Subject: study BENZENE -SOLUBLE FRACTION AND TOTAL PARTICULATE 5042 (ASPHALT FUME) MW: variable CAS: 8052-42-4 asphalt; none, asphalt fume RTECS: CI990000, asphalt; none, asphalt fume METHOD: 5042, Issue 1 EVALUATION: PARTIAL Issue 1: 15 January 1998 OSHA: No PEL NIOSH: C 5 mg/m3 (15 -min) as total particulates ACGIH: 5 mg/m3 PROPERTIES: not defined SYNONYMS: bitumen fumes SAMPLING MEASUREMENT SAMPLER: FLOW RATE: VOL-MIN: -MAX: SHIPMENT: SAMPLE STABILITY: BLANKS: FILTER (tared 37 -mm, 2 -pm, PTFE filter) 1 to 4 L/min 28 L @ 5 mg/m3 400 L @ 5 mg/m3 routine not determined 5 field blanks per day ACCURACY RANGE STUDIED: not determined BIAS: OVERALL PRECISION NrT): not determined not determined ACCURACY: not determined TECHNIQUE: GRAVIMETRIC ANALYTE: Airborne total particulate (TP) material and the benzene -soluble fraction (BSF) EXTRACTION: 3 mL benzene; ultrasonic bath, 20 minutes BALANCE: 0.001 mg sensitivity; use same balance, if practical, before and after sample collection CALIBRATION: Check and maintain calibration of balance according to manufacturer's recommendations RANGE: TP: 0.13 to 2 mg per sample BSF: 0.14 to 2 mg per sample ESTIMATED LOD: TP: 0.04 mg per sample BSF: 0.04 mg per sample PRECISION (Sr): TP: 0.048 at 0.10 mg per sample BSF: 0.061 at 0.21 mg per sample APPLICABILITY: The working range is 0.14 to 2 mg/m3 for a 1000-L sample. The method is applicable to 15 -minute samples. The method was evaluated for asphalt fume; however, it is nonspecific and determines the concentrations of total particulate and the soluble fraction of the total particulate to which a worker is exposed. Therefore, for each sample matrix collected other than asphalt fume, a surrogate standard must be selected and spiked onto sampling media. These spiked samples will be used to determine recoveries, precision, and accuracy, also LOD and LOO if necessary; moreover, other solvents besides benzene can be evaluated. The particle size of the particulate should be less than 40 pm, and preferably less than 30 pm. If particle sizes are larger than this, another sampler should be used. INTERFERENCES: Changes in temperature or humidity during pre- and post -collection weighing may affect accuracy. A controlled laboratory environment is needed to exclude positive interferences due to dust contamination. Losses may occur from air stripping or volatilization of a collected sample during sampling, shipping, or analysis. OTHER METHODS: The total particulate portion of this method is based on NMAM 0500 [1]. Other methods applicable to asphalt fume are NMAM 5800. Polycyclic Aromatic Compounds [2], and NMAM 2550. Benzothiazole in Asphalt Fume [3]. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME): METHOD 5042, Issue 1, dated 15 January 1998 - Page 2 of 7 NIOSH Manual of Analytical Methods (NMAM), Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME): METHOD 5042. Issue 1, dated 15 January 1998 - Page 3 of 7 REAGENTS: EQUIPMENT: 1. Benzene,* 5 ppm evaporation residue. e.g., 1. Sampler: 37 -mm, 2 -pm pore size, PTFE Aldrich Chemical Co. Cat. No. 27.070-9 or membrane filter laminated to PTFE (Zefluor. equivalent. Pall Gelman Sciences, Cat. No. P5PJ037: 2. Acetone,* HPLC grade. Supelco. Cat_ No. 2-0043: SKC Cat_ No. 225- 3. Hexane,* HPLC grade. 17-07: or equivalent hydrophobic filter), with 4. Nitrogen,* purified and filtered. cellulose support pad in a 37 -mm cassette filter holder. 2. Personal sampling pump, 1 to 4 L/min, with flexible connecting tubing. 3 Balance. readable to 0.001 mg. 4. Static neutralizer, 'Po; replace according to manufacturer's recommendations. * See SPECIAL PRECAUTIONS. 5. Environmental chamber or room for balance (e.g., 20 ± 1 C, constant ± 5% relative humidity. and dust -free). 6. Weighing cups.* PTFE, 2-mL (Fisher Cat. No. 2006529. or equivalent), in a carrying rack. 7. Vacuum oven. equipped with in -line filter on vacuum release valve to remove dust. NOTE: Keep the interior of the vacuum oven dust -free for maximum sensitivity, reproducibility, and accuracy. 8. Forceps_ 9. Test tubes.** glass, 13 -mm x 100 mm, with PTFE-lined screw caps. 10. Pipet.** glass. volumetric, 3-mL, with bulb. 11. Pipet.** glass, Mohr, 2-mL. with bulb. 12. Clarification units, 6-mL PTFE-treated reservoir with 1 -pm PTFE frit (Daigger and Company, Inc., Lincolnshire. IL, Cat. No LID-2102-10US. or equivalent). 13. Pressure regulator, valve, tubing. in -line filter to remove dust and organics, with adapter for applying nitrogen pressure to the clarification unit. 14. Ultrasonic bath. ** Rinse the weighing cups as follows. a. Wash with acetone until all visible residue is removed b. Rinse with hexane for several seconds. c. Air dry. d. Discard any weighing cups that are not visibly clean. Rinse all glassware with acetone then hexane; air dry. SPECIAL PRECAUTIONS: Benzene is a suspect carcinogen [4]. Asphalt fumes are considered a potential occupational carcinogen [4]. Benzene, hexane, and acetone are highly flammable. Prepare samples and standards in a well -ventilated hood and avoid skin contact. Use care when working with compressed gases. PREPARATION OF FILTERS BEFORE SAMPLING: NIOSH Manual of Analytical Methods (NMAM). Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME): METHOD 5042. Issue 1. dated 15 January 1998 - Page 4 of 7 Numberthe backup pads with a ballpoint pen and place them, numbered side down. in the filter cassette bottom sections. 2. Preweigh the filters by the weighing procedure given in step 3 Record the mean tare weight of sample filters. W, and field blanks. B (pg). 3. Weighing procedure: a. Equilibrate the filtersor weighing cups in an environmentally controlled weighing area or chamber for at least two hours. b. Zero the balance before each weighing. c. Using forceps, pass each filter or weighing cup over a static neutralizer. Repeat this step if the filter or weighing cup does not release easily from the forceps or attracts the balance pan. Static electricity can cause erroneous weight readings. d. Weigh each filter or weighing cup until a constant weight is obtained (two successive weighings within 10 pg). Record the mean of the last two weighings to the nearest microgram. 4. Assemble the filter in the filter cassette and close firmly to prevent leakage. Place a plug in each opening of the filter cassette. Place a cellulose shrink band around the filter cassette. allow to dry and mark with the same number as the backup pad. SAMPLING: 5. Calibrate each personal sampling pump with a representative sampler in line. 6. Sample at an accurately known flow rate between 1 to 4 L/min for a total sample volume of 28 L to 400 L. Do not exceed a total filter loading of approximately 2 mg total particulate. 7. Collect five field blanks for each day of samplin4or determining the limit of detection (LOD) and the limit of quantitation (LOQ)_ 8. Replace plugs in cassettes and pack securely for shipment to the laboratory. Recommend samples be refrigerated upon receipt at the laboratory. CALIBRATION AND QUALITY CONTROL: 9. Use the same balance. if practical, for weighing filters and weighing cups before and after sample collection or benzene evaporation. Check and maintain calibration of balance according to manufacturer's recommendations. Zero the balance before each weighing. 10. Process three tared media blanks through the measurement procedures for total particulate and benzene -soluble fraction. TOTAL PARTICULATE MEASUREMENT: 11 After sampling: a. Allow refrigerated sample cassettes to come to room temperature before proceeding. b. Wipe dust from the external surface of the filter cassette with a moist paper towel to minimize contamination. Discard the paper towel. c. Remove the top and bottom plugs from the filter cassette. Equilibrate sampler for at least two hours in the balance room or environmental chamber. d. Remove the shrink band. pry open the cassette. and gently remove the filter to avoid loss of sample. e. Reweigh (step 3) each filter, including field blanks_ Record the mean post -sampling weight. yMr B (pg). Also, record anything remarkable about a filter (e.g., overload. leakage, wet, torn. etc.) f. After weighing, transfer the filter carefully with forceps to a clean test tube and cap the tube. NIOSH Manual of Analytical Methods (NMAM). Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME). METHOD 5042. Issue 1, dated 15 January 1998 - Page 5 of 7 CALCULATIONS FOR TOTAL PARTICULATE: 12. Calculate the concentration of total particulate, 0: (mg/m3), in the air volume sampled, V (L). CTP ( W2 W1 ) ( B2 B1 ), mg/m 3 V where: W1 = mean tare weight of filter before sampling (pg) W2 = mean post -sampling weight of sample -containing filter (pg) B1 = mean tare weight of field blank filters (µg) B2 = mean post -sampling weight of field blank filters (µg) BENZENE -SOLUBLE FRACTION MEASUREMENT: 13. Condition clarification unit by rinsing the reservoir with 1.5 mL of benzene. Use nitrogen pressure to force the benzene through the frit. Appropriately dispose of the benzene rinse. 14. Extract benzene -soluble fraction. a. Add 10 mL benzene via a 3-mL volumetric pipet to the filter -containing test tube (step 11.e.) Recap the test tube. b. Place the test tube upright in beaker containing water to the same level as the liquid in the test tube. Place the beaker and test tube in ultrasonic bath and agitate for 20 minutes. c. Transfer benzene extract to conditioned clarification unit and force the extract through into a clean test tube, using nitrogen pressure as in step 13. Discard sampling filter and clarification unit. NOTE: Be sure the end of the clarification unit is well below the opening of the test tube to prevent sample loss by spattering. 15. Preweigh clean weighing cups by the weighing procedure in step 3. Record the mean tare weight, 3W or B3 (µg). NOTE: The weighing cup should already be prerinsed and dried as described in the Equipment section. a. Identify each tared weighing cup by labeling its place in the carrying rack. b. Transfer a 1.5-mL aliquot of the benzene extract via a 2-mL Mohr pipet to the tared weighing cup. NOTE An aliquot may be taken from the remaining extract at this step if other analyses (e.g., polycyclic aromatic compounds) are to be performed on the sample. Apply the appropriate aliquot factor in calculations. 16. Place the weighing cup rack in a vacuum oven preheated to 40C. Apply vacuum until pressure in the oven is 7 to 27 kPa (50 to 200 mm Hg). Allow solvent to evaporate (about two hours). Release the vacuum by slowly opening a release valve that has an in -line filter to remove room dust. 17 Reweigh the weighing cup by the weighing procedure in step 3. Record the mean post -sampling weight, W4 or B, (pg). Also, record anything remarkable about the sample (e.g., overload, leakage, wet, spattering. etc.). 18. After weighing, clean the weighing cup as described in the Equipment section. CALCULATIONS FOR BENZENE -SOLUBLE FRACTION: 19. Calculate the concentration of benzene -soluble fraction, Q, (mg/m ), in the volume of air sampled, V (L): CBSF [( W4 3 - (B4 B3)]•2 3 V , mg/m where: W = mean tare weight of sample weighing cup (µg) W:. = mean post -sampling weight of sample weighing cup (pg) B,, = mean tare weight of field blank weighing cups (µg) B., = mean post -sampling weight of field blank weighing cups (pg) NIOSH Manual of Analytical Methods (NMAM). Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME) METHOD 5042. Issue 1. dated 15 January 1998 - Page 6 of 7 2 = aliquot factor EVALUATION OF METHOD: Asphalt fume collected during a previous NIOSH investigation [5] was spiked on tared PTFE filters. allowed to dry at least overnight, and extracted using benzene. The results are summarized in the table below. Spiking level (mg)* Total Particulates Benzene -Soluble Fraction Recovery (%) S, Recovery (%) S, 1.85 102 5.97 97.9 0.738 1 17 103 3.98 98.8 2 02 0.62 94.0 5.85 94.8 1.85 0.23 91 6 3.50 96.9 6 10 0.12 82.1 3.91 80.9 9 54 0 058 110 16.4 92.1 13.5 0.025 105 11.4 73.1 17.4 ix rep Ica es per leve The pooled relative standard deviation $,) for the total particulates was 4.8% at loadings greater than or equal to 0.10 mg per sample_ For the benzene -soluble fraction, the pooled relative standard deviation was 6.1% at loadings greater than or equal to 0.21 mg per sample. The accuracy criterion is based on determining the range of analyte loadings and the analyte loading on the sample media that will give at least 95% confidence of obtaining a measurement of the analyte that is within 25% of the true value 95% of the time Since no independent method for determining the total particulate concentration is available. no estimate of the bias for the total particulate data was made: therefore, the maximum allowable bias was calculated at which the accuracy criterion could still be met Based on the spiking data, if the total particulate loading was greater than or equal to 0.10 mg per filter, the measurement determination will be within 25% of the true valu®5% of the time if the true bias is less than 10.0%. The bias for the benzene -soluble fraction was negative (see the data above). and since the bias for the benzene - soluble fraction varied little, the bias was pooled over the spiking range of 1 85 to 0.20 mg per filter. It was determinedthat the 25% accuracy criterion was met if the benzene -soluble fraction was greater than or equal to 0.20 mg per filter. The limit of detection (LOD) and the limit of quantitation (LOQ) were determined using field blanks [6]. The LOD is equal to three times the standard deviation of the field blank weight differences (post -sampling weight - tare weight). and the LOQ is equal to ten times the standard deviation of the field blank weight differences. Field sample values should be compared to the LOD and LOQ values only after the field samples have been blank corrected The standard deviations of the field blank weights were 0 013 mg per sample for total particulates and 0 014 mg per sample for the benzene -soluble fraction. Therefore. the LOD and LOQ for total particulates were 0.04 and 0 13 mg per sample. respectively The LOD and LOQ for the benzene -soluble fraction were 0.04 and 0.14 mg per sample. respectively These LOD and LOQ values should only be compared to blank corrected field sample data A user check of the method was performed in which tared PTFE filters were spiked with 1.08, 0.392. or 0.216 mg of pyrene per filter and then analyzed by an independent chemist [6] A mean total particulate recovery of 103% (S = 5 85%) was obtained, and the mean benzene -soluble fraction recovery was 109% ,(S 9.91%). Correlation of benzene -soluble mass with total particulate was linear. with'R 0 994, and the mean NIOSH Manual of Analytical Methods (NMAM), Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME) METHOD 5042. Issue 1 dated 15 January 1998 - Page 7 of 7 ratio of benzene -soluble mass to total particulate was 106% (& 7.80%). In other experiments, three of 60 field blanks (three sets of 20 field blanks each) had a significantly higher than expected benzene -soluble fraction when compared with the other field blanks [6]. This event had two undesirable consequences: (1) Because the average weight of the field blanks was increased. the field samples were over corrected. and (2) the standard deviation of the field blank weights was increased resulting in higher LOD and LOQ values. For example, if the set of twenty field blanks with one high result is randomly assigned to groups of three (repeatedly), the standard deviation of the groups with the high result could exceed the standard deviation of the other groups by more than 1.6 times, Since this event also may occurwith field samples, these elevated results were not excluded when the data were evaluated. Although these events were observed with a syringe type clarification unit and not the recommended clarification unit. the cause of this event was not determined. Thereforet is important to collect as many field blanks as is reasonable (five blanks per day): also, it may be advisable to establish a monitoring program to track the occurrence of elevated field blanks and. if possible. to identify and eliminate the cause(s) In another experiment, the recommended clarification unit (PTFE-treated reservoir and a PTFE filter) was evaluated along with three syringe type clarification units [6]. The recommended clarification unit gave lower average extractable material than the syringeype clarification units: also, the recommended clarification unit did not release increasing amounts of extractable material upon prolonged contract with solvent Prerinsingthe recommended clarification unit appeared to lower the average amount of extractable material Additionally, the recommended clarification unit eliminated the need for using a glass syringe and was more convenient to use than the syringe type clarification units. In a preliminary asphalt fume spiking experiment, benzene and methylene chloride were evaluated as extraction solvents [6]. Asphalt fume [5] was spiked on tared PTFE filter media at the following concentrations: 3.38, 0.68, 0.14. and 0.034ng per filter. Benzene gave recoveries greater than 100% for all concentrations of asphalt fume spiked on PTFE filters While methylene chloride gave recoveries greater than 96% for the two highest levels spiked, at the two lower levels the recoveries were less than 67%. REFERENCES: [1] NIOSH [1994] Particulate not otherwise regulated. total: Method 0500. In. Eller PM. Cassinelli ME. eds. NIOSH Manual of Analytical Methods (NMAM). 4'h ed Cincinnati, OH' National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113. [2] NIOSH [1998]. Polycyclic aromatic compounds: Method 5800. In: Eller PM, Cassinelli ME, eds NIOSH Manual of Analytical Methods (NMAM). 4'" ed . 2'1 Supplement. Cincinnati. OH National Institute for Occupational Safety and Health. DHHS (NIOSH) Publication No. 98-119 [3] NIOSH [1998]. Benzothiazole in asphalt fume: Method 2550 In. Eller PM. Cassinelli ME. eds. NIOSH Manual of Analytical Methods (NMAM). 4 ed . 2' Supplement Cincinnati. OH: National Institute for Occupational Safety and Health. DHHS (NIOSH) Publication No.98-119. [4] NIOSH [1992]. NIOSH recommendations for occupational safety and health, compendium of policy documents and statements Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No 92-100. [5] Sivak A. Niemeier R. Lynch D. Beltis K. Simon S. Salomon R. Latta R. Belinky B, Menzies K. Lunsford A. Cooper C. Ross A. Bruner R [1997]. Skin carcinogenicity of condensed asphalt roofing fumes and their fractions following dermal application to mice. Cancer Letters 1 17113-123. [6] NIOSH [1998]. NIOSH backup data report for total particulate and benzene -soluble fraction (asphalt fume). NIOSH Method 5042 (unpublished) METHOD WRITTEN BY: Larry D Olsen (Team Leader), Barry Belinky. Peter Eller, Robert Glaser. R Alan Lunsford. Charles Neumeister, Stanley Shulman, NIOSH/DPSE NIOSH Manual of Analytical Methods (NMAM). Fourth Edition Tisa Juanicorena From: Sent: To: Cc: Subject: Kim Ogle Tuesday, November 07, 2017 6:33 AM Esther Gesick; Tisa Juanicorena Johnson, Anne FW: Simon Contractors 11/8 presentation Internet Article, American Lung Association Health Effects of Ozone and Particle Pollution, date 2017 Article less than 10 pages, please add to file From: doylegreg5@aol.com[mailto:doylegreg5@aol.com] Sent: Tuesday, November 7, 2017 4:54 AM To: Kim Ogle <kogle@weldgov.com> Subject: Simon Contractors 11/8 presentation Original Message From: email <emailaddthis.com> To: doylegreg5 <doylegreg5@aol.com> Sent: Mon, Nov 6, 2017 9:09 pm Subject: How healthy is the air you breathe? http://www.lung.org/our-initiatives/healthy-air/sota/health-risks/#.WgEyDcBuuDM.email This message was sent by laura.doyle[a�crmcwy.org via http://addthis.com. Please note that AddThis does not verify email addresses. To stop receiving any emails from AddThis. please visit: http://www.addthis.com/privacy/email-opt- out?e=rGTTAM4D0gjFCtBa9w7YA5kM2Al 1 Tisa Juanicorena From: Sent: To: Cc: Subject: Kim Ogle Tuesday, November 07, 2017 6:30 AM Esther Gesick; Tisa Juanicorena Johnson, Anne FW: Simon Contractors 11/8 presentation National Center for Biotechnology Information Internet article. less than 2 pages. please add to file From: doylegreg5@aol.com[mailto:doylegreg5@aol.com] Sent: Tuesday, November 7, 2017 4:52 AM To: Kim Ogle <kogle@weldgov.com> Subject: Simon Contractors 11/8 presentation Original Message From: Sent by NCBI <nobody@ncbi.nlm.nih.gov> To: doylegreg5 <doylegreg5@aol.com> Sent: Mon, Nov 6. 2017 10:30 pm Subject: 1 selected item: 16395464 - PubMed This message contains search results from the National Center for Biotechnology Information (NCBI) at the U.S. National Library of Medicine (NLM). Do not reply directly to this message Sent on: Tue Nov 7 00:28.42 2017 1 selected item: 16395464 PubMed Results Item 1 of 1 (Display the citation in PubMed) 1.J Environ Monit. 2006 Jan;8(1):89-99. Epub 2005 Nov 29. Road pavers' occupational exposure to asphalt containing waste plastic and tall oil pitch. Vaananen V1, Elovaara E, Nykyri E, Santonen T, Heikkila P. Author information: 1 Finnish Institute of Occupational Health, Topeliuksenkatu 41 aA, FI-00250, Helsinki, Finland. virpi.vaananen@ttl.fi Abstract Waste plastic (WP) and tall oil pitch (T), which are organic recycled industrial by-products, have been used as a binder with bitumen in stone mastic asphalt (SMA) and asphalt concrete (AC). We compared the exposure over one workday in 16 road pavers participating in a survey at four paving sites, using mixes of conventional asphalt (SMA, AC) or mixes 1 containing waste material (SMA-WPT, AC-WPT). The concentrations of 11 aldehydes in air were 515 and 902 microg m(-3) at the SMA-WPT and AC-WPT worksites, being 3 and 13 times greater than at the corresponding worksites laying conventional asphalt. Resin acids (2-42 microg m(-3)), which are known sensitizers, were detected only during laying of AC-WPT. The emission levels (microg m(-3)) of total particulates (300-500), bitumen fumes (60-160), bitumen vapour (80-1120), naphthalene (0.59-1.2), phenanthrene (0.21-0.32), pyrene (<0.015-0.20), benzo(a)pyrene (<0.01) and the sum of 16 PAHs (polycyclic aromatic hydrocarbons, 1.28-2.00) were similar for conventional and WPT asphalts. The dermal deposition of 16 PAHs on exposure pads (on workers' wrist) was low in all pavers (0.7-3.5 ng cm( -2)). Eight OH-PAH biomarkers of naphthalene, phenanthrene and pyrene exposures were quantified in pre- and post -shift urine specimens. The post -shift concentrations (mean +/- SD, micromol mol(-1) creatinine) of 1- plus 2 - naphthol; 1-,2-,3-,4- plus 9-phenanthrol; and 1-hydroxypyrene were, respectively, for asphalt workers: 18.1+/- 8.0, 2.41 +/- 0.71 and 0.66+/- 0.58 (smokers); 6.0+/- 2.3, 1.70+/- 0.72 and 0.27+/- 0.15 (non-smokers); WPT asphalt workers: 22.0+/- 9.2, 2.82+/- 1.11 and 0.76+/- 0.18 (smokers); 6.8+/- 2.6, 2.35+/- 0.69 and 0.46+/- 0.13 (non- smokers). The work -related uptake of PAHs was low in all pavers, although it was significantly greater in smokers than in non-smokers. The WPT asphalt workers complained of eye irritation and sore throat more than the pavers who had a much lower exposure to aldehydes and resin acids. PMID: 16395464 [Indexed for MEDLINE] 2 Tisa Juanicorena From: Sent: To: Cc: Subject: Kim Ogle Tuesday, November 07, 2017 6:22 AM Tisa Juanicorena; Esther Gesick Johnson, Anne FW: presentation 11/8 re Simon Contractors US Department of Labor Internet article. Article less than 2 pages, please add to file From: doylegreg5@aol.com[mailto:doylegreg5@aol.com] Sent: Tuesday, November 7, 2017 4:50 AM To: Kim Ogle <kogle@weldgov.com> Subject: presentation 11/8 re Simon Contractors Original Message From: email <email(a�addthis.com> To: doylegreg5 <doylegreg5(a�aol.com> Sent. Mon, Nov 6, 2017 8:00 pm Subject: Crystalline Silica Exposure https://www.osha.gov/Publications/osha3176. html#.WgEhsg86A4Q.email This message was sent by laura.doyle©crmcwy.orq via http://addthis.com. Please note that AddThis does not verify email addresses. To stop receiving any emails from AddThis, please visit: http://www.addthis.com/privacy/email-opt- out?e=b QekAOTH5glmh3KOp4Vk1ScFZl 1 Tisa Juanicorena From: Sent: To: Cc: Subject: Kim Ogle Tuesday, November 07, 2017 6:21 AM Tisa Juanicorena; Esther Gesick Johnson, Anne FW: submission for presentation against Simon Contractors 11/8 Article less than 10 pages, please add to file From: doylegreg5@aol.com[mailto:doylegreg5@aol.com] Sent: Tuesday, November 7, 2017 4:50 AM To: Kim Ogle <kogle@weldgov.com> Subject: submission for presentation against Simon Contractors 11/8 Original Message From: laura <wordpress@healthjournalism.orq> To: doylegreg5 <doylegreg5@aol.com> Sent: Mon, Nov 6, 2017 8'58 pm Subject: [Shared Post] Air pollution within legal limits still can be deadly for older adults laura (laura.doyle(a�crmc.wy) thinks you may be interested in the following post: Air pollution within legal limits still can be deadly for older adults https://healthjournalism.org/blog/2017/09/air-pollution-within-legal-limits-still-can-be-deadly-for-older-adults/ This report contains the collective views of an international group of experts and does not necessarily represent the decisions or the stated policy of the United Nations Environment Programme, the International Labour Organization, or the World Health Organization. Concise International Chemical Assessment Document 59 ASPHALT (BITUMEN) The layout and pagination of this pdf file are not identical to the version in press Corrigenda published by 12 April 2005 have been incorporated in this file First draft prepared by Ms Joann A. Wess, Dr Larry D. Olsen, and Dr Marie Haring Sweeney, National Institute for Occupational Safety and Health, Cincinnati, Ohio, USA Published under the joint sponsorship of the United Nations Environment Programme, the International Labour Organization, and the World Health Organization, and produced within the framework of the Inter -Organization Programme for the Sound Management of Chemicals. World Health Organization Geneva, 2004 The International Programme on Chemical Safety (IPCS), established. in 1980, is a joint venture of the United Nations Environment Programme (UNEP), the International Labour Organization (ILO), and the World. Health Organization (WHO). The overall objectives of the IPCS are to establish the scientific basis for assessment of the risk to human health and the environment from exposure to chemicals, through international peer review processes, as a prerequisite for the promotion of chemical safety, andto provide technical assistance in strengthening national capacities for the sound management of chemicals. The Inter -Organization Programme for the Sound Management of Chemicals (IOMC) was established in 1995 by UNEP, ILO, the Food and Agriculture Organization of the United Nations, WHO, the United. Nations Industrial Development Organization, the United. Nations Institute for Training and. Research, and the Organisation for Economic Co-operation and Development (Participating Organizations), following recommendations made by the 1992 UN Conference on Environment and. Development to strengthen cooperation and increase coordination in the field of chemical safety. The purpose of the IOMC is to promote coordination of the policies and activities pursuedby the Participating Organizations, jointly or separately, to achieve the sound management of chemicals in relation to human health and the environment. WHO Library Cataloguing -in -Publication Data Asphalt (bitumen). (Concise international chemical assessment document ; 59) 1.Hydrocarbons - adverse effects 2.Risk assessment 3.Epidemiologic studies 4.Occupational exposure I.International Programme on Chemical Safety II.Series ISBN 92 4 153059 6 (LC/NLM Classification: QV 633) ISSN 1020-6167 ©World Health Organization 2004 All rights reserved. Publications of the World. Health Organization can be obtained. from Marketing and. Dissemination, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel: +41 22 791 2476; fax: +41 22 791 4857; email: bookorders@who.int). Requests for permission to reproduce or translate WHO publications — whether for sale or for noncommercial distribution — should be addressed to Publications, at the above address (fax: +41 22 791 4806; email: permissions@who.int). The designations employed andthe presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. The mention of specific companies or of certain manufacturers' products does not imply that they are endorsedor recommendedby the World. Health Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. The World Health Organization does not warrant that the information contained in this publication is complete and correct andshall not be liable for any damages incurred as a result of its use. Risk assessment activities of the International Programme on Chemical Safety, including the production of Concise International Chemical Assessment Documents, are supported financially by the Department of Health and Department for Environment, Food & Rural Affairs, UK, Environmental Protection Agency, Food. and. Drug Administration, and. National Institute of Environmental Health Sciences, USA, European Commission, German Federal Ministry of Environment, Nature Conservation and Nuclear Safety, Health Canada, Japanese Ministry of Health, Labour and Welfare, and the Swiss Agency for Environment, Forests and Landscape. Technically and linguistically edited. by Marla Sheffer, Ottawa, Canada, and printed. by Wissenchaftliche Verlagsgesellschaft mbH, Stuttgart, Germany TABLE OF CONTENTS FOREWORD 1 1. EXECUTIVE SUMMARY 4 2. IDENTITY AND PHYSICAL/CHEMICAL PROPERTIES 6 2.1 Definitions and terminology 6 2.2 Production of asphalt and some asphalt products 8 3. ANALYTICAL METHODS 11 3.1 Chemical analysis 11 3.2 Biological analysis 11 4. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE 12 5. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION 12 6. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE 12 6.1 Environmental levels 12 6.2 Human exposure 13 7. COMPARATIVE KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS 14 8. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS 15 8.1 Irritation 15 8.2 Genotoxicity 16 8.2.1 Mutagenic effects 16 8.2.2 Micronuclei formation and chromosomal aberrations 16 8.2.3 DNA adduct formation 16 8.2.4 Intercellular communication 17 8.3 Toxic responses and CYPIA1 17 8.4 Carcinogenicity 17 9. EFFECTS ON HUMANS 20 9.1 Acute effects 20 9.1.1 Respiratory effects 21 9.1.2 Other acute effects 22 9.1.3 Burns 22 9.2 Chronic effects 23 9.2.1 Lung cancer among pavers 23 9.2.2 Lung cancer among roofers and asphalt roofing materials production workers 23 9.2.3 The IARC study of asphalt workers 23 9.2.4 Other asphalt exposures and cancers 26 9.3 Other effects 29 10. EFFECTS ON OTHER ORGANISMS IN THE LABORATORY AND FIELD 29 11. EFFECTS EVALUATION 29 1 1. l Evaluation of health effects 29 l 1.1.1 Hazard identification and dose —response assessment 29 iii Concise International Chemical Assessment Document 59 11.1.2 Criteria for setting tolerable intakes/concentrations for asphalt 30 11.1.3 Sample risk characterization 30 11.1.4 Uncertainties in the hazard characterization 30 11.1.4.1 Chemistry 31 11.1.4.2 Animal studies 31 11.1.4.3 Human studies 31 11.1.4.4 Potential for exposure 31 11.1.4.5 Conclusion 32 11.2 Evaluation of environmental effects 32 12. PREVIOUS EVALUATIONS BY INTERNATIONAL BODIES 32 REFERENCES 33 APPENDIX 1 SOURCE DOCUMENT 38 APPENDIX 2 CICAD PEER REVIEW 39 APPENDIX 3 CICAD FINAL REVIEW BOARD 40 APPENDIX 4 -ABBREVIATIONS AND ACRONYMS 41 INTERNATIONAL CHEMICAL SAFETY CARD 42 RESUME D'ORIENTATION 44 RESUMEN DE ORIENTACION 47 iv Asphalt (Bitumen) FOREWORD Concise International Chemical Assessment Documents (CICADs) are the latest in a family of publications from the International Programme on Chemical Safety (IPCS) — a cooperative programme of the World Health Organization (WHO), the International Labour Organization (11,0), and the United Nations Environment Programme (UNEP). CICADs join the Environmental Health Criteria documents (EHCs) as authoritative documents on the risk assessment of chemicals. International Chemical Safety Cards on the relevant chemical(s) are attached at the end of the CICAD, to provide the reader with concise information on the protection of human health and on emergency action. They are produced in a separate peer -reviewed procedure at IPCS. They may be complemented by information from IPCS Poison Information Monographs (PIM), similarly produced separately from the CICAD process. CICADs are concise documents that provide sum- maries of the relevant scientific information concerning the potential effects of chemicals upon human health and/or the environment. They are usually based on selected national or regional evaluation documents or on existing EHCs. Before acceptance for publication as CICADs by IPCS, these documents undergo extensive peer review by internationally selected experts to ensure their completeness, accuracy in the way in which the original data are represented, and the validity of the conclusions drawn. The primary objective of CICADs is characteri- zation of hazard and dose —response from exposure to a chemical. CICADs are not a summary of all available data on a particular chemical; rather, they include only that information considered critical for characterization of the risk posed by the chemical. The critical studies are, however, presented in sufficient detail to support the conclusions drawn. For additional information, the reader should consult the identified source documents upon which the CICAD has been based. Risks to human health and the environment will vary considerably depending upon the type and extent of exposure. Responsible authorities are strongly encour- aged to characterize risk on the basis of locally measured or predicted exposure scenarios. To assist the reader, examples of exposure estimation and risk characteriza- tion are provided in CICADs, whenever possible. These examples cannot be considered as representing all 1 possible exposure situations, but are provided as guidance only. The reader is referred to EHC 170.' While every effort is made to ensure that CICADs represent the current status of knowledge, new informa- tion is being developed constantly. Unless otherwise stated, CICADs are based on a search of the scientific literature to the date shown in the executive summary. In the event that a reader becomes aware of new informa- tion that would change the conclusions drawn in a CICAD, the reader is requested to contact IPCS to inform it of the new information. Procedures The flow chart on page 2 shows the procedures followed to produce a CICAD. These procedures are designed to take advantage of the expertise that exists around the world — expertise that is required to produce the high -quality evaluations of toxicological, exposure, and other data that are necessary for assessing risks to human health and/or the environment. The IPCS Risk Assessment Steering Group advises the Coordinator, IPCS, on the selection of chemicals for an IPCS risk assessment based on the following criteria: • there is the probability of exposure; and/or • there is significant toxicity/ecotoxicity. Thus, it is typical of a priority chemical that • it is of transboundary concern; • it is of concern to a range of countries (developed, developing, and those with economies in transition) for possible risk management; • there is significant international trade; • it has high production volume; • it has dispersive use. The Steering Group will also advise IPCS on the appro- priate form of the document (i.e., a standard CICAD or a de novo CICAD) and which institution bears the respon- sibility of the document production, as well as on the type and extent of the international peer review. The first draft is usually based on an existing national, regional, or international review. When no appropriate source document is available, a CICAD may be produced de novo. Authors of the first draft are usually, but not necessarily, from the institution that developed the original review. A standard outline has been developed to encourage consistency in form. The International Programme on Chemical Safety (1994) Assessing human health risks of chemicals: derivation of guidance values for health -based exposure limits. Geneva, World Health Organization (Environmental Health Criteria 170) (also available at http://www.who.intipesi). Concise International Chemical Assessment Document 59 CICAD PREPARATION FLOW CHART Selection of priority chemical, author institution, and agreement on C1CAD format Preparation of first draft Primary acceptance review by IPCS and revisions as necessary Selection of review process Peer review Review of the comments and revision of the document Final Review Board: Verification of revisions due to peer review comments, revision, and approval of the document Editing Approval by Coordinator, IPCS Publication of CICAD on web and as printed text Advice from Risk Assessment Steering Group Criteria of priority: • there is the probability of exposure; and/or • there is significant toxicity/ecotoxicity. Thus, it is typical of a priority chemical that • it is of transboundary concern; • it is of concern to a range of countries (developed, developing, and those with economies in transition) for possible risk management; • there is significant international trade; • the production volume is high; • the use is dispersive. Special emphasis is placed on avoiding duplication of effort by WHO and other international organizations. A usual prerequisite of the production of a CICAD is the availability of a recent high - quality national/regional risk assessment document = source document. The source document and the C1CAD may be produced in parallel. If the source document does not contain an environmental section, this may be produced de novo, provided it is not controversial. If no source document is available, IPCS may produce a de novo risk assessment document if the cost is justified. Depending on the complexity and extent of controversy of the issues involved, the steering group may advise on different levels of peer review: • standard IPCS Contact Points • above + specialized experts • above + consultative group 2 Asphalt (Bitumen) first draft undergoes primary review by IPCS to ensure that it meets the specified criteria for CICADs. The second stage involves international peer review by scientists known for their particular expertise and by scientists selected from an international roster compiled by IPCS through recommendations from IPCS national Contact Points and from IPCS Participating Institutions. Adequate time is allowed for the selected experts to undertake a thorough review. Authors are required to take reviewers' comments into account and revise their draft, if necessary. The resulting second draft is submitted to a Final Review Board together with the reviewers' comments. At any stage in the international review process, a consultative group may be necessary to address specific areas of the science. When a CICAD is prepared de novo, a consultative group is normally convened. The CICAD Final Review Board has several important functions: • to ensure that each CICAD has been subjected to an appropriate and thorough peer review; • to verify that the peer reviewers' comments have been addressed appropriately; • to provide guidance to those responsible for the preparation of CICADs on how to resolve any remaining issues if, in the opinion of the Board, the author has not adequately addressed all comments of the reviewers; and • to approve CICADs as international assessments. Board members serve in their personal capacity, not as representatives of any organization, government, or industry. They are selected because of their expertise in human and environmental toxicology or because of their experience in the regulation of chemicals. Boards are chosen according to the range of expertise required for a meeting and the need for balanced geographic repre- sentation. Board members, authors, reviewers, consultants, and advisers who participate in the preparation of a CICAD are required to declare any real or potential conflict of interest in relation to the subjects under discussion at any stage of the process. Representatives of nongovernmental organizations may be invited to observe the proceedings of the Final Review Board. Observers may participate in Board discussions only at the invitation of the Chairperson, and they may not participate in the final decision -making process. 3 Concise International Chemical Assessment Document 59 1. EXECUTIVE SUMMARY This CICAD on asphalt (bitumen) was based upon a review prepared by the US National Institute for Occu- pational Safety and Health (NIOSH, 2000). Additional data were identified through an updated literature search to February 2003. Information on the peer review of the source document is presented in Appendix 1. Informa- tion on the peer review of this CICAD is presented in Appendix 2. This CICAD was approved as an interna- tional assessment at a meeting of the Final Review Board, held in Varna, Bulgaria, on 8-11 September 2003. Participants at the Final Review Board meeting are listed in Appendix 3. The International Chemical Safety Card on asphalt (ICSC 0162), produced by the International Programme on Chemical Safety (IPCS, 2002), has also been reproduced in this document. Asphalt (CAS No. 8052-42-4), more commonly referred to as bitumen in Europe, is a dark brown to black, cement -like semisolid or solid or viscous liquid produced by the non-destructive distillation of crude oil during petroleum refining. Oxidized asphalt (CAS No. 64742-93-4), also called air -blown or air -refined asphalt, is asphalt (CAS No. 8052-42-4) that has been treated by blowing air through it at elevated temperatures to produce physical properties required for the industrial use of the final product. Performance specifications (e.g., paving asphalts and roofing asphalts), not chemical composition, direct asphalt production. The exact chemical composition of asphalt is dependent on the chemical complexity of the original crude petroleum and the manufacturing process. Crude petroleum consists mainly of aliphatic compounds, cyclic alkanes, aromatic hydrocarbons, polycyclic aromatic compounds (PACs), and metals (e.g., iron, nickel, and. vanadium). The proportions of these chemicals can vary greatly because of significant differences in crude petroleum from oil field to oil field or even at different locations in the same oil field. While the manufacturing process may change the physical properties of asphalt dramatically, the chemical nature of the asphalt does not change unless thermal cracking occurs. Although no two asphalts are chemically identical and chemical analysis cannot be used to define the exact chemical structure or chemical composition of asphalt, elemental analyses indicate that most asphalts contain 79-88 weight per cent (wt%) carbon, 7-13 wt% hydrogen, traces to 8 wt% sulfur, 2- 8 wt% oxygen, and traces to 3 wt% nitrogen. When asphalts are heated, vapours are released; as these vapours cool, they condense. As such, these vapours are enriched in the more volatile components present in the asphalt and would be expected to be chemically and potentially toxicologically distinct from the parent material. Asphalt fumes are the cloud of small 4 particles created by condensation from the gaseous state after volatilization of asphalt. However, because the components in the vapour do not condense all at once, workers are exposed not only to asphalt fumes but also to vapours. The physical nature of the fumes and vapours has not been well characterized. Nevertheless, a chemical analysis of oxidized roofing asphalt and non - oxidized paving asphalt fumes identified many of the same chemical classes. In addition, differences in the way in which asphalts are handled. during paving and. roofing operations probably influence the composition of asphalt fumes and vapours. Since the compositions of asphalts and asphalt fumes and vapours vary depending on temperature, manufacturing process, presence of additives and modifiers, and work practices, it should be no surprise to learn that laboratory -generated asphalt fumes that mimic asphalt fumes in the environment are difficult to produce. Researchers have concluded that temperature, rate of stirring, and pulling versus pushing the collection air all affect the chemical composition of the fumes. The major types of asphalt products are paving asphalts and roofing asphalts. Asphalt is also used in asphalt -based paints as protective coatings to prevent corrosion of metals; in lining irrigation canals, water reservoirs, dams, and sea defence works; in adhesives in electrical laminates; and as a base for synthetic turf. In the USA, approximately 300 000 workers are employed at hot -mix asphalt facilities and paving sites; an esti- mated 50 000 workers are employed in asphalt roofing operations; and about 1500-2000 workers are employed in approximately 100 rooting manufacturing plants. In Western Europe, there are approximately 4000 asphalt mixing plants employing 5-10 individuals per plant. Approximately 100 000 members of paving crews apply these asphalt mixes to road surfaces across Western Europe. Although a variety of sample collection and ana- lytical methods are available for evaluating asphalt fume exposures, most of them are non-specific and cannot be used to characterize total asphalt fume exposure. Also, readily accessible body fluids and/or physiological functions have been sampled or monitored for biomar- kers of exposure to asphalt fumes. Biomarkers specific to asphalt fume exposures have not yet been identified. Limited data are available on the concentration of asphalt in environmental media. Characterization of concentrations of asphalt fractions in air samples and. plant samples collected at various distances from a highway indicated that these concentrations were <4 X 10 3 mg/m3 and <4 mg/g dry plant material, respectively. An assessment of the effects of runoff from asphalt pavement on streams in California, USA, indicated that concentrations of all polycyclic aromatic hydrocarbon (PAH) analytes in all stream and road runoff samples Asphalt (Bitumen) were below the detection limit of 0.5 µg/litre. Although detectable levels of heavy metals were present in stream and runoff water, the authors concluded that no signi- ficant upstream versus downstream differences existed in the concentration of any heavy metal across all streams. Metal concentrations were elevated in runoff water from road surfaces relative to upstream samples. These elevated concentrations could be due to sources other than asphalt (e.g., vehicle emissions, crankcase oil drippings, etc.). While asphalt fume concentrations associated with health effects have not been well characterized, symp- toms of eye, nose, or throat irritation are reported by workers during open-air paving. In the occupational setting, results of recent studies indicate that, in general, most time -weighted average (TWA) air concentrations for total particulates (TP) and benzene -soluble particu- lates (BSP) ranged from 0.041 to 4.1 mg/m3 and from 0.05 to L26 mg/m3, respectively. Average personal exposures, calculated as full -shift TWAs, were generally below 1.0 mg/ m3 for TP and 0.3 mg/m3 for BSP. Asphalt fumes and vapours may be absorbed. following inhalation and dermal exposure. Because asphalt is a complex mixture, its pharmacokinetic behaviour will vary depending upon the properties of the individual constituents. Therefore, it is inappropriate to make generalizations regarding the extent of absorption, distribution, and metabolism of asphalt. Results of several in vitro studies indicate that while field -generated paving asphalt fume condensates were not mutagenic and did not induce DNA adduct forma- tion, paving fume condensates generated in the labora- tory were mutagenic and did induce DNA adduct formation. In contrast, one study reported that the particulate fractions of asphalt fumes collected in the personal breathing zone (PBZ) of workers during paving operations were mutagenic in the Ames Salmonella assay. Moreover, intratracheal exposure of rats to field - generated asphalt paving fumes caused a statistically significant increase in the level and activity of CYP lA l (a major PAH-inducible isozyme of cytochrome P450) in the lung and increased micronuclei formation in bone marrow erythrocytes. Only laboratory -generated roofing asphalt fumes have been tested in genotoxicity studies. These fumes have been shown to be mutagenic, to cause increased micronuclei formation, and to inhibit inter- cellular communication in Chinese hamster lung fibro- blasts (V79 cells) and in human epidermal keratinocytes. Equivocal results have been reported for asphalt -based. paints. While in one study none of the asphalt -based. paints examined demonstrated mutagenic activity, in another study other asphalt -based paints induced DNA adduct formation in adult and fetal human skin samples. Results of carcinogenicity studies indicated that laboratory -generated roofing asphalt fume condensates 5 caused tumours when applied dermally to mice and that some asphalt -based paints contained chemicals capable of initiating tumours in mice. No animal studies have examined the carcinogenic potential of either field- or laboratory -generated paving asphalt fume condensates. Acute effects of exposure to asphalt among workers in the various sectors of the asphalt industry (hot -mix plants, terminals, roofing application, paving, roofing manufacturing) include symptoms of irritation of the serous membranes of the conjunctivae (eye irritation) and the mucous membranes of the upper respiratory tract (nasal and throat irritation) and coughing. These health effects appear to be mild in severity and transient in nature. Additional symptoms include skin irritation, pruritus, rashes, nausea, stomach pain, decreased. appetite, headaches, and fatigue, as reported by workers involved. in paving operations, insulation of cables, and. the manufacture of fluorescent light fixtures. Results from recent studies indicated that some workers involved in paving operations experienced lower respiratory tract symptoms (e.g., coughing, wheezing, and. shortness of breath) and pulmonary function changes; bronchitis has also been reported. The lowest TP exposure that caused respiratory tract problems was 0.02 mg/m3. However, data from the available studies are insufficient to determine the relationship between asphalt fume exposures and the above reported health effects. Burns may also occur when hot asphalt is handled. Burned areas usually include the head and neck, arms, hands, and legs. The largest study to examine the health effects of occupational exposure to asphalt included a cohort of 29 820 workers from eight different countries engaged in road paving, asphalt mixing, roofing, waterproofing, or other specified jobs where exposure to asphalt fumes was possible. Overall mortality for the entire cohort (exposed and non -exposed workers) was below expected (standardized mortality ratio [SMR] = 0.92). For job classifications involving bitumen or asphalt exposure, overall mortality was not elevated (SMR = 0.96); mortality from lung cancer was increased among bitumen workers when compared with ground and building construction workers (SMR = 1.17, 95% confidence interval [CI] = L04-1.30). Overall mortality from head and neck cancer was elevated for bitumen workers only (SMR = 1.27, 95% CI = L02-1.56). Mortality from other malignant neoplasms was not increased. Further analysis suggested a slight increase in lung cancer mortality among road pavers after adjusting for coal tar pitch and allowing for a 15 -year lag (SMR = 1.23, 95% CI = L02-1_48). The investigators (Boffetta et al., 2003b) assessed two different metrics for exposure: average and. Concise International Chemical Assessment Document 59 cumulative exposure. For lung cancer, a positive association was observed for lagged average level of exposure, but not for lagged cumulative exposure. Corresponding indices of unlagged. average and cumulative exposure showed a positive dose —response with lung cancer risk based on 63 deaths; relative risks [RRs] were 1.43 (95% CI= 0.87-2.33), 1.77 (0.99- 3.19), and 153 (1.58-7.89) for 2.2-4.6, 4.7-9.6, and 9.7+ mg/ m3 years of cumulative exposure and 177 (95% CI = 1.69-4.53), 2.43 (L38-4.29), and 3.16 (L.83 -5A7) for 1.03-1.23, 1.24-1.36, and 1.37+ mg/ m3 average exposure (P -value of test for trend, 0.01 for both variables). The investigators concluded. that the exposure —response analyses suggest an association between lung cancer mortality and indices of average level of exposure to bitumen fumes; however, they could. not rule out that confounding played some role in this association. A meta -analysis of 20 epidemiological studies failed to find overall evidence for a lung cancer risk among pavers and highway maintenance workers exposed to asphalt (RR = 0.87, 95% CI = 0.76-1.08). However, the analysis demonstrated an overall statistically significant excess of lung cancer among roofers (RR = 1.78, 95% CI = 1.5-2A). Because, in the past, roofers have been exposed to coal tar and asbestos, which are known human carcinogens, it is uncertain to what extent these findings may be attributable to asphalt exposures. The same meta -analysis reported increases in risk of bladder cancer (RR = L22, 95% CI = 0.95—L53), stomach cancer (RR = L28, 95% CI = L03 —L59), and leukaemia (RR = L41, 95% CI = 1.05—L85) in workers generally classified as asphalt workers, but not roofers. Interpretation of the findings of these 20 studies is limited by a lack of consistency among studies and the potential for confounding by other substances. Further- more, many of these findings are from studies organized by broad job classifications that are prone to errors in defining asphalt exposures. The extremely limited nature of the available data to serve as a basis for estimation of exposure of the general population should be borne in mind when attempting to determine exposure of the general population to asphalt, asphalt fumes and vapours, and asphalt -based paints. The concentrations of asphalt fractions polar aromatics (polars), naphthene aromatics (aromatics), and saturates measured in air samples collected 2.0- 816 m from the highway were 0.54-196 x 10 3 mg/m3 air, 1.77-9.50 x 10 4 mg/m3 air, and 0.21-1.23 x 10 A mg/m3 air, respectively. These values are extremely low in comparison with occupational exposures determined in the various sectors of the asphalt industry; personal exposures to TP and BSP ranged from 0.041 to 4.1 mg/m3 and from 0.05 to 1.26 mg/m3, respectively. However, the chemical composition of the air samples 6 collected along the highway and at the worksites may differ. In addition to respiratory absorption, dermal absorption may also occur and play a pivotal role in asphalt exposure. The frequency and concentration of potential asphalt exposures may be lower for the general population than for workers. However, in the general population, there are individuals who may be more sensitive to exposures and therefore exhibit more symptoms or other effects. The extent to which these symptoms occur in the general population has not been studied. In weighing the available data that explore the relationship between exposure to asphalt and asphalt fumes and vapours and adverse health effects, it is important to consider them in the context of the overall limitations of the information. These uncertainties may be caused by the basic chemistry of asphalt, which is a mixture, the small number of in vivo studies, the inclu- sion of coal tar in roofing and paving asphalts in past decades (and the inclusion in some current formula- tions), and the mixed results of human studies. However, these limitations or uncertainties should not preclude a judgement regarding human and environmental health. Under various performance specifications, it is likely that asphalt fumes and paints contain carcinogenic substances. 2. IDENTITY AND PHYSICAL/CHEMICAL PROPERTIES 2.1 Definitions and terminology Asphalt and some asphalt products are described. below: • Asphalt (CAS No. 8052-42-4) or bitumen: the residuum produced from the distillation of crude petroleum at "atmospheric and under reduced pressures in the presence or absence of steam" (Puzinauskas & Corbett, 1978). Asphalt is a black or dark brown solid or viscous liquid at room temperature; insoluble in water at 20 °C; partially soluble in aliphatic organic solvents; and soluble in carbon disulfide, chloroform, ether, and acetone (Sax & Lewis, 1987). Outside the USA, asphalt is more commonly referred to as bitumen, and a mixture of bitumen with mineral matter is referred. to as asphalt (CONCAWE, 1992). In this document, asphalt is used to refer to the residuum both with and without the addition of mineral matter. Asphalt (Bitumen) • Oxidized asphalt (CAS No. 64742-93-4) or oxidized bitumen: also known as air -blown or air -refined asphalt; asphalt (CAS No. 8052-42-4) that has been treated by blowing air through it at elevated temperatures to produce physical properties required for the industrial use of the final product. Oxidized asphalts are typically used in roofing operations, pipe coating, undersealing for Portland cement concrete pavements, hydraulic applications (AI, 1990b), and manufacture of paints (Speight, 1992). They are usually classified by their penetration value and softening point (CONCAWE, 1992). • Natural asphalts or natural bitumens: naturally occurring deposits of asphalt -like material. While these deposits have physical properties that are similar to those of petroleum -derived asphalt, the composition is different (CONCAWE, 1992). Natural asphalt deposits occur in various parts of the world, mainly as a result of mineral oil seepage from the ground. The best known natural deposit is Trinidad's Pitch Lake; asphalt deposits can also be found in Venezuela, the Dead Sea, Switzerland, and. the Athabasca oil sand.s in northeastern Alberta (1PCS, 1982; Budavari, 1989; Lewis, 1993). These natural asphalts are not discussed in this document. • Asphalt cement: asphalt that is refined to meet specifications for paving, roofing, industrial, and. special purposes (Al, 1 990b). Asphalt cements are used mainly as binders (4-10% of the mixture) in hot -mix asphalts and serve to hold the aggregate together (Al, 1990b; Speight, 1992; Roberts et al., 1996). The grade of asphalt cement is measured by either penetration or viscosity. • Penetration -grade asphalts: asphalts that are further processed by air -blowing, solvent precipitation, or propane deasphalting. A combination of these processes may be used to produce different grades that are classified according to their penetration value (CONCAWE, 1992). • Cutback asphalt: an asphalt that is liquefied by the addition of diluents (typically petroleum solvents). It is used in both paving and roofing operations, depending on whether a paving or roofing asphalt is liquefied (AI, 1990b; Speight, 1992; Roberts et al., 1996). It is further classified according to the solvent used to liquefy the asphalt cement to produce rapid-, medium-, or slow -curing asphalt. Rapid -curing cutback asphalts are made by adding gasoline or naphtha and are mainly used as surface treatments, seal coats, and tack coats. Medium - curing cutback asphalts are made by the addition of kerosene, and slow -curing cutback asphalts are made by the addition of diesel or other gas oils. 7 Medium- and slow -curing cutback asphalts are mainly used as surface treatments, prime coats, tack coats, mix -in -place road mixtures, and patching mixtures (Speight, 1992; Roberts et al., 1996). • Emulsified asphalt: a mixture of two normally immiscible components (asphalt and water) and an emulsifying agent (usually soap). It is used for seal coats on asphalt pavements, built-up roofs, and other waterproof coverings (Stein, 1980; Al, 1990b; Speight, 1992; Roberts et al., 1996). Emulsified asphalts are further graded according to their setting rate (i.e., rapid, medium, and slow). Rapid -setting grades are used for surface treatment, seal coating, and penetration macadams; medium -setting grades are used for patch mixtures; and slow -setting grades are used for mix -in -place road mixtures, patch mixtures, tack coats, fog coats, slurry seals, and soil stabilization (Speight, 1992; Roberts et al., 1996). • Hot -mix asphalt: paving material that contains mineral aggregate coated and cemented together with asphalt cement (AI, 1990b). • Mastic asphalt: a mixture of asphalt and fine mineral material in proportions such that it may be poured hot into place and compacted by hand - troweling to a smooth surface (AI, 1990b). • Asphalt -based paints: a specialized cutback asphalt product that contains relatively small amounts of other materials that are not native to asphalt or to the diluents typically used in cutback products, such as lampblack, aluminium flakes, and mineral pig- ments. They are used as a protective coating in waterproofing operations and other similar applica- tions (AI, 1990b). • Hard bitmens: produced using "similar processes to penetration grades but have lower penetration values and softening points." They are mainly used to manufacture bitumen paints and enamels. They are normally classified by their softening point and "designed by a prefix, H (hard) or HVB (high vacuum bitumen)" (CONCAWE, 1992). The European Committee for Standardization (CEN, 2000) has published a recommended terminology for bitumen and bituminous binders. The main classes of bitumens include paving bitumen, modified bitumen, special bitumen, industrial bitumen, petroleum cut -back bitumen, petroleum fluxed bitumen, and bitumen emulsion. Concise International Chemical Assessment Document 59 2.2 Production of asphalt and some asphalt products Performance specifications, not chemical composi- tion, direct asphalt production. To meet these perfor- mance specifications, the asphalt may be air -blown or further processed by solvent precipitation or propane deasphalting. Additionally, the products of other refining processes may be blended with the asphalt to achieve the desired performance specifications. Therefore, the exact chemical composition of asphalt is dependent on the chemical complexity of the original crude petroleum and the manufacturing process. Crude petroleum consists mainly of aliphatic compounds, cyclic alkanes, aromatic hydrocarbons, PACs (a class of chemicals that includes PAHs and heterocyclic derivatives in which one or more of the carbon atoms in the PAH ring system have been replaced by a heteroatom of nitrogen [N -PAC], oxygen [O -PAC], or sulfur [S -PAC]; Vo-Dinh, 1989), and metals (e.g., iron, nickel, and vanadium). The propor- tions of these chemicals can vary greatly because of significant differences in crude petroleum from oil field to oil field or even at different locations in the same oil field (Al, 1990a). While the manufacturing process may change the physical properties of asphalt dramatically, the chemical nature of the asphalt does not change unless thermal cracking occurs. Raising the temperature will increase the likelihood of cracking and cause more volatiles and even higher -boiling components to be released from the residuum. Solvent precipitation (usually using propane or butane) removes high -boiling components from a vacuum -processed asphalt, which are then used to make other products. Solvent precipitation results in a harder asphalt that is less resistant to temperature changes and often blended with straight -reduced or vacuum - processed asphalts. The air -blowing process can be a continuous or batch operation. Since the continuous operation is faster and results in a softer asphalt, a continuous operation is preferred for processing paving asphalts (Speight, 1992; Roberts et al., 1996). Air blowing combines oxygen with hydrogen in the asphalt, producing water vapour. This decreases saturation and. increases cross -linking within and. between different asphalt molecules. The process is exothermic (heat producing) and may cause a series of chemical reactions, such as oxidation, condensation, dehydration, dehydrog- enation, and polymerization. These reactions cause the amount of asphaltenes (hexane -insoluble materials) to increase and the amounts of polar aromatics (hard. resins), cycloalkanes, and non -polar aromatics (soft resins) to decrease, while the amounts of aliphatic compounds (oils and waxes) remain about the same (Table 1); at the same time, the oxygen content of the asphalt increases (Moschopedis & Speight, 1973; Corbett, 1975; Puzinauskas & Corbett, 1978; Boduszynski, 1981; Speight, 1992; Roberts et al., 1996). 8 Although no two asphalts are chemically identical and chemical analysis cannot be used to define the exact chemical structure or chemical composition of asphalt, elemental analyses indicate that most asphalts contain 79-88 wt% carbon, 7-13 wt% hydrogen, traces to 3 wt% nitrogen, traces to 8 wt% sulfur, and traces to 8 wt% oxygen (examples shown in Table 2) (Speight, 1992). While heteroatoms (i.e., nitrogen, oxygen, and. sulfur) make up only a minor component of most asphalts, the heteroatoms profoundly influence the differences in physical properties of asphalts from different crude sources (Speight, 1992; Roberts et al., 1996). Asphalt is used for paving, roofing, industrial, and. special purposes. Oxidized asphalt is used in roofing operations, pipe coating, undersealing for concrete pavements, hydraulic applications, membrane envelopes, some paving -grade mixes (Al, 1990b), and the manufac- ture of paints (Speight, 1992). From a scientific point of view, asphalts probably should be classified as to whether or not they have been oxidized. However, most publications have classified asphalts according to the performance specifications for which they were manufactured (e.g., paving asphalts and roofing asphalts). This greatly complicates our under- standing of the chemistry of asphalts and the presenta- tion of materials in this document, because most asphalts used in paving are not made from oxidized asphalts, but most asphalts used in roofing are made from oxidized asphalts (Speight, 1992; Roberts et al., 1996). The situation is further complicated by the addition of additives and modifiers, differences in application temperatures, and work practices. Three asphalt products are used in paving processes: asphalt cements, cutback asphalts, and emulsified asphalts. Cutback and emulsified asphalts are also called liquid asphalts because they are liquid at ambient tem- peratures. As mentioned previously, most asphalts used. in paving operations are not oxidized. The asphalts are heated to about 149-177 °C and mixed with heated (143-163 °C) mineral aggregate. Once transported to the worksite, the hot -mix asphalt is applied to the roadway. The temperature of application is generally between 112 and 162 °C (AI, 1990a; FAA, 1991; Speight, 1992; Roberts et al., 1996). Oxidized asphalts may or may not be used in roofing manufacturing plants to produce shingles, roll goods, built-up roofing felts, and underlayment felts; these asphalts are shipped hot and kept hot until used in the manufacturing process (AREC, 1999). In addition, some cutback and emulsified asphalts are also used in roofing operations (Speight, 1992). However, most oxidized asphalts are used to produce "mopping -grade" roofing asphalts. These asphalts are generally shipped as a solid and heated in a kettle at the worksite until they Asphalt (Bitumen) Table 1: Changes in physical properties and chemical classes in an asphalts with increasingly longer air -blowing times.' Air -blowing times` To T2 Ta Physical properties Softening point (CC) Penetration (mm/10) Chemical class, wt% Asphaltenes Hard resins Soft resins Oils Waxes 54.4 85 96.1 36 13 9 14.8 45.5 25.0 12.3 2.5 26.9 36.6 22.3 11.9 2.0 31.4 36.1 20.9 10.0 1.8 173.3 51.3 19.6 16.9 11.1 1.6 Total 100.0 99.7 100.2 100.5 a Straight -reduced Arkansas asphalt. b Adapted from Speight (1992). To = no air -blowing time; To < T, < T2 < T3. Table 2: Elemental analysis of asphalts from different crude sources.' Crude sources Carbon Hydrogen Nitrogen Sulfur Oxygen Vanadium Nickel (wt%) (wt%) (wt%) (wt%) (wt%) (mg/kg) (mg/kg) Mexican blend Arkansas -Louisiana Boscan California 83.77 9.91 0.28 5.25 0.77 180 22 85.78 10.19 0.26 3.41 0.36 7 0.4 82.90 10.45 0.78 5.43 0.29 1380 109 86.77 10.94 1.10 0.99 0.20 4 6 a Adapted from Speight (1992). become a liquid. Table 3 lists the recommended application temperatures (Appendix C in Al, 1990a) and the recommended maximum heating temperatures (AREC, 1999) for these asphalts. Table 3: Recommended application temperatures and recommended maximum heating temperatures used with "mopping -grade" roofing asphalts. Type Recommended application temperature' (CC) Recommended maximum heating temperature' (°C) I I III IV 166-179 185-199 202-216 221-229 246 260 274 274 Adapted from Al (1990a, Appendix C) and AREC (1999). b Adapted from AREC (1999). Differences in the way in which asphalts are handled during paving and roofing operations probably influence the composition of asphalt fumes and vapours. When a hot -mix paving asphalt arrives at the worksite, the asphalt has been cooling since leaving the plant and may not be used immediately when it arrives at the 9 worksite. Conversely, roofing asphalts are heated continuously and stirred occasionally at the worksite until the asphalt is needed. Since the compositions of asphalts and asphalt fumes and vapours vary depending on temperature, manufacturing process, presence of additives and. modifiers, and work practices, it should be no surprise to learn that laboratory -generated asphalt fumes that mimic asphalt fumes in the environment are difficult to pro- duce. Researchers (Kriech & Kurek, 1993; Kriech et al., 1999) have shown how generation conditions can affect the composition of fumes. Using a variety of analytical techniques gas chromatography with flame ionization detection (GC/FID), GC with flame photometric detec- tion, GC with atomic emission detection, and GC with mass spectrometry (GC/MS) — they compared laboratory -generated asphalt fumes with fumes collected from the headspace in a storage tank at a hot -mix plant (paving asphalt), from the headspace in roofing kettles, and from PBZ samples. They concluded that tempera- ture, rate of stirring, and pulling versus pushing the collection air all affected the chemical composition of the fumes. Concise International Chemical Assessment Document 59 Table 4: Analysis by GC/MS of chemical composition of asphalt fume fractions A —E from an oxidized "mopping -grade" (Type III) roofing asphalt collected during laboratory generation at 316 °C.' Fraction Compound class" A B C D E Hydrocarbons Alkanes, C9 -C27 Alkenes/cycloalkanes Benzenes, C2 —C6 Indanes, Co —C4 Indenes, C0 —C3 Naphthalenes, Cc —Cs Biphenyls, C3 —C2 Fluorenes, Anthracenes/phenanthrenes, C3 —C4 Pyrenes/fluoranthenes, Co —C2 Chrysenes/benz[a]anthracenes, Co —C2 Sulfur -containing compounds Benzothiophenes, Co —C9 Dibenzothiophenes/naphthothiophenes, C9 —C4 Tricarbocyclic fused -ring thiophenes, C6 —C, Oxygen -containing compounds Benzofurans, Co —C2 Dibenzofurans, Co —C2 Acetophenones, Fluorenones, C6 —C3 Dihydroindenones, C6 —C4 Cycloalkenones, C6 —C11 Dihydrofuranones Isobenzofuranones, C9 —C3 Phenols, Naphthols, C6 —C2 Furanones, C, —C3 Alkanones, Cs —C22 Alkanoic acids, Cs —C,4 Benzoic acids, Co —C4 Nitrogen -containing compounds Carbazoles, Co —C4 Oxygen- and sulfur -containing compounds Hydroxybenzenethiols, C9 —C4 ++ +++ • Adapted from Lunsford & Cooper (1989). • Degree of alkyl substitution given by C , where n = number of substituent carbon atoms. • Relative abundance across fractions, but not classes, indicated by +++ > ++ > +. o — = Not observed. When asphalts are heated, vapours are released; as these vapours cool, they condense. As such, these vapours are enriched in the more volatile components present in the asphalt and would be expected to be chemically and potentially toxicologically distinct from the parent material. Asphalt fumes are the cloud of small particles created by condensation from the gaseous state after volatilization of asphalt (NIOSH, 1977). However, because the components in the vapour do not condense all at once, workers are exposed not only to asphalt fumes but also to vapours. The physical nature of the 10 fumes and vapours has not been well characterized, but the fume should be fairly viscous. The asphalt fume particles may collide and stick together, making it difficult to characterize the fume particle size. Some of the vapours may condense only to the liquid phase, thus forming a viscous liquid with some solids. Table 4 shows the results of a chemical analysis of a laboratory - generated oxidized asphalt fume (Lunsford & Cooper, 1989). A chemical analysis of non -oxidized paving asphalt fumes, PBZ samples from two sites, identified Asphalt (Bitumen) many of the same chemical classes as shown for the oxidized asphalt fume in Table 4 (Kriech et al., 2002a). 3. ANALYTICAL METHODS 3.1 Chemical analysis This section is not intended. to be an all-inclusive list of the analytical sampling and. analysis method.s avail- able for characterizing asphalt fumes and vapours. Emphasis is placed on validated methods that have been used in multiple studies. Although a variety of sample collection and. analytical methods are available for evaluating asphalt fume exposures, most of them are non-specific and cannot be used to characterize total asphalt fume exposure. Many studies have focused on TP and. BSP determination for assessing asphalt fume exposures. NIOSH Methods 0500 (NIOSH, 1984, 1994) and 5023 (NIOSH, 1984) have commonly been used to determine these analytes, but on different samples. Using NIOSH Method 0500, the TP sample is collected by drawing a known volume of air through a tared polyvinyl chloride (PVC) filter; using NIOSH Method 5023, the BSP is collected by drawing a known volume of air through a polytetrafluoroethylene (PTFE) filter. The PVC filter is analysed gravimetrically to determine the TP, and the PTFE filter is analysed by extracting with benzene and gravimetrically determining the BSP. In some recent studies, because NIOSH Method 5023 had been with- drawn and because both TP and BSP can be determined on the same sampler, NIOSH Method 5042 (NIOSH, 1998) has been used. In this method, the TP and BSP sample is collected by drawing a known volume of air through a tared PTFE filter. After the tared PTFE filter is analysed gravimetrically to determine the TP, the filter is reanalysed by extracting with benzene and gravimetric- ally determining the BSP. The working range is 0.13- 2 mg/m3 for a 1000 -litre sample. The limit of detection (LOD) and limit of quantification (LOQ) for TP are 0.04 and 0.13 mg per sample, respectively; the LOD and LOQ for BSP are 0.04 and 0.14 mg per sample, respectively. While other solvents have been used (such as cyclohexane, acetonitrile, and methylene chloride) to measure the soluble particulate, the results should not be compared, because the extraction capabilities of these solvents vary. In addition, these methods d.o not measure distinct chemical components or even a distinct class of chemicals in the asphalt fume sample. Although many researchers have reported results for PAHs in asphalt fumes, results obtained using high-performance liquid 11 chromatography (HPLC)/fluorescence and GC/FID methods are suspect. Because asphalt fumes are composed of many alkylated isomers of PAHs, along with O -PACs and S -PACs, with the exception of naphthalene and some three-ring PAHs, they are so chemically complex that they cannot be separated into discrete compounds. The greater the lack of resolution between compounds, the less reliable the quantification results. Because of the poor resolution obtained with asphalt fume samples, quantification is unreliable when these methods are used. Moreover, an alternative method (such as GC/MS or HPLC/MS) is required to confirm the identity of any suspected. PAHs, including naph- thalene and other possible baseline -resolved PAHs. Any compounds reported using these methods are tentative identifications at best, and the more complex the matrix, the more unreliable these identifications become. Furthermore, since chromatographic software programs assign peak identification based on the largest peak in a given time window and. not on retention time, the wrong peak may be assigned and analysed. Also, for HPLC, a gradient elution (e.g., mobile -phase composition varies during the chromatographic run) is used, which might result in varying retention times, thus further complicat- ing the selection of the correct peak for identification and analysis (NIOSH, 2000). NIOSH Method 5800 (NIOSH, 1998) can be used to estimate the total PAC content of asphalt fumes. This method uses an HPLC pump to provide a mobile phase into which a sample is injected. The sample then passes through two fluorescence detectors. Since no liquid chromatographic column is used, the entire sample reaches the flow cell at once, resulting in a rapid and sensitive analysis of the sample. The two fluorescence detectors are used to monitor different excitation and emission wavelengths. One set of wavelengths is more sensitive to two- and three-ring PACs, and the second set of wavelengths is more sensitive to four- and higher -ring PACs (NIOSH, 2000; Neumeister et al., 2003). 3.2 Biological analysis Readily accessible body fluids and/or physiological functions have been sampled or monitored for biomar- kers of exposure to asphalt fumes. Biomarkers specific to asphalt fume exposures have not yet been identified. However, urinary 1-hydroxypyrene (1-OHP) (Hatjian et al., 1995a,b, 1997; Toraason et al., 2001, 2002), DNA strand breaks and oxidative damage in peripheral blood leukocytes (Toraason et al., 2001, 2002), and DNA or protein adducts (Herbert et al., 1990; Lee et al., 1991) have been used with limited success as general indica- tors of exposure to asphalt fumes and PAHs. Concise International Chemical Assessment Document 59 4. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE Natural asphalt deposits occur in various parts of the world, mainly as a result of mineral oil seepage from the ground. The best known natural deposit is Trinidad's Pitch Lake; asphalt deposits can also be found in Venezuela, the Dead Sea, Switzerland, and the Atha- basca oil sands in northeastern Alberta (1PCS, 1982; Budavari, 1989; Lewis, 1993). In addition, asphalt is produced from crude petroleum, and it is these petroleum -based asphalts that are the focus of this document. A broad spectrum of asphalt modifiers and additives spanning categories such as antioxidants, anti stripping agents, extenders, fibres, fillers, hydrocarbons, oxidants, plastics, rubbers, waste materials, and miscellaneous products are also employed with the various asphalts (Speight, 1992; Roberts et al., 1996). Their presence may affect the composition of asphalt fumes and vapours and worker exposure. The major types of asphalt products are paving asphalts and roofing asphalts. Asphalt is also used in asphalt -based paints as protective coatings to prevent corrosion of metals; in lining irrigation canals, water reservoirs, dams, and sea defence works; in adhesives in electrical laminates; and as a base for synthetic turf (Lewis, 1993). In the USA, approximately 30 million tonnes of asphalt materials were produced in 2000 for paving and non -paving applications (Al, 2001). In 2001, approx- imately 16 million tonnes of bitumen (asphalt) were produced in Western Europe, of which 14 million tonnes were used in road pavement applications (D. Lyall, Eurobitume, Brussels, personal communication, 2002). 5. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION No specific data are available relating to transport and distribution among media, environmental transfor- mation and. degradation, interaction with physical, chemical, or biological factors, and bioconcentration. However, a recent report by CONCAWE (2001) indicates that although constituents of bitumen (asphalt) have octanol/water partition coefficient (log K„54) values in excess of 6 and are potentially bioaccumulative, in practice, their very low water solubilities and high relative molecular masses (ranging from 500 to 15 000) are such that their bioavailability to aquatic organisms is 12 expected to be limited. The bioaccumulation of bitumen components would therefore be highly unlikely. Bitumens (asphalts) would not be readily degrad- able. However, basing toxicological conclusions on the activity of single components may not be relevant to the physical/chemical interactions of a complex mixture such as asphalt. Cooper & Kratz (1997) determined the components of runoff from asphalt pavement in fish (rainbow trout Oncorhynchus mykiss, brown trout Salmo trutta, and Paiute sculpin Cottus beldingi) and invertebrates from streams in California, USA. Concentrations of the PAH analytes in fish and invertebrate tissues were below the detection limit of 0.2 mg/kg. While concentrations of lead and cadmium in fish tissues were below the detection limits of 0.5 and 0.05 mg/kg, respectively, concentrations of zinc were higher in invertebrate tissues than in fish tissues and also significantly elevated at downstream relative to upstream sites (P = 0.05), ranging from 26 to 98 mg/kg. Invertebrate tissue concentrations of cadmium were independent of collection sites within streams and ranged from below detectable limits to 0.28 mg/kg. However, there is a potential for contributions from fuel, combustion, and crankcase deposits, as well as metals contained in tire tread rubber dust from tire abrasions (see also section 6). 6. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE 6.1 Environmental levels Limited data are available on the concentration of asphalt in environmental media. Asphalt fractions, including polars, aromatics, and. saturates, were characterized in airborne particles and air samples collected 2.0-83.6 m from a highway in Denmark and. in plant samples (grass, leaves, and. wheat straw) collected 2.0-10.0 m from the highway (Kebin et al., 1996). The percentage of asphalt in these airborne particles was 1.61-11.02%. Concentrations of asphalt fractions in air samples were 0.54-3.96 x 10 3 mg polars/m3 air, 1.77-9.50 x 10 A mg aromatics/m3 air, and. 0.21-L23 x 10 4 mg saturates/m3 air. Concentrations of asphalt fractions for polars, aromatics, and saturates in mg/g dry plant material were: 0.96, 0.89, and 0.37 for grass; 0.93 and 3.07, 2.91 and 3.89, and 1.28 and 1.53 for leaves; and 1.19 and 0.29, 1.38 and 1.30, and 0.63 and 0.56 for wheat straw (at 5 m and 10 m, respectively), respectively. However, diesel and gasoline exhaust from nearby traffic may have contributed to the composition of these fractions. Asphalt (Bitumen) An assessment was made of the effects of runoff from asphalt pavement on streams in California, USA (Cooper & Kratz, 1997). Concentrations of PAHs and selected heavy metals (lead, zinc, cadmium) were determined in water samples collected from water draining road surfaces and from waters upstream and downstream from the point where water discharged from road surfaces into stream sites. Results of analyses indicate that concentrations of all PAH analytes in all stream and road runoff samples were below the detection limit of 0.5 µg/litre. Although detectable levels of heavy metals were present in stream and runoff water, the authors concluded that no significant upstream versus downstream differences existed in the concentrations of any heavy metal across all streams. Furthermore, concentrations of metals were elevated in runoff waters from the road surfaces relative to upstream samples. Elevated metal concentrations could be due to sources other than asphalt (i.e., vehicle emissions, crankcase oil drippings, industrial operations, etc.). Kriech et al. (2002 b) conducted a laboratory study to determine 29 PACs in leachate water of six paving asphalt and four roofing asphalt samples. Samples were leached according to US Environmental Protection Agency (EPA) method. SW 846-131 1. Results indicated. that none of the roofing samples tested leached any of the 29 PACs. While four of the paving samples did not leach any of the 29 PACs, leachate of two paving samples contained detectable amounts of naphthalene and phenanthrene; however, the levels were well below drinking -water limits (0.015 mg/litre) in the USA. Similarly, Brantley & Townsend (1999) performed a series of leaching tests on samples of reclaimed asphalt from facilities in Florida, USA. None of 16 EPA priority pollutant PAHs were detected in the water leachates of any of these samples. The authors pointed out that during normal use of pavement, the asphalt may come in contact with vehicle exhaust, lube oils, gasoline, and metals from brake pads. In addition, Brandt & DeGroot (2001) demonstrated that PAH concentrations in leachate water from 10 asphalts were well below the European maximum tolerable concentration for potable water (0.1 lig/litre). 6.2 Human exposure Quantitative information on levels of asphalt in drinking -water and foodstuffs has not been identified. However, experiments conducted to determine whether the use of asphalt seal coating in ductile -iron pipe would. contribute significant concentrations of PACs in drinking -water indicated that the highest concentration found. in three experiments was 5 ng/litre (Miller et al., 1982). The significance of these experiments is unclear, since they represented a worst -case scenario and the pipes were aged for only 1 month in a laboratory setting. In the USA, approximately 300 000 workers are employed at hot -mix asphalt facilities and paving sites (APEC, 1999); an estimated 50 000 workers are employed in asphalt roofing operations; and about 1500- 2000 workers are employed in approximately 100 roof- ing manufacturing plants (AREC, 1999). In Western Europe, there are approximately 4000 asphalt mixing plants employing 5-10 individuals per plant. Approxi- mately 100 000 members of paving crews apply these asphalt mixes to road surfaces across Western Europe (Burstyn, 2001). Data collected between 1994 and 1997 during seven paving surveys conducted in the USA by NIOSH (2000) indicated that, in general, most TWA PBZ air concentra- tions for both TP and BSP were below 0.5 mg/m3. Geometric mean (GM) full -shift PBZ samples for TP and BSP ranged from 0.041 to 0.48 mg/m3 and from 0.073 to 0.12 mg/m3, respectively. However, GM data collected. during paving operations in a tunnel in Boston, Massachusetts, USA (Sylvain & Miller, 1996), indicated. that PBZ exposures to TP and. BSP were about 3 times higher than exposures measured. during the seven NIOSH surveys at open-air roadway paving sites (NIOSH, 2000). Personal exposures to TP and. BSP ranged from 1.09 to 2.17 mg/m3 and from 0.30 to 1.26 mg/m3, respectively (Sylvain & Miller, 1996). Other studies examined exposures to asphalt not only at road paving sites, but also at hot -mix plants, refineries and terminals, roofing manufacturing plants, and roofing application sites in the USA (Hicks, 1995; Exxon, 1997; Gamble et al., 1999). GM exposures for TP and BSP at these sites are presented in Table 5. GM exposures for TP and BSP varied across all industry types: TP ranged from 0.18 to 1.40 mg/m3, and BSP ranged from 0.05 to 0.27 mg/m3. Heikkil6 et al. (2002) reported GM exposures for TP from asphalt (described by the author as bitumen fume) of 0.4, 0.5, and 4.1 mg/m3 for paving operator, screed operator, and manual mastic paver, respectively. Similarly, Burstyn et al. (2000) reported higher GM asphalt fume exposures (described by the author as bitumen) during mastic laying operations (2.29 mg/m3) compared with expo- sures during paving operations (0.28 mg/m3). These values indicate that exposures may be higher in situa- tions such as mastic laying. Several investigators have attempted to assess asphalt exposure by the dermal route. Wolff et al. (1989) collected dermal wipe samples by wiping a 3 x 3 cm area of the forehead of workers exposed to asphalt during the application of hot asphalt to roofs in order to evaluate the extent to which dermal absorption of PAHs may contribute to the total body burden. These dermal wipe samples were analysed for specific PAHs. In the Wolff et al. (1989) study, PAH residues per square 13 Concise International Chemical Assessment Document 59 Table 5: Geometric mean of personal exposures for total particulates (TP) and benzene -soluble particulates (BSP). Geometric mean of personal exposures (mg/m3) Type of industry TPa BSPa TPb BSP' Road paving Hot -mix plants Refineries and terminals Roofing manufacturing Roofing application 0.37 0.78 0.18 1.40 0.55 0.24 0.15 0.16 0.27 0.25 0.33 0.45 0.19 0.60 0.34 0.09 0.06 0.05 0.08 0.12 a Adapted from Hicks (1995). b Adapted from Exxon (1997) and Gamble et al. (1999). centimetre of skin were higher in postshift samples (6.1- 31 ng/cm2) than in preshift samples (0.44-2.2 ng/cm2). However, workers monitored during the entire roofing application were potentially exposed to PAHs during both the removal of the old coal tar pitch roof and the application of hot asphalt for the new roof. Hicks (1995) collected dermal wipe samples by wiping a 4 x 8 cm area from the back of the hand or forehead of workers at the various asphalt sectors described in Table 5. The PAH concentrations determined from these postshift samples ranged from 2.2 to 520 ng/cm`. Workers in paving operations produced the largest number of PAHs detected (12 of 16), while refinery and roofing workers had the fewest (2 of 16). However, the HPLC/fluores- cence technique used by these authors cannot reliably identify and quantify components of asphalt; their results are presented for completeness only. Toraason et al. (2001, 2002) examined urinary 1- OHP concentrations at the beginning and end of the same work week (4 days later) in seven roofers who applied hot asphalt products but had no coal tar exposure during the preceding 3 months. All seven workers were smokers at the time of the study. Urinary 1-OHP con- centrations were statistically significantly increased. (P < 0.05) at the end of the work week (start of work week 0.26 0.13 lunol/mol creatinine; end of work week 0.58 0.29 lunol/mol creatinine). The average weekly TWA exposure for TP and BSP for a crew of six asphalt -only roofers was 0.24 0.10 mg/m3 and 0.08 f 0.02 mg/m3, respectively. The TWA exposures for TP and. BSP for a seventh roofer in another crew were 0.31 mg/m3 and. 0.18 mg/m3, respectively. Heikkila et al. (2002) measured preshift and post - shift urinary 1-OHP concentrations in 32 road pavers participating in a study to evaluate asphalt fume expo- sures of workers employed at 13 paving sites where 11 different asphalt mixtures were applied. The mean TP exposure for the 11 asphalt mixtures ranged from 0.2 to 4.2 mg/m3 (AM [arithmetic mean] = 0.6 mg/m3; GM = 0.5 mg/m3). The mean TP exposure for all mixtures was below 0.5 mg/m3, with the exception of manual mastic paving (4.2 mg/m3) and stone mastic asphalt (2.0 mg/m3). The control group consisted of 78 smoking and non-smoking unexposed office workers obtained from a national reference group for 1-OHP in Finland. The authors reported that mean 1-OHP concentrations were statistically significantly higher (P < 0.05) among pavers (AM = 6.6 nmol/litre, standard deviation [SD] = 9.8) than in controls (AM = 1.6 nmol/litre, SD = 2.6) and twice as high among pavers who were smokers (preshift: AM = 8.5 nmol/litre, SD = 10.5) as among pavers who were non-smokers (preshift: AM = 4.0 nmol/litre, SD = 8.0) (P < 0.05) (P. Heikkila, personal communication, Finnish Institute of Occupational Health, Helsinki, 2003). A similar trend was observed in postshift data (data not shown). There was no difference between non- smoking road pavers or non-smoking referents (data not shown), suggesting that smoking strongly influences urinary 1-OHP concentrations and may not be a sensitive measure of occupational asphalt fume exposure. No studies that report exposures to cutback asphalts, emulsified asphalts, or asphalt -based paints (products applied at or near ambient temperatures) have been found. Because these products are liquids, workers may be exposed via inhalation and dermal contact. 7. COMPARATIVE KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS Mixtures do not lend themselves to kinetic analyses. Because asphalt is a complex mixture, its pharmaco- kinetic pattern will vary depending upon the properties and interactions of the individual constituents. The pharmacokinetics of some asphalt components, particu- larly the PAHs, have been studied in considerable detail (Syracuse Research Corporation, 1985). The long -chain aliphatic hydrocarbons constitute major components of asphalt; routes of uptake include inhalation, ingestion, and dermal uptake. Data indicate that following inhalation, hydrocarbons with 9-16 14 Asphalt (Bitumen) carbons were absorbed in the blood, brain, liver, kid- neys, and fat of rats (ATSDR, 1998). Aerosols of hydrocarbons with more than 16 carbons were absorbed in liver and lungs of mice. These long -chain aliphatic compounds may be oxidatively metabolized via cyto- chrome P450 oxidases. Aliphatic hydrocarbons with between five and eight carbons may be oxidized to several alcohol, ketone, and carboxylic acid derivatives. Aliphatic hydrocarbons with 9-16 carbons are oxida- tively metabolized via cytochrome P450 isozymes to fatty acids and alcohols. Evidence indicates that metab- olism of these hydrocarbons may be quite slow. In general, these compounds are slowly eliminated in the urine and faeces. The major routes of uptake of PAHs in humans are the lungs and respiratory tract after inhalation of PAH- containing aerosols or of particulates to which a PAH in the solid state has become absorbed; the gastrointestinal tract after ingestion of contaminated food or water; and. the skin as a result of contact with PAH-bearing mater- ials (IPCS, 1998). In general, the oxidative metabolism of PAHs involves epoxidation of double bonds, a reaction catalysed by cytochrome P450 -dependent mono-oxygenases, rearrangement or hydration of the epoxides to yield phenols or diols, respectively, and conjugation of the hydroxylatedderivatives with glutathione, sulfate, or glucuronic acid. However, in certain cases, radical cations and sulfate esters of hydroxymethyl derivatives may also be important (IPCS, 1998). Whole body distribution of PAHs has been studied in rodents. These studies have demonstrated that detectable levels of PAHs occur in almost all internal organs and that organs high in adipose tissue can serve as storage depots from which the PAHs are generally released (IPCS, 1998). In general, these compounds are eliminated by urinary or biliary excretion of metabolites. 8. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS In vivo and in vitro animal studies have evaluated the genotoxicity, carcinogenicity, and other toxic effects of asphalt -based paints and asphalt fumes. Because of the difficulty in obtaining a sufficient quantity of paving and roofing asphalt fumes in the field, many of the studies used laboratory -generated asphalt fume conden- sates. 8.1 Irritation Irritation studies (eye, skin, respiratory tract) have been reviewed previously in N1OSH (1977), IPCS (1982), and IARC (1985). 15 Exposure of rabbits to asphalt vapours was reviewed (NIOSH, 1977). The asphalts in the study were from the USA and England, with no further details provided. Additional experimental details (temperature of vapour generation, concentrations of the vapour, duration and frequencies of exposures) were not provided. Exposure to asphalt vapours caused only minor, transient conjunc- tivitis in the eyes of rabbits. After frequent exposures, a slight infiltration of the cornea was sometimes noted; however, this disappeared several days after exposures ceased. No other toxic effects were observed in the rabbits (N1OSH, 1977). In a skin painting study summarized. in IARC (1985), Swiss albino mice were exposed to samples of eight different bitumens (class 1). They received. biweekly applications of 25 gl of bitumen solution (10% in benzene) to shaved areas of their backs for approx- imately 81 weeks. Skin effects included epidermal hyperplasia, along with inflammatory infiltration of the dermis and cutaneous ulceration with abscess formation. In another study (Hueper & Payne, 1960), 30 guinea -pigs (Strain 13) and 65 Bethesda black rats were placed in chambers and exposed to roofing asphalt fumes and vapours for 5 h/day, 4 days/week, for 2 years. These fumes and vapours were derived from an air - blown petroleum asphalt by placing 700-10 000 g of the asphalt into an evaporating dish and heating it to 120- 135 °C. Fresh asphalt was placed in the evaporating dish once a week, while on other days only the amount lost was replaced. (Asphalt typically would not be heated repeatedly during the course of a week; therefore, these fumes and vapours may not be representative of a typical exposure. Further experimental details were not pro- vided.) Exposure to these asphalt fumes and vapours caused "extensive chronic fibrosing pneumonitis with peribronchial adenomatosis" (Hueper & Payne, 1960). While exposure conditions in Simmers (1964) are not representative of real -world exposures, results are included for completeness. "The asphalt used in this study was a pooled sample from six different California refineries and contained both steam and air -blown samples." In the first experiment, 20 C57 Black mice were exposed to an asphalt aerosol made from an asphalt emulsion. Mice were exposed to this aerosol 30 min/day, 5 days/week, for up to 410 treatments. (Three mice survived 410 treatments, while 10 mice survived 280 or more treatments.) Effects included congestion, acute bronchitis, pneumonitis, bronchial dilatation, and some peribronchial round cell infiltration. In the second. experiment, asphalt smoke was generated by placing 250-350 g of the asphalt sample into a tin container and heating to 120 °C, causing the asphalt to boil and give off a yellowish -brown smoke. Thirty C57 Black mice were exposed for 6-7.5 h/day, 5 days/week, for 21 months. Effects included peribronchial round cell Concise International Chemical Assessment Document 59 infiltration, bronchitis, pneumonitis, loss of cilia, and. epithelial atrophy. A study to evaluate possible toxic effects of asphalt fumes after inhalation exposure of male and female Wi star WU rats was conducted by the Fraunhofer Institute (Fraunhofer, 2001) to determine concentrations and a maximally tolerated dose for a future carcino- genicity study. The composition of the asphalt fumes was designed to mimic exposure during road paving in Germany (Pohlmann et al., 2001). Rats (16 per group) were exposed nose only to clean air (control) or to target concentrations of 4, 20, or 100 mg/m3 of asphalt fumes for 6 h/day, 5 days/week, for 14 weeks. The mean actual concentrations (aerosol + vapour phase) analysed by infrared spectroscopy were 195, 20A2, and. 106.55 mg/m3. The composition of the exposure atmosphere (% particulate/% vapour) was 24.6/75A, 42.9/57.1, and 68./31.9 for 4, 20, and 100 mg/m3, respectively. The number median aerodynamic diameter as measured with the scanning mobility particle sizer system was 105 nm in the 4 mg/m3, 82 nm in the 20 mg/m3, and 86 nm in the 100 mg/m3 asphalt fumes. No mortality related to the asphalt fume exposure occurred. Results indicate that exposure to 100 mg/m3 asphalt fumes caused a significantly lower body weight in male rats and statistically significant (P -values not presented) exposure -related histopathological changes (e.g., hyalinosis, basal cell hyperplasia, mucous cell hyperplasia, inflammatory cell infiltration) in the nasal and paranasal cavities. Under the experimental condi- tions described above, the no -observed -adverse -effect level for asphalt fumes is 20 mg/m3. 8.2 Genotoxicity 8.2.1 Mutagenic effects A number of studies evaluated potential mutagenic effects of paving and roofing asphalt and asphalt -based paints using the Ames Salmonella assay. An evaluation of available data indicates that asphalt fumes collected at 146-157 °C from the headspace of an asphalt storage tank at a hot -mix asphalt production plant were not mutagenic in the modified Ames Salmonella assay, while fume condensates generated in the laboratory at 149 °C and 316 °C were mutagenic (Reinke & Swanson, 1993; Reinke et al., 2000). Asphalt fume condensates generated at 316 °C were more mutagenic than the fumes generated at 149 °C. In contrast, a study by Heikkila et al. (2003) demonstrated that the particulate fractions of asphalt fumes collected in the PBZ of workers during paving operations were mutagenic in the Ames Salmonella assay, recycled asphalts being more mutagenic than the particulate fractions of new asphalt. Additionally, another study did not demonstrate any mutagenicity in mice exposed by nose only to paving asphalt fumes (Micillino et al., 2002). Asphalt fume samples collected above an open port of the heated. cement storage tank at hot -mix plants were not muta- genic using a spiral Salmonella mutagenicity assay (Burr et al., 2002). In other studies, paving and roofing asphalt fumes generated in the laboratory under a variety of conditions were also mutagenic (Al, 1990a; NTP, 1990; Machado et al., 1993; De Meo et al., 1996). None of the asphalt -based paints examined by Robinson et al. (1984) demonstrated mutagenic activity in either the presence or absence of metabolic activation (S9). 8.2.2 Micronuclei formation and chromosomal aberrations Condensates of Type I and. Type Ill roofing asphalt fumes generated in the laboratory at 316 °C using the same methodology as in Sivak et al. (1989) and roofing asphalt fumes generated by Sivak et al. (1989) (informa- tion on the methodology can be found in section 8.4) caused a dose -related increase in micronucleus forma- tion in exponentially growing Chinese hamster lung fibroblasts (V79 cells) (Qian et al., 1996, 1999). The authors suggested that Type 1 and Type III roofing asphalt fume condensates are aneuploidogens and possess some clastogenic activities. These condensates caused mainly cytogenetic damage by spindle apparatus alterations in cultured mammalian cells. Ma et al. (2002) exposed male Sprague-Dawley rats intratracheally to asphalt fume condensates (saline control, 0.45 mg/kg body weight, or 8.8 mg/kg body weight) collected at the top of a paving storage tank (160 °C). Exposure to 0.45 mg asphalt fume condensate/kg body weight caused a non -significant increase in micronuclei formation, while 8.8 mg asphalt fume condensate/kg body weight (the highest concentration tested) caused a statistically significant (P < 0.05) increase in micronuclei formation in bone marrow polychromatic erythrocytes. However, all results were negative when three paving asphalt fume condensates generated in the field and in the laboratory were tested at 5, 10, 15, 20, 30, 40, 60, 80, and. 120 ng/ml in a chromosomal aberration assay using Chinese hamster ovary cells (Reinke & Swanson, 1993; Reinke et al., 2000). 8.2.3 DNA adduct formation De Meo et al. (1996) and Genevois et al. (1996) tested paving asphalt fume condensates generated in the laboratory at 160 and 200 °C for their ability to induce DNA adduct formation in vitro and in vivo, respectively. All of the fume condensates induced DNA adduct formation in vitro when added to calf thymus DNA, although no specific DNA adducts were identified (De Meo et al., 1996). Additionally, the same paving asphalt fume condensates induced DNA adducts in the skin, lungs, and lymphocytes of BD4 rats treated with them dermally, but specific types of DNA adducts were not identified (Genevois et al., 1996). In a later study, 16 Asphalt (Bitumen) Genevois-Charmeau et al. (2001) exposed three BD6 rats by nose only to paving asphalt fume condensates. A DNA adduct was detected only in the lungs of the exposed rats. Male Parkes mice that received multiple topical applications of asphalt -based paints showed accumula- tions of DNA adducts in both skin and lung tissue (Schoket et al., 1988a). After topical application, asphalt -based paints also induced. DNA adduct formation in adult and fetal human skin samples maintained in short-term tissue culture. A single 15 -mg dose per skin patch of asphalt -based paint induced 0.22 fmol adducts (Schoket et al., 1988b). However, the specific types of DNA adducts were not identified in either study. 8.2.4 Intercellular communication The five laboratory -generated asphalt roofing fume fractions used by Sivak et al. (1989) were tested for inhibition of intercellular communication. All fractions inhibited intercellular communication in Chinese hamster lung fibroblasts (V79 cells) (Toraason et al., 1991). Similarly, Wey et al. (1992) examined the effect of these fractions on intercellular communication in human epidermal keratinocytes. All fractions inhibited intercellular communication in a concentration - dependent fashion. Modulation of gap functional intercellular communication has been implicated as an important effect of tumour promoters. The inhibition of intercellular communication by a tumour promoter is believed to isolate an initiated or preneoplastic cell from the regulatory signals of surrounding cells, leading to the development of neoplasms (NIOSH, 2000). 8.3 Toxic responses and CYP1A1 Ma et al. (2002) exposed male Sprague-Dawley rats intratracheally to asphalt fume condensates (saline con- trol or 0.45, 2.22, or 8.8 mg/kg body weight) collected at the top of a paving asphalt storage tank (160 °C). Expo- sure to 8.8 mg asphalt fume condensate/kg body weight, the highest concentration tested., causeda statistically significant (P < 0.05) dose -dependent increase in both the level and activity of CYP1A1 in the lung. However, CYP2B 1 levels and activity were not significantly affected. 8.4 Carcinogenicity' Several studies have reported carcinogenicity in mice following applications of laboratory -generated asphalt roofing fume condensates (Thayer et al., 1981; Niemeier et al., 1988; Sivak et al., 1989, 1997), raw The Final Review Board is aware of a 2 -year nose -only inhalation carcinogenicity study in rats on paving fumes (Fraunhofer Institute), which is in progress. 17 roofing asphalt (Sivak et al., 1989, 1997), and asphalt - based paints (Robinson et al., 1984; Bull et al., 1985) to the skin of mice. However, in another study (Emmett et al., 1981), raw roofing asphalt applied dermally to mice was not carcinogenic. Thayer et al. (1981) and. Niemeier et al. (1988) investigated the tumorigenicity of fume condensates generated in the laboratory at 232 and 316 °C from Type I and. Type III roofing asphalt` and applied biweekly for 78 weeks to the skin of male CD -1 and C3H/HeJ mice. Eighteen groups of 50 mice per strain received these applications. Half of each group was exposed to simu- lated sunlight. Tumours were produced in both strains of mice by fume condensates of both types of asphalt (see Tables 6 and 7). The majority of benign tumours were papillomas; the majority of malignant tumours were squamous cell carcinomas. Both strains of mice exposed. to asphalt fumes had significantly (P = 0.01) more tumours than the control groups, although the C3H/HeJ mice demonstrated a greater tumorigenic and carcino- genic response than did the CD -1 mice. The C3H/HeJ mice showed a significant increase (P = 0.01; Fisher - Irwin exact test) in tumorigenic response for both types of condensed asphalt fumes generated at 316 °C com- pared with tumours generated at 232 °C. The mean time to tumour appearance was longer for all groups of CD -1 mice compared with the corresponding C3H/HeJ groups. The mean latency period ranged from 39.5 to 56.1 weeks among the C3H/HeJ groups and from 47 to 76.5 weeks among the CD -1 groups treated with the asphalt fume condensates. Niemeier et al. (1988) concluded that the carcinogenic activity of the asphalt fume condensates may have been due to the high concentrations of aliphatic hydrocarbons, which have co -carcinogenic effects, and that higher generation temperatures may increase carcinogenic effects. Sivak et al. (1989, 1997) heated Type III roofing asphalt from the same lot used by Niemeier et al. (1988) at 316 °C, generated fume condensates, and separated them by HPLC (see Belinky et al., 1988, for a descrip- tion of this procedure). The chemical composition of fractions A through E, as analysed by GC/MS, can be found in Table 4. Raw roofing asphalt, neat asphalt fumes, asphalt heated to 316 °C with fumes allowed to escape, reconstituted asphalt fumes, and the asphalt fume fractions individually and in various combina- tions — were then tested for their carcinogenic and tumour -promoting activity in male C3H/HeJ and Sencar mice. Fractions A through E were dissolved in a 1:1 solution of cyclohexane and acetone to yield concentra- tions proportional to their presence in the unfractionated. (neat) asphalt fume condensate, i.e., 64.1%, 8.3%, 2 Mopping -grade roofing asphalts, Types I —IV, are differenti- ated by their softening points. Concise International Chemical Assessment Document 59 Table 6: Final histopathology of tumours induced in CD -1 mice treated dermally with roofing asphalt fume condensates' Tumour -bearing animals Tumours Material tested Sunlight' Benign Malignant Papilloma Squamous cell carcinoma Total` Type I asphalt at 232 °C° Type I asphalt at 316 °C° Type III asphalt at 232 °C° Type III asphalt at 316 °C° Benzo[a]pyrene (B(a)P)e Cyclo hexane/aceto net 6 2 13 3 9 5 13 4 24 9 0 0 1 0 1 2 3 1 11 3 12 0 12 3 0 3 18 0 19 3 0 3 11 1 13 5 1 7 17 1 20 5 1 6 43 10 58 11 1 18 0 0 • Adapted from Thayer et al. (1981). b There were 50 animals per group, and half of each group was exposed to sunlight. • Other tumour types observed included fibrosarcomas, kerato-acanthomas, fibromas, and unclassified benign epitheliomas. o 25 mg of total solid per application. e 5 pg per application. 50 pl of a 1:1 solution. Table 7: Final histopathology of tumours induced in C3H/HeJ mice treated dermally with roofing asphalt fume condensates.' Material tested Sunlight' Tumour -bearing animals Tumours Benign Malignant Papilloma Squamous cell carcinoma Total` Type I asphalt at 232 °C° Type I asphalt at 316 °C° Type III asphalt at 232 °C° Type III asphalt at 316 °C° Benzo[a]pyrene (B(a)P)e Cyclohexa ne/acetone' 24 14 13 18 15 11 12 20 11 7 0 22 27 31 26 25 20 28 18 27 27 0 0 34 22 27 36 32 14 24 34 12 11 0 2 26 25 31 26 19 19 36 20 29 22 76 62 78 73 66 54 82 65 53 43 0 0 2 4 ' Adapted from Thayer et al. (1981). b There were 50 animals per group, and half of each group was exposed to sunlight. • Other tumour types observed included fibrosarcomas, kerato-acanthomas, fibromas, and unclassified benign epitheliomas. o 25 mg of total solid per application. e 5 pg per application. 50 pl of a 1:1 solution. 10.5%, 11.5%, and. 5.6%, respectively. They were then applied biweekly to 40 groups of male C3H/HeJ mice and two groups of male Sencar mice (30 mice per group) for 104 weeks (2 years). Table 8 shows all the treatment groups, the number of papillomas and carcinomas per group, the number of tumour -bearing mice, and the average time (in weeks) to carcinoma development. The 18 raw roofing asphalt and neat asphalt fumes induced. carcinomas (local skin cancers) in 3 of 30 and. 20 of 30 C3H/HeJ mice, respectively. However, the heated asphalt with fumes allowed to escape did not induce any tumours. Fractions B and C induced carcinomas in 10 of 30 and 17 of 30 C3H/HeJ mice, respectively, while fractions A, D, and. E failed to induce any carcinomas Asphalt (Bitumen) Table 8: Tumorigenic response in all treatment groups.' Group number Treatment Total number of tumours per Average Asphalt group' Number of time to dose tumour- carcinoma (mg)` Papilloma Carcinoma bearing mice (weeks)e 1 Raw asphalt 25 1 3 4 101 2 Heated asphalt (less fume) 25 3 Heated asphalt (plus fume) 25 4 Neat asphalt fume 25 12' 25' 21 74 5 Solvent control 0 6 Fraction A 16 7 Fraction B 2.3 2 10' 11 98 8 Fraction C 2.6 4 18' 20 86 9 Fraction D 23 10 Fraction E 1.6 11 Fractions A + B + C + D + E 24.8 30' 23' 25 75 12 Fractions A + B 18.3 10' 8' 13 97 13 Fractions A + C 18.6 12' 16t 15 90 14 Fractions A + D 18.3 15 Fractions A + E 17.6 16 Fractions B + C + D + E 8.8 9' 18' 19 81 17 Fractions A + B + C + D 23.2 17' 22' 24 80 18 Fractions A + B + C + E 22.5 26' 30' 27 77 19 Fractions B + C + D 7.2 15' 22' 21 86 20 Fractions B + C 4.9 12' 26' 26 73 21 Fractions A + C + D + E 22.5 5' 14' 17 89 22 Fractions A + B + D + E 22.2 5 7' 9 97 23 Fractions A + D + E 19.9 2 24 0.01% benzo[a]pyrene (B(a)P) 0g 1 28' 27 56 25 0.001% B(a)P Og 2 3 5 103 26 0.0001% B(a)P Og 27 Fraction A + 0.01% B(a)P 16 7' 28' 24 70 28 Fraction A + 0.001% B(a)P 16 1 1 2 106 29 Fraction A + 0.0001% B(a)P 16 1 1 106 30 Fraction D + 0.01% B(a)P 2.3 14' 34' 29 64 31 Fraction D + 0.001 % B(a)P 2.3 2 2 32 Fraction D + 0.0001% B(a)P 2.3 1 1 106 33 Fraction E + 0.01% B(a)P 1.6 111 23' 24 61 34 Fraction E + 0.001% B(a)P 1.6 2 2 106 35 Fraction E + 0.0001% B(a)P 1.6 36 B(a)P then fraction A 16" 37 B(a)P then fraction D 2.3h 38 B(a)P then fraction E 1.6h 39 B(a)P alone 0 40 Sentinel mice' 0 41 Sencar fume 25 21' 18' 20 83 42 Sencar control 0 • Adapted from Sivak et al. (1989, 1997). b Groups 1-40 consisted of 30 male C3H/HeJ mice per group, and groups 41 and 42 consisted of 30 male Sencar mice per group. • Asphalt, asphalt plus fume, or asphalt fume alone were applied twice weekly for 104 weeks; 50 pl per application. • Only histologically confirmed skin tumours are given. • Based on gross observation. There were significantly more tumours, earlier onset of tumours, or both in these groups compared with controls. e 5, 0.5, 0.05 pg B(a)P per 50 pl application per group, respectively. " Mice were initiated with a single application of 200 mg B(a)P/50 pl followed by twice -weekly applications of indicated fractions. Five mice were sacrificed prior to the initiation of the study and after 6, 12, 18, and 24 months. 19 Concise International Chemical Assessment Document 59 when applied alone. All the combinations of the frac- tions induced carcinomas only if they included. B or C. The A and D combination, the A and. E combination, and the A, D, and E combination failed to induce any carcinomas. Furthermore, fractions A, D, and. E failed to act as either tumour promoters or co -carcinogens. Eighteen of the 30 Sencar mice treated with the asphalt fume condensate developed carcinomas. Fractions contained. PACs that included. PAHs, S -PACs, and 0 - PACs, such as alkylatedaryl thiophenes, alkylated. phenanthrenes, alkylated acetophenones, and alkylated. dihydrofuranones. Fraction B contained most of the 5 - PACs, and only a few were carried over to fraction C. Fraction C contained a small amount of four -ring PACs. In an earlier study, Emmett et al. (1981) examined the carcinogenic potential of a standard roofing asphalt (asphalt type not provided) dissolved in redistilled. toluene at a 1:1 ratio by weight. Fifty milligrams of this solution was applied twice a week to the shaved intra- scapular region of the back of 50 male C3H/HeJ mice for 80 weeks. The vehicle control group received 50 mg of toluene biweekly, and the positive control group received 50 mg of 0.01% benzo[a]pyrene (B(a)P) in toluene biweekly. No tumours were observed in male C3H/HeJ mice that had been treated dermally with the roofing asphalt. Asphalt -based paint formulations are used to pre- vent corrosion in drinking -water distribution systems (Miller et al., 1982). Four of these formulations (labelled A through D) were evaluated for their potential tumour - initiating ability using female Sencar mice in mouse skin bioassays (Robinson et al., 1984; Bull et al., 1985). The asphalt -based paints were formulations containing xylene or xylene and mineral spirits with between 89% and 98% cutback asphalt. These asphalt -based paints initiated tumour development in female Sencar mouse skin. Table 9 presents data demonstrating their tumour - initiating activity, provides gross tumour observations, and classifies tumours examined histologically. Asphalt paint formulation D was analysed for its ability to act as a complete carcinogen; a dose of 200 hl was applied to 40 female Sencar mice once a week for 30 weeks, and the mice were sacrificed after 52 weeks. Under the experimental conditions provided, of the female Sencar mice treated. with asphalt D, only 1 in 40 (3%) devel- oped a tumour (papilloma), while 3 of 40 mice in the group treated with mineral spirits developed papillomas. Robinson et al. (1984) concluded that the four asphalt - based paints contained chemicals capable of initiating tumours in mice and that a number of these tumours were carcinomas. However, asphalt D was not a complete carcinogen. 9. EFFECTS ON HUMANS 9.1 Acute effects Two studies conducted in the late 1990s assessed the relationship between airborne concentrations of TP and BSP from asphalt fumes and vapours and symptom prevalence and pulmonary function parameters among workers employed in one or another segment of the US asphalt industry (Exxon, 1997; Gamble et al., 1999; Bun et al., 2002). Gamble et al. (1999) examined 170 work- ers employed in five segments of the US asphalt industry — hot -mix asphalt manufacturing, hot -mix asphalt paving operations, asphalt distribution terminals, roofing manufacturing, and roofing application. On each of 2 consecutive days, pre- and postshift symptom prevalence surveys and forced vital capacity (FVC), forced expira- tory volume in l s (FEV 1), and forced expiratory fraction (FEF25 7,) were taken. Symptom prevalence was also obtained during the workshift on each of the days. PBZ monitors were used to evaluate airborne exposures. The results of the study and a comprehensive compilation of the methods are included in Exxon (1997). In a partnership with the US Federal Highway Administration, NIOSH conducted a study to develop and field-test new methods to assess asphalt fume exposures, characterize and compare occupational exposure to crumb -rubber modified asphalt (CRM) and. "conventional asphalt," andevaluate the potential health effects of exposure (Burr et al., 2002). For each site, the conventional asphalt hadthe same formulation as the CRM, but did not contain crumb -rubber. This CICAD contains information only from the analysis of seven conventional asphalt paving sites. Two groups of workers (exposed and unexposed) were recruited at each site; medical evaluations were conducted over 4 days — 2 days for CRM and 2 days for conventional asphalt. A general health questionnaire was completed by each participant at the beginning of a site survey, asking about recent history of eye, nose, or throat irritation, cough, shortness of breath, wheezing, and history of chronic respiratory conditions. Smoking and work histories were also obtained. A questionnaire addressing acute symp- toms was distributed to workers pre- and postshift, 3 times during the workshifl. Peak expiratory flow rate was measured just prior to completing the acute symp- tom questionnaire. Area and PBZ monitoring were conducted to evaluate airborne exposures. A total of 94 workers employed at any of the seven paving sites participated in the study. Results are presented in the following section. 20 Asphalt (Bitumen) Table 9: Tumour -initiating activity of asphalt -based paints.' Dose (pi) Gross observations unless Animals Material otherwise with Number of tested indicated' tumours° tumours Squamous cell abnormalities in histopathology after 52 weeks Examined/ initiatedd Papillomas Carcinomas' Tumours' Asphalt A Asphalt B Asphalt C Asphalt D Mineral spirits' Acetone B(a)P DMBAh 200 600 200 600 200 600 200' 600 600 200 10.0 pg 2.65 pg 18/40 (45) 21/40 (53) 17/40 (43) 20/40 (50) 19/40 (48) 23/40 (58) 21/40 (53) 15/40 (38) 5/40 (13) 6/30 (20) 22/30 (73) Not given 25 31 23 34 28 51 33 22 6 6 99 Not given 36 38 31 35 31 36 33 35 37 23 27 8 4 8 5 4 4 11 9 2 1 4 11 3 2 2 0 2 5 4 6 3 0 0 9 6 6 10 5 6 8 13 9 4 1 4 15 8 Adapted from Robinson et al. (1984) and Bullet al. (1985). The 200-pl dose was administered in one dose, while the 600-pl dose was administered as three weekly 200-pl doses. All animals were treated with 1 pg tetradecanoyl phorbol acetate (TPA) in 200 pl of acetone 3 times weekly for 20 weeks beginning 2 weeks after the last initiating dose. Data represent cumulative tumour counts through 40 weeks. Number in parentheses indicates percentage. Each treatment group except the DMBA treatment group contained 40 female Sencar mice. Only 20 were in the DMBA treatment group. The asphalt D group also had one animal with a fibrosarcoma and one with a basal cell carcinoma. Total number of animals having squamous cell papillomas and/or carcinomas does not agree with number of animals with squamous cell tumours because some animals had both types. Also analysed for its ability to act as a complete carcinogen. Results indicated that 1 of 40 Sencar mice tested developed a tumour (papilloma). Also tested (200 pl) as a complete carcinogen. Results indicated that 3 of 40 Sencar mice tested developed tumours (papillomas). DMBA = dimethyl benzanthracene. 9.1.1 Respiratory effects Among worker populations, acute effects of expo- sure to asphalt fumes include symptoms of irritation of the serous membranes of the conjunctivae (eye irritation) and the mucous membranes of the upper respiratory tract (nasal and throat irritation). These effects are best described in asphalt road pavers (Norseth et al., 1991; Almaguer et al., 1996; Hanley & Miller, 1996a,b; Kinnes et al., 1996; Miller & Burr, 1996a,b, 1998; Sylvain & Miller, 1996; Exxon, 1997; Gamble et al., 1999; Burr et al., 2002) and typically appear to be of mild severity and transitory in nature (Almaguer et al., 1996; Hanley & Miller, 1996a,b; Kinnes et al., 1996; Miller & Burr, 1996a,b, 1998; Exxon, 1997). Similar symptoms have also been reported in workers exposed to asphalt fumes during the application of hot asphalt roofing material (Exxon, 1997), during the manufacture of asphalt roofing shingles (Apol & Okawa, 1977; Exxon, 1997), and at hot -mix asphalt plants and. terminals (Exxon, 1997). Unexpected asphalt fume exposure was reported. from fluorescent lights (Chase et al., 1994) and during cable insulating operations (Zeglio, 1950). Tavris et al. (1984) suggested that the 3 -month outbreak of headache, 21 eye irritation, sore throat, nasal congestion, and. nausea in an office complex was due to malfunctioning fluores- cent light ballast, which overheated and resulted. in melt- ing and volatilization of contained asphalt. Correction of the problem resulted in almost complete disappearance of symptoms within 2 weeks. In one study of five different asphalt exposure situations (hot -mix plants, terminals, roofing application, roofing manufacturing, and paving), although symptoms were reported, no significant dose —response associations were found between measured exposures and symptoms (Exxon, 1997). However, in the NIOSH study of conventional asphalt pavers, airborne concentrations of TP, BSP, and. PACs were significantly higher on days when symptoms of the eye, nose, or throat were present compared with days when symptoms were not reported (P = 0.02, P < 0.01, and P <0.01, respectively) (Burr et al., 2002). While asphalt fume concentrations associated with the health effects noted above have not been well charac- terized, symptoms of eye, nose, or throat irritation were reported by workers during open-air paving. Average personal exposures, calculated as full -shift TWAs, were generally below 1.0 mg/m3 for TP and 0.3 mg/ m3 for BSP (Almaguer et al., 1996; Hanley & Miller, 1996a,b; Concise International Chemical Assessment Document 59 Kinnes et al., 1996; Miller & Burr, 1996a,b, 1998; Exxon, 1997). Lower respiratory tract symptoms (coughing, wheezing, shortness of breath) (Zeglio, 1950; Nyqvist, 1978; Almaguer et al., 1996; Hanley & Miller, 1996a,b; Kinnes et al., 1996; Miller & Burr, 1996a,b, 1998; Sylvain & Miller, 1996; Exxon, 1997) and changes in pulmonary function (e.g., bronchial lability) (Waage & Nielson, 1986; Hanley & Miller, 1996a; Kinnes et al., 1996; Miller & Burr, 1996b; Sylvain & Miller, 1996) have been described among workers exposed to asphalt fumes. Some workers experienced lower respiratory tract problems or changes in pulmonary function when exposed to TP at concentrations ranging between 0.02 and. 1 mg/m3 during open-air highway paving (Almaguer et al., 1996; Hanley & Miller, 1996a,b; Kinnes et al., 1996; Miller & Burr, 1996a,b, 1998; Exxon, 1997; Gamble et al., 1999). Kinnes et al. (1996) reported significant changes in pulmonary function in one of seven workers engaged in open-air asphalt paving. In three of nine workers engaged in underground paving, increased bronchoreactivity was noted, although only one paver reported symptoms (Sylvain & Miller, 1996). TP con- centrations ranged from 1.09 to 2.17 mg/m3 and BSP concentrations ranged from 0.3 to 1.26 mg/m3 during underground paving (Sylvain & Miller, 1996). The study of workers in five asphalt industry segments (Exxon, 1997; Gamble et al., 1999) found no significant associ- ation between pulmonary function measurements (FVC, FEVI, or FEF2≤ 75 over a workshift) and asphalt expo- sures among workers. Some limited evidence suggests that personal health factors (e.g., pre-existing asthma) or exposures to greater amounts of asphalt fumes, such as those found during underground paving, may increase workers' risk for lower respiratory tract symptoms or changes in pulmonary function (Norseth et al., 1991; Sylvain & Miller, 1996). However, the current data are insufficient to determine the relationship between asphalt fume exposures and these health effects. In addition, other potentially confounding exposures, such as gasoline and diesel exhaust and road and tire dust, may also contribute an as yet unquantifiedpotential for respiratory irritation. Acute and chronic bronchitis, possibly related to chronic lower respiratory tract irritation, have been reported among asphalt workers in several studies (Zeglio, 1950; Baylor & Weaver, 1968; Hasle et al., 1977; Nyqvist, 1978; Maintz et al., 1987; Hansen, 1991). 9.1.2 Other acute effects Skin irritation, pruritus, or rashes were also reported after exposure to asphalt -based materials (Tavris et al., 1984; Schaffer et al., 1985; Waage & Nielson, 1986; Chase et al., 1994; Miller & Burr, 1996a,b, 1998). Given the presence of confounding co -exposures (i.e., diesel 22 fuel exhaust products, coal tar, fibreglass) and environ- mental conditions (wind., heat and humidity, ultraviolet radiation), the extent to which asphalt fumes may be associated. with these skin problems is unclear. Symptoms of nausea, stomach pain, decreased. appetite, headaches, and fatigue have also been reported. among workers exposed to asphalt (Tavris et al., 1984; Schaffer et al., 1985; Waage & Nielson, 1986; Norseth et al., 1991; Chase et al., 1994; Exxon, 1997; Gamble et al., 1999). With the exception of the studies by Norseth et al. (1991), Exxon (1997), and. Gamble et al. (1999), none of the other reports examined comparison groups with which to analyse exposure —response effects. Norseth et al. (1991) found increased frequency of fatigue and reduced appetite among asphalt -exposed workers compared with controls. No significant dose — response associations were found between measured exposures and symptoms in any of five asphalt exposure situations (Exxon, 1997; Gamble et al., 1999). The extent to which asphalt fumes may be associated with the above symptoms is unclear, given potential con- founders. 9.1.3 Burns Although burns due to hot asphalt comprise a small percentage of all reported burns, they are often severe and difficult to treat (James & Moss, 1990; Baruchin et al., 1997). While hot asphalt cools quickly on contact, it can retain sufficient heat to continue to cause damage while it remains on the skin. Furthermore, as it cools, it hardens and. adheres to the skin, making it difficult to remove. Burned areas usually include the extremities (head. and. neck, arms, hands, and legs); however, in a few cases, the burned areas also include the torso. James & Moss (1990) conducted a retrospective review covering a 9 -year period (between January 1, 1979, and December 31, 1987) of all inpatients treated for asphalt burns at the Burns Unit, Frenchay Hospital (Bristol, United Kingdom). Of the 24 inpatients (23 males, average age 33 years) treated, 22 were injured while working. Of the patients with reported occupation, 19 were employed as roofers or road workers. Injuries occurred as a result of explosions involving hot asphalt, tipping over of hot asphalt containers, falling off ladders into asphalt, or spilling hot asphalt while carrying it. The mean burn size was 3% (range 0.25-9.0%) of total body surface area. Sixteen patients (67%) required surgical treatment and skin grafts. The time between injury and surgery averaged 8 days (range 2-22 days), and the hospital stay averaged 9 days (range 1-21 days). Twenty-two patients were discharged from care and were able to return to work within 2 months; two were unemployed at the time of the injury. Asphalt (Bitumen) Baruchin et al. (1997) conducted a retrospective review covering a 10 -year period (between January 1, 1985, and January 1, 1995) of all inpatients treated for asphalt burns at either the Soroka Medical Center (Beer - Sheba, Israel) or the Barzilai Medical Center (Ashkelon, Israel). Of the 92 inpatients (all males, average age 29.6 years), 90 were injured while working. Eighty-four workers were injured when hot asphalt was spilled on them or they fell into it, four workers were injured when pipes carrying hot asphalt burst, and the remaining two workers were burned as a result of traffic accidents. The mean burn size was 3.87% of total body surface area. Fifty-three patients (58%) did not require surgical treatment, but did stay an average of 8.8 days in the hospital. Thirty-nine patients (42%) required surgical treatment and skin gratis. The average hospital stay for these patients was 10.7 days. On average, all patients lost 9.65 work days. 9.2 Chronic effects 9.2.1 Lung cancer among pavers Cohort epidemiological studies of lung cancer among workers engaged in asphalt paving, asphalt mixing plants, or highway maintenance and exposed to asphalt fumes have yielded contradictory results (Table 10). That is, while several studies have reported an elevated risk of lung cancer (Hansen, 1989a, 1991; Engholm et al., 1991; Partanen et al., 1997), design limitations of some of these studies preclude drawing any strong conclusions. Of particular concern is the possible presence of confounding from co -exposures to coal tar and other potential lung carcinogens (e.g., diesel exhaust, silica, and asbestos) (Hansen, 1989a) as well as from smoking (Engholm et al., 1991). No excess of lung cancer was found among highway maintenance workers (Bender et al., 1989). A meta -analysis of 20 epidemio- logical studies failed to find overall evidence for a lung cancer risk among pavers and highway maintenance workers exposed to asphalt (RR = 0.87, 95% CI = 0.76- 1.08) (Partanen & Boffetta, 1994). 9.2.2 Lung cancer among roofers and asphalt roofing materials production workers Cohort mortality and case —control studies of roofers have generally found an excess risk of lung cancer (Tables 11 and 12) (Hammond et al., 1976; Menck & Henderson, 1976; Schoenberg et al., 1987; Zahm et al., 1989; Engholm et al., 1991; Hrubec et al., 1992; Morabia et al., 1992; Pukkala, 1995). In contrast to pavers, the meta -analysis of 20 epidemiological studies by Partanen & Boffetta (1994) demonstrated an overall statistically significant excess of lung cancer among roofers (RR = 1.78, 95% CI = 1.5-2.1). However, it is uncertain to what extent these findings may be attrib- utable to asphalt exposures. In the past, roofers have 23 been exposed to coal tar and asbestos, which are known human lung carcinogens, as well as asphalt. In most studies, information on cigarette smoking was not available for analysis. Hence, while strong epidemiolog- ical evidence of an association between lung cancer and work as a roofer exists, it is uncertain whether asphalt or other substances are responsible for these findings. In an update of a study by Chiazze et al. (1993) of workers involvedin roofing materials manufacturing and. asphalt production, Watkins and colleagues (Watkins et al., 2002) conducted a case —control study of lung cancer and non-malignant respiratory disease (NMRD). Cases and controls were identified from among deaths occur- ring between 1977 and 1997 among active and retired. workers. Controls were matched by age, race, and gender. History of smoking (ever/never) was available for approximately 65% of cases and controls. Quantita- tive data on worker asphalt exposure were not collected until 1977. For each worker, lifetime cumulative expo- sure to asphalt prior to 1977 was estimated using histori- cal data and industrial hygiene measurements collected from 1977 to 1996. Each worker was assigned three exposure estimates ever/never and number of years of exposure to asphalt and two different estimates of cumulative exposure based on the extrapolation of measurements from 1977 to 1996 for the processes in which the workers were employed. The results of the analyses were presented as unadjusted odds ratios (unOR). For lung cancer, the unOR for smoking was 11.32 (95% CI = 1.87O, and all unORs for each asphalt exposure scenario exceeded unity. However, only the unOR for smoking was statistically significantly elevated. With the exception of smoking, the unORs for NMRD were generally less than 1. These data suggest that smoking contributes more strongly to lung cancer and NMRD than asphalt exposure. The authors caution that the study is limited by missing data on smoking for one-third of the cases and controls; that work history records were missing for 3 lung cancer cases and 19 lung cancer controls; and that exposure to asbestos, but not coal tar, occurred in both the asphalt and roofing plants. It should also be noted that cases and controls were selected only from among deaths of active and retired employees and not from among any workers ever employed at the facilities. What bias this might add to the study was not explained by the authors. 9.2.3 The IARC study of asphalt workers The largest study to examine health effects of occupational exposure to asphalt included a cohort of 29 820 workers engaged in road paving, asphalt mixing, roofing, waterproofing, or other specified jobs where exposure to asphalt fumes was possible. An underlying purpose of the study was to determine if asphalt (termed bitumen by the authors) was a human carcinogen. Historically, asphalt contained coal tar, a known lung Concise International Chemical Assessment Document 59 Table 10: Epidemiological studies of asphalt exposure: cohort studies of diseases in pavers.' Number Author, country, of study Dates of case Type or site of and occupation subjects ascertainment condition Number of deaths or cases Risk ratio 95% CI or P value Hansen (1989a), 679 1959-1986 All cancers Denmark, mastic Lung cancer asphalt workers Mouth Oesophagus Rectum 74 SIR 1.95` 1.53-2.44 27 SIR 3.44° 2.27-5.01 2 SIR 11.11° 1.35-40.14 3 SIR 6.98d 1.44-20.39 7 SIR 3.18d 1.28-6.56 Hansen (1991), Denmark, mastic asphalt workers' 679 1959-1986 All causes All cancers Lung cancer Non -lung cancer Bronchitis, emphysema, asthma 148 SMR 1.57d 1.34-1.85 62 SMR 229d 1.75-2.93 25 SMR 2.90d 1.88-4.29 37 SMR 2.00d 1.41-2.76 9 SMR 2.07d 0.95-3.93 Engholm et al. (1991), Sweden, pavers' 2572 1971-1985 All causes All cancers Stomach cancer Stomach cancer Lung cancer Lung cancer 96 SMR 0.69 47 SIR 0.86 5 SMR 2.01 6 SIR 2.07 7 SMR 1.10 8 SIR 1.24 NR NR NR NR NR NR Bender et al. (1989), USA, highway maintenance workersg'" 4849 1945-1984 All causes 1530 SMR 0.9 0.86-0.96 All cancers 274 SMR 0.83 0.73-0.94 Lung cancer 57 SMR 0.69 0.52-0.90 Mouth, pharyngeal 2' SMR 11.10 1.30-40.10 cancer Gastrointestinal 3' SMR 5.82 1.20-17.00 cancer Prostate cancer 11k SMR 2.98 P < 0.01 Kidney, bladder, other 7' SMR 2.92 1.17-6.02 urinary organ cancers Leukaemia 8" SMR 4.49 1.94-8.84 Partanen et al. (1997), Finland, road pavers (males only) Lung cancer Lung cancer NR SMR 1.5 1.2-1.9 NR SIR 1.4" 0.9-1.9 Abbreviations: CI = confidence interval; NR = not reported; SIR = standardized incidence ratio; SMR = standardized mortality ratio. Possible exposure to coal tar pitch. Author concluded that smoking unlikely to account for 3 -fold excess of cancer; exposure data limited to comparison population were based on Danish general population. All mastic asphalt workers (n = 679). Mastic asphalt workers aged 40-89 years (n = 547). Follow-up of Hansen (1989a); limitations the same as in previous analysis. Median follow-up for cohort 11.5 years; median age of cohort 42 years. No exposure assessment. Comparison populations for mortality and incidence studies were based on Swedish general population. Mortality and incidence studies did not control for smoking. Follow-up case —control study found RR = 3 for lung cancer after adjusting for smoking, but limited by small number of cases. Reference group was male population of Minnesota; quantitative exposure data limited. Highway maintenance workers employed as pavers, landscapers, mowers, garage workers, and office workers. No adjustment for smoking. Employed ?40 years. Urban workers with 40-49 years of latency. Started working 1955-1964. Workers with 40-49 years of latency. Employed 30-39 years. Asphalt exposure. 24 Asphalt (Bitumen) Table 11: Epidemiological studies of asphalt exposure: cohort studies of diseases in roofers.' Author, country, and Number of Dates of case Type or site of occupation study subjects ascertainment condition Number of deaths or cases Risk ratio 95% CI or P value Hammond et al. (1976), USA, roofer, waterprooferb 5939 1960-1971 Menck& Henderson 2000 (1976), USA, roofer' Engholm et al. (1991), 704 Sweden, roofer' 1968-1970 Lung cancer Respiratory disease' Lung cancer 1971-1985 Lung cancer Hrubec et al. (1992), 52 1954-1980 USA, roofer, slater9 Pukkala (1995), 47 000 1971-1985 Finland, asphalt roofer Stomach cancer Lymphatic, haematopoietic cancer Leukaemia Lung cancer Lung cancer 99 SMR 1.59` 71 SMR 1.67 NR NR 3 SMR 8.78 P>0.01 3 deaths 4 cases 3 cases 5 deaths 1 case 2 deaths SMR 2.79 SIR 3.62 RR 6.0' SMR 2.01 SIR 1.98 SMR 2.68 NR NR NR NR NR NR 1 case SIR 2.26 NR 4 deaths RR 3.0 1.30-6.75' 18 cases SIR 3.25' 1.92-5.13 a Abbreviations: CI = confidence interval: NR = not reported; RR = relative risk; SIR = standardized incidence ratio; SMR standardized mortality ratio. Exposure to coal tar pitch; no adjustment for smoking or quantitative exposure assessment. Classified as roofer based on the usual occupation as recorded on death certificate. More than 20 years since joining union. Pneumonia, tuberculosis, influenza excluded. Median follow-up for cohort 11.5 years; median age of cohort 42 years. No exposure assessment. Reference population was male Swedish population. Mortality and incidence studies did not control for smoking. Follow-up case —control study found RR = 6 after adjusting for smoking, but limited by small number of cases. Adjusted for smoking. Adjusted for smoking; occupation, industry of employment obtained through self -reports of 300 000 US Armed Forces veterans who served between 1917 and 1940. Fifty-two veterans reported occupational category as "roofers and slaters." 90% confidence interval. Adjusted for age, calendar time, and social class. Table 12: Epidemiological studies of asphalt exposure: case —control studies of lung cancer in roofers. Author, country, and occupation Number of study Number of subjects Dates of case subjects with lung cancer ascertainment Cases Controls Cases Controls Odds ratio' 95% Clb Zahm et al. (1989), USA, roofer` Schoenberg et al. (1987), USA, roofer, slater' Morabia et al. (1992), USA, roofer, slater' 1980-1985 4431 11 326 1967-1976 763 900 1980-1985 1793 3228 6 7 13 8 7 6 2.1 0.6-8.2 1.7 0.7-4.4 2.1 0.7-6.2 a Adjusted for smoking b CI = confidence interval. • Case identified from Missouri, USA, cancer registry. Matched controls were Missouri residents diagnosed with cancer, excluding cancers of lip, oral cavity, oesophagus, lung, bladder, ill defined and unspecified sites. Occupation was abstracted from cancer registry records. No exposure data available. o Cases were white male residents of six New Jersey, USA, municipalities with high lung cancer rates during 1967-1976. Matched controls were selected either by a random sample of New Jersey drivers' licence files or through the state mortality files. Occupation was obtained from interviews of next -of -kin. • Cases diagnosed between 1980 and 1989 at 24 hospitals in metropolitan areas of the USA. Controls were matched by age, race, hospital, and admission date and were not admitted for a tobacco -related condition. "Usual occupation" was obtained from interviews of cases and controls. 25 Concise International Chemical Assessment Document 59 carcinogen; over the past several decades, coal tar has been removed from paving and roofing asphalts. Additionally, this study, a meta -analysis, provided the opportunity to conduct a large study with a robust exposure assessment and sufficient power to detect excesses of lung cancer, if such an excess existed. Workers were first employed between 1913 and. 1999 in asphalt -exposed jobs in seven European countries (Denmark, Finland, France, Germany, Norway, Netherlands, Sweden) and Israel (IARC, 2001; Boffetta et al., 2003a,b). The cohort was divided into job exposure categories: 1) road paving (asphalt paving, surface dressing, mastic asphalt laying, emulsion paving, recycling, andother jobs in road. paving; 2) asphalt mixing; 3) unspecified whether road paving or asphalt mixing; 4) waterproofing and roofing; 5) other and. unspecified bitumen jobs. A comparison group was composed of 32 245 building and ground construction workers. All subjects were male and worked at least one full season in the target companies. A semiquantitative exposure matrix was constructed for each member of the cohort (Burstyn, 2001). The matrix took into account work history, exposure to bitumen fume, coal tar, and four- to six -ring PAHs, and other job -related exposures using data from industrial hygiene measurements and questionnaires. This study comprehensively analysed mortality using standard lifetable analyses and multi- variate Poisson regression analyses to examine con- founding effects of other workplace exposures as assessed by the exposure matrix. In total, 1 287 209 person -years of observation were accumulated by the entire cohort, of which 481 089 were from bitumen workers and 537 281 were from the comparison group. By the end of the follow-up period, 10 096 cohort members were deceased, of whom 3987 were bitumen workers and 3876 were building and ground construc- tion workers. In addition to the analysis of the entire cohort, separate country -specific analyses are available (Bergdahl & Jarvholm, 2003; Hooiveld et al., 2003; Kauppinen et al., 2003; Randem et al., 2003a,b; Shaham et al., 2003; Stucker et al., 2003). Analysis by country found differences in site -specific mortality patterns, particularly increases in lung cancer in the German cohort (IARC, 2001); however, here we report only overall mortality and lung cancer mortality by job classi fi cation. Overall mortality for the entire cohort (exposed and non -exposed workers) was below expected (SMR = 0.92, 95% CI = 0.90-0.94) (Boffetta et al., 2003a). For job classifications involving bitumen or asphalt expo- sure, overall mortality was not statistically significantly elevated (SMR = 0.96, 95% CI = 0.930.99); mortality 26 from lung cancer' among bitumen workers was increased compared with ground and building construction workers (SMR = 1. 17, 95% CI = 1.04- 1.30) (Table 13). Overall mortality from head and neck cancer was elevated for bitumen workers only (SMR = 1.27, 95% CI = L02-1.56). Mortality from other malignant neoplasms was not increased.. Further analysis suggested a slight increase in lung cancer mortality among road pavers after adjusting for coal tar pitch and allowing fora 15 -year lag (SMR = 1.23, 95% CI = 1.02- 1.48) (Boffetta et al., 2003b). The investigators (Boffetta et al., 2003b) assessed two different metrics for exposure: average and cumu- lative exposure. For lung cancer, a positive association was observed for lagged average level of exposure, but not for lagged cumulative exposure. Corresponding indices of unlagged average and cumulative exposure showed a positive dose —response with lung cancer risk based on 63 deaths: RRs were L43 (95% CI = 0.87- 2.33), 1.77 (0.99-3.19), and 153 (1.58-7.89) for 2.2- 4.6, 4.7-9.6, and 9.7+ mg/m3 years of cumulative exposure, 2.77 (95% CI = L69-4.53), 2A3 (1.38-4.29), and 3A6 (1.83-5.47) for 1.03—L23, 1.24—L36, and 1.37+ mg/m3 average exposure (P -value of test for trend, 0.01 for both variables). The investigators concluded that the exposure —response analyses suggest an associa- tion between lung cancer mortality and indices of average level of exposure to bitumen fume; however, they could not rule out that confounding played some role in this association. 9.2.4 Other asphalt exposures and cancers Studies have reported increased risk of cancer among workers in occupations with the potential for exposures to asphalt (Tables 10, 14-16). Case —control studies of renal pelvis, ureter, and bladder cancers found elevated risk among occupations with reported expo- sures to asphalt or tar (Jensen et al., 1988; Risch et al., 1988) or petroleum or asphalt (Mommsen et al., 1983) and in road or highway maintenance workers (Bonassi et al., 1989). Isolated studies have reported elevated risk estimates for cancers of the brain (Hansen, 1989b), bladder and other urinary organs (Bender et al., 1989; Hansen 1989b), mouth and pharynx (Bender et al., 1989; Hansen, 1989a), stomach (Engholm et al., 1991), liver (Austin et al., 1987), and other digestive organs (Bender et al., 1989; Hansen, 1989a,b; Siemiatycki, 1991), leukaemia (Bender et al., 1989; Engholm et al., 1991), respiratory cancer (Hansen, 1989b), and lung cancer (Vineis et al., 1988). However, two other case —control studies found no excess of lung cancer (Zahm et al., 1989; Chiazze et al., 1993). ' Although Boffetta et al. (2003a) refer to this as lung cancer, IARC (2001) lists it as trachea, bronchus, and lung cancer (see Table 13). Asphalt (Bitumen) Table 13: IARC epidemiological cohort study of cancer mortality among European asphalt workers by job class.'b`'° Unspecified Unspecified Cause of Bitumen Asphalt Asphalt paver/mixer bitumen death worker (job Road paver paver (job mixer (job (job class Roofer (job worker (job (ICD) class 1) (job class 11) class 111) class 12) 13) class 14) class 15) All causes 0.96e 0.94 0.89 0.77 0.80 0.88 1.08 (001-999) (0.93-0.99)f (0.90-0.98) (0.85-0.94) (0.67-0.87) (0.68-0.93) (0.74-1.04) (1.02-1.15) 3987/4163.48g 2411/2569.75 1368/1531.19 234/305.82 162/202.96 141/159.64 1162/1073.40 481 089" 320 060 212 860 41 470 15 039 34 519 88 742 All 0.95 0.96 0.95 0.66 0.73 1.21 1.01 malignant (0.90-1.01) (0.89-1.04) (0.86-1.06) (0.50-0.86) 0.50-1.02 (0.88-1.62) (0.90-1.13) neoplasms 1016/1064.87 623/646.60 362/379.25 55/83.55 33/45.32 44/36.48 292/289.16 (140-208) Trachea, 1.17 1.17 1.15 1.12 1.18 1.33 1.13 bronchus, (1.04-1.30) (1.01-1.35) (0.93-1.40) (0.73-1.66) (0.61-2.07) (0.73-2.23) (0.92-1.37) and lung 330/283.15 189/161.98 100/87.07 25/22.29 12/10.15 14/10.55 99/87.81 (162) • Adapted from IARC (2001). • Abbreviations: ICD = International Classification of Diseases; IARC = International Agency for Research on Cancer. • All countries. o More than one season of employment. C Standardized mortality ratio. 95% confidence interval. g Observed/expected. • Person -years. Table 14: Epidemiological studies of asphalt exposure: case —control studies of bladder, renal pelvis, and ureter cancer.' Author, country, and exposure or occupations Dates of case ascertainment Site Number of study subjects Number of study subjects with cancer Cases Controls Cases Controls Risk ratio 95% CI Mommsen et al. Not given Bladder 212 259 2 3 RR 2.36 NS (1983), Denmark, petroleum or asphalt' Risch et al. (1988), 1979-1982 Bladder 739 781 739 781 OR 1.44° 0.78-2.74 Canada, asphalt or OR 3.11e 1.19-9.68 tar` OR 2.02f 1.08-4.97 Bonassi et al. Not given Bladder 121 342 2 6 OR 1.40 0.27-7.28 (1989), USA, road mendersg Jensen et al. (1988), 1979-1982 Renal 96 294 9 6 RR 5.5 1.6-19.6 Denmark, asphalt or pelvis, tar" ureter Abbreviations: CI = confidence interval; NS = not statistically significant; OR = odds ratio; RR = relative risk. Cases identified as patients of Department of Oncology and Radiotherapy in Aarhus, Denmark. Controls matched by age, gender, geographic region, and urbanization were identified by the National Registry in Denmark. Occupational exposures and smoking history were obtained for cases and controls by questionnaire. Cases diagnosed in metropolitan areas of Canada. Population controls matched by age, sex, area of residence. Lifetime occupa- tional history and smoking history were obtained for all cases and controls by questionnaire. Study limited by low participation rate. Ever exposed to "tar and asphalts" (n = 46). Exposed during full-time job of at least 6 months 8-28 years before diagnosis (n = 23). Trend with duration. Odds ratio for trend at 10 years' duration. Cases diagnosed in the Bormida Valley, Italy. Population controls selected from demographic registries of the cases matched by age at year of bladder cancer diagnosis and by sex. Interview of subject or next -of -kin obtained data on smoking history and occupation. Jobs were classified into categories with potential for PAH exposure. Cases diagnosed in eastern Denmark. Hospital -based controls were matched by sex and age and did not have renal diseases or diseases related to smoking. Occupational history and smoking history were obtained on cases and controls through questionnaire. 27 Concise International Chemical Assessment Document 59 Table 15: Epidemiological cohort study of asphalt exposure during manufacture of asphalt products, Denmark.ae,`'tl Number of study subjects Exposed Unexposed Type of condition Number of deaths or cases SMR 95% CI 1320 43 024 All cancers Digestive cancer Respiratory cancer Bladder cancer Brain cancer 29 6 11 3 3 1.59e 1.57 1.52 2.91 5.00 1.06-2.28 0.58-3.43 0.76-2.71 0.60-8.51 1.03-14.61 • From Hansen (1989b). • Abbreviations: CI = confidence interval; SMR = standardized mortality ratio. • Case ascertainment was for 1970-1980. ° Workers employed at asphalt plants, roofing felt plants, and one tar plant compared with the Danish general population. Study limited by lack of data on length of employment in the asphalt industry and extent of asphalt exposure. Smoking data were not available. e Workers ?45 years of age between 1975 and 1980. Table 16: Epidemiological studies on asphalt exposure: case —control studies of respiratory cancer and other diseases.a Number of study Author, country, and Dates of case subjects Odds occupation ascertainment Site Cases Controls Cases Controls ratio 95% CI Number of study subjects with disease Vineis et al. (1988), 1974-1981 Lung cancer 2973 3210 45 37 1.4 0.9-2.3 USA, roofers and asphalt workersb Zahm et al. (1989), 1980-1985 Lung cancer 4431 11 326 32 64 0.9 0.6-1.5 USA, pavers, surfacers, materials - moving equipment operators` Chiazze et al. (1993), Not given Lung cancer 144 260 111 251 0.96 0.65-1.42 USAd'e NMRD 101 183 79 171 1.34 0.82-2.2 Austin et al. (1987), Not given Hepato- 80 146 7 5 3.2 0.9-11 USA''9 cellular carcinoma Siemiatycki (1991), Not given Colon 3730 533' 22 1.6 1.1-2.5 Canada" cancer a Abbreviations: CI = confidence interval; NMRD = non-malignant respiratory diseases. Meta -analysis of lung cancer cases studied in five case —control studies and identified through cancer registries, hospital registries, or admissions or from death certificates. Controls were identified through similar sources as the cases and matched at least by age and gender. Smoking history was obtained for 98% of cases and controls. Cases identified from Missouri, USA, cancer registry. Matched controls were Missouri residents diagnosed with cancer, excluding cancers of lip, oral cavity, oesophagus, lung, bladder, ill defined and unspecified sites. Occupation was abstracted from cancer registry records. No exposure data were available. Cases and controls matched by age and survival to end of follow-up or death identified from historical cohort of production and maintenance workers who died while employed or who retired at a fibreglass manufacturing facility that also produced asphalt -coated roofing products. Complete occupational demographics and personal histories including smoking history were obtained by question- naire for cases and controls. Historical exposure reconstruction was conducted and an estimate of cumulative exposure to asphalt and other products was developed for each cohort member. Potential confounding exposures include respirable silica, talc (fibre contamination), and formaldehyde. Exposed to asphalt fumes of >0.01 mg/m3 cumulative exposure concentration. Exposed to asphalt. Cases diagnosed at five US hospitals. Hospital -based controls were matched on age, sex, race, and hospital location. Occupational history was obtained from cases and controls by interview. Subjects were also asked about exposure to substances on the job, including asphalt. No exposure data were collected. Cases identified among males aged 35-70 residing in Montreal metropolitan area. Population -based controls were stratified to the age distribution of the cases. Comprehensive interviews obtained detailed occupational history including exposure to chemicals and smoking history from cases and controls. No quantitative exposure data were collected. Number of controls not available. 28 Asphalt (Bitumen) In a meta -analysis of 20 epidemiological studies of workers generally classified as asphalt workers, but not roofers, Partanen & Boffetta (1994) reported increases in risk of bladder cancer (RR = L22, 95% CI = 0.95—L53), stomach cancer (RR = L28, 95% CI = L03 —L59), and leukaemia (RR = L41, 95% CI = 1.05—L85). Interpretation of the findings of these studies is limited by a lack of consistency among studies and the potential for confounding by other substances. Further- more, many of these findings are from studies organized by broad job classifications that are prone to errors in defining asphalt exposures (Mommsen et al., 1983; Jensen et al., 1988; Risch et al., 1988; Bender et al., 1989; Bonassi et al., 1989; Siemiatycki, 1991; Partanen & Boffetta, 1994). Thus, the evidence for an association between exposure to asphalt and cancers is weak and requires further confirmation by studies with better con- trol of confounding variables and better identification of asphalt exposures. 9.3 Other effects Toraason et al. (2001, 2002) examined. DNA strand breaks in leukocytes at the beginning and end of the same work week (4 days later) in seven roofers (all were smokers at time of study) who applied hot asphalt prod- ucts, but had no coal tar exposure during the preceding 3 months. Using the comet assay, estimates of DNA strand breaks were significantly (P < 0.05) increased at the end of the work week (start of work week 13.6 ± 1.9; end of work week 16.7 ± L4). Exposure data related to this study were presented previously in section 6.2. Fuchs et al. (1996) measured primary DNA damage (strand breaks) and DNA adducts in mononuclear cells of workers exposed to asphalt. These workers included roofers (n = 7), pavers (n = 18), and asphalt painters (n = 9). The control group (n = 34) consisted of students and office workers. All roofers and 10 members of the con- trol group smoked. The roofers studied had significantly greater (P < 0.002) numbers of DNA strand breaks, and these were found to increase during the work week. Because the type of roofing work and materials used were not defined, exposure to coal tar could not be excluded. Pavers and asphalt painters did not differ statistically from controls in the incidence of DNA strand breaks; however, the number of strand breaks was found to increase during the work week in the group of pavers. DNA adducts were found in 10 of 14 samples obtained from pavers and asphalt painters, and DNA adduct concentrations were positively correlated with age and years of exposure. Technical problems pro- hibited analysis of DNA adducts in other subjects. Jarvholm et al. (1999) examined sister chromatid exchanges and micronuclei in peripheral lymphocytes of non-smoking (non-smokers or ex -smokers who had. 29 stopped smoking at least 3 years before the examination) Swedish road pavement workers. The study included 28 non-smoking road pavers and 30 non-smoking referents. Asphalt paving operations were performed in teams that consisted of 4-7 members with different tasks. Although the study showed that the Swedish road pavers have an increased exposure to PAHs from bitu- men fumes, no significant increases occurred in the sister chromatid exchanges or micronuclei of exposed workers compared with referents. 10. EFFECTS ON OTHER ORGANISMS IN THE LABORATORY AND FIELD Data on the effects of asphalt on other organisms in the laboratory and field are limited. Assessment of quantitative structure —activity relationships (QSAR) relating log K„5. values of single hydrocarbons to toxicity indicate that bitumens (asphalts) would not be expected. to cause acute toxicity in aquatic organisms (CONCAWE, 2001). A 56 -day laboratory study (Miller et al., 1980) using natural soil media was conducted with Phasiolus vul- garis (bean) seeds or Zea mays (corn) seeds. The bean and corn seeds were exposed to either 4.09 or 20.5 g of asphalt/ 1.8 kg of soil for 56 days. Results indicated that the asphalt had no effect on the growth of either bean or corn seeds. 11. EFFECTS EVALUATION 11.1 Evaluation of health effects 11.1.1 Hazard identification and dose -response assessment Asphalt fumes and vapours cause irritation of the eyes, nose, and. respiratory tract in animals and. humans. Available data indicate that while laboratory -generated. paving and roofing asphalt fume condensates were mutagenic in the Ames Salmonella assay, field - generated paving asphalt fume condensates were not mutagenic. Paving asphalt fumes generated in the laboratory induced DNA adduct formation in vitro and in vivo. A field -generated fume collected from the headspace of an asphalt storage tank was not mutagenic in the Ames assay; however, asphalt fume condensates collected at the top of a paving storage tank caused chromosomal damage when administered intratracheally to rats. Laboratory -generated roofing asphalt fume Concise International Chemical Assessment Document 59 condensates also induced micronuclei formation and. inhibited intracellular communication in mammalian cells. No studies using asphalt fumes generated during roofing operations have been reported. Data from studies in animals indicated that roofing asphalt fume condensates generated in the laboratory and applied dermally caused benign and malignant skin tumours in several strains of mice. No animal studies have examined the carcinogenic potential of asphalt fumes collected during roofing and paving operations or of laboratory -generated paving asphalt fume conden- sates. Additionally, several formulations of asphalt - based paints caused benign and malignant skin tumours in mice, but were not mutagenic in the Ames Salmonella assay. Results of several animal studies are conflicting with regard to the carcinogenicity of raw asphalt. Raw asphalt induced a weak carcinogenic response when applied to the skin of mice in one study, while in the other studies it was not carcinogenic. Although burns due to hot asphalt comprise a small percentage of all reported burns, they are often severe and difficult to treat. Burned areas usually include the extremities (head and neck, arms, hands, and legs); however, in a few cases, the burned areas also include the torso. Some workers exposed to asphalt fumes during paving operations experienced lower respiratory tract symptoms such as coughing, wheezing, shortness of breath, and changes in pulmonary function. The lowest TP exposure that caused respiratory tract problems was 0.02 mg/m3. A meta -analysis of epidemiological studies of roofers indicated an excess of lung cancer among them, but it was uncertain whether this excess was related to asphalt fumes and vapours and/or to carcinogens such as coal tar or asbestos or cigarette smoking. Epidemiolog- ical studies of pavers exposed to asphalt yielded. contradictory results regarding lung cancer. Design limitations andconfounders such as smoking and diesel exhaust precluded any strong conclusions regarding an association between lung cancer and working as an asphalt paver. Furthermore, a meta -analysis of these studies failed to find overall evidence for a lung cancer risk among pavers exposed to asphalt fumes and. vapours. A few studies reported an association between bladder, renal pelvis, ureter, brain, liver, and other digestive cancers and occupations having potential exposures to asphalt fumes and vapours. However, because of limitations in study design and lack of exposure data, no association can be made at this time between exposure to asphalt fumes and vapours and the induction of these types of cancers. 30 11.1.2 Criteria for setting tolerable intakes/ concentrations for asphalt No human data are available to serve as a basis for characterization of a dose —response relationship between asphalt fume and vapour exposure and the occurrence of either acute or chronic effects. Studies of asphalt pavers and roofers are limited by study design and the inability to account for appropriate confounders, making it difficult to establish a clear dose —response relationship. Available worker exposure data are only suggestive of a possible dose —response relationship between asphalt fume and vapour exposure and the occurrence of acute effects and cannot be extrapolated to the general popu- lation at this time. 11.1.3 Sample risk characterization The extremely limited nature of the available data to serve as a basis for estimation of exposure of the general population should be borne in mind when attempting to determine exposure of the general population to asphalt, asphalt fumes and vapours, and asphalt -based paints. The concentrations of asphalt fractions polars, aromatics, and saturates measured in air samples collected 2.0-83.6 m from the highway were 0.54- 3.96 x l0 3 mg/m3 air, 1.77-9.50 x l0 4 mg/m3 air, and 0.21—L23 X 10 4 mg/m3 air, respectively. As noted previously, these values are extremely low in compari- son with occupational exposures determined in the various sectors of the asphalt industry; personal expo- sures to TP and BSP ranged from 0.041 to 4.1 mg/m3 and from 0.05 to L26 mg/m3, respectively. However, the chemical composition of the air samples collected along the highway and at the worksites may differ. In addition to respiratory absorption, dermal absorption may also occur and play a pivotal role in asphalt exposure. 11.1.4 Uncertainties in the hazard characterization The uncertainties identified in this section apply to all types of asphalt, as the commonalities generally out- weigh the differences. In weighing the available data that explore the relationship between exposure to asphalt or asphalt fumes and vapours and adverse health effects, it is important to consider them in the context of the overall limitations of the information. These uncertain- ties may be caused by the basic chemistry of asphalt, which is a mixture, the small number of in vivo studies, the inclusion of coal tar in roofing and. paving asphalts in past decades (and the inclusion in some current formula- tions), and. the mixed results of human studies, to name a few. However, these limitations or uncertainties should. not preclude a judgement regarding human and environ- mental health. Asphalt (Bitumen) 11.1.4.1 Chemistry The chemical properties of asphalts present a recognized source of uncertainty. Many aspects affect the chemical properties and. constituents of the asphalt used for paving, roofing, and other applications. These issues are discussed at length in the source document. Recognized items that affect chemical properties of asphalt include the source of the crude petroleum, manufacturing and refining processes (oxidized versus non -oxidized), modifiers and additives, and application temperature. However, it must be kept in mind that the chemical composition of all types of asphalts is similar in many respects. Elemental analysis indicates that most asphalts contain 79-88 wt% carbon, 7-13 wt% hydro- gen, traces to 8 wt% sulfur, 2-8 wt% oxygen, and traces to 3 wt% nitrogen. 11.1.4.2 Animal studies The use of results from studies in experimental animals and in vitro assays demonstrates the difficulty in ascribing the occurrence of adverse health effects in humans to exposure to asphalt and asphalt fumes and. vapours. While all laboratory -generated roofing and paving asphalt fume condensates were positive for mutagenicity in the Ames Salmonella assay, fumes collected above the head.space of an asphalt storage tank and during paving operations were not. In contrast, the particulate fractions of asphalt fumes collected in the PBZ of workers during paving operations were muta- genic, and intratracheal instillation of field -generated paving asphalt fume condensates in rats caused not only increased micronuclei formation in bone marrow ery- throcytes, but also a statistically significant increase in the level and activity of CYP1A1 in the lung. Data on asphalt -based paints are equivocal; while some of the paint formulations exhibited mutagenicity, others did not. Data on chronic health effects in laboratory studies are limited. Although several studies have examined the carcinogenic potential of laboratory -generated roofing asphalt fume condensates administered dermally and found them to be carcinogenic, there are no studies that have examined the carcinogenic potential of field - generated roofing and paving asphalt fume condensates administered via inhalation, recognized as the primary route of human exposure. None of the above data lends itself to development of a dose —response curve for quantifying an identifiedend-point in laboratory animals that can be extrapolated to humans. 11.1.4.3 Human studies It is likely that the concern over human exposure to chemical constituents of asphalt or asphalt fumes and vapours originates from the discovery of scrotal cancer 31 among chimney sweeps by Sir Percival Pott in 1775. The exposure of the sweeps was not to asphalt, per se, but to a class of chemicals generated as by-products of combustion of coal and other fossil fuels, namely PAHs. Some of the earlier studies of asphalt exposure examined skin cancers as a possible consequence of exposure. A series of toxicological studies of roofing asphalt, without coal tar, found evidence of carcinogenic potential, whereas the human studies found little evidence of increased risk of skin cancers. Risk of increased mortality from lung cancer in roofers was assessed as early as the 1970s. Early studies of pavers or roofers are generally less informative because of small study population sizes, insufficient and. unspecific data on exposure to bitumen or asphalt, and residual confounding due to co -exposure to coal tar pitch and other lung carcinogens (e.g., asbestos, PAHs, tobacco smoke). Roofers and pavers may also have differing risks. In a meta -analysis of 20 epidemiological studies, the overall mortality risk from lung cancer was statistically significantly increased for roofers, but not for pavers. It is not clear whether these differences are due to differences in the type of asphalt used in roofing or paving operations or to study design issues. Furthermore, there are no epidemiological studies of workers exposed only to asphalt or asphalt fumes or vapours. The largest and most recent mortality study of a cohort of more than 30 000 workers with exposure to asphalt or asphalt fumes and vapours found slight increases in lung cancer mortality; however, even after controlling for potential coal tar exposure, they could not with certainty attribute a causal relationship to bitumen exposure. Further assessment of the cohort using a case — control design of lung cancer cases may clarify the results. With respect to acute effects, in a series of studies, workers applying paving asphalt exposed to higher TP and BSP fractions report increased nose, throat, and eye irritation. In addition, case reports of other types of asphalt fume exposure suggest that irritation may be due to the asphalt exposure. In one instance, symptoms resolved within 2 weeks after exposure ceased. One other study of five segments of the asphalt industry reported symptoms among workers, but they were not statistically associated with airborne concentrations of TP or BSP. One might conclude that if there were few symptoms at the concentrations at which the workers in this study were exposed, the reported airborne concen- trations could be considered an upper limit for occupa- tional exposures. 11.1.4.4 Potential for exposure The potential for exposure to bitumen/asphalt fumes or vapours varies with the type of asphalt application Concise International Chemical Assessment Document 59 (e.g., paving or roofing) and the task of the worker. For example, the kettle operator on roofing jobs has been shown to have a higher likelihood of exposure than someone who is applying the roofing material. The kettle operator must, at times, open the kettle to add new asphalt, check viscosity, etc. In some studies, individuals who operate the paving machines generally have higher exposures than other paving workers; in other studies, however, labourers or truck drivers had higher expo- sures. Furthermore, work practices and types of machin- ery available to the crew may also increase or decrease potential for exposure. Nevertheless, in the mix of things, these differences may even out over the years as individuals move from one job to another. Although this may be considered an uncertainty, it most likely has a lesser impact on an individual's overall risk. It is possible to show, with certainty, that workers exposed to asphalt or asphalt fumes and vapours do indeed take in and metabolize the chemical constituents of asphalt. While the current biomarker methodology is in its infancy and the specificity and sensitivity of the tests need improvement, it is clear that asphalt -exposed workers have exposure through both dermal and respir- atory routes. In situations where individuals from the general population live or work near asphalt production facilities or roofing or paving operations, the potential for dermal and/or respiratory exposure to asphalt fumes and vapours exists. The frequency and concentration of these potential exposures may be lower for the general population than for workers. However, in the general population, there are individuals who may be more sensitive to exposures and therefore exhibit more symptoms or other effects. The extent to which these symptoms occur in the general population has not been studied. 11.1.4.5 Conclusion Studying the possible health effects attributed to chemical mixtures, including resulting fumes and vapours, is complex. Despite the uncertainties, limita- tions, and mixed study results, what is clear is that asphalt fume condensates produce malignant skin tumours in mice; and that, when exposed to airborne concentrations of asphalt or asphalt fumes and vapours, workers report symptoms of irritation of the eyes, nose, and throat and, in some, lower airway changes and demonstrate metabolism of the chemical constituents of asphalt fumes and vapours. Taken as a whole, these results suggest that effects do occur in mammalian systems and that the limitations or uncertainties should not preclude taking steps to manage human exposures. Under various performance specifications, it is likely that asphalt fumes and paints contain carcinogenic substances. 32 11.2 Evaluation of environmental effects The lack of available information precludes adequate assessment of potential risks to environmental organisms. 12. 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Toraason M, Hayden C, Marlow D, Rinehart R, Mathias P, Werren D, Olsen LD, Neumeister CE, Mathews ES, Cheever KL, Marlow KL, DeBord DG, Reid TM (2002) DNA strand breaks, oxidative damage, and 1 -OH pyrene in roofers with coal - tar pitch dust and/or asphalt fume exposure. International Archives of Occupational and Environmental Health, 75:279. Vineis P, Thomas T, Hayes RB, Blot WJ, Mason TJ, Rickle LW, Correa P, Fontham ETH, Schoenberg J (1988) Proportion of lung cancers in males, due to occupation, in different areas of the USA. International Journal of Cancer, 42:851-856. Vo-Dinh T (1989) Significance of chemical analysis of polycyclic aromatic compounds and related biological systems. In: Vo-Dinh T, ed. Chemical analysis of polycyclic aromatic compounds. A series of monographs on analytical chemistry and its 37 Concise International Chemical Assessment Document 59 applications. Vol. 101. New York, NY, John Wiley & Sons, pp. 1-5. Waage J, Nielson E (1986) En undersmkelse over losemiddeieksponering undere asfaltutleggning. Specialopgave. Hordaland vegkontor. Bergen [cited in Fries & Knudsen, 1990]. Watkins DK, Chiazze L Jr, Fryar CD, Fayerweather W (2002) A case control study of lung cancer and non-malignant respiratory disease among employees in asphalt roofing manufacturing and asphalt production. Journal of Occupational and Environmental Medicine, 44(6):551-558. Wey HE, Breitenstein MJ, Toraason MA (1992) Inhibition of intercellular communication in human keratinocytes by fractionated asphalt fume condensates. Carcinogenesis, 13(6):1047-1050. Wolff MS, Herbert R, Marcus M, Rivera M, Landrigan PJ (1989) Polycyclic aromatic hydrocarbon (PAH) residues on skin in relation to air levels among roofers. Archives of Environmental Health, 44(3):157-163. Zahm SH, Brownson RC, Chang JC, Davis JR (1989) Study of lung cancer histologic types, occupation, and smoking in Missouri. American Journal of Industrial Medicine, 15:565-578. Zeglio P (1950) Changes in the respiratory tract from bitumen vapors. Rassegna di Medicinalndustriale, 19:268-273. 38 APPENDIX 1 - SOURCE DOCUMENT NIOSH (2000) Hazard review: health effects of occupational exposure to asphalt. Cincinnati, OH, US Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health (DHHS (NIOSH) Publication No. 2001-110) The source document may be obtained from: NIOSH Publications Dissemination 4676 Columbia Parkway Cincinnati, OH 45226-1998 USA Telephone: 1-800-35-NIOSH (1-800-356-4674) Fax: 513-533-8573 E-mail: pubstaft@cdc.gov The document is also available online at http://www.cdc.goviniosh/pdfs/01-110.pdf. All draft publications are first reviewed by NIOSH scientists who have expertise in the area of interest. Comments are incor- porated into the next iteration of the document. Final drafts are reviewed externally by scientists with expertise in the field and representatives of stakeholder industries, labour organizations, government entities, and interested members of the public. Comments and reviews are incorporated into the final text. Subsequent to publication and dissemination, the document is reviewed and approved by the Director of NIOSH. The document on asphalt was reviewed by: Asphalt Institute Asphalt Paving Environmental Council Asphalt Roofing Environmental Council Asphalt Roofing Manufacturers' Association National Asphalt Pavement Association National Roofing Contractors' Association Roof Coating Manufacturers' Association Ernest J. Bastian Jr, Federal Highway, Washington, DC M.J.J. Castegnaro, International Agency for Research on Cancer, Lyon, France Gary Foureman, US Environmental Protection Agency, Research Triangle Park, NC Frank Hanley, International Union of Operating Engineers, Washington, DC Ben A. Hatjian, University of Balamand, Beirut, Lebanon Jill Jarnberg, National Institute for Working Life, Umea, Sweden Asphalt (Bitumen) Bengt Jarvholm, National Institute for Working Life, Umea, Sweden William Kojola, Department of Occupational Safety and Health, American Federation of Labor — Congress of Industrial Organizations, Washington, DC Earl J. Kruse, United Union of Roofers, Waterproofers, and Allied Workers, Washington, DC Jan-Olof Levin, National Institute for Working Life, Umea, Sweden Joellen Lewtas, US Environmental Protection Agency, Seattle, WA David M. Lyall, Eurobitume, Brussels, Belgium James Melius, Laborers' Health and Safety Fund of North America, Washington, DC Timo Partanen, Finnish Institute of Occupational Health, Helsinki, Finland Richard Rinehart, Harvard School of Public Health, Boston, MA Max von Devivere, European Asphalt Association, Breukelen, The Netherlands William Wagner, American Conference of Governmental Industrial Hygienists, Cincinnati, OH Dave Warshawsky, University of Cincinnati, Cincinnati, OH Sheila Zahm, National Cancer Institute, Rockville, MD 39 APPENDIX 2 - CICAD PEER REVIEW The draft CICAD on asphalt (bitumen) was sent for review to IPCS national Contact Points and Participating Institutions, as well as to identified experts. Comments were received from: Asphalt Institute Asphalt Paving Environmental Council Asphalt Roofing Environmental Council European Bitumen Association International Union of Operating Engineers Laborers' Health & Safety Fund of North America R. Benson, Drinking Water Program, US Environmental Protection Agency, Denver, CO, USA B. Boffetta, International Agency for Research on Cancer, Lyons, France R. Chhabra, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA I. Desi, Department of Public Health, University of Szeged, Hungary L. Fishbein, Fairfax, VA, USA H. Gibb, National Center for Environmental Assessment, US Environmental Protection Agency, Washington, DC, USA P. Heikkila, Finnish Institute of Occupational Health, Helsinki, Finland R.F. Hertel, Federal Institute for Risk Assessment, Berlin, Germany J. Hopkins, Toxicology Advice & Consulting Ltd, Sutton, United Kingdom P. Howden, Health and Safety Executive, Bootle, Merseyside, United Kingdom B. Jernstrom, Karolinska Institute, Stockholm, Sweden J. Kielhorn, Fraunhofer Institute, Hanover, Germany J. Ma, National Institute for Occupational Safety and Health, Morgantown, WV, USA P. Siegel, National Institute for Occupational Safety and Health, Morgantown, WV, USA J.L. Stauber, Commonwealth Scientific & Industrial Research Organisation, Bangor, NSW, Australia H.W. Thielmann, Deutsches Krebsforschungszentrum, Heidelberg, Germany D. Willcocks, National Industrial Chemicals Notification and Assessment Scheme, Sydney, Australia K. Ziegler-Skylakakis, Commission of the European Communities, Luxembourg Concise International Chemical Assessment Document 59 APPENDIX 3 — CICAD FINAL REVIEW BOARD Varna, Bulgaria 8-11 September 2003 Members Dr I. Benchev, Sofia, Bulgaria Dr R. Chhabra, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA Dr C. De Rosa, Agency for Toxic Substances and Disease Registry, Centers for Disease Control and Prevention, Atlanta, GA, USA Dr S. Dobson, Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire, United Kingdom Dr G. Dura, National Institute of Environment, J6zsef Fodor Public Health Centre, Budapest, Hungary Dr L. Fishbein, Fairfax, VA, USA Dr H. Gibb, National Center for Environmental Assessment, US Environmental Protection Agency, Washington, DC, USA Dr R.F. Hertel, Federal Institute for Risk Assessment, Berlin, Germany Mr P. Howe, Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire, United Kingdom Dr S. Ishimitsu, Division of Safety Information on Drug, Food and Chemicals, National Institute of Hygienic Sciences, Tokyo, Japan Dr D. Kanungo, Central Insecticides Board, Directorate of Plant Protection, Quarantine & Storage, Ministry of Agriculture, Haryana, India Dr J. Kielhorn, Fraunhofer Institute for Toxicology and Experimental Medicine, Hanover, Germany Ms B. Meek, Environmental Health Directorate, Health Canada, Ottawa, Ontario, Canada Dr T. Morita, Division of Safety Information on Drug, Food and Chemicals, National Institute of Hygienic Sciences, Tokyo, Japan Mr F.K. Muchiri, Directorate of Occupational Health and Safety Services, Nairobi, Kenya Dr L. Olsen, Biological Monitoring & Health Assessment Branch, Division of Applied Research & Technology, National Institute for Occupational Safety and Health, Cincinnati, OH, USA Dr N. Rizov, National Center of Hygiene, Medical Ecology and Nutrition, Sofia, Bulgaria Dr P. Schulte, Education and Information Division, National Institute for Occupational Safety and Health, Cincinnati, OH, USA Dr J. Sekizawa, Faculty of Integrated Arts and Sciences, Tokushima University, Tokushima, Japan 40 Dr F. Petrova Simeonova, Sofia, Bulgaria Dr S. Soliman, Faculty of Agriculture, Alexandria University, El Shatby, Alexandria, Egypt Dr J. Stauber, CSIRO Energy Technology, Centre for Advanced Analytical Chemistry, Bangor, NSW, Australia Mr P. Watts, Toxicology Advice & Consulting Ltd, Surrey, United Kingdom Ms D. Willcocks, National Industrial Chemicals Notification and Assessment Scheme, Sydney, NSW, Australia Dr K. Ziegler-Skylakakis, European Commission, Luxembourg Observers Dr S. Jacobi, Degussa AG, Fine Chemicals, Hanau-Wolfgang, Germany Mr M. Southern, Shell International Petroleum Company Ltd, London, United Kingdom Dr W. ten Berge, DSM, Heerlen, The Netherlands Secretariat Dr A. Aitio, International Programme on Chemical Safety, World Health Organization, Geneva, Switzerland Mr T. Ehara, International Programme on Chemical Safety, World Health Organization, Geneva, Switzerland Asphalt (Bitumen) APPENDIX 4 - ABBREVIATIONS AND ACRONYMS l-OHP AM B(a)P BSP CAS CI CICAD CRM CYP1A1 DMBA DNA EHC EPA FEF25_7s FEV, FID FVC GC GM HPLC IARC ICD ILO IPCS Kow LOD LOQ MS NIOSH NMRD N -PAC NR NS O -PAC OR PAC PAH PBZ PIM PTFE PVC QSAR RR SD SIR SMR 1-hydroxypyrene arithmetic mean benzo[a]pyrene [a] pyre ne benzene -soluble particulates Chemical Abstracts Service confidence interval Concise International Chemical Assessment Document crumb -rubber modified asphalt cytochrome P450, subfamily I (aromatic compound -inducible), polypeptide 1 dimethyl benzanthracene deoxyribonucleic acid Environmental Health Criteria Environmental Protection Agency (USA) forced expiratory fraction forced expiratory volume in 1 s flame ionization detection forced vital capacity gas chromatography geometric mean high-performance liquid chromatography International Agency for Research on Cancer International Classification of Diseases International Labour Organization International Programme on Chemical Safety octanollwater partition coefficient limit of detection limit of quantification mass spectrometry National Institute for Occupational Safety and Health (USA) non-malignant respiratory disease polycyclic aromatic compound in which one or more of the carbon atoms in the PAH ring system have been replaced by a hetero- atom of nitrogen not reported not statistically significant polycyclic aromatic compound in which one or more of the carbon atoms in the PAH ring system have been replaced by a hetero- atom of oxygen odds ratio polycyclic aromatic compound polycyclic aromatic hydrocarbon personal breathing zone Poison Information Monograph polytetrafluoroethylene polyvinyl chloride quantitative structure —activity relationship relative risk standard deviation standardized incidence ratio standardized mortality ratio 41 S -PAC TP TPA TWA UNEP unOR USA US EPA WHO wt% polycyclic aromatic compound in which one or more of the carbon atoms in the PAH ring system have been replaced by a hetero- atom of sulfur total particulates tetradecanoyl phorbol acetate time -weighted average United Nations Environment Programme unadjusted odds ratio United States of America United States Environmental Protection Agency World Health Organization weight per cent ASPHALT 0612 May 2003 CAS No: 8052-42-4 Bitumen RTECS No: Petroleum bitumen UN No: 1999 TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/SYMPTOMS PREVENTION FIRST AID/FIRE FIGHTING FIRE Combustible. Water in large amounts. EXPLOSION EXPOSURE AVOID ALL CONTACT! Inhalation Cough. Shortness of breath. Ventilation. Local exhaust or breathing protection. Fresh air, rest. Skin On contact with heated material serious skin burns. Heat -insulating gloves. Protective clothing. Rinse with plenty of water, do NOT remove clothes. Refer for medical attention. Eyes Redness. Pain. Safety goggles. First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor. Ingestion Do not eat, drink, or smoke during work. Wash hands before eating. SPILLAGE DISPOSAL PACKAGING & LABELLING Let solidify. Sweep spilled substance into containers. UN Hazard Class: 3 UN Pack Group: Ill EMERGENCY RESPONSE STORAGE Transport Emergency Card: TEC (R)-30GF1-III PCSIt// \ y' (rG____ � , �� 'v u y International V i'. - U V L U \ly�go Programme on % --�- V �i1��iL �� Chemical Safety v �- UNEP Prepared in the context of cooperation between the International Programme on Chemical Safety and the European Commission © IPCS 2002 SEE IMPORTANT INFORMATION ON THE BACK. * * t * * k * * ** 0612 ASPHALT IMPORTANT DATA Physical State; Appearance DARK BROWN OR BLACK SOLID. Occupational exposure limits TLV: asphalt (bitumen) fume as benzene -soluble aerosol, 0.5 mg/m3 as TWA; A4; (ACGIH 2003). MAK not established. Routes of exposure The substance can be absorbed into the body by inhalation of its aerosol. Inhalation risk Evaporation at 20°C is negligible; a harmful concentration of airborne particles can, however, be reached quickly when dispersed or when heated. Effects of short-term exposure The substance is irritating to the eyes and the respiratory tract. The substance when heated causes burns on the skin. Effects of long-term or repeated exposure Fumes of this substance are possibly carcinogenic to humans. PHYSICAL PROPERTIES Boiling point: above 300°C Solubility in water: none Melting point: 54-173°C Flash point: above 200°C c.c Relative density (water = 1): 1.0-1.18 Auto -ignition temperature: above 400°C ENVIRONMENTAL DATA NOTES Do NOT take working clothes home. ADDITIONAL INFORMATION LEGAL NOTICE Neither the EC nor the IPCS nor any person acting on behalf of the EC or the IPCS is responsible for the use which might be made of this information ©IPCS 2002 Concise International Chemical Assessment Document 59 RESUME D'ORIENTATION Le present CICAD consacre a l'asphalte (bitume) s'inspire d'une mise au point preparee par le National Institute for Occupational Safety and Health (NIOSH) des Etats-Unis (NIOSH, 2000). Le depouillement de references bibliographiques plus recentes arrete a fevrier 2003 a permis de completer les donnees presentees. Des renseignements sur l'examen par des pairs du document original sont donnes a l'appendice 1. L'appendice 2 fournit des informations sur l'examen de ce CICAD par des pairs. Ce CICAD a ete approuve en tant qu'evalua- tion internationale lors de la reunion du Comite d.'evalu- ation finale qui s'est tenue a Varna (Bulgarie) du 8 au 11 septembre 2003. La liste des participants a cette reunion figure a l'appendice 3. La fiche internationale sur la securite chimique de l'asphalte (ICSC 0162), etablie par le Programme international sur la securite chimique (1PCS, 2002), est egalement reprod.uite dans le present document. L'asphalte (No CAS 8052-42-4), plus commune- ment appele bitume en Europe, se presente sous la forme dun solide, dun semi-solide ou dun liquid.e visqueux de couleur brun fonce a noir, ayant l'apparence du ciment. 11 est obtenu par distillation non d.estructrice d.0 parole brut lors du raffinage. L'asphalte oxyde (No CAS 64742-93-4), egalement denomme asphalte souffle ou raffine est un asphalte (No CAS 8052-42-4) qui a ete traite par soufflage d.'air a temperature elevee dans le but de lui dormer les proprietes physiques necessaires a un usage ind.ustriel. Dans la fabrication de l'asphalte, on ne cherche pas a obtenir un produit de composition chim- ique d.eterminee, mais un prod.uit qui reponde a des specifications qui le qualifient pour certaines utilisations (par ex. asphalte pour revetement des sols ou etanche- ification de toitures). La composition chimique exacte de l'asphalte depend de la complexite chimique du parole brut initial et du procede de fabrication utilise. Le parole brut est principalement constitue de composes aliphat- iques, de cycloalcanes, d.'hydrocarbures aromatiques et de composes aromatiques polycycliques (CAP) et it contient egalement des metaux comme le fer, le nickel ou le vanadium. La proportion de ces differentes substances varie considerablement car le parole brut vane lui meme sensiblement d.'un champ petrolifere a l'autre et meme d'un point a l'autre d.'un meme champ. Le procede de fabrication peut modifier les propnetes physiques de l'asphalte de fawn spectaculaire, mais la nature chimique du produit ne change pas, sauf en cas de craquage thermique. Il n'y a pas deux asphaltes qui soient chimiquement identiques et t'analyse chimique n'est d.'aucune utilite pour definir la structure ou la composition chimiques exacter du produit, mais t'analyse elementaire montre que la plupart des asphaltes contiennent 79 a 88 % en poid.s de carbone, 7 a 13 % en poid.s d.'hydrogene, du souffle dans une proportion allant de traces a 8 % en poid.s et 2 a 8 % en poid.s d.'oxygene avec une teneur en azote allant de traces a 3 % en poid.s. Lorsqu'il est chauffe, l'asphalte emet des vapeurs qui se cond.ensent par refroidissement. Ces vapeurs contiennent evidemment une forte proportion d.es constituants les plus volatils de l'asphalte et on peut s'attendre a ce qu'elles soient chimiquement et toxico- logiquement distinctes du materiau initial. Les fumees d.'asphalte sont constituees de images de petites parti- cules qui se foment par condensation de la phase gazeuse apres volatilisation de l'asphalte. Toutefois, comme les constituants de la vapeur ne se cond.ensent pas tous immediatement, les travailleurs sont exposes non seulement aux fumees mais aussi aux vapeurs. La nature physique de ces fumees et vapeurs nest pas parfaitement determinee. Toutefois, l'analyse chimique de l'asphalte oxyde utilise pour les toitures et celle de l'asphalte non oxyde utilise pour le revetement des sols a permis de mettre en evidence un grand hombre de composes appartenant a la meme classe. Par ailleurs, l'asphalte pour le revetement du sol et l'asphalte pour toitures ne subissent pas les memes manipulations et cela influe sans doute sur la composition des fumees et des vapeurs. Comme la composition de ces fumees et vapeurs depend de la temperature, du procede de fabri- cation, de la presence d.'additifs et d.'agents modifi- cateurs ou encore de la maniere de les travailler, it n'est pas surprenant qu'il soit difficile de produire en labora- toire des fumees d.'asphalte identiques a celles que t'on retrouve Bans l'environnement. Scion les chercheurs, la temperature, la vitesse d 'agitation, et le fait d.'aspirer l'air pour capter les fumees au lieu de le chasser sont autant de facteurs qui influent sur la composition des fumees. On distincue principalement l'asphalte destine au revetement des sols et celui qui est utilisee pour les toitures. On utilise egalement de l'asphalte pour la confection de certaines peintures d.estinees a servir d'enduits protecteurs contre la corrosion des metaux. On l'emploie aussi pour le revetement des canaux, des reser- voirs d'eau, des barrages et des ouvrages maritimes de protection contre la houle, comme adhesif dans les strati- fies pour isolation electrique et comme base dans le gazon artificiel. Aux Etats-Unis, environ 300 000 per- sonnes travaillent dans des ateliers de fabrication a chaud. ou au revetement des sols; on estime que 50 000 couvreurs utilisent de l'asphalte pour des travaux de toiture et qu'environ 1500 a 2000 personnes travail - lent d.ans quelque 100 ateliers de fabrication de couver- tures bituminees. En Europe occidentale, it y a environ 4000 ateliers de production d.'asphalte employant chacun de 5 a 10 personnes et environ 100 000 cantonniers travaillent a 1'asphaltage des chaussees. Pour determiner 1'exposition aux fumees d.'asphalte, on dispose de diverses methodes de prelevement et 44 Asphalt (Bitumen) d.'analyse, mais la plupart d'entre elles manquent de specificite et ne peuvent pas etre utilisees pour caracteriser 1'exposition totale a ces fumees. On a procede a des preleveinents de liquides biologiques ou a I'exploration de fonctions physiologiques facilement accessibles en vue de mettre en evidence des biomar- queurs de 1'exposition aux fumees d'asphalte. En fait, on n'a pas encore trouve de biomarqueurs qui soient specifiques de 1'exposition aux fumees d'asphalte. Les donnees dont on dispose sur la concentration d.'asphalte dans les divers compartiments du milieu restent limitees. La mesure de la concentration d.'asphalte dans des echantillons d'air et de vegetaux preleves a differentes distances dune autoroute donne les valeurs respectives suivantes : < 4 x 10 3 mg/m3 dans Fair et < 4 mg/g par de substance vegetale seche. Selon une etude portant sur l'effet des eaux de ruissellement qui se d.eversent dans les cours d.'eau apres passage sur des revetements d.'asphalte, la concentration en HAP (hydrocarbures aromatiques polycycliques) dans ces eaux et dans celles de tous les cours d'eau est inferieure a la limite de detection qui est de 0,5 hg/litre. Malgre la presence de metaux lourds dans l'eau des cours d.'eau et dans l'eau de ruissellement, les auteurs de cette etude ont conclu que d.ans tous les cours d'eau, la difference de teneur en metaux lourds entre les echantillons d'aval et les echantillons d.'amont n'etait pas significative. On constatait cependant une concentration elevee de metaux lourds dans les echantillons d'eaux de ruissellement par rapport aux valeurs obtenues en amont de ces ruissellements. Ces teneurs elevees en metaux lourds pourraient avoir une autre origine que l'asphalte du revetement routier (par exemple, les echappements de vehicules a moteur, des fuites d'huile de carter, etc.). On n'a pas parfaitement caracterise les concen- trations de fumees d'asphalte qui sont susceptibles d'avoir des effets sur la sante, mais les cantonniers qui procedent au revetement des chaussees en plein air se plaignent d'irritation au niveau des yeux, du nez et de la gorge. Des etudes recentes effectuees en milieu professionnel montrent qu'en general, la concentration moyenne ponderee par rapport au temps (TWA) des particules aeroportees totales et des particules solubles dans le benzene vont la plupart du temps de 0,041 a 4,1 mg/m3 et de 0,05 a 1,26 mg/ m3, respectivement. La d.uree moyenne d'exposition individuelle, exprimee par la TWA sur toute la duree d'un poste, est generalement inferieure a 1,0 mg/m3 dans le cas des particules aeroportees totale et a 0,3 mg/m3 dans le cas des particules solubles dans le benzene. Il peut y avoir absorption de vapeurs et de fumees d.'asphalte apres inhalation ou exposition cutanee. Comme l'asphalte est un melange complexe, son comportement pharmacocinetique vane en fonction des proprietes de chacun de ses constituants. 11 est done tout a fait vain de tenter de tirer des conclusions generales quant au taux d'absorption, a la distribution et au metabolisme de ce produit. Les resultats d.'un certain hombre d.'etudes in vitro montrent que les condensats de fumees d.'asphalte provenant du revetement des sols ne sont pas mutagenes et ne conduisent pas a la formation d 'adduits avec 1'ADN, mais que ces memes condensats se revelent mutagenes et generateurs d'adduits avec I'ADN lorsqu'ils sont produits en laboratoire. Selon une autre etude, en revanche, les fractions particulaires de fumees d.'asphalte recueillies dans la zone de respiration individ.uelle de cantonniers en train de travailler au revetement d.'une chaussee, se sont revelees mutagenes dans le test d.'Ames sur Salmonella. De plus, chez des rats exposes par voie intratracheale a des fumees d.'asphalte prelevees sur le terrain lors du revetement de sols, on a observe une augmentation statistiquement significative du taux et de l'activite de la CYP1A1 (une importante isozyme du cytochrome P450 inductible par les HAP) dans le poumon et un accroissement de la formation de micronoyaux dans les erythrocytes med.ullaires. Seules les fumees d.'asphalte pour toiture prod.uites en laboratoire ont subi des tests de geno- toxicite. Ces fumees se sont revelees mutagenes, elles ont provoque la formation de micronoyaux en quantites accrues et inhibe la communication intercellulaire chez des fibroblastes pulmonaires de hamster chinois (cellules V79) et des keratinocytes epidermiques humains. Les peintures a base d.'asphalte ont donne des resultats ambigus. Selon une etude, aucune des peintures examinees n'a presente d'activite mutagene, tandis que selon une autre, d.'autres peintures de ce type ont provoque la formation d'adduits avec l'ADN dans des echantillons de peau humaine adulte et foetale. Les resultats des etudes de cancerogenicite indiquent que les condensats de fumees d'asphalte pour toiture obtenus en laboratoire entrainent 1'apparition de tumeurs lorsqu'on les applique sur la peau de Souris et que certaines peintures a base d.'asphalte contiennent des substances chimiques capables de declencher la formation de tumeurs chez ces animaux. Aucune etude sur I'animal n'a ete effectuee en vue de determiner le pouvoir cancerogene des condensats de fumees d 'asphalte pour revetements de sols produites sur le terrain ou en laboratoire. Chez les travailleurs des diverses branches de l'industrie de l'asphalte (ateliers de production par malaxage a chaud, terninaux, etancheification des toitures, asphaltage des sols, fabrication de bardeaux d'asphalte etc.) qui sont exposes ace produit, on observe des symptdmes d'irritation des membranes sereuses de la conjonctive (irritation oculaire) et des muqueuses des voies respiratoires superieures (irritation du nez et de la 45 Concise International Chemical Assessment Document 59 gorge) ainsi que de la toux. Les effets sur la sante des travailleurs sont passagers et sans gravite. Des ouvriers employes a des travaux de revetement des sols, a 1'isolation de cables et a la fabrication d.'appareillage electrique comme les tubes fluorescents par exemple ont fait etat d.'autres symptdmes tels qu'une irritation cutanee, un prurit, un erytheme, des nausees, des d.ouleurs gastriques, une perte d.'appetit, des cephalees et de la fatigue. Les resultats d.'etud.es recentes indiquent que certains travailleurs employes a l'asphaltage des sols ont presente des symptomes temoignant d.'effets au niveau des voles respiratoires inferieures (par ex. de la toux, une respiration sifflante et de la d.yspnee) et d.'anomalies de la fonction pulmonaire. Des cas de bronchite ont egalement ete signales. L'exposition la plus faible aux particules totales qui ait cause des problemes respiratoire etait de 0,02 mg/m3. Toutefois, les d.onnees fournies par les etudes existantes sont insuffisantes pour determiner s'il y a une relation entre l'exposition aux fumees d'asphalte et les effets indiques ci-dessus. Des brillures peuvent egalement se produire lors de la manipulation a chaud de l'asphalte. Les territoires cutanes ou se produisent ces brulures se situent generale- ment au niveau du cou et de la tete, des bras, des mains et des, jambes. La plus vaste etude relative aux effets sanitaires de l'exposition professionnelle a l'asphalte a porte sur une cohorte de 29 820 ouvriers appartenant a huit pays qui etaient employes au revetement des chaussees, au malaxage de l'asphalte, a la confection de bardeaux, a des travaux d'etancheification ou a d'autres travaux susceptibles de les exposer a des fumees d'asphalte. La mortalite globale pour l'ensemble de la cohorte (c'est-a- dire les ouvriers exposes et non exposes) s'est revelee inferieure aux previsions avec un taux comparatif de mortalite (SMR) de 0,92. En ce qui concerne les activites professionnelles co3nportant une exposition au bitume ou a l'asphalte, la mortalite globale n'etait pas tres elevee (SMR = 0,96); la mortalite par cancer du poumon etait plus elevee chez les ouvriers utilisant du bitume que chez les travailleurs du BTP (bailments et travaux publics) (SMR de 1,17 avec un intervalle de confiance a 95 % de 1,04-1,30). La mortalite globale imputable a des cancers de la tete et du cou n'etait elevee que chez les ouvriers utilisant du bitume (SMR = 1,27, intervalle de confiance a 95 % = 1,02-1,56). 11 n'y avait pas d'accroissement de la mortalite imputable a d'autres types de cancers. Une analyse plus poussee indique une legere augmentation de la mortalite chez les cantonniers apres correction pour tenir compte de l'exposition au goudron et en prenant un recul 15 ans (SMR= 1,23, IC a 95 %= 1,02-1,48). Les chercheurs (Boffetta et al., 2003b) ont evalue deux manieres differentes de quantifier l'exposition : l'exposition moyenne ou l'exposition cumulee. Dans le cas du cancer du poumon, ils ont observe une association positive avec le niveau moyen d'exposition avec un certain recul, mais aucune association avec le niveau cu rule avec le meme recul. Les indices correspondants d'exposition moyenne et cumulee avec recul ont revele pour 63 d.eces l'existence dune relation dose-reponse avec le risque de cancer du pompon. Le risque relatif (RR) etait de 1,43 (IC a 95 % = 0,87-2,33), de 1,77 (0,99-3,19) et de 3,53 (1,58-7,89) respectivement pour 2,2-4,6, 4,7-9,6 et 9,7+ mg/m3 annees d'exposition cumulee et 2,77 (IC a 95 % = 1,69-4,53), 2,43 (1,38- 4,29) et 3,16 (1,83-5,47) respectivement pour une exposition moyenne de 1,03-1,23, 1,24-1,36 et 1,37+ mg/m3 (valeur de P dans le test de tendance egale a 0,01 pour les deux variables). Les chercheurs ont conclu de leurs analyse exposition-reponse qu'il y avait une association entre la mortalite par cancer du poumon et les indices d'exposition moyenne aux fumees de bitume; toutefois, ils n'excluent pas qu'un facteur de confusion soit pour quelque chose dans l'association constatee. Une meta -analyse de 20 etudes epidemiologiques n'a pas pu mettre en evidence un risque de cancer du poumon chez des cantonniers et des personnels d'entretien de chaussees exposes a de I'asphalte (RR = 0,87; IC a 95 % = 0,76-1,08). Toutefois, l'analyse a montre l'existence d'un exces general statistiquement significatif de cancers du poumon chez des couvreurs utilisant de I'asphalte (RR = 1,78, IC a 95 % = 1,5-2,1). Comme ces couvreurs avaient ete precedemment exposes a du goudron et a de l'amiante, qui sont notoirement cancerogenes pour l'Homme, on ignore dans quelle mesure ces observations relatives au cancer du poumon sont attribuables a l'asphalte. Cette meme meta -analyse a conclu a une augmen- tation du risque de cancer de la vessie (RR = 1,22, IC a 95 % = 0,95-1,53), de cancer de 1'estomac (RR = 1,28, IC 95% = 1,03-1,59) et de leucemie (RR= 1,41, IC a 95 % = 1,05-1,85) chez des ouvriers generalement classes comme travailleurs utilisant de l'asphalte, mais sans etre des couvreurs. L'interpretation des resultats de ces 20 etudes epid.emiologiques est limitee par leur manque de coherence et par le fait que la presence d'autres substances pourrait constituer un facteur de confusion. De plus, nombre de ces resultats proviennent d'etud.es organisees par grandes classes professionnelles, ce qui peut conduire a des erreurs concernant l'exposi- tion a l'asphalte. 11 ne faut pas perdre de vue le caractere extreme- ment limite des d.onnees qui servent a estimer l'expo- sition de la population dans son ensemble lorsqu'on cherche a determiner l'exposition de cette population a l'asphalte, a ses fumees et a ses vapeurs, ainsi qu'aux peintures a base d.'asphalte. La concentration des diffe- rentes fractions de l'asphalte - composes aromatiques 46 Asphalt (Bitumen) polaires (polaires), les derives aromatiques naphteniques (composes aromatiques) et composes satures - mesuree dans les echantillons d'air preleves a 2,0-83,6 m d'une autoroute etait respectivement egale a 0,54-3,96 x 10 3 mg/m3, 1,77- 9,50 x 10 4 mg/m3 et 0,21-1,23 x 10 4 mg/m3. Ces valeurs sont extremement faibles comparativement a celles de l'exposition determinees dans les diverses branches de I'industrie de I'asphalte; l'exposition du personnel aux particules totales et aux particules solubles dans le benzene vont respectivement de 0,041 a 4,1 mg/m3 et de 0,05 a 1,26 mg/m3. Cela etant, la composition chimique des echantillons d.'air preleves le long de l' autoroute ou sur des sites ind.ustriels nest pas forcement id.entique. Outre 1'absorption par la voie respiratoire, l'absorption cutanee peut egalement intervenir de fawn importante dans l'exposition a l'asphalte. Il est possible que l'exposition a l'asphalte soit moms frequente et moms forte pour la population generale que pour les travailleurs. Toutefois, dans cette population, certains individ.us peuvent etre plus sensibles a l'exposition et par consequent, presenter d.avantages de symptdmes et autres effets. On n'a pas etudie quelle est la proportion de ces symptomes dans la population generale. Lorsqu'on evalue les donnees existantes qui permettent d.'etudier la relation entre l'exposition a I'asphalte, ses fumees et ses vapeurs et certains effets sanitaires indesirables, it faut garder a l'esprit leurs limites. Ces incertitudes peuvent decouler de la chimie de base de l'asphalte - qui est un melange -, du hombre peu eleve d.'etudes in vivo, du fait que les couvreurs et les cantonniers ont aussi utilise du goudron au cours des derrieres decennies (et utilisent encore des produits qui en contiennent) et enfin, des resultats mitiges foumis par les etudes sur des sujets humains. Neanmoins, ces limites et ces incertitudes ne devraient pas empecher d.'emettre un jugement au sujet du risque que ce produit represente pour la sante humaine et la salubrite de 1'environnement. Il est vraisemblable que les fumees d.'asphalte et les peintures a base d.'asphalte contiennent des substances cancerogenes scion les diverses specifications d."utilisation. 47 RESUMEN DE ORIENTACION Este CICAD sobre el asfalto (betun) se baso en un examen preparado por el lnstituto Nacional de Salud. y Seguridad en el Trabajo de los Estados Unidos (NIOSH, 2000). Se obtuvieron datos adicionales mediante una busqueda bibliografica actualizada hasta febrero de 2003. La informacion acerca del catheter del examen colegiad.o del documento original figura en el apendice 1. La informacion sobre el examen colegiado de este CICAD aparece en el apendice 2. Este CICAD se aprobo como evaluacion internacional en una reunion de la Junta de Evaluacion Final celebrada en Varna (Bulgaria) del 8 al 11 de septiembre de 2003. La lista de partici- pantes en esta reunion figura en el apendice 3. La Ficha internacional de seguridad quimica sobre el asfalto (ICSC N° 0162), preparada por el Programa Inter- nacional de Seguridad de las Sustancias Quimicas (IPCS, 2002), tambien se reproduce en el presente documento. El asfalto (CAS N° 8052-42-4), normalmente mas conocido en Europa como betun, es un liquido semi- solido, solido o viscoso parecido al cemento de un color entre marron oscuro y negro que se produce por destilacion no destructiva del petroleo bruto durante el proceso de refinado. El asfalto oxidado (CAS N° 64742- 93-4), denominado tambien asfalto soplado o refinado por aire, es asfalto (CAS N° 8052-42-4) que ha sido tratado soplando a traves de el aire a temperatura elevada a fin de conseguir las propiedades fisicas necesarias para el use industrial del producto. La produccion de asfalto viene determinada por las especificaciones de rendimiento (por ejemplo, asfalto para pavimentacion y para techado), no por la compo- sicion quimica. La composicion quimica exacta del asfalto depende de la complejidad quimica del petroleo bruto original y del proceso de fabricacion. El petroleo bruto consiste fundamentalmente en compuestos alifaticos, alcanos ciclicos, hidrocarburos aromaticos, compuestos aromaticos policiclicos y metales (por ejemplo, hierro, niquel y vanadio). La proporcion de estas sustancias quimicas puede variar notablemente debido a diferencias significativas del petroleo bruto de un yacimiento a otro o incluso entre distintos puntos del mismo yacimiento. Si bien el proceso de fabricacion puede modificar sustancialmente las propiedades fisicas del asfalto, sus caracteristicas quimicas no cambian a menos que se produzca desintegracion termica. Aunque no hay dos asfaltos quimicamente identicos y no se puede utilizar el analisis quimico para definir su estructura o composicion quimica exacta, el analisis elemental indica que la mayor parte de los asfaltos contienen entre un 79 y un 88% en peso de carbono, entre un 7 y un 13% en peso de hidrogeno, entre cantidades insignificantes y un 8% en peso de azufre, Concise International Chemical Assessment Document 59 entre un 2 y un 8% en peso de oxigeno y entre canti- dades insignificantes y un 3% en peso de nitrogen. Cuand.o se calienta el asfalto se desprend.en vapores, que al enfriarse se cond.ensan. En estos vapores como tales abundan sobre todo los componentes etas volatiles presentes en el asfalto y cabria esperar que fueran distintos del material original d.esd.e el punto de vista quimico y posiblemente d.esd.e el toxicologico. Los humos de asfalto son la nube de pequei3as particulas formad.as por condensacion a partir del estad.o gaseoso tras la volatilizacion del asfalto. Sin embargo, d.ad.o que no todos los componentes del vapor se cond.ensan al mismo tiempo, los trabajad.ores no solo estan expuestos a los humos de asfalto, sino tambien a los vapores. No se ha determinad.o bien el caracter fisico de los humos y los vapores. No obstante, en un analisis quimico de los humos de asfalto oxidad.o para techado y de asfalto no oxidado para pavimentacion se identificaron numerosas sustancias quimicas del mismo tipo. Ademas, la manera en la cual se utiliza el asfalto durante las operaciones de pavimentacion y de techado probablemente influye en la composicion de los humos y los vapores. Habida cuenta de que la composicion del asfalto y de sus humos y vapores varia en funcion de la temperatura, el proceso de fabricacion, la presencia de aditivos y modificadores y las practicas de trabajo, no resulta sorprendente que en el laboratorio sea dificil generar humos de asfalto seme- jantes a los que se producen en el inedio ambiente. Los investigadores han llegado a la conclusion de que la temperatura, la velocidad. de agitacion y la aspiracion frente a la expulsion del aire que se recoge son factores que influyen en la composicion quimica de los humos. Los principales tipos de productos son el asfalto para pavimentacion y para techado. El asfalto tambien se utiliza en pinturas para revestimientos de proteccion contra la corrosion de los metales; en el recubrimiento de canales de riego, d.epositos de agua, presas y obras de defensa contra el mar; en adhesivos de laminados electricos; y como base para la turba sintetica. En los Estados Unidos hay unos 300 000 trabajadores en instalaciones que utilizan asfalto en mezcla caliente y en operaciones de pavimentacion; se calcula que hay 50 000 trabajadores en actividades de techad.o con asfalto; y son alreded.or de 1500-2000 las personas que trabajan en unas 100 instalaciones de fabricacion de techados. En Europa occidental existen unas 4000 instalaciones de mezcla de asfalto, en cada una de las cuales trabajan entre 5 y 10 personas. Alred.edor de 100 000 miembros de equipos de pavimentacion aplican estas mezclas de asfalto a la superficie de las carreteras en toda Europa occidental. Aunque se dispone de una serie de metodos de recogida y analisis de muestras para la evaluacion de la exposicion a los humos de asfalto, la mayor parte de ellos no son especificos y no se pueden utilizar para 48 caracterizar la exposicion total a este tipo de humo. Tambien se han obtenid.o muestras de fluid.os corporates y/o funciones fisiologicas facilmente accesibles o se han analizado en busca de biomarcadores de la exposicion a los humos de asfalto. No se han encontrado todavia biomarcad.ores especificos de dicha exposicion. Se dispone de d.atos limitad.os sobre la concentra- cion de asfalto en los distintos compartimentos del med.io ambiente. La caracterizacion de la concentracion de fracciones de asfalto en muestras de aire y de plantas recogidas a distintas distancias de una autopista puso de manifiesto que dichas concentraciones eran <4 x 10 3 mg/m3 y <4 mg/g de material vegetal seco, respectiva- mente. En una evaluacion de los efectos de la escorrentia del pavimento de asfalto hacia las corrientes de agua en California (Estados Unidos) se observe' que las concentraciones de todos los analitos de hidrocarburos aromaticos policiclicos en today las muestras de corrientes de agua y escorrentias de carreteras eran inferiores al limite de deteccion de 0,5 ug/l. Aunque habia niveles detectables de metales pesados en el agua de las corrientes y la escorrentia, los autores llegaron a la conclusion de que en ningun caso habia diferencias significativas entre corriente arriba y corriente abajo en cuanto a la concentracion de ningun metal pesado. La concentracion de metales era mas elevada en el agua de escorrentia de la superficie de las carreteras que en las muestras tomadas corriente arriba. Estas concentraciones elevadas se podrian derivar de fuentes distintas del asfalto (por ejemplo, emisiones de los vehiculos, perdidas de lubrificante en el carter, etc.). Aunque no se han caracterizado bien las concen- traciones de humos de asfalto asociadas con efectos en la salud, se han notificado sintomas de irritacion ocular, nasal o de la garganta en asfaltadores que trabajaban al aire libre. Los resultados de estudios recientes realizad.os en el entorno ocupacional indican que, en general, la mayor parte de las concentraciones en el aire como promedio ponderad.o por el tiempo del total de particulas y de particulas solubles en benceno eran de 0,041 a 4,1 mg/m3 y de 0,05 a 1,26 mg/m3, respectivamente. El promedio de la exposicion de las personas, calculado como promedio ponderad.o por el tiempo en turnos completos, fue en general inferior a 1,0 mg/m3 para el total de particulas y de 0,3 mg/m3 para las particulas solubles en benceno. Puede haber absorcion de humos y vapores de asfalto tras la exposicion por inhalacion y cutanea. Debido a que el asfalto es una mezcla compleja, su comportamiento farmacocinetico variara en funcion de las propiedad.es de sus distintos componentes. Por consiguiente, no se pued.en hacer generalizaciones con respecto a su grado de absorcion, distribucion y metaboli smo. Asphalt (Bitumen) Los resultados de varios estudios in vitro indican que, si bien los humos condensados de asfalto para pavimentacion generados sobre el terreno no eran mutagenicos ni inducian la formacion de aductos de ADN, los obtenidos en el laboratorio producian ambos efectos. En cambio, en un estudio se notifico que las fracciones particuladas de los humos de asfalto recog- idos en la zona de respiracion de los trabajadores durante las operaciones de pavimentacion eran mutagenicos en la valoracion de Ames con Salmonella. Ademas, la exposicion intratraqueal de ratas a los humos de la pavimentacion con asfalto generados sobre el terreno provoco un aumento estadisticamente significativo del nivel y la actividad. de la CYP 1 A 1 (isoenzima impor- tante del citocromo P450 inducible por hidrocarburos aromaticos policiclicos) en el pulmon y una mayor formacion de micronficleos en los eritrocitos de la med.ula &sea. Solamente se han realizad.o pruebas de genotoxicid.ad. con humos de asfalto para techado generados en el laboratorio. Se ha d.emostrad.o que estos humos son mutagenicos, determinan una mayor formacion de micronficleos e inhiben la comunicacion intercelular en los fibroblastos del pulmon del hamster chino (celulas V79) y en queratinocitos epid.ermicos humanos. Se han notificad.o resultados contradictorios para las pinturas con base de asfalto. Si bien en un estudio ninguna de las pinturas examinad.as d.emostro una actividad. mutagenica, en otro estudio otras pinturas ind.ujeron la formacion de aductos de ADN en muestras de piel humana de adultos y de efectos. Los resultados de los estudios de carcinogenicidad indicaron que los humos condensados de asfalto para techado generados en el laboratorio provocaban tumores cuando se aplicaban por via cutanea a ratones y que algunas pinturas con base de asfalto contenian sustancias quimicas capaces de inducir tumores en ratones. En ningun estudio con animates se ha examinado el potencial carcinogenico de los humos condensados de asfalto para pavimentacion generados sobre el terreno o en el laboratorio. Los efectos agudos de la exposicion al asfalto de los trabajadores de los distintos sectores de esta industria (instalaciones de mezcla en caliente, terminates, aplicacion del asfalto para techado, pavimentacion, fabricacion de asfalto para techado) incluyen sintomas de irritacion de las membranas serosas de la conjuntiva (irritacion ocular) y de las membranas mucosas de las vias respiratorias superiores (irritacion nasal y de la garganta) y tos. Estos efectos en la salud. parecen ser de caracter leve y transitorio. Otros sintomas son irritacion cutanea, prurito, eritemas, nauseas, dolor de estomago, d.isminucion del apetito, dolor de cabeza y fatiga, segue han informado trabajadores que intervenian en opera- ciones de pavimentacion, aislamiento de cables y fabricacion de aparatos de luz fluorescente. Los resultados de estudios recientes han indicado que algunos trabajadores que intervenian en operaciones de pavimentacion experimentaron sintomas en las vias respiratorias inferiores (por ejemplo tos, sibilancia y disnea) y cambios en la funcion pulmonar; tambien se ha notificado bronquitis. La exposicion mas baja al total de particular que provoco problemas en las vias respira- torias fue de 0,02 mg/m3. Sin embargo, los datos obtenidos de los estudios disponibles no son suficientes para determinar la relacion entre la exposicion a los humos de asfalto y los efectos en la salud. senalados mas arriba. Se pueden producir quemaduras cuando se maneja asfalto caliente. Las zonas afectadas suelen ser la cabeza y el cuello, los brazos, las manos y las piernas. El estudio mas amplio para examinar los efectos en la salud. de la exposicion ocupacional al asfalto se realizo con una cohorte de 29 820 trabajadores proced.entes de ocho paises distintos que participaban en la pavimenta- cion de carreteras, la mezcla de asfaltos, el techado, la impermeabilizacion u otras tareas especificas en las que era posible la exposicion a los humos de asfalto. La mortalidad global en la cohorte completa (trabajad.ores expuestos y no expuestos) fue inferior a la prevista (razon normalizada de mortalidad. [SMR] = 0,92). En la clasificacion de los trabajos relacionados con la expo- sicion al betun o el asfalto, la mortalidad global no fue elevada (SMR= 0,96); la mortalidad. por cancer de pulmon fue mayor entre los trabajadores del betun que en los de la construccion de superficie y de edificios (SMR = 1,17, intervalo de confianza [IC] del 95% = 1,04-1,30). La mortalidad global por cancer de cabeza y cuello fue elevada solo en los trabajadores del betun (SMR= 1,27, IC del 95% = 1,02-1,56). No se observo aumento de la mortalidad. por otros neoplasmas malig- nos. Analisis ulteriores parecian indicar un ligero aumento de la mortalidad. por cancer de pulmon en los trabajadores de la pavimentacion de carreteras tras el ajuste de la brea de alquitran mineral y dejando trans- currir 15 anos (SMR= 1,23; IC del 95%= 1,02-1,48). Los investigadores (Boffeta et al., 2003b) evaluaron dos sistemas de medicion diferentes para la exposicion: exposicion media y acumulativa. En el caso del cancer de pulmon, se observo una asociacion positiva para un nivel de exposicion media diferida, pero no para una exposicion acumulativa diferida. Los indices correspon- dientes de la exposicion media y acumulativa no diferidas pusieron de manifiesto una relacion dosis- respuesta positiva con riesgo de cancer de pulmon basada en 63 fallecimientos; los riesgos relativos [RR] fueron 1,43 (IC del 95% = 0,87-2,33), 1,77 (0,99-3,19) y 3,53 (1,58-7,89) para 2,2-4,6, 4,7-9,6 y 9,7+ mg/n3 anos de exposicion acumulativa y 2,77 (IC del 95% = 1,69- 4,53), 2,43 (1,38-4,29) y 3,16 (1,83-5,47) para 1,03-1,23, 1,24-1,36 y 1,37+ mg/m3 de exposicion media (valor P 49 Concise International Chemical Assessment Document 59 de la prueba para la tendencia, 0,01 para ambas variables). Los investigad.ores llegaron a la conclusion de que el analisis de la relacion exposicion-respuesta parecia ind.icar una asociacion entre la mortalid.ad. por cancer de pulmon y los indices del nivel medio de exposicion a los humos de betun; sin embargo, no pudieron d.esechar la posibilidad. de que hubiera factores de confusion que desempeuaran alguna funcion en esta asociacion. En un metaanalisis de 20 estudios epidemiologicos no se logro encontrar una prueba global de riesgo de cancer de pulmon en los pavimentadores y trabajadores encargados del mantenimiento de las autopistas expuestos al asfalto (RR = 0,87, IC del 95% = 0,76- 1,08). Sin embargo, el analisis demostro un exceso global estadisticamente significativo de cancer de pulmon en los techadores (RR = 1,78, IC del 95% = 1,5- 2,1). Dado que en el pasado los techadores han estado expuestos al alquitran de hulla y al amianto, que son carcinogenos humans conocidos, es dificil saber en que medida estos resultados pueden ser atribuibles a la exposicion al asfalto. En el mismo metaanalisis se notifico un aumento del riesgo de cancer de vejiga (RR = 1,22, IC del 95% = 0,95-1,53), cancer de estomago (RR= 1,28, IC del 95% = 1,03-1,59) y leucemia (RR = 1,41, IC del 95% = 1,05- 1,85) en trabajadores generalmente clasificados como del asfalto, pero no en los techadores. La interpretacion de los resultados de estos 20 estudios se ve limitada por la falta de coherencia entre los estudios y el potencial de confusion atribuible a otras sustancias. Ademas, muchos de estos resultados proceden de estudios organizados para clasificaciones amplias de trabajo, con posibilidad de errores en la definicion de la exposicion al asfalto. Hay que tener en cuenta el caracter extremadamente limitado de los datos disponibles que sirven de base para la estimacion de la exposicion de la poblacion general a la hora de intentar determinar su exposicion al asfalto, los humos y vapores de asfalto y las pinturas con base de asfalto. La concentracion de las fracciones de asfalto aromaticos polares (polares), aromaticos naftalenicos (aromaticos) y saturados- medidas en muestras de aire recogidas a 2,0-83,6 metros de distancia de la autopista fueron de 0,54-3,96 x 10 3 mg/m3de aire, 1,77-9,50 x 10 4 mg/m3 de aire y 0,21-1,23 x 10 4 mg/m3 de aire, respectivamente. Estos valores son enormemente bajos en comparacion con las exposiciones ocupacionales d.eterminadas en diversos sectores de la ind.ustria del asfalto; la exposicion personal a las particulas totales y las particulas solubles en benceno oscilaban entre 0,041 y 4,1 mg/m3 y entre 0,05 y 1,26 mg/m3, respectivamente. Sin embargo, la composicion quimica de las muestras de aire recogidas junto a la autopista yen los lugares de trabajo puede variar. Tambien se pued.e prod.ucir una absorcion cutanea, ademas de la respiratoria, que 50 desempeue una funcion esencial en la exposicion al asfalto. La frecuencia y la concentracion de la posible exposicion al asfalto tal vez sean mas bajas para la poblacion general que para los trabajadores. Sin embargo, en la poblacion general hay personas que podrian ser mas sensibles a la exposicion y por este motivo presentar mas sintomas u otros efectos. No se ha estudiado en que medida se presentan estos sintomas en la poblacion general. A la hora de ponderar los datos disponibles relativos a la relacion entre la exposicion al asfalto y sus humos y vapores y los efectos adversos en la salud., es importante tenerlos en cuenta en el marco de las limitaciones globales de la informacion. Estas incertid.umbres pued.en deberse a la quimica basica del asfalto, que es una mezcla, el pequeno numero de estudios in vivo, la inclusion de alquitran de hulla en los asfaltos para techado y pavimentacion en decenios pasados (y en algunas formulaciones actuales) y los desiguales resultados de los estudios en personas. Sin embargo, estos limitaciones o incertidumbres no deben impedir un juicio con respecto a la salud. de las personas y el medio ambiente. Es probable que los humos y las pinturas de asfalto de diversas especificaciones de rendimiento contengan sustancias carcinogenicas. THE CONCISE INTERNATIONAL CHEMICAL ASSESSMENT DOCUMENT SERIES Acrolein (No. 43, 2002) Acrylonitrile (No. 39, 2002) Arsine: Human health aspects (No. 47, 2002) Azodicarbonamide (No. 16, 1999) Barium and barium compounds (No. 33, 2001) Benzoic acid and sodium benzoate (No. 26, 2000) Benzyl butyl phthalate (No. 17, 1999) Beryllium and beryllium compounds (No. 32, 2001) Biphenyl (No. 6, 1999) Bromoethane (No. 42, 2002) 1,3 -Butadiene: Human health aspects (No. 30, 2001) 2-Butoxyethanol (No. 10, 1998) Carbon disulfide (No. 46, 2002) Chloral hydrate (No. 25, 2000) Chlorinated naphthalenes (No. 34, 2001) Chlorine dioxide (No. 37, 2001) 4-Chloroaniline (No. 48, 2003) Chloroform (No. 58, 2004) Crystalline silica, Quartz (No. 24, 2000) Cumene (No. 18, 1999) 1,2-Diaminoethane (No. 15, 1999) 3,3'-Dichlorobenzidine (No. 2, 1998) 1,2-Dichloroethane (No. 1, 1998) 1,1-Dichloroethene (Vinylidene chloride) (No. 51, 2003) 2,2-Dichloro-1,1,1-trifluoroethane (HCFC-123) (No. 23, 2000) Diethylene glycol dimethyl ether (No. 41, 2002) Diethyl phthalate (No. 52, 2003) N,N-Dimethylformamide (No. 31, 2001) Diphenylmethane diisocyanate (MDI) (No. 27, 2000) Elemental mercury and inorganic mercury compounds: human health aspects (No. 50, 2003) Ethylenediamine (No. 15, 1999) Ethylene glycol: environmental aspects (No. 22, 2000) Ethylene glycol: human health aspects (No. 45, 2002) Ethylene oxide (No. 54, 2003) Formaldehyde (No. 40, 2002) 2-Furaldehyde (No. 21, 2000) Glyoxal (No. 57, 2004) HCFC-123 (No. 23, 2000) Hydrogen sulfide: human health aspects (No. 53, 2003) Limonene (No. 5, 1998) Manganese andits compounds (No. 12, 1999) Methyl and ethyl cyanoacrylates (No. 36, 2001) Methyl chloride (No. 28, 2000) Methyl methacrylate (No. 4, 1998) N-Methyl-2-pyrrolidone (No. 35, 2001) Mononitrophenols (No. 20, 2000) N-Nitrosodimethylamine (No. 38, 2001) (continued on back cover) THE CONCISE INTERNATIONAL CHEMICAL ASSESSMENT DOCUMENT SERIES (continued) Phenylhydrazine (No. 19, 2000) N-Phenyl-l-naphthylamine (No. 9, 1998) Polychlorinated biphenyls: human health aspects (No. 55, 2003) Silver and silver compounds: environmental aspects (No. 44, 2002) 1,1,2,2-Tetrachloroethane (No. 3, 1998) 1,1,1,2-Tetrafluoroethane (No. 11, 1998) Thiourea (No. 49, 2003) o-Toluidine (No. 7, 1998) Tributyltin oxide (No. 14, 1999) 1,2,3-Trichloropropane (No. 56, 2003) Triglycidyl isocyanurate (No. 8, 1998) Triphenyltin compounds (No. 13, 1999) Vanadium pentoxide and other inorganic vanadium compounds (No. 29, 2001) To order further copies of monographs in this series, please contact Marketing and Dissemination, World Health Organization, 1211 Geneva 27, Switzerland (Fax No.: 41-22-7914857; E-mail: bookorders@who.int). The C1CAD documents are also available on the web at http://www.who.intipcsira_siteicicads.htm. BENZENE -SOLUBLE FRACTION AND TOTAL PARTICULATE (ASPHALT FUME) MW: variable CAS: 8052-42-4 asphalt; none, asphalt fume 5042 RTECS: C1990000, asphalt; none, asphalt fume METHOD: 5042, Issue 1 EVALUATION: PARTIAL Issue 1: 15 January 1998 OSHA: No PEL NIOSH: C 5 mg/m3 (15 -min) as total particulates ACGIH: 5 mg/m3 PROPERTIES: not defined SYNONYMS: bitumen fumes SAMPLING MEASUREMENT SAMPLER: FLOW RATE: VOL-MIN: -MAX: SHIPMENT: SAMPLE STABILITY: BLANKS: FILTER (tared 37 -mm, 2-µm, PTFE filter) 1 to 4 L/min 28 L @ 5 mg/m3 400 L @ 5 mg/m3 routine not determined 5 field blanks per day ACCURACY RANGE STUDIED: not determined BIAS: not determined OVERALL PRECISION (SrT): not determined ACCURACY: not determined TECHNIQUE: ANALYTE: EXTRACTION: BALANCE: CALIBRATION: RANGE: ESTIMATED LOD: PRECISION (S,): GRAVIMETRIC Airborne total particulate (TP) material and the benzene -soluble fraction (BSF) 3 mL benzene; ultrasonic bath, 20 minutes 0.001 mg sensitivity; use same balance, if practical, before and after sample collection Check and maintain calibration of balance according to manufacturer's recommendations TP: 0.13 to 2 mg per sample BSF: 0.14 to 2 mg per sample TP: 0.04 mg per sample BSF: 0.04 mg per sample TP: 0.048 at 0.10 mg per sample BSF: 0.061 at 0.21 mg per sample APPLICABILITY: The working range is 0.14 to 2 mg/m3 for a 1000-L sample. The method is applicable to 15 -minute samples. The method was evaluated for asphalt fume; however, it is nonspecific and determines the concentrations of total particulate and the soluble fraction of the total particulate to which a worker is exposed. Therefore, for each sample matrix collected other than asphalt fume, a surrogate standard must be selected and spiked onto sampling media. These spiked samples will be used to determine recoveries, precision, and accuracy, also LOD and LOQ if necessary; moreover, other solvents besides benzene can be evaluated. The particle size of the particulate should be less than 40 µm, and preferably less than 30 µm. If particle sizes are larger than this, another sampler should be used. INTERFERENCES: Changes in temperature or humidity during pre- and post -collection weighing may affect accuracy. A controlled laboratory environment is needed to exclude positive interferences due to dust contamination. Losses may occur from air stripping or volatilization of a collected sample during sampling, shipping, or analysis. OTHER METHODS: The total particulate portion of this method is based on NMAM 0500 [1]. Other methods applicable to asphalt fume are NMAM 5800, Polycyclic Aromatic Compounds [2], and NMAM 2550, Benzothiazole in Asphalt Fume [3]. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME): METHOD 5042, Issue 1, dated 15 January 1998 - Page 2 of 7 NIOSH Manual of Analytical Methods (NMAM), Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME): METHOD 5042, Issue 1, dated 15 January 1998 - Page 3 of 7 REAGENTS: EQUIPMENT: 1. Benzene,* ≤ 5 ppm evaporation residue, e.g., 1. Sampler: 37 -mm, 2-µm pore size, PTFE Aldrich Chemical Co. Cat. No. 27,070-9 or membrane filter laminated to PTFE (Zefluor, equivalent. Pall Gelman Sciences, Cat. No. P5PJ037; 2. Acetone,* HPLC grade. Supelco, Cat. No. 2-0043; SKC Cat. No. 225- 3. Hexane,* HPLC grade. 17-07; or equivalent hydrophobic filter), with 4. Nitrogen,* purified and filtered. cellulose support pad in a 37 -mm cassette filter holder. 2. Personal sampling pump, 1 to 4 L/min, with flexible connecting tubing. 3. Balance, readable to 0.001 mg. 4. Static neutralizer, 210Po; replace according to manufacturer's recommendations. * See SPECIAL PRECAUTIONS. 5. Environmental chamber or room for balance (e.g., 20 ± 1 `C, constant ± 5% relative humidity, and dust -free). 6. Weighing cups,* PTFE, 2-mL (Fisher Cat. No. 2006529, or equivalent), in a carrying rack. 7. Vacuum oven, equipped with in -line filter on vacuum release valve to remove dust. NOTE: Keep the interior of the vacuum oven dust -free for maximum sensitivity, reproducibility, and accuracy. 8. Forceps. 9. Test tubes,** glass, 13 -mm x 100 mm, with PTFE-lined screw caps. 10. Pipet,** glass, volumetric, 3-mL, with bulb. 11. Pipet,** glass, Mohr, 2-mL, with bulb. 12. Clarification units, 6-mL PTFE-treated reservoir with 1-µm PTFE frit (Daigger and Company, Inc., Lincolnshire, IL, Cat. No. LID-2102-10US, or equivalent). 13. Pressureregulator, valve, tubing, in -line filter to remove dust and organics, with adapter for applying nitrogen pressure to the clarification unit. 14. Ultrasonic bath. * Rinse the weighing cups as follows. a. Wash with acetone until all visible residue is removed. b. Rinse with hexane for several seconds. c. Air dry. d. Discard any weighing cups that are not visibly clean. Rinse all glassware with acetone then hexane; air dry. ** SPECIAL PRECAUTIONS: Benzene is a suspect carcinogen [4]. Asphalt fumes are considered a potential occupational carcinogen [4]. Benzene, hexane, and acetone are highly flammable. Prepare samples and standards in a well -ventilated hood and avoid skin contact. Use care when working with compressed gases. PREPARATION OF FILTERS BEFORE SAMPLING: NIOSH Manual of Analytical Methods (NMAM), Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME): METHOD 5042, Issue 1, dated 15 January 1998 - Page 4 of 7 1. Numberthe backup pads with a ballpoint pen and place them, numbered side down, in the filter cassette bottom sections. 2. Preweigh the filters by the weighing procedure given in step 3. Record the mean tare weight of sample filters, W1 and field blanks, B, (pg). 3. Weighing procedure: a. Equilibrate the filtersor weighing cups in an environmentally controlled weighing area or chamber for at least two hours. b. Zero the balance before each weighing. c. Using forceps, pass each filter or weighing cup over a static neutralizer. Repeat this step if the filter or weighing cup does not release easily from the forceps or attracts the balance pan. Static electricity can cause erroneous weight readings. d. Weigh each filter or weighing cup until a constant weight is obtained (two successive weighings within 10 pg). Record the mean of the last two weighings to the nearest microgram. 4. Assemble the filter in the filter cassette and close firmly to prevent leakage. Place a plug in each opening of the filter cassette. Place a cellulose shrink band around the filter cassette, allow to dry and mark with the same number as the backup pad. SAMPLING: 5. Calibrate each personal sampling pump with a representative sampler in line. 6. Sample at an accurately known flow rate between 1 to 4 Llmin for a total sample volume of 28 L to 400 L. Do not exceed a total filter loading of approximately 2 mg total particulate. 7. Collect five field blanks for each day of samplinjor determining the limit of detection (LOD) and the limit of quantitation (LOQ). 8. Replace plugs in cassettes and pack securely for shipment to the laboratory. Recommend samples be refrigerated upon receipt at the laboratory. CALIBRATION AND QUALITY CONTROL: 9. Use the same balance, if practical, for weighing filters and weighing cups before and after sample collection or benzene evaporation. Check and maintain calibration of balance according to manufacturer's recommendations. Zero the balance before each weighing. 10. Process three tared media blanks through the measurement procedures for total particulate and benzene -soluble fraction. TOTAL PARTICULATE MEASUREMENT: 11. After sampling: a. Allow refrigerated sample cassettes to come to room temperature before proceeding. b. Wipe dust from the external surface of the filter cassette with a moist paper towel to minimize contamination. Discard the paper towel. c. Remove the top and bottom plugs from the filter cassette. Equilibrate sampler for at least two hours in the balance room or environmental chamber. d. Remove the shrink band, pry open the cassette, and gently remove the filter to avoid loss of sample. e. Reweigh (step 3) each filter, including field blanks. Record the mean post -sampling weight, yNr BZ (µg). Also, record anything remarkable about a filter (e.g., overload, leakage, wet, torn, etc.) f. After weighing, transfer the filter carefully with forceps to a clean test tube and cap the tube. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME): METHOD 5042, Issue 1, dated 15 January 1998 - Page 5 of 7 CALCULATIONS FOR TOTAL PARTICULATE: 12. Calculate the concentration of total particulate, c (mg/nn3), in the air volume sampled, V (L). C (W2- W1 ) - (B2- B1) mg/m3 TP V where: W1 = mean tare weight of filter before sampling (µg) WZ = mean post -sampling weight of sample -containing filter (µg) B1 = mean tare weight of field blank filters (µg) BZ = mean post -sampling weight of field blank filters (µg) BENZENE -SOLUBLE FRACTION MEASUREMENT: 13. Condition clarification unit by rinsing the reservoir with 1.5 mL of benzene. Use nitrogen pressure to force the benzene through the frit. Appropriately dispose of the benzene rinse. 14. Extract benzene -soluble fraction. a. Add 3.0 mL benzene via a 3-mL volumetric pipet to the filter -containing test tube (step 11.e.) Recap the test tube. b. Place the test tube upright in beaker containing water to the same level as the liquid in the test tube. Place the beaker and test tube in ultrasonic bath and agitate for 20 minutes. c. Transfer benzene extract to conditioned clarification unit and force the extract through into a clean test tube, using nitrogen pressure as in step 13. Discard sampling filter and clarification unit. NOTE: Be sure the end of the clarification unit is well below the opening of the test tube to prevent sample loss by spattering. 15. Preweigh clean weighing cups by the weighing procedure in step 3. Record the mean tare weight,3W or B3 (µg). NOTE: The weighing cup should already be prerinsed and dried as described in the Equipment section. a. Identify each tared weighing cup by labeling its place in the carrying rack. b. Transfer a 1.5-mL aliquot of the benzene extract via a 2-mL Mohr pipet to the tared weighing cup. NOTE: An aliquot may be taken from the remaining extract at this step if other analyses (e.g., polycyclic aromatic compounds) are to be performed on the sample. Apply the appropriate aliquot factor in calculations. 16. Place the weighing cup rack in a vacuum oven preheated to 40C. Apply vacuum until pressure in the oven is 7 to 27 kPa (50 to 200 mm Hg). Allow solvent to evaporate (about two hours). Release the vacuum by slowly opening a release valve that has an in -line filter to remove room dust. 17. Reweighthe weighing cup by the weighing procedure in step 3. Record the mean post -sampling weight, W4 or B4 (µg). Also, record anything remarkable about the sample (e.g., overload, leakage, wet, spattering, etc.). 18. After weighing, clean the weighing cup as described in the Equipment section. CALCULATIONS FOR BENZENE -SOLUBLE FRACTION: 19. Calculate the concentration of benzene -soluble fraction, csF (mg/mil, in the volume of air sampled, V (L): E( W4 - W3 ) ( B4 B3 )] - 2 mg/m 3 CBSF V where: W3 = mean tare weight of sample weighing cup (µg) W4 = mean post -sampling weight of sample weighing cup (µg) B3 = mean tare weight of field blank weighing cups (µg) B4 = mean post -sampling weight of field blank weighing cups (µg) NIOSH Manual of Analytical Methods (NMAM), Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME): METHOD 5042, Issue 1, dated 15 January 1998 - Page 6 of 7 2 = aliquot factor EVALUATION OF METHOD: Asphaltfume collected during a previous NIOSH investigation [5] was spiked on tared PTFE filters, allowed to dry at least overnight, and extracted using benzene. The results are summarized in the table below. Spiking level (mg)* Total Particulates Benzene -Soluble Fraction Recovery (%) Sr Recovery (%) Sr 1.85 102 5.97 97.9 0.738 1.17 103 3.98 98.8 2.02 0.62 94.0 5.85 94.8 1.85 0.23 91.6 3.50 96.9 6.10 0.12 82.1 3.91 80.9 9.54 0.058 110 16.4 92.1 13.5 0.025 105 11.4 73.1 17.4 *Six replicates per level The pooled relative standard deviation $r) for the total particulates was 4.8% at loadings greater than or equal to 0.10 mg per sample. For the benzene -soluble fraction, the pooled relative standard deviation was 6.1% at loadings greater than or equal to 0.21 mg per sample. The accuracy criterion is based on determining the range of analyte loadings and the analyte loading on the sample media that will give at least 95% confidence of obtaining a measurement of the analyte that is within 25% of the true value 95% of the time. Since no independent method for determining the total particulate concentration is available, no estimate of the bias for the total particulate data was made; therefore, the maximum allowable bias was calculated at which the accuracy criterion could still be met. Based on the spiking data, if the total particulate loading was greater than or equal to 0.10 mg per filter, the measurement determination will be within 25% of the true valuE95% of the time if the true bias is less than 10.0%. The bias for the benzene -soluble fraction was negative (see the data above), and since the bias for the benzene - soluble fraction varied little, the bias was pooled over the spiking range of 1.85 to 0.20 mg per filter. It was determinedthatthe 25% accuracy criterion was met if the benzene -soluble fraction was greater than or equal to 0.20 mg per filter. The limit of detection (LOD) and the limit of quantitation (LOQ) were determined using field blanks [6]. The LOD is equal to three times the standard deviation of the field blank weight differences (post -sampling weight - tare weight), and the LOQ is equal to ten times the standard deviation of the field blank weight differences. Field sample values should be compared to the LOD and LOQ values only after the field samples have been blank corrected. The standard deviations of the field blank weights were 0.013 mg per sample for total particulates and 0.014 mg per sample for the benzene -soluble fraction. Therefore, the LOD and LOQ for total particulates were 0.04 and 0.13 mg per sample, respectively. The LOD and LOQ for the benzene -soluble fraction were 0.04 and 0.14 mg per sample, respectively. These LOD and LOQ values should only be compared to blank corrected field sample data. A user check of the method was performed in which tared PTFE filters were spiked with 1.08, 0.392, or 0.216 mg of pyrene per filter and then analyzed by an independent chemist [6]. A mean total particulate recovery of 103% (Sr = 5.85%) was obtained, and the mean benzene -soluble fraction recovery was 109% ,(S 9.91 %). Correlation of benzene -soluble mass with total particulate was linear, with2R 0.994, and the mean NIOSH Manual of Analytical Methods (NMAM), Fourth Edition BENZENE -SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME): METHOD 5042, Issue 1, dated 15 January 1998 - Page 7 of 7 ratio of benzene -soluble mass to total particulate was 106% (S= 7.80%). In other experiments, three of 60 field blanks (three sets of 20 field blanks each) had a significantly higher than expected benzene -soluble fraction when compared with the other field blanks [6]. This event had two undesirable consequences: (1) Because the average weight of the field blanks was increased, the field samples were over corrected, and (2) the standard deviation of the field blank weights was increased resulting in higher LOD and LOQ values. For example, if the set of twenty field blanks with one high result is randomly assigned to groups of three (repeatedly), the standard deviation of the groups with the high result could exceed the standard deviation of the other groups by more than 1.6 times. Since this event also may occurwith field samples, these elevated results were not excluded when the data were evaluated. Although these events were observed with a syringe type clarification unit and not the recommended clarification unit, the cause of this event was not determined. Thereforeil is important to collect as many field blanks as is reasonable (five blanks per day); also, it may be advisable to establish a monitoring program to track the occurrence of elevated field blanks and, if possible, to identify and eliminate the cause(s). In another experiment, the recommended clarification unit (PTFE-treated reservoir and a PTFE filter) was evaluated along with three syringe type clarification units [6]. The recommended clarification unit gave lower average extractable material than the syring4ype clarification units; also, the recommended clarification unit did not release increasing amounts of extractable material upon prolonged contract with solvent. Prerinsingthe recommended clarification unit appeared to lowerthe average amount of extractable material. Additionally,the recommended clarification unit eliminated the need for using a glass syringe and was more convenient to use than the syringe type clarification units. In a preliminary asphalt fume spiking experiment, benzene and methylene chloride were evaluated as extraction solvents [6]. Asphalt fume [5] was spiked on tared PTFE filter media at the following concentrations: 3.38, 0.68, 0.14, and 0.034ng per filter. Benzene gave recoveries greater than 100% for all concentrations of asphalt fume spiked on PTFE filters. While methylene chloride gave recoveries greater than 96% for the two highest levels spiked, at the two lower levels the recoveries were less than 67%. REFERENCES: [1] NIOSH [1994]. Particulate not otherwise regulated, total: Method 0500. In: Eller PM, Cassinelli ME, eds. NIOSH Manual of Analytical Methods (NMAI , 4' ed. Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113. [2] NIOSH [1998]. Polycyclic aromatic compounds: Method 5800. In: Eller PM, Cassinelli ME, eds. NIOSH Manual of Analytical Methods (NMAPR), 4' ed., 2" Supplement. Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 98-119. [3] NIOSH [1998]. Benzothiazole in asphalt fume: Method 2550. In: Eller PM, Cassinelli ME, eds. NIOSH Manual of Analytical Methods (NMAIIR), 4th ed., 2rid Supplement Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No.98-119. [4] NIOSH [1992]. NIOSH recommendations for occupational safety and health, compendium of policy documents and statements. Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 92-100. [5] SivakA, Niemeier R, Lynch D, Beltis K, Simon 5, Salomon R, Latta R, Belinky B, Menzies K, Lunsford A, Cooper C, Ross A, Bruner R [1997]. Skin carcinogenicity of condensed asphalt roofing fumes and their fractions following dermal application to mice. Cancer Letters 117:113-123. [6] NIOSH [1998]. NIOSH backup data report for total particulate and benzene -soluble fraction (asphalt fume), NIOSH Method 5042 (unpublished). METHOD WRITTEN BY: Larry D. Olsen (Team Leader), Barry Belinky, Peter Eller, Robert Glaser, R. Alan Lunsford, Charles Neumeister, Stanley Shulman, NIOSH/DPSE. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition AIHA Journal 63:628-635 (2002) Ms. #194 AUTHORS Anthony J. Kriech' Joseph T. Kurek' Herbert L. Wissela Linda V. Osborn' Gary R Blackburn6 'Heritage Research Group, 7901 West Morris Street, Indianapolis, IN 46231; bPetrolabs Inc., 133 Industrial Drive, Ivyland, PA 18974 Evaluation of Worker Exposure to Asphalt Paving Fumes Using Traditional and Nontraditional Techniques Forty-five workers at 11 paving sites across the United States were evaluated for exposure to paving asphalt (bitumen) fumes. Traditional measures of exposure such as total particulate matter (TPM) and benzene soluble matter (BSM) were monitored. In addition, total organic matter (TOM), which includes both the BSM residue and the more volatile components that pass through the filter and are collected on sorption material, was quantified and further characterized using a gas chromatography technique and a recently developed fluorescence test. The latter method, which indirectly estimates the content of four- to six -ring polycyclic aromatic compounds, is used as a predictor of carcinogenicity. The correlation between fluorescence emission intensity and carcinogenicity for 36 laboratory generated fume fractions, as measured in a mouse skin -painting bioassay, was then used to estimate the carcinogenic potential of worker monitoring samples. Emission levels, and therefore predicted carcinogenicity, for these samples were at least 17 -fold below the value corresponding to a minimal carcinogenic effect. This result was consistent with more extensive chemical analysis (using gas chromatography/mass spectrometry) of two of the samples, which showed the predominant constituents to be alkanes, monocycloparaffins, alkyl -benzenes, alkyl -naphthalenes, and alkyl- benzothiophenes. The geometric mean exposures for all worker studies were 0.21 mg/m3 (TPM), 0.06 mg/m3 (BSM), and 1.23 mg/m3 (TOM). Keywords: asphalt (bitumen), carcinogenicity, fluorescence, fumes, paving, polycyclic aromatic compounds Considerable research has been directed in recent years toward the question of whether exposure to asphalt fumes leads to adverse health consequences. In the majority of these studies two endpoints have re- ceived the most attention: respiratory irritation(' and carcinogenicity.(1,2) Comprehensive review of the available data(') has, by and large, concluded that asphalt fumes can be respiratory irritants. For this reason, a rec- ommended exposure limit (REL) of 5 mg/m3 total particulate was promulgated by the Nation- al Institute for Occupational Safety and Health (NIOSH) based on prevention of respiratory ir- ritation as a 15 -min ceiling. However, when it comes to carcinogenicity, there has been no such consensus �7 This is largely the consequence of fundamental difficulties asso- dated with any carcinogenicity evaluation of as- phalt fumes. In field operations the quantity of fumes typically collected is too small (particularly in road paving, the principal use of asphalt in the United States) to permit the kind of detailed an- alytical or biological assessments required for con- clusive results. Most studies have therefore em- phasized measurement of endpoints such as total particulate matter (TPM) or benzene soluble mat- ter (BSM), which are available in sufficient quan- tities for reliable determinations. Although these endpoints are useful measures of total exposure, they reveal little or nothing about the central question of carcinogenic potential of the fume. 628 Al HA Journal (63) September/October 2002 Copyright 2002, American Industrial Hygiene Association TABLE I. Asphalt Type and Job Site Information Site State Asphalt GradeA Engineering Controls Mixture Temperature °Cg Tank Temperature °C A B C D E F G H J K Average (DC) Minnesota Minnesota New York Indiana Indiana Indiana Arizona Oregon Kansas Florida Mississippi PG 58-28 PG 58-28 PG 64-22 PG 64-22 PG 64-22 PG 64-22 PG 64-28 Neat AC -20 (AR -4000) AC -20 (AR -4000) AC-20/AC-30 Blend AC -30 yes no no yes yes no no no no yes yes 121-143 121-134 137-152 116-132 127-141 127-140 127-146 138-149 138 143-152 141-165 149 149 149 146 146 141 171 160 138 148 149 131-145 150 APG = performance grade; AC = asphalt cement; AR = asphalt residue. BTemperature taken during the paving application process. Likewise, a controlled laboratory study (e.g., Sivak et al.(2)) has been hampered by an inability to produce fumes similar (or pref- erably, identical) to those encountered by the worker in the field. Although this study produced condusive results within the con- text of the experiment, the significant compositional differences between the surrogate fume and the "real world" fume have pre- cluded their application to any worker safety evaluation. Retrospective epidemiology studies also have failed to create consensus on the question of carcinogenicity(1) Here the primary problem is confounders, principal among them coal tar, diesel ex- haust, and cigarette smoke. In addition, major work practice dif- ferences within the industry make generalization of findings dif- ficult, if not impossible. Recognition of these difficulties has led to various refinements in exposure monitoring techniques,(3) the development of more representative laboratory fume generators,(¢) and the targeting of analytical techniques to the cohort of compounds (four- to six - ring polycyclic aromatic compounds, PACs) known to mediate the carcinogenicity of petroleum -derived materials such as asphalt. In this publication the authors report results from one such analytical technique,(5) a fluorescence assay with the sensitivity nec- essary for workplace studies and the selectivity required to estimate relative levels of four- to six -ring PACs in the presence of an enor- mously complex and much larger background of aliphatic and ar- omatic compounds. As with another method widely used for car- cinogenicity evaluations of petroleum materials,(6) the method relies on correlation between the endpoint measured and accepted indices of carcinogenic potency for a series of petroleum -derived materials (including a series of laboratory -generated asphalt fume fractions) already tested in the mouse skin -painting bioassay. Once the method was shown to be useful for predicting the carcinogenic potential,(5) it was used, together with the standard industrial hygiene methods previously mentioned (TPM and BSM), simulated distillation and, in two cases, more detailed using gas chromatography/mass spectrometry (GC/MS) analysis, in monitoring 11 paving work sites across the United States. Sites were selected to get a cross section of worker exposure in various climatic regions, using different work practices and sources of as- phalt cements. The sites were located in the following states: Min- nesota, New York, Indiana, Arizona, Oregon, Kansas, Florida, and Mississippi. MATERIALS AND METHODS Materials Specific information regarding the asphalt type and conditions of use is listed in Table I for these 11 job sites. Personal Air Sampling Workers were fitted with monitoring devices to allow determina- tion of asphalt fume exposure. Each sample was collected on a preweighed 37 -mm polytetrafluoroethylene membrane filter housed in a closed -face 37 -mm cassette. After the air passed through the filter, it went through a sorption (XAD-2) tube to collect the more volatile components. Previous studies have used charcoal tubes in a similar manner,(' -9) Samples were collected at a nominal flow rate of 1.5 L/min. Covered with aluminum foil to protect them from ultraviolet light, the samples were trans- ported to the laboratory at .4°C and refrigerated until extraction, which was performed within 48 hours of sample receipt. TPM Gravimetric analysis for TPM was conducted according to NIOSH Method 5042(1°) with the filters prerinsed with methylene chloride prior to obtaining preweights. The following supplies were pur- chased from SKC: filters (225-17-07), spacers (225-23), cellulose pads (225-2700), and cassettes (225-2050). BSM After the amount of TPM was determined, each filter was extract- ed with benzene to determine the BSM. This was performed using NIOSH method 5042(10) except for the use of 5 mL (versus 3 mL) of benzene for extraction and the evaporation of all of the solvent instead of using only half of the material. Extraction of Fume from XAD-2 Collection using XAD-2 in series with a filter appears to trap the bulk of the asphalt fume, although some of the more volatile com- ponents may be compromised. Ideally, a system that includes XAD-2 plus charcoal might provide more complete capture, but the differences are minimal and pump concerns prevented that AI HA Journal (63) September/October 2002 629 approach from being pursued. The XAD-2 [SKC Inc., cat no. 226-30-04] tubes were recapped after removal from each worker and transported to the laboratory as specified earlier. After com- plete wetting of the XAD-2 with enough methylene chloride to fill the tube, and soaking for a minimum of 10 min, the asphalt fumes were eluted to a final volume of 10 mL. Each XAD-2 ex- tract was then combined with its partner filter extract after BSM for TOM analysis. The BSM residue was triple rinsed into the corresponding XAD-2 extract and evaporated at room tempera- ture with no turbulence to a final volume of 10.0 mL. Tank Air Sampling To collect tank fumes, an air sample was obtained using a 100g XAD-2 [Supelco, cat. no. 20279] flash chromatography column. Using this assembly, fumes in the headspace of the tank were col- lected via a coil of methylene chloride -rinsed copper tubing using a high flow pump at a flow rate of —12 L/min. The end of the copper tubing was positioned approximately 30 cm below the manway of the tank and at least 1.5 m above the level of the liquid asphalt. The other end was attached via silicone tubing to the base of the XAD-2 flash chromatography column. Soaked in methylene chloride for a period of 30 min, taking care to assure complete wetting of all surfaces of the XAD-2 resin, the asphalt fume was eluted using methylene chloride to a final volume of 1.0 L. Fluo- rescence spectroscopy, Sim-Dis, and GC/MS analyses were per- formed on each of these samples. GC/FID Analysis Extracts from the combined BSM + XAD-2 residues (TOM) were analyzed by GC/flame ionization detector to determine the amount of TOM and the boiling point distribution (Sim-Dis). Determinations were made from the same chromatogram gener- ated by injection of a 2.0 µL aliquot onto a Varian model 3400 gas chromatograph equipped with a 1077 split/splitless injector at 290°C (detector at 330°C) using helium as carrier gas. Sepa- ration was accomplished using a bonded, 5% diphenyl/95% di- methylsiloxane (J&W DB-5) column, 30 m X 0.32 mm ID 0.25- µvm film, temperature programmed from 40°C (3 min) to 305°C at 10°C/min and held for 12 min, with a column flow rate of 2.0 mL/min. TOM was calculated using an external standard method against a kerosene (AccuStandard, Inc. FU -005N or equivalent) calibra- tion curve for the kerosene -ranged fraction (Group 1) and a #2 diesel fuel standard (AccuStandard, Inc. FU -017N or equivalent) for any later eluting components (Group 2) if applicable (SW 846- 8015 Mod.).(11) Groups 1 and 2 concentrations (mg/L) were add- ed; then the units were converted to grams per cubic meter for reporting purposes. The boiling point distributions (Sim-Dis) were obtained fol- lowing ASTM D-288712) protocol. GC/MS Analysis The TOM extracts were also analyzed by GC/MS using a Varian Ion Trap GC/MS. With the trap temperature at 215°C, two mi- croliters were injected into a bonded 5% diphenyl/95% dimethyl- siloxane capillary column (SGE BP5, 25-m X 0.22 -mm ID with a 0.25-µm). With the injector and transfer line temperatures at 280°C, the oven was held at 40°C for 3 min and programmed to rise to 320°C at 10°C/min, and then held for 11.5 min. For two of the samples, evaluation of the major constituents within each major compound class was accomplished from the summation of characteristic mass fragments to determine the concentration of hydrocarbon types. Each mass to charge (m/z) ion extracted chromatogram was integrated and the peak heights summed, with results expressed in mass percentage, similar to ASTM D2425.03) The mass scan range was 49-600 amu and the mass to charge ions monitored are listed in Table II. Asphalt Fume Fluorescence (AFF) Test For this screening test a Perkin Elmer LS50B luminescence spec- trometer was used as described elsewhere.(5) Following a cyano- propyl dean -up, samples were analyzed at an excitation wave- length of 385 nm and an emission wavelength of 415 nm. After accounting for the contribution of two- and three-ring materials, results estimate the presence of materials likely to contain poten- tially cancer -causing four- to six -ring PACs. Results are reported as mg/m3 as DPA (diphenylanthracene), which was purchased from Supelco (Aldrich D20,500-1 97%). RESULTS AND DISCUSSION TPM, BSM, and TOM Data for the 11 Paving Sites Table III summarizes the field data for workers at each site, with the first two columns showing the more conventional measures of exposure, TPM and BSM. The range of individual exposures was 0.03-0.64 mg/m3 of TPM, with an average exposure of 0.25 mg/m3. The range for BSM values was nondetectable to 0.31 mg/m3, with an average of 0.10 mg/m3. These values are con- sistent with other studies of exposure conducted on paving asphalt workers(7-9,14,15) as compared in Table IV. The geometric mean for these task exposures is 0.21 mg/m3 for TPM and 0.060 mg/m3 for BSM. This compares to geometric means of 0.33 mg/m3 and 0.13 mg/m3 previously reported using comparable methodology,(7-9,14,15) as a weighted average of the geometric means of the asphalt paving segment for other large studies, all shown in Table IV. The third column of Table III shows the TOM data, which ranges from 0.15 to 8.32 mg/m3. Comparison of TOM and BSM indicate that the BSM measurement is capturing less than 10% of the total organic exposure. This is not surprising based on simu- lated distillation data (Table III), which shows that virtually all of the TOM exposure is similar in boiling range to a combination of gasoline and kerosene, petroleum fractions comprised largely of highly volatile constituents. Such compounds would not be trapped by filtration unless adsorbed onto partides or present in aerosol droplets. Even so, previous studies(16} of BSM from asphalt fumes have shown that aerosol droplets collected on a filter lose significant mass over time due to air stripping of volatile compo- nents. Additionally, rodent bioassays(2) conducted on asphalt fumes were based on condensed fumes, not the aerosol fraction left on the filter. Collecting the total organic matter allows a more direct comparison of field measurements to this study. Simulated Distillation (Sim-Dis) Data for the 11 Paving Sites The TOM residue provided the necessary material to further char- acterize the nature of the total asphalt fume exposure. The Sim- Dis data in Table III show that the average boiling point ranged from 180-302°C (10-90% mass distilled). By comparison, the boiling point range of gasoline includes anything less than 252°C, and the kerosene range is ---180-300°C, boiling point ranges typ- ical of hydrocarbons with carbon numbers between 10 and 17 and corresponding to aromatic compounds with one to three rings. The average simulated distillation data from this study shows a 630 AI HA Journal (63) September/October 2002 TABLE II. GC/MS Summary of Results for Paving Asphalt Fumes on Worker Samples Non -PACs Worker Worker #64 Site H #87 Site J Average #64 Site H #87 Site J Average Compound Type miz % of Non -PAC Fraction % of Total Alkanes Monocycloparaffins Alkyl -benzenes 71 +85 67 +68+69 81 +82+83 96 +97 subtotal 91 +92 105+106 119+120 133+134 147+148 subtotal 45.8 16.3 14.5 5.3 36.0 0.5 0.7 0.6 10.1 6.3 18.2 Non -PAC total 100.0 Compound Type miz 28.1 20.8 13.0 6.7 40.6 5.2 9.7 7.7 3.4 5.3 31.4 100.0 36.9 18.5 13.7 6.0 38.3 2.8 5.2 4.1 6.8 5.8 24.8 28.6 10.2 9.0 3.3 22.5 0.3 0.5 0.4 6.3 4.0 11.4 100.0 62.5 PACs 22.0 16.3 10.2 5.3 31.7 4.1 7.6 6.0 2.7 4.1 24.5 25.3 13.2 9.6 4.3 27.1 2.2 4.0 3.2 4.5 4.0 17.9 78.3 70.4 Worker Worker #64 Site H #87 Site J Average #64 Site H #87 Site J Average of PAC Fraction % of Total Naphthalene Alkyl -naphthalenes Phenanthrene/Anthracene Alkyl-phenanthrene/anthracene Benzothiophene Alkyl-benzothiophene Dibenzothiophene Alkyl-dibenzothiophene 4 -Ring PACs Alkyl 4 -ring Benzofuran Alkyl-benzofuran Dibenzofuran Alkyl-dibenzofuran PAC total Total of all compounds 128 127+141 155+169 subtotal 178 191 +205 219+233 subtotal 134 147+161 175+189 subtotal 184 197+211 +225 subtotal 202 215+226 118 131+145+159 168 181 +195+209 4.0 43.7 28.7 76.5 0.7 0.7 0.0 1.4 0.2 18.2 2.0 20.4 0.6 1.1 1.7 0.0 0.0 0.0 0.0 0.0 0.0 100.0 2.2 37.6 29.9 69.8 1.5 2.2 0.0 3.7 0.5 19.1 1.2 20.8 1.4 4.3 5.7 0.0 0.0 0.0 0.0 0.0 0.0 3.1 40.7 29.3 73.1 1.1 1.4 0.0 2.5 0.4 18.6 1.6 20.6 1.0 2.7 3.7 0.0 0.0 0.0 0.0 0.0 0.0 100.0 100.0 1.5 16.4 10.8 28.7 0.3 0.3 0.0 0.6 0.1 6.8 0.7 7.6 0.2 0.4 0.6 0.0 0.0 0.0 0.0 0.0 0.0 37.5 0.5 8.1 6.5 15.1 0.3 0.5 0.0 0.8 0.1 4.2 0.3 4.6 0.3 0.9 1.2 0.0 0.0 0.0 0.0 0.0 0.0 1.0 12.2 8.6 21.9 0.3 0.4 0.0 0.7 0.1 5.5 0.5 6.1 0.3 0.7 0.9 0.0 0.0 0.0 0.0 0.0 0.0 21.7 29.6 100.0 100.0 Note: All of the EPA 16 PAHs were investigated. The 228,252,276 & 278 ions were nondetected. volatility range very similar to that of kerosene. In addition to it showing primarily aliphatic hydrocarbons, it shows the absence of high molecular weight components boiling from 300°C and above. Asphalt Fume Fluorescence Assay Data for the 11 Paving Sites Empirically derived from NIOSH retains,t2t the wavelength pair selected for this method shows a direct correlation with animal skin -painting study data. These test materials included five high- performance liquid chromatography subfractions of a Type III roofing asphalt fume generated in the laboratory at 316°C, which were skin -painted individually and in various combinations. Other recent studies(7) used a fluorescence methods") (but at two dif- ferent sets of wavelengths) to estimate two and three-ring PACs and four- and higher -ring PACs in asphalt fume. Although these other wavelengths may provide increased intensity over the wave- length pair chosen here, they do not show the same good corre- lation with asphalt fume cancer data. The fluorescence data for personal samples collected at 11 work sites are shown in Table III. The average value was <0.02 µg/ m3 as DPA. Using a comparable calculation for the NIOSH frac- tions and whole fume, results range from 0.08 (Fraction E, also noncarcinogenic) to 8.69 (Fraction C, highly carcinogenic). A comparison of the fluorescence results for the worker exposure samples and the NIOSH fractions is presented in Figure 1. The strong correlation between fluorescence response and car- cinogenic or mutagenic potency(3,'A) make the new assay a valuable tool for assessing the small quantities of asphalt fume available in AI HA Journal (63) September/October 2002 631 TABLE III. Summary of Field Sampling Results of Paving Workers Worker Description TPM BSM TOM Simulated Distillation Data °C Fluorescence mg/m' mg/m' mg/di' 16% 50% 90% itg/m' as DPA Site A Site B Site C Site D Site E Site F Site G Site H Site I Site J Site K No. of samples No. < LOD (limit of detection) Minimum Maximum Average Std. dev. Geometric mean foreman paver operator dumpman screedman foreman operator dumpman screedman monitor paver operator flagman dumpman screedman, raker paver operator lute/screedman screedman/shovel screedman 0.11 0.04c 0.70 193 238 301 <0.14 0.27 0.05 0.49 188 239 312 <0.17 0.38 0.21 1.71 191 243 324 <0.15 0.24 0.16 0.97 188 235 295 <0.14 0.25 0.04 0.95 179 234 295 <0.13 0.12 0.06 1.56 191 241 300 <0.14 0.46 0.22 1.76 191 242 301 <0.13 0.26 0.15 2.40 196 250 305 <0.14 0.12 0.09 1.39 191 242 300 <0.13 0.25 0.04c 0.95 195 255 321 <0.09 0.05c 0.00 0.15c BC BC BC <0.10 0.12 0.06 1.56 181 238 315 <0.69 0.12 0.09 1.39 166 225 285 <0.43 0.03c 0.00' 0.50 172 233 279 <0.19 0.13 0.02 0.63 172 236 280 <0.24 0.28 0.00' 0.68 165 208 273 <0.22 0.09 0.05' 0.33 165 230 280 <0.15 paver operator 0.11 0.02' 0.34 150 200 230 <0.14 screedman 0.16 0.04 0.70 186 236 286 <0.13 dump person for shuttle 0.15 0.06 0.89 181 241 294 <0.15 shuttle operator 0.17 0.01' 0.48 187 234 277 <0.13 shuttle operator 0.13 0.05' 1.22 206 253 310 <0.10 paver operator 0.15 0.08 0.96 196 248 293 <0.13 screedman 0.22 0.14 1.72 205 254 303 <0.14 dump person for shuttle 0.14 0.05 0.75 185 244 303 <1.12 dumpman yield (ticket) screedman paver operator screedman roller paver operator sampling technician screedman paver operator raker screedman 0.62 0.14 1.82 202 259 450 <0.03 0.38 0.13 3.07 196 257 352 <0.04 0.64 0.30 4.79 208 264 331 <0.03 0.31 0.04 1.33 215 257 300 <0.05 0.42 0.20 8.32 195 247 304 <0.04 0.36 0.07 2.13 196 251 298 <0.05 A A 4.63 192 244 304 <0.04 0.22 0.08 2.53 182 244 306 <0.05 0.19 0.05' 1.03 143 197 303 <0.04 0.17 0.06 1.09 174 232 294 <0.03 0.09 0.03' 1.07 144 181 250 <0.04 0.17 0.01' 0.49 149 198 289 <0.04 dumpman 0.19 0.05c 1.85 166 236 303 <0.04 shovelman/dumpman 0.52 0.31 1.74 179 257 347 <0.03 screedman 0.24 0.23 0.60 148 178 234 <0.03 paver operator 0.25 0.19 1.50 166 253 347 <0.03 screedman paver operator screedman laborer 0.46 0.22 2.42 174 244 308 <0.04 0.46 0.24 3.66 151 217 310 <0.07 0.55 0.30 3.43 164 238 306 <0.04 0.44 0.15 1.89 164 234 303 <0.03 44 44 45 44 44 44 45 2 19 1 1 1 1 45 0.09 0.06 0.33 143 217 230 <0.03 0.64 0.31 8.32 215 244 450 <1.12 0.26 0.16 1.69 180 233 302 <0.02 0.15 0.08 1.47 18 12 33 0.01 0.23 0.06 1.23 163 235 301 <0.04 Note: If < detection limit, then 1/2 the number was used to calculate the statistical data. TPM — total particulate matter; BSM — benzene soluble matter; TOM — total organic matter. AFilter lost, Binsufficient material, 632 AI HA Journal (63) September/October 2002 TABLE IV. Comparison of TPM and BSM Results (mg/m3) With Other Studies Source Year TPM BSM n Hicks'" Gamble'') NIOSH/FHWA-AZj8 NIOSH/FHWA-CA2'°) NIOSH/FHWA-MAI1o, This study' Total no. Average Std. deviation Geometric mean 1995 1997 1996 1996 1997 1998 0.37 0.33 0.20 0.48 0.15 0.21 0.29 0.13 0.27 0.24 0.09 0.11 0.12 0.07 0.06 0.12 0.07 0.10 37 80 14 16 14 44 205 "Task exposures. Other studies were time -weighted averages. worker monitoring studies. Because NIOSH fractions A, D, and E show low but detectable fluorescence values (w (11.36 g/m3 as DPA), but no carcinogenicity, a level of fluorescence below which samples would be predicted to be noncarcinogenic in a standard mouse skin -painting bioassay can be established. The low fluorescence intensity values observed in this study predict that paving asphalt fumes pose low, if any, carcinogenic hazard to workers. This result is thus consistent with the more traditional measures discussed above, and with all the more de- tailed analyses reported here, both chemical and biological. GC/MS Data for Two Paving Sites Total ion chromatograms for the individual workers show typical asphalt fume patternst19t with two examples of worker exposure to the "total" asphalt fume shown in Figure 2. These two samples were selected for more detailed investigation of composition be- cause one (Site H #64) had the highest TOM value, and the other (Site J #87) had the highest fluorescence intensity per gram. On average, 70% of the components were non -PAC hydrocarbons and 30% were PACs. Within the PAC segment, 94.3% were alkylated two- and three-ring PACs: alkylated naphthalenes (70.0 %), alkyl- ated benzothiophenes (20.6%), alkylated dibenzothiophenes (2.7%), and alkylated phenanthrenes (1.4%). The parent com- pounds naphthalene, phenanthrene/anthracene, benzothiophene, and dibenzothiophene account for 5.6% of the PAC fraction, which is 1.6% of the whole fume. All of the traditional Environ- mental Protection Agency 16 polycyclic aromatic hydrocarbons were looked for in these two samples, with no detectable levels of any four -to six -ring PACs. Table II shows the GC/MS summary of results for these two worker samples. Data From Analyses of 11 Storage Tank Samples The samples collected above the level of the liquid asphalt in stor- age tanks (Table V) showed an average boiling point range from 10-90% distilled of 162-285°C (with a low of 149-257°C and a high of 171-334°C), indicating a slightly more volatile fume than that from the worker cassettes (180-302°C). This volatility difference is likely a consequence of the manu- facturing processes used to convert asphalt cement and crushed stone (termed "aggregate") into hot mix asphalt (HMA) used in paving. First, the asphalt cement in the storage tank is mixed and coated as a thin film onto the preheated aggregate. The resulting HMA is then typically stored in a heated silo until it is placed on trucks and taken to the job site. In all these steps there are op- portunities to volatilize the lowest boiling components in the fume. Previous studiest18) have shown tank fumes to exhibit a Sim- Dis from 10-90% in the range of 193 to 263°C, which compares favorably to this study. Micrograms per cubic meter as DPA 9 8 7 6 5 4 3 2 :. 1 ' 0.02 0.25 o z, Worker Exposure 7.12 8.69 • 0.35 t' s� A B C D Light marble = non -carcinogenic Dark marble = carcinogenic 1.27 0.08 t E W FIGURE 1. Fluorescence data comparing worker data to NIOSH Fractions A through E and the whole fume (W). Fractions A, 0, and E were noncarcinogenic. Al HA Journal (63) September/October 2002 633 Chromatogram Plot E:\9685\9°05_915 Date: 19/09/98 11:26:00 Comment: S-11 t164 XAD • FILTER PAVING Scan: 1150 Set: 1 Group: 0 Reteniou: 18.20 RIC: 384106 Masses: 49-Z72 Plotted: 300 to 2080 Range: i to 2337 1881 = 411;258 1002 r - Y I TOf 400 6.33 Chromatogram Plot Comment: It8? Scail : 1158 Plotted: 306 160; N 1 T E N S T Y TOTH SITE H 1280 18.93 25.33 1600 E:\9605\9805093 Date: 11/07/96 14:14:40 Se: 1 Group: 0 Retention: 18.20 1!IC: 42457 Massey: 5E--291 to 2008 Rangy: 1 to 2210 1901 = 326501 SITE J 4BH 5.33 000 12.6E 120fl 19.99 1680 35.33 Top row (scan number) Bottom row (time in minutes) FIGURE 2. GC/MS total ion chromatograms —two worker exposures As reported above for the worker monitoring samples, tank able evidence of the components that caused cancer in the samples also showed no levels of fluorescence above the detection NIOSH rodent studies. Whereas conventional methods (TPM limit, and BSM) were comparable to previous studies, the use of a nonstandard endpoint (TOM) provides a far more accurate rep- resentation of actual asphalt fume exposure with as much as 90% CONCLUSIONS of the fume undetected using TPM or BSM. Compositionally, asphalt fumes are comprised of primarily volatile hydrocarbons including alkanes, monocydoparaffins, alkyl -benzenes, alkyl - The fluorescence test was shown to be an effective screening naphthalenes, and alkyl-benzothiophenes, with a kerosene -like method for worker asphalt fume samples, showing no measur- boiling point range. 634 AI HA Journal (63) September/October 2002 TABLE V. Summary of the Tank Samples Site Amount Collected (grams) Fluorescence (mg/kg as DPA) Simulated Distillation °C 10% 50% 90% A B C D E F G H J K Average 5.5 11.3 10.4 39.7 10.7 7.1 12.9 35.9 9.6 3.7 6.1 <100 <108 <282 <46 <278 <189 <425 <151 <147 <120 <19 171 177 149 184 160 158 164 179 148 143 152 243 237 195 220 209 213 219 216 196 209 209 334 329 257 273 269 270 325 272 257 280 268 13.9 <170 162 215 285 ACKNOWLEDGMENTS he authors wish to thank the Asphalt Pavement Environmental I Council (National Asphalt Pavement Association, Asphalt In- stitute, and State Asphalt Pavement Associations) for their support of the research effort. Special thanks to the 11 companies that graciously agreed to participate in this study, and to NIOSH for the test materials from their animal bioassays and their assistance in the development of the UV/fluorescence method. The authors would also like to acknowledge the support of the local Interna- tional Union of Operating Engineers and Laborers International Union of North America, whose members participated in this study. Finally, Ed Johnson (field sampling) and Caralyn Clark (manuscript) have been invaluable throughout these years of research. REFERENCES 1. National Institute for Occupational Safety and Health (NIOSH): Hazard Review: Health Effects of Occupational Exposure to Asphalt [DHHS/NIOSH pub. no. 2001-110]. Cincinnati, Ohio: NIOSH, 2000. 2. Sivak, A., R. Niemeier, D. Lynch, et al.: Skin carcinogenicity of condensed asphalt roofing fumes and their fractions following dermal application to mice. Cancer Lett. 117:113-123 (1997). 3. Ekstrom, L.G., A.J. Kriech, C. Bowen, S. Johnson, and D. Breu- er: International sampler study for bitumen fumes. J. Environ. Mon- itoring 3(5):439-445 (2001). 4. Kurek, J.T., A.J. Kriech, H.L. Wissel, L.V. Osborn, and G.R. Blackburn: Laboratory generation and evaluation of paving asphalt fumes. Transp. Res. Rec. 1661:35-40 (1999). 5. Osborn, L.V., J.T. Kurek, A.J. Kriech, and F.M. Fehsenfeld: Lu- minescence spectroscopy as a screening tool for the potential carci- nogenicity of asphalt fumes. J. Environ. Monitoring 3(5):185-190 (2001). 6. Blackburn, G.R., T.A. Roy, W.T. Bleicher Jr., M.V. Reddy, and C.R. Mackerer: Comparison of biological and chemical predictors of dermal carcinogenicity of petroleum oils. Poly. Aromatic Comp. 11: 201-210 (1996). 7. Miller, A.K., and G. Burr: Health Hazard Evaluation Report (NIOSH HETA 96-0072-2603). Cincinnati, Ohio: National Insti- tute for Occupational Safety and Health, 1996. 8. Hanley, K.W., and A.K. Miller: Health hazard evaluation report (NIOSH HETA 96-0130-2619). Cincinnati, Ohio: National Insti- tute for Occupational Safety and Health, 1996. 9. Miller, A.K., and G. Burr: Health hazard evaluation report (NIOSH HETA No. 97-0232-2674). 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Hicks, J.B.: Asphalt industry cross-sectional exposure assessment study. Appl. Occup. Environ. HYg. 10:840-848 (1995). 15. Gamble, J.P., M.J. Nicolich, N.J. Barone, and W.J. Vincent: Ex- posure -response of asphalt fumes with changes in pulmonary function and symptoms. Scand J Work Environ Health 25:186-206 (1999). 16. Brandt, H.C.A., P.C. de Groot, M.K.B. Molyneux, and P.E. Tin- dle: Sampling and analysis of bitumen fumes, Ann. Occup. Hyg. 29: 27-80 (1985). 17. National Institute for Occupational Safety and Health (NIOSH): Polycyclic aromatic compounds (Analytical Method 5800). In P.M. Eller editor, NIOSH Manual of Analytical Methods, 4th ed., Cincin- nati, Ohio: NIOSH, 1998. 18. Kriech, A.J., J.T. Kurek, L.V. Osborn, G.R. Blackburn, and P.M. Fehsenfeld: Rio -directed fractionation of laboratory -generated as- phalt fumes; relationship between composition and carcinogenicity. PAC 14-15:189-199 (1999). 19. McCarthy, B.M., G.R. Blackburn, A.J. Kriech, J.T. Kurek, H.L. Wissel, and L.V. Osborn: Comparison of field versus laboratory gen- erated asphalt fumes. Transp. Res. Rec. 1661:54-59 (1999). AI HA Journal (63) September/October 2002 635 FEI Perspectii.,s January 2013 Insights om HEI's research`' Understanding the Health Effects of Ambient Ultrafine Particles HEI Review Panel on Ultrafine Particles HEALTH EFFECTS INSTITUTE Understanding the Health Effects of Ambient Ultrafine Particles HEI Review Panel on Ultrafine Particles HEI Perspectives 3 Health Effects Institute Boston, Massachusetts Trusted Science • CleanerAir • Better Health Publishing history:This document was posted at www.healtheffects.org in January 2013. Citation for document HEI Review Panel on Ultrafine Particles. 2013. Understanding the Health Effects of Ambient Ultrafine Particles. HEI Perspectives 3. Health Effects Institute, Boston, MA. O0 2013 Health Effects Institute, Boston, Mass., U.S.A. Cameographics, Blue Hill, Me., Compositor. Printed by Recycled Paper Printing, Boston, Mass. Library of Congress Catalog Number for the HEI Report Series: WA 754 R432. Cover paper: made with at least 55% recycled content, of which at least 30% is post -consumer waste; free of acid and elemental chlorine. Text paper: made with 100% post -consumer waste recycled content; acid free; no chlorine used in processing. The book is printed with soy -based inks and is of permanent archival quality. CONTENTS About HEI I Contributors Executive Summary vii PROJECT REPORT HE! Review Panel an Ultrafine Particles 7 CHAPTER I. Introduction 7 WhatAre UFPs and Why Is There ConcernAboutThem? 7 Time for a Broad Perspective 8 CHAPTER 2. Ambient UFPs: Sources, Emissions, and Exposures. To What Extent do Motor Vehicles Contribute? 10 HowAre UFPs Measured? 10 Measurement of Ultrafine Particle Mass I I Reconstructed Particle Mass (PMa 1) 11 Time -resolved Measurements of UFP Chemical Composition 13 Surface Area Concentration 13 Number Concentration 13 Summary of UFP Measurements 14 Sources of Ambient UFPs 14 Emissions Inventories 14 Source Apportionment 1.5 Particle Number Counts by Location 16 Summary of Ambient UFP Sources 17 Emissions of UFPs from Motor Vehicles 17 Generation and Characterization of UFPs in Engine Emissions 18 Diesel Engines 18 Spark -Ignition Engines 21 Non -Exhaust Sources 22 Potential Effects of Other New Fuels and Tech nologies 22 Buses Powered by CNG 22 Biodiesel 22 Ethanol 22 Electric Drive Tech nologies 23 Summary of MotorVehicle UFP Emissions 23 Characterizing Human Exposure to Ambient UFPs 23 Factors Affecting Concentrations and Composition of Ambient UFPs 23 Spatial Variation of Ambient UFP Concentrations 25 HEI Perspectives 3 Sidebar 1. Regional Nucleation Events 25 Temporal Variations 27 Copollutant Concentrations 28 Microenvironmental Exposures to UFPs 28 Ambient Contributions to Indoor Concentrations of UFPs 29 In -Vehicle Exposures 29 Implications for Other Countries 30 Modeling UFP Concentrations 30 Summary of Evidence Characterizing Human Exposure to Ambient UFPs 31 CHAPTER 3. Do UFPs Affect Health? What Is the Evidence from Experimental Studies in Animals and Humans? 3 Deposition, Clearance, andTranslocation of UFPs 32 Particle Clearance and Retention in the RespiratoryTract 33 Particle Translocation 33 Laboratory Animal Studies 33 Human Studies 34 Summary of Particle Deposition, Clearance, andTranslocation 35 Experimental Studies of Adverse Effects of Exposure to UFPs in Animals and Humans 35 Laboratory Animal Studies 36 Sidebar 2. Diesel Engine Exhaust — Components and Health Effects in Clinical and Animal Studies 36 Respiratory Responses 37 Allergic Responses 38 Cardiovascular Responses 39 Neurological Responses 41 Summary of Animal Studies 41 Experimental Human Exposures to UFPs 41 Respiratory Responses 42 Cardiovascular Responses 44 Other Responses 47 Summary and Conclusions for Experimental Studies 47 CHAPTER 4. Do UFPs Affect Human Health at Environmental Concentrations? What Is the Evidence from Epidemiologic Studies? Evidence Base Previous Reviews 47 48 48 HEI Perspectives 3 Long -Term Effects Short -Term Effects Mortality 51 Cardiorespiratory Acute Morbidity 52 Respiratory Effects 53 Respiratory Symptoms 53 Pulmonary Function 53 Allergy and Atopy 54 Cardiovascular Effects 54 Heart -Rate Variability 54 Arrhythmia and Related Endpoints 54 Ischemia 55 Vascular Reactivity 55 Blood Pressure 55 Soluble Markers 55 Exposure Assessment Considerations Copollutant Confounding 57 Exposure Measurement Error 57 Population -Based (Time -Series) Studies 57 Panel Studies 57 Addressing Potential Exposure Error 58 Epidemiologic Studies Using Measures of UFP Mass 58 49 49 57 Summary and Conclusions from Epidemiology 63 Inconsistency of Results by Endpoint 63 Exposure Assessment Assessment of the Independence of UFP Effects 63 63 CHAPTER 5. Summary and Conclusions Summary Conclusions Where Do We Go From Here? 66 Experimental Studies 66 Epidemiologic Studies 66 Better Characterization of Ambient UFP Exposures 67 64 64 65 REFERENCES 67 APPENDIX A. Overview of HEI Research Program on UFPs 86 APPENDIX B. Primary Research Articles 92 ABBREVIATIONS AND OTHER TERMS 106 HEI Board, Committees, and Staff 107 ABOUT HEI The Health Effects Institute is a nonprofit corporation chartered in 1980 as an independent research organization to provide high -quality impartial, and relevant science on the effects of air pollution on health.To accomplish its mission, the institute Identifies the highest -priority areas for health effects research; Competitively funds and oversees research projects; Provides intensive independent review of HEI-supported studies and related research; Integrates HEI's research results with those of other institutions into broader evaluations; and Communicates the results of HEI's research and analyses to public and private decision makers. HEI typically receives half of its core funds from the U.S. Environmental Protection Agency and half from the worldwide motor vehicle industry. Frequently, other public and private organizations in the United States and around the world also support major projects or research programs. For this project, the preparation and publication of this document was partially supported by the Federal HighwayAdministration. HEI has funded more than 280 research projects in North America, Europe, Asia, and Latin America, the results of which have informed decisions regarding carbon monoxide, air toxics, nitrogen oxides, diesel exhaust, ozone, particulate matter, and other pollutants. These results have appeared in the peer -reviewed literature and in more than 200 comprehensive reports published by HEI. HEI's independent Board of Directors consists of leaders in science and policy who are committed to fostering the public —private partnership that is central to the organization.The Health Research Committee solicits input from HEI sponsors and other stakeholders and works with scientific staff to develop a Five -Year Strategic Plan, select research projects for funding, and oversee their conduct.The Health Review Committee, which has no role in selecting or overseeing studies, works with staff to evaluate and interpret the results of funded studies and related research. All project results and accompanying comments by the Health Review Committee are widely disseminated through HEI'sWeb site (wwwhea/theffects.org), printed reports, newsletters and other publications, annual conferences, and presentations to legislative bodies and public agencies. vii CONTRIBUTORS In Spring 201 1, the Health Effects Institute appointed an expert panel to review and critique the scientific litera- ture on the ultrafine particles their sources, the role of automobile emissions, and their potential health ef- fects at ambient levels of exposure. The panel consisted of scientists from a variety of disciplines and was chaired by Mark Frampton, a professor of medicine and envi- ronmental medicine at the University of Rochester HEI Review Panel on Ultrafine Particles Mark W. Frampton, Chair, Professor of Medicine and Environmental Medicine, University of Rochester Medical Center; member, HE1 Review Committee Michael Brauer, Professor, School of Population and Public Health, University of British Columbia; member, HE1 Review Committee Michael Kleeman, Professor, Department of Civil & Envi- ronmental Engineering, University of California —Davis Peer Reviewers Nigel N. Clark, George Berry Chair of Engineering, West Virginia University Jack R. Harkema, University Distinguished Professor, Department of Pathobiology and Diagnostic Investiga- tion, Michigan State University College of Veterinary Medicine Philip K. Hopke, Bayard D. Clarkson Distinguished Pro- fessor; Director, Institute for a Sustainable Environment; and Director, Center for Air Resources Engineering and Science, Clarkson University Nino Kunzli, Head, Department of Epidemiology and Public Health, and Deputy Director, Swiss Tropical and Public Health Institute HEI Science Staff Katherine Walker, Project Leader, Senior Scientist Kate Adams, Senior Scientist Rashid Shaikh, Director of Science HEI Publications Staff Suzanne Gabriel, Editorial Assistant Hope Green, Editorial Assistant Fred Howe, Consulting Proofreader Medical School. HEI is indebted to the panel for its ex- pertise, cooperation, and enthusiasm. The panel also re- ceived support from a team of HEI staff under the leadership of Katherine Walker, Senior Scientist. A draft of the resulting report was submitted for outside peer review; the help of the peer reviewers in improving the quality of this document is gratefully acknowledged. Wolfgang G. Kreyling, Biophysicist Emeritus, Institute of Lung Biology and Disease, Helmholtz Zentrum Munchen, German Research Center for Environmental Health Leonidas Ntziachristos,Assistant Professor, Laboratory of Applied Thermodynamics, Mechanical Engineering Department, Aristotle University Thessaloniki Stefanie Ebelt Sarnat, Assistant Professor, Department of Environmental Health, Rollins School of Public Health, Emory University Jonathan Levy, Professor of Environmental Health, Boston University School of Public Health Morton Lippmann, Professor, Nelson institute of Environ- mental Medicine, New York University Medical Center Juha Pekkanen, Professor, Department of Environmental Health, National Institute for Health and Welfare, Unit of Public Health and Clinical Nutrition, University of East- ern Finland Kent Pinkerton, Professor and Director, Center for Health and the Environment, University of California —Davis Ira Tager, Emeritus Professor, School of Public Health, Divi- sion of Epidemiology, University of California —Berkeley Clifford P Weisel, Professor, Environmental and Occupa- tional Health Sciences Institute, Rutgers University Geoffrey H. Sunshine, Senior Scientist Jacqueline Presedo, Research Assistant Morgan Younkin, Research Assistant Carol Moyer, Consulting Science Editor Ruth Shaw, Consulting Compositor ix EXECUTIVE SUMMARY Understanding the Health Effects of Ambient Ultrafine Particles INTRODUCTION Over the past 30 years, a large body of scientific literature has emerged that provides evidence of associations between short-term and long-term exposures to ambient particulate matter (PM) and increased mortality and hospitalization from car- diovascular and respiratory diseases. Most of the evidence is based on epidemiologic studies of human exposure to PM with aerodynamic diame- ters 10 micrometers (PM10) or 2.5 micrometers (PM2 5). However, scientists and regulators have long known that PM in the ambient air is a com- plex mixture including particles of different sizes and chemical composition. What has been less clear is whether certain characteristics of the ambient mixture are more harmful to public health than others and are therefore the most important to control. In its 1998 blueprint for a research pro- gram on airborne PM, the United States National Research Council identified improved under- standing of ultrafine particles (UFPs) as a priority. UFPs make up the smallest size fraction in what is a continuum of airborne particles with diame- ters ranging from a few nanometers to several micrometers. By convention, UFPs have been defined as particles that are 100 nanometers or less in diameter (s 100 nm). Given their small size, UFPs contribute little to the mass of PM in ambient air, but they are the dominant contributors to par- ticle number. Motor vehicles, especially those powered by diesel engines, have often been cited as a leading source of ambient UFP emissions and of human exposure. The work of the HEI Review Panel on Ultrafine Particles was sup- ported with funding from the United States Environmental Pro- tection Agency (Assistance Award CR-83234701) and motor vehicle manufacturers. Support for the preparation and publica- tion of this document was provided by the Federal Highway Administration (Grant DTFH61-09-G-00010). This report has not been subjected to peer or administrative review by any of the sponsors and may not necessarily reflect their views, and no offi- cial endorsement should be inferred. Concern about UFPs developed from early evi- dence, primarily from animal and in vitro studies, that suggested that they could be inhaled more deeply into the lung and might be more toxic than larger particles. The first epidemiologic studies that included particle number measurements also suggested that UFPs might be associated with the same adverse effects in humans that have been attributed to larger particle size fractions. Scien- tists hypothesized that UFPs would have greater toxicity than larger particles in part because their vast numbers and small diameters mean that they have a high surface area, a potentially important interface through which to transmit any toxic chemicals that might be adsorbed. In the decades since concerns were first raised about UFPs, the role they might play in the adverse health effects associated with exposures to air pol- lution has remained an important research target at institutions around the world, including HEI. National and local air quality authorities in the United States and in other regions of the world continue to assess the need for specific action on UFPs in reviews of ambient air quality standards and other regulatory programs. At the same time, under existing regulatory and technological changes, UFP emissions from motor vehicles are already changing. The resulting impacts on ambient concentrations, and ultimately on human exposures, are difficult to predict. TIME FOR A BROAD PERSPECTIVE Given this context, HEI formed a special panel (see Contributors list) to review the scientific evi- dence available on UFPs and to present its evalua- tion in this third issue of the HEI Perspectives series: Understanding the Health Effects of Ambient Ultrafine Particles. Health Effects Institute Perspectives 3 © 2013 1 Understanding the Health Effects of Ambient Ultrafine Particles The Panel structured its assessment of the scientific evi- dence regarding ambient UFPs as responses to three ques- tions: • Ambient UFPs — sources, emissions, and exposures: To what extent do motor vehicles contribute? (Chapter 2); • Do UFPs affect health? What is the evidence from exper- imental studies in animals and humans? (Chapter 3); • Do UFPs affect human health at environmental concen- trations? What is the evidence from epidemiologic stud- ies? (Chapter 4). Chapter 2 explores the contribution of motor vehicles within the broader context of the multiple sources of ambient UFPs. It discusses in detail the changing profiles of mobile -source emissions, the spatial and temporal pat- terns of ambient UFP concentrations, and the implications of all these factors for the design and interpretation of studies of UFP exposure and health. The next two chapters explore the health evidence on UFP exposures from a broad array of study designs using animal and human subjects. Chapter 3 focuses on the evi- dence from experimental studies in animals and in humans because they can directly test hypotheses about the causal role of specific exposures. Chapter 4 focuses on observational epidemiologic studies of people exposed to UFPs in the environment, in mostly urban settings. Because they involve studies of people exposed to concentrations of air pollutants found in the real world, epidemiologic studies of UFPs have the potential to provide more direct evidence with which to determine whether UFPs affect human health at concentra- tions found in the environment. Chapters 3 and 4 both focus on various measures of intermediate markers and health endpoints that represent the multiple hypothesized pathways for UFP effects. Most of these pathways are shared by PM generally, but some pathways may be especially relevant for UFPs. In identifying experimental and epidemiologic studies for its assessment, the Panel made a number of choices to make sure that responses to the questions were most informed by studies relevant to the understanding of the potential risks of inhaling ambient UFPs, particularly those related to motor vehicle exhaust. For the experimental studies, it considered only studies involving exposures to UFPs via the inhalation route, which is physiologically rel- evant and directly comparable with the results of epidemi- ologic studies. The Panel therefore excluded in vitro studies or studies in which particles were directly instilled into the lungs or airways. The Panel focused on exposures to combustion -related UFPs and therefore largely excluded the vast literature on engineered nanoparticles. The Panel also placed particular emphasis on both experimental and epidemiologic studies of UFPs that included analyses of exposures to copollutant gases and larger particle size frac- tions, because of the potential of such studies to provide insight into the role of UFPs themselves in any health effects observed. Finally, Chapter 5 summarizes each chapter's main con- clusions and attempts to identify some of the broader les- sons, about both the specific health effects associated with exposures to UFPs and possible directions for future studies that could enhance our understanding of emis- sions, exposures, and effects of UFPs. SUMMARY AND CONCLUSIONS A substantial body of literature has now been published on the sources of UFPs, their spatial and temporal distribu- tion in ambient air, their inhalation and fate in the body, their mechanisms of toxicity, and their adverse effects in animals and in humans. The purpose of this issue of HEI Perspectives is to provide a broad assessment of what has been learned about UFPs and what remains poorly under- stood. The Panel's findings in response to the three ques- tions posed at the outset of this Executive Summary are summarized briefly below. AMBIENT UFPs -- SOURCES, EMISSIONS, AND EXPOSURES: TO WHAT EXTENT DO MOTOR VEHICLES CONTRIBUTE? As products of combustion and secondary atmospheric transformations, ambient UFPs have multiple sources whose relative contributions to ambient concentrations vary with location, season, and time -of -day. However, in urban areas, particularly in proximity to major roads, motor vehicle exhaust can be identified as the major con- tributor to UFP concentrations. Diesel vehicles have been found to contribute substantially, sometimes in dispropor- tion to their numbers in the vehicle fleet. However, the absolute and relative contributions of dif- ferent vehicle types to motor vehicle emissions are chang- ing rapidly. On the one hand, under the force of regulations to reduce particle mass and number emissions from diesel and other vehicles, the emissions, and therefore ambient levels, of UFPs will decrease. On the other hand, this de- crease may be partially offset by UFP emissions from the 2 Executive Summary growing use of certain types of gasoline direct injection tech- nology to boost fuel efficiency. The role that will be played by new fuels, such as ethanol and biodiesel blends and natural gas, remains largely ill-defined. The collective effect of all these changes has not been thoroughly explored and will likely vary regionally, depending on the rate and extent to which they are deployed in different parts of the world. It has been more challenging to characterize human exposure to ambient UFPs than to the more regionally dis- persed and routinely monitored pollutants, such as PM2.5• UFP concentrations are highly variable spatially, declining rapidly with distances from roadways, for example, such that UFPs often differ substantially from one location to another within the same city. Given their small contribu- tion to mass, UFPs are not well reflected in PM mass mea- surements and they are not routinely monitored in most locations. Studies of UFPs have relied on a variety of detec- tion methods, most commonly measures of number con- centration. In addition, UFPs are highly correlated with other combustion -related pollutants, such as carbon mon- oxide and nitrogen oxides. These correlations must be taken into account when evaluating exposure to sources such as traffic, or when designing epidemiologic studies and interpreting their results. Reliance on measurements at central -site monitors to represent broad population expo- sure — a central feature in epidemiologic studies of long- term exposures to PM2.5 and other pollutants — is likely to lead to errors in estimates of exposure to UFPs. Despite the high spatial variability of UFPs, the UFP num- ber concentrations measured at multiple locations within cities do tend to be reasonably correlated in time, rising and falling in similar patterns over the course of a day. Moderate- ly high temporal correlations between UFP number concen- trations at central monitors, outdoors at residences, and even indoors at residences have been observed in some, but not all, cities. The correlations are not always as strong as those observed for PM2 5, but in some locations they can be sufficient to support epidemiologic studies on the effects of short-term variations of number concentrations on human health, using study designs that have been employed for larger particle size fractions. However, the temporal vari- ability in UFP number concentration can be similar to that of other PM size fractions and gaseous pollutants, making it difficult to differentiate the effects of UFP number concen- tration in such study designs. DO UFPs AFFECT HEALTH? WHAT IS THE EVIDENCE FROM EXPERIMENTAL STUDIES IN ANIMALS AND HUMANS? Experimental studies have provided a rationale for the hypothesis that the adverse health effects of exposure to UFPs differ from those of larger particles. As a result of their physical characteristics, inhaled UFPs differ from larger particles in their deposition patterns in the lung, their clearance mechanisms, and in their potential for translocation from the lung to other tissues in the body. Some animal studies have also demonstrated translocation of UFPs via the olfactory nerve to the brain. Both animal and human studies provide evidence for respiratory and cardiovascular effects associated with exposure to UFPs. Observed effects in selected studies include lung function changes, airway inflammation, enhanced allergic responses, vascular thrombogenic effects, altered endothelial function, altered heart rate and heart rate variability, accelerated atherosclerosis, and increased markers of brain inflammation. Largely, with the exception of brain effects, the findings are similar to those observed for exposures to fine particles. While selected studies show evidence for UFP effects, the current evidence, when considered together, is not suf- ficiently strong to conclude that short-term exposures to UFPs have effects that are dramatically different from those of larger particles. There are limitations and inconsisten- cies in the findings from short-term studies on UFP health effects, and there are no long-term animal exposure studies of UFP health effects. Relatively few studies have directly compared UFPs with other particle size fractions. These factors constrain our ability to draw definitive conclusions about the specific consequences of exposure to UFPs. DO UFPs AFFECT HUMAN HEALTH AT ENVIRONMENTAL CONCENTRATIONS? WHAT IS THE EVIDENCE FROM EPIDEMIOLOGIC STUDIES? A growing number of epidemiologic studies conducted over roughly the past 10 years have evaluated impacts of UFPs. These studies have provided suggestive, but often inconsistent, evidence of adverse effects of short-term expo- sures to ambient UFPs on acute mortality and morbidity from respiratory and cardiovascular diseases. One explana- tion that must be considered for the results to date is weak- ness in the true underlying relationship between UFP exposures and adverse effects — that the null hypothesis being tested by these studies is true. However, limitations of the current studies are likely to play a role; UFPs have not been assessed routinely in large epidemiologic studies of air pollution health effects, in part because ambient monitoring 3 Understanding the Health Effects of Ambient Ultrafine Particles of UFPs has not been conducted in most locations or has not been done with the same measurement techniques. As a result, studies tend to be smaller and the likelihood of expo- sure measurement error tends to be greater for UFPs relative to PM2.5 and other pollutants; both of these factors reduce statistical power to test confidently for what may be small but important health outcomes. The available observational study designs have also not been able to clearly determine whether UFPs have effects independent of those for related pollutants. Where studies have measured UFPs, few have assessed whether the effects associated with UFPs are independent of other pol- lutants. When they have, the effects of UFPs have not been consistently discernible from those of other pollutants with which they often occur or share similar sources (e.g., traffic). Of 42 articles published since 1997 that cited any significant health associations with UFPs measured as number concentration, 37 articles also noted significant effects for other particle size fractions or traffic -related pol- lutants, and 10 articles did not consider any traffic -related gases in the analysis. No epidemiologic studies of long-term exposures to ambient UFPs have been conducted. This is because the most common epidemiologic study designs for long-term exposures are dependent on spatial contrasts in concentra- tions that have been more difficult to characterize for UFPs than for PM2.5. OVERALL CONCLUSIONS Airborne PM has been the focus of extensive research and debate in the United States and around the world for several decades. Considerable evidence from a broad array of experimental and epidemiologic studies has led to strong scientific consensus on the independent associa- tions of airborne PM, in particular PM2.5 and PM10, with adverse respiratory and cardiovascular effects on human health. This evidence has provided the foundation for many regulatory decisions to limit both PM emissions, including those from motor vehicles, and ambient PM con- centrations to which people might be exposed. What role have ambient concentrations of UFPs played in the adverse effects that have been observed in human populations exposed to ambient air pollution? Several factors — the unique physical properties of UFPs, their interactions with tissues and cells, their poten- tial for translocation beyond the lung — have led scientists to expect that UFPs may have specific or enhanced toxicity relative to other particle size fractions and may contribute to effects beyond the respiratory system. However, the con- siderable body of research that has been conducted has not provided a definitive answer to this question. Toxicologic studies in animals, controlled human exposure studies, and epidemiologic studies to date have not provided consistent findings on the effects of exposures to ambient levels of UFPs, particularly in human populations. The current evi- dence does not support a conclusion that exposures to UFPs alone can account in substantial ways for the adverse effects that have been associated with other ambient pollutants such as PM2.5. The fact that the current database of experimental and epidemiologic studies does not support strong and consis- tent conclusions about the independent effects of UFPs on human health does not mean that such effects, as one part of the broader effects attributable to PM2.5, can be entirely ruled out. There are limitations in the evidence base attrib- utable to underlying deficiencies in exposure data, to numerous challenges in comparing and synthesizing results of existing studies, and to the inherent complexity of the task that scientists have set out to accomplish. WHERE DO WE GO FROM HERE? There are many considerations beyond the scientific opinions expressed in this issue of HEI Perspectives that inform the level of confidence in the evidence necessary for policy makers to "ensure that resources spent in the future on control technology and regulatory compliance will have a reasonable probability of success" (U.S. National Research Council 1998). Among them is the need to weigh carefully the value to scientific understanding and to regulatory deci- sions of continuing to treat UFPs as an individual pollutant versus alternative approaches that focus on the health effects of exposure to traffic or to the broader air pollution mixture. As part of that discussion, this report lays out possible research steps toward addressing some of the limitations of the current evidence on the specific role of UFPs. Exper- imental study designs could include controlled exposures to UFPs and related copollutants in studies that replicate key animal research results on effects beyond the lung (e.g., in the cardiovascular and central nervous systems), that extend analyses to other animal species and disease models, and that involve long-term exposures. Epidemio- logic studies could include more carefully targeted designs that exploit contrasts in ambient UFP exposures but that improve the ability to characterize the independent effects of exposure to UFPs, more consistent and comparable 4 Executive Summary study designs that would support meta -analyses, and designs that permit assessment of the impacts of long-term exposures. Ultimately, many of the underlying challenges posed by the existing evidence on ambient UFPs relate to limitations in characterization and analysis of exposure, so recommendations for exploration of alternative exposure metrics, spatial modeling techniques, and statistical methods are also included. Regardless of the evidence for a specific role for UFPs, many of the recent PM regulatory decisions affecting fuels, engine designs, and exhaust aftertreatment in countries around the world are likely to result in significant reduc- tions in emissions of both fine and ultrafine particles. The time course of these and other changes in the emissions of UFPs or their precursors and their impact on ambient concentrations will depend on a number of factors, includ- ing shifts in the size, age, and composition of the vehicle fleet in particular regions. Monitoring and evaluation of such changes will be essential in the years to come; without them, questions will remain about whether or not these changes have addressed the most important characteristics of the air pollution mixture. REFERENCE U.S. National Research Council. 1998. Research Priori- ties for Airborne Particulate Matter: I. Immediate Priorities and a Long -Range Research Portfolio. National Academy Press, Washington, D.C. 5 HEI PERSPECTIVES 3 Understanding the Health Effects of Ambient Ultrafine Particles HEI Review Panel on Ultrafine Particles CHAPTER 1. Introduction The history of air pollution research and management has been characterized by efforts to identify the key pollutants responsible first for the major air pollution episodes that plagued the industrializing countries in the early part of the 20th century, and later, for the more subtle geographic varia- tions in air pollution levels and health effects. Terms like smoke and haze have given way to more specific chemical entities — specific gaseous pollutants and solid particulate matter. In turn, the study of particulate matter (PM*) expo- sures, which began with crude measures of total suspended particles, evolved to focus on increasingly smaller particle size fractions that are more likely to be inhaled, beginning with PM 10 micrometers in aerodynamic diameter (PM10), then ≤ 2.5 micrometers in aerodynamic diameter (PM2.5), and recently on the complex mixture of constitu- ents of which they are comprised. The fundamental motiva- tion underlying these research efforts has been to identify those characteristics of air pollution that are most haz- ardous to human health and whose control would most likely lead to reductions in risks to public health. Interest in ultrafine particles (UFPs) — particles ≤ 100 nanometers in diameter — is very much a part of this history. WHAT ARE UFPs AND WHY IS THERE CONCERN ABOUT THEM? UFPs in ambient air make up the smallest size fraction in what is a continuum of particles with diameters ranging The work of the HEI Review Panel on Ultrafine Particles was supported with funding from the United States Environmental Protection Agency (Assis- tance Award CR-83234701) and motor vehicle manufacturers. Support for the preparation and publication of this document was provided by the Fed- eral Highway Administration (Grant DTFH61-09-G-00010). This report has not been subjected to peer or administrative review by any of the sponsors and may not necessarily reflect their views, and no official endorsement should be inferred. * A list of abbreviations and other terms appears at the end of this docu- ment. from a few nanometers to several micrometers (illustrated in Figure 1 for a typical roadway aerosol). By convention, UFPs have been defined as particles less than or equal to 100 nanometers in diameter (< 100 nm or 0.1 pm). UFP size fractions may also be characterized more generally in terms of the processes by which they are formed; nucleation mode particles (< 50 nm) and the larger accumulation mode particles (> 50 nm) (HEI 2010). UFPs technically are part of the larger size ranges that have been the primary subjects of air pollution studies (i.e., PM10 and PM2.5). They contribute little to the mass of particles measured in these ranges, but are the dominant contributors to particle number. Over the last 30 years, a large body of scientific litera- ture has emerged that provides evidence of associations between short-term and long-term exposures to ambient PM10 and PM2.5 and increased rates of mortality and hos- pitalization, primarily from cardiovascular and respiratory diseases. The most influential evidence first came from observational epidemiologic studies in the United States and around the world (e.g., Pope et al. 1992; Dockery et al. 1993; Anderson et al. 1997; Samet et al. 2000a,b; HEI 2003; Pope and Dockery 2006). The biological explanations for these findings were then, and continue to be, the subject of substantial research and debate. Evidence from studies in laboratory animals had begun to accumulate by the early 1990s, which suggested that UFPs might penetrate more deeply into the lung and might be more toxic than larger particles (Oberdorster et al. 1990; Ferin et al. 1992; International Commission on Radiological Protection [ICRP1 1994). Of concern to air pollution scien- tists is that particles in the UFP size range account for the vast percentage of particle numbers in ambient air, even though they make up a small fraction of the PM2.5 or PM10 mass (see Figure 1). A measured PM2.5 mass concentration of 10 pg/m3 for example, might contain as many as 2.4 mil- lion 20-nm particles/cm3, but could also be represented by a single 2.5 pm particle (Oberdorster et al. 1995). Seaton and colleagues (1995) hypothesized that this urban particu- late cloud of UFPs, could cause "alveolar inflammation, Health Effects Institute Perspectives 3 © 2013 7 Understanding the Health Effects of Ambient Ultrafine Particles 4.0 PM10 (10,000 nm) 3.5 PM2 (2,500 nm) 3.0 Normalized Concentration (1/Ctatai}dCidlog DP 2.5 2.0 7 1.5 Nucleation Mode 1.0 0.5 0.0 UFP (<100 nm) Accumulation Mode 10 100 1000 Diameter (nm) • Number Surface - - - Mass Coarse Mode 10,000 Figure 1. Normalized particle size distributions of typical roadway aerosol. Dp represents the particle diameter; (1/Ctotai)dCidlog Dp represents the loga- rithmic particle -concentration -distribution function weighted by number, volume (surface), and mass. Here, C is the concentration (number, surface, or mass) in a particular size range and Clot is total concentration summed over all sizes. (Source: David Kittelson and Win Watts, reprinted from HEI 2010.) with release of mediators capable, in susceptible individ- uals, of causing exacerbations of lung disease and of increasing blood coagulability, thus also explaining the observed increases in cardiovascular deaths associated with urban pollution episodes." The high surface area per unit of mass of UFPs, a function of their vast numbers and small diameters, has also been hypothesized to be an important characteristic that might predict greater toxicity of particles in that size range. An early toxicologic study by Oberdorster and colleagues (1992), in which they instilled 20 nm titanium dioxide par- ticles in the tracheas of rats, found that increased pulmo- nary toxicity was associated with the surface area of the particles. Other investigators have noted that surface area is a potentially important interface by which particles interact with biological systems and help to transport toxic metals or chemicals that may be adsorbed to the particles (Donaldson et al. 2005; Kreyling et al. 2006a; Maier et al. 2008). Such early studies, coupled with later epidemiologic evidence that UFPs might be associated with adverse effects in humans similar to those observed for other particle size fractions (Pekkanen et al. 1997; Peters et al. 1997; Wichmann et al. 2000), motivated the U.S. National Research Council to identify UFPs as a research priority in their series of reports laying out a blueprint for a multifac- eted research agenda on airborne PM (U. S. National Research Council 1998, 1999, 2001, 2004). TIME FOR A BROAD PERSPECTIVE In the decades since concerns were first raised about UFPs, these particles have remained an important research target at institutions around the world. At HEI, research on UFPs has been part of an ongoing effort to advance under- standing of the associations between exposures to ambient PM and adverse effects on human health (see Appendix Table A.1 for a complete overview of HEI's research pro- gram involving UFPs, including published HEI reports with their related journal articles and ongoing HEI research). HEI's work has included some of the early research by Oberdorster and colleagues (2000) on the pul- monary effects of model UFP exposures in susceptible rats 8 HEI Perspectives 3 and mice, as well as the first epidemiologic study to inves- tigate and to observe an association of short-term daily exposure to UFPs with mortality (Wichmann et al. 2000). Several additional studies are still underway and include novel methods to improve real-time measurement and characterization of UFPs, modeling of personal exposures to UFPs from primary exhaust and secondary aerosols, and toxicologic and epidemiologic studies in settings with dis- tinct variations in UFP concentrations. Motor vehicles have often been cited as a key source of exposure to UFPs, and two recent HEI reviews have laid the initial groundwork on this issue. The HEI Special Report on traffic (HEI 2010) was an extensive review of the literature on traffic -related emissions, exposures, and asso- ciated health effects. As part of that report, UFPs were explored as one of several possible surrogate markers for exposure to traffic, but the evidence for supporting such a role for UFPs was found to be limited. HEI's Communica- tion 16, a report of the HEI Special Committee on Emerging Technologies (HEI 2011), identified potential changes in UFP number emissions and composition that might be associated with future fuels and technologies. Reflecting these ongoing concerns, UFPs continue to be considered by national and local air quality authorities in the United States and elsewhere in reviews of ambient air quality standards and other regulatory programs. The U.S. Environmental Protection Agency (U.S. EPA) assessed the evidence on UFPs as part of its most recent scientific review of the National Ambient Air Quality Standards (U.S. EPA 2009). While the agency judged the present health effects and air quality data to be insufficient to sup- port an individual standard for UFPs, its scientific advi- sory panel, which reviews the U.S. EPA assessments, suggested that the role of UFPs continue to be evaluated and that future PM monitoring efforts be extended to the ultrafine range (Clean Air Scientific Advisory Committee [CASAC] 2010). In Europe, UFPs are one of several air pol- lutants being evaluated under the World Health Organiza- tion —led project known as REVIHAAP, which is designed to inform revisions of European Union policies on air quality in 2013. Though not directly based on health considerations, the European Union has introduced particle number emissions standards for all diesel passenger and commercial vehicles, which are being introduced gradually over the period 2011-2013, and has required recently that they be extend- ed to gasoline vehicles. These limits regulate the number of nonvolatile particles and effectively ensure that particle fil- ters will be installed on both diesel and gasoline vehicles. Future trends in the United States and other industrial- ized countries in the ambient levels of UFPs are somewhat hard to predict. On the one hand, the emissions, and there- fore ambient levels, of UFPs will decrease under the force of regulations to reduce particle emissions from diesel vehicles; on the other hand, the growing use of gasoline direct injection technology — which raises fuel efficiency — is likely to increase UFP levels. The role that will be played by new fuels, such as ethanol and biodiesel blends and natural gas, remains largely ill-defined at this point. Where are we now? With nearly two decades of research behind us, regulatory actions are underway that will influ- ence emissions of UFPs. However, resolving questions about the specific role that ambient levels of UFPs may play in potential adverse effects on human populations remains a challenge. Given this context, HEI decided to form a special panel (listed on page ix) to review the scien- tific evidence available on UFPs. The expert panel held an initial meeting in July 2011 to lay the groundwork for the report and worked collaboratively thereafter with HEI staff to draft it. The draft was sent to 10 external peer reviewers and was revised extensively in response to their com- ments. The final result of this process is the current issue in the series of HEI Perspectives, in which we have sought to provide a broad overview of the scientific evidence regarding ambient UFPs, structured as responses to three questions: 1. Ambient UFPs -- sources, emissions, and exposures: To what extent do motor vehicles contribute? Mobile sources are often cited as the leading source of human exposure to ambient UFPs. Chapter 2 explores the basis for this common statement by examining the many factors that affect the magnitude and potential for human exposures to ambient UFPs. We begin with a survey of the multiple sources of ambient UFPs and how they are measured. We then discuss in more detail the changing profiles of mobile -source emissions, the spatial and temporal patterns of ambient UFP concentrations, and the implications of all these factors for the design and interpretation of health studies of UFP exposures. 2. Do UFPs affect health? What is the evidence from experimental studies in animals and humans? Experimental studies play a critical role in the study of relationships between exposure and disease. They can be designed to characterize the patterns and mecha- nisms of particle deposition, clearance, and uptake that may be important to understanding the potential differ- ential toxicity of particles. With carefully designed exposures and selected health endpoints in a controlled setting, these studies provide direct tests of hypotheses about the causal role of particular exposures. Chapter 3 focuses on the evidence from experimental studies 9 Understanding the Health Effects of Ambient Ultrafine Particles involving exposures to UFPs via the inhalation route, which is both more physiologically relevant and more directly comparable with the results of epidemiologic studies reviewed for the next question. We therefore excluded in vitro studies or studies in which particles have been directly instilled or deposited into the lungs or airways. 3. Do UFPs affect human health at environmental concen- trations? What is the evidence from epidemiologic studies? Because they involve studies of people exposed to con- centrations of air pollutants found in the real world, ep- idemiologic studies of UFPs have the potential to provide more direct evidence with which to answer whether UFPs affect human health at concentrations found in the environment. In Chapter 4, we evaluate the epidemiologic evidence: 1) for specific health end- points, with an assessment of the consistency and co- herence of observed associations, and 2) with respect to key study design and data issues, including how UFPs are measured, how exposures are assigned to subjects, and the extent to which potential confounding of the UFP effects by copollutants has been assessed. Our responses to each of these questions have attempted to focus on literature most germane to the key issues. For example, our review of sources, emissions, and exposure has focused on studies that exemplify the major phe- nomena related to assessing ambient UFPs. In identifying experimental and epidemiologic studies for our assess- ment, we have focused on those involving combustion - related UFPs in order to make our assessment most rele- vant to conclusions about ambient UFPs, particularly those related to motor vehicle exhaust. We have therefore largely excluded the vast literature on engineered nanoparticles that has developed over the last decade, although we recognize that contributions from that litera- ture may also provide insights. We also have placed partic- ular emphasis on both experimental and epidemiologic studies of UFPs that include analysis of exposures to copollutant gases and larger particulate fractions because of their potential to provide insight to the role of UFPs themselves in any health effects observed. Finally, Chapter 5 summarizes the main conclusions from Chapters 2-4 and attempts to draw some of their broader lessons. In particular, we discuss what the evidence to date allows us to conclude about the health effects associ- ated with exposures to UFPs themselves, and how they differ from those of other particle size fractions and combus- tion -related cop ollutants. Possible directions for future studies that could enhance our understanding of emissions of, exposures to, and effects of UFPs are also provided. CHAPTER 2. Ambient UFPs: Sources, Emissions, and Exposures. To What Extent do Motor Vehicles Contribute? Many concerns about ambient UFPs have focused on their relationship to motor vehicle emissions. However, as a product of many combustion processes, as well as of sec- ondary chemical and physical processes in the atmo- sphere, UFP concentrations measured in ambient air are affected by many factors over space and time. This chapter therefore seeks to provide greater perspective on the extent to which motor vehicle emissions may contribute to ambient concentrations of UFPs and ultimately to overall human exposure to ambient UFPs. The chapter begins with a basic summary of the various methods by which UFPs are measured and characterized that provides a common terminology for the remaining chapters in which the methods are applied to health stud- ies. It then presents a general overview of sources of ambi- ent UFPs at regional and urban scales, offering some perspective on the relative contribution of motor vehicles and traffic. The next subsection provides some background on exhaust and non -exhaust emissions from current engine technology and briefly discusses the implications of chang- es in engine and fuel technologies for future emissions. The remainder of the chapter focuses on the potential for human exposure to ambient UFPs — in particular, on how concen- trations and composition of UFPs vary over time and in dif- ferent locations where human populations live, travel, and work. We conclude with a discussion of how such data might be used in animal and human studies to better assess the potential effects of UFPs on health. HOW ARE UFPs MEASURED? Several different sampling and analysis methods have been developed to analyze UFPs at different points in emission and in ambient air. Single -vehicle measurement offers the possibility of discerning engine, fuel, and after - treatment effects on UFP emissions and assessing the effect of technology on emissions. Typically conducted in laboratory settings, these measurements may be made under controlled conditions, with set vehicle operating conditions, in a repeatable manner. Such measurements are dedicated to only a few vehicles, may involve stepwise in -laboratory dilution that differs from the faster and con- tinuous atmospheric dilution, and may therefore result in sampling artifacts. To avoid such limitations, investigators look to ambient sampling of vehicular aerosol to provide a more repre- sentative picture of the aerosol to which people in the 10 HEI Perspectives 3 vicinity of roads may actually be exposed. Ambient aero- sols reflect interactions of emitted particles with the envi- ronment (e.g., mixing with other particles and gases, photochemical reactions) that can occur over time and space. Disadvantages of this approach for characterizing the contributions of specific vehicles are that the ambient air may include aerosols contributed from different vehi- cles and vehicle types and typically reflects contributions from background pollutant concentrations and other local emission sources. These challenges are not unique to the characterization of vehicular emissions and their contributions to ambient UFP concentrations. They affect efforts to study other sources as well. In general, all ambient measurements reflect the product of dynamic atmospheric and chemical processes that are likely to differ over time and geography. However, one of the factors that has sometimes compli- cated comparison of data on UFP emissions, concentra- tions, exposures — and ultimately health effects — has been the many technologies and metrics (mass, composi- tion, surface area, and particle number counts) that have been used to measure and describe them. To support dis- cussions in this and later chapters, the following section describes the various methods by which UFPs are cur- rently characterized; a simple summary of the terminology and the particle size ranges typically measured by the methods discussed is provided in Table 1. Measurement of UItrafine Particle Mass While the measurement of the ambient concentrations of larger particle size fractions (Le., PM2 5 and PM10) is typically based on the total mass per unit volume of air, or mass concentration, several factors make such measure- ments problematic for UFPs defined as those with diame- ters less than 100 nm (PM0.1). First, direct measurements of UFP mass are challenging because the mass concentra- tion of particles in the UFP range is very low. Ambient PM01 concentrations are typically less than 1 pg/m3, and commercial balances usually have practical detection limits of ± 1-5 pg for collection media (for example, filters) that weigh a few milligrams. These collection media can sustain only low flow rates (< 100 liters/min), so long col- lection times are required for sufficient mass to be col- lected for measurement. These sampling requirements in turn can influence another factor that can significantly affect sensitivity of mass measurements methods for these small size ranges — gas -to -particle artifacts. That is, chem- ical compounds in the gaseous phase may adsorb on parti- cles to produce a positive artifact or, vice versa, desorb from the particle to produce a negative artifact. Although such processes generally occur in atmospheric conditions as well, the prolonged exposure of the PM to the air flow through the instrument may exacerbate these effects during sampling. In practice, particle mass concentrations have been more typically estimated for UFPs in larger size fractions known as quasi-ultrufines; that is, UFPs < 0.180 pm (PM0.18) or < 0.250 pm (PM0.25) in diameter. Measures of quasi -ultra - fine particle mass have been most commonly obtained with a class of instruments known as cascade impactors (see Table 1). In these instruments, particles are sorted and col- lected on a series of impactor surfaces, each corresponding to a successively smaller aerodynamic diameter cut -point. After collection on the cascade impactor stages, the mass for the fractions of interest is measured by gravimetric anal- ysis. Or, in the case of the electrical low pressure impactor (ELPI) the particles are precharged and then the resultant current is measured on the impaction stages corresponding to various particle size ranges. Multiple stages of cascade impaction are necessary for accurate UFP mass measurements, in part to remove larger particles from collection on UFP impaction stages. However, larger particles do sometimes bounce or other- wise pass through, and the results can be significantly altered by the accidental inclusion of a few larger size fraction particles with masses that are orders of magni- tude greater than those of the UFPs. All of these factors have tended to favor forms of detection other than direct gravimetric analysis. Reconstructed Particle Mass (PM0.1) As an alternative to direct UFP mass measurements, the concentration of individual chemical components can be measured in the PM0.1 size range and combined to effec- tively reconstruct the total PM0.1 mass. Detection limits for the dominant chemical components of PM0.1 are usually much better than gravimetric detection limits for UFPs, making reconstructed PM0.1 mass potentially more accu- rate. These measurements have the added advantage that they provide composition data that can also be used in PM0.1 source -apportionment analyses. The bulk of PM0.1 mass is typically composed of carbona- ceous material with smaller contributions from inorganic ions, reflecting the dominant combustion sources for these particles. The carbonaceous material can be broadly defined as compounds containing elemental carbon (EC) and organic carbon (OC). The EC and OC categories can be fur- ther separated into individual compounds, which can be especially useful for PM0.1 source -apportionment studies. Due to the large fraction of carbonaceous compounds in 11 Understanding the Health Effects of Ambient Ultrafine Particles Table 1. Overview of Ultrafine Particle Measurement Methodsa Metric (units) Abbreviation Particle Size Ranges Time Resolution Method Selected Instruments Size -distributed particle mass concentration (ug/m3) Size -distributed number concentration (particles/cm3) Number concentration (particles/cm3) Size distributed number concentration (particles/cm3) Size distribution (dN/dlogDp) Particle size, number and mass Surface area (pm2/cm3) Composition PMx_y PMx_y 10 nm-18 pm Various cut -points: <56nm <100nm <180nm <250nm < 2.5 pm <10pm 7 nm-10 pm Various stages Total NC 2.5 nm- 1000 nm (range can vary) Various ranges: 3-30 nm 30-300 nm 300-800 nm 2 nm-1 pm 5.6-560 nm NCx_y NCx_y SAx_y 5.6-560 nm 5 nm-2.5 pm 10 nm- 1000 nm 20 nm- 100 nm 2.5 nm- 1000 nm (from SMPS) Integrated (hr) Cascade impaction Integrated (hr) 1 sec 1 min Electrical low pressure impaction CPC DMA 1 sec DMA 10 samples/sec DMA 10 Hz data, 200 ms T10-90% response 1 sec Electrical mobility measurement Diffusion charging and electrometer Ionization and attachment of lead (Pb) Cascade Impactors: MOUDI Nano-MOUDI Sioutas ELPI Many models SMPS FMPS, ELPI EEPS DMS500 Nanoparticle Surface Area Monitor, DiSCmini, AeroTrak Epiphaniometer 1 min Derived from size SMPS (from SMPS) counts assuming spherical particles, uniform density Various cut -points Integrated (hr) Cascade impaction, Cascade Impactors (see above) extraction, mass (see above) spectrometry 1-10 sec Mass spectrometry Aerodyne AMS Aerosol time of flight TSI 3800-030 mass spectrometry Aerosol time of flight NAMS mass spectrometry 40 nm-1 pm 30-300 nm 10-30 nm <1sec <1sec a AMS = aerosol mass spectrometer; EEPS = engine exhaust particle sizer; ELPI = electrical low pressure impactor; FMPS = fast mobility particle sizer; CPC = condensation particle counter; MOUDI = micro -orifice uniform deposit impactor; NAMS = nanoaerosol mass spectrometer; SMPS = scanning mobility particle sizer. 12 HEI Perspectives 3 UFPs, efforts to reconstruct particle mass have focused more on using trace carbonaceous compounds to recon- struct total OC or EC in the particles (Kleeman et at 2009). While larger dust particles may be mistakenly collected on UFP impaction stages, these tend to be made up primarily of crustal material, such as aluminum and silica. The measurement of chemical composition is more costly and cumbersome than that of mass and is not cur- rently suited to routine monitoring. However, information about chemical composition may be valuable when testing health effects hypotheses related to specific UFP compo- nents or sources. Time-ResoIved Measurements of UFP Chemical Composition With the previous methods, the chemical composition of UFPs or quasi-UFPs is measured by collecting particles on substrates over some period. More recently, aerosol mass spectrometers and aerosol time -of -flight mass spec- trometers have been developed that can measure the chemical composition signature of individual ambient UFPs (or groups of particles) over very short periods, sec- onds to minutes, for example (Bein et at 2005; Toner et al. 2008; Klems et al. 2011). With these methods, the sampled particles are first broken down into their component major ions (laser ablation/ionization), which are then analyzed by mass spectrometer. The qualitative spectra produced by each particle can be grouped with similar spectra and com- pared to source libraries to identify probable emissions sources (Toner et al. 2008). These methods enable highly time -resolved source -apportionment studies of UFP number concentrations (UFP NC). As part of an HEI- funded project, Klems and colleagues (2011) have been developing a nanoaerosol mass spectrometer to measure the composition of individual particles in the 18-24 nm size range and have deployed it to assess the contribution of particular motor vehicles to ambient UFP number and mass concentrations at a major intersection in Delaware, Maryland. However, such methods are still undergoing development and have not been widely applied. Surface Area Concentration Given hypotheses about the biological relevance of the high surface area to mass ratio for UFPs, scientists have been particularly interested in measures of surface area to characterize UFP concentrations for use in health studies. As with determining particle size, however, defining a sur- face area that best describes biological interactions has not been straightforward. Most often, surface area is estimated from particle number and size distribution data and then making assumptions about particle shape, density, and other factors. Instruments have been developed to measure UFP surface area directly. The epiphaniometer estimates the Fuchs surface area as a function of radioactive decay from 211Pb atoms attached to the measured particles (Gaggeler et al. 1989). Other surface area measurements entail exposing the UFPs to an electrical charge and mea- suring the resultant current (DiSCmini; Nanoparticle Sur- face Area Monitor; AeroTrak). Whether calculated or direct measurements characterize the surface area concentration of UFPs in ways that are biologically relevant has not yet been thoroughly studied. Number Concentration Perhaps the most straightforward measurement of UFP concentration is to count the total number of particles per unit volume of air, typically referred to as particle number concentration (NC) or for this document total NC. Given the relative ease and reliability with which they can be measured, total NC data are far more common than mea- sures of particle mass, composition, or surface area. NC is also often assumed to be a reasonable proxy for surface area, as NC is assumed to be dominated by smaller parti- cles and basic geometry dictates that, for a given mass of particles, surface area increases rapidly with decreasing particle diameter. Total NC is generally measured continuously by con- densation particle counters (CPC) in which particles previ- ously enlarged by condensation of vapor on the particle surface are counted when they pass through a laser beam. Depending on the instrument, this method can count parti- cles as small as 3 nm in diameter and typically includes particles up to 1000 nm or more in diameter. Although total NC measured this way is not strictly delimited by the 100 nm size definition for UFPs, it is often assumed to be dominated by particles in the UFP range (refer to Figure 1). These instruments are very versatile and can provide number concentrations for discrete size ranges within the full distribution when used in combination with particle sizers such as differential mobility analyzers (DMA) which separate particles by size before they undergo condensa- tion. The scanning mobility particle sizer (SMPS), for example, is an instrument consisting of both a DMA and a CPC. Due to cost and ease of use considerations, measure- ment networks have generally favored deployment of par- ticle counters alone, although the use of size -differentiated particle counters is increasing. For this document, we have attempted to distinguish number concentrations for specific size ranges, when available, from total NC, rather than referring to all as UFPs. Despite the appeal of these instruments, it is worth noting that number counts obtained by the different methods have potential limitations as indicators of UFP concentrations that should be taken into account when 13 Understanding the Health Effects of Ambient Ultrafine Particles interpreting and comparing results of different studies (Morawska et al. 2008). Although total NC has frequently been assumed to be synonymous with UFPs < 100 nm, par- ticle size distributions in other environments are likely to differ from the idealized example for roadside aerosols shown in Figure 1. As indicated in Table 1, particle counters have different lower size limits, and unless specifically lim- ited to 100 nm or another upper limit, number concentra- tions can have different meanings. Indeed, in a review of 52 studies, Morawska and colleagues (2008) compared total NC measurements obtained using CPCs with those obtained using methods that provide number counts for discrete particle size ranges (i.e., either differential mobility particle sizers [DMPS] or SMPS) for similar envi- ronments and estimated that mean and median number concentrations measured by CPC were significantly higher than those measured using DMPS or SMPS. Estimates of, or assumptions about relative surface area concentration, could also be affected. The implications of such differ- ences for health studies have not been evaluated. Summary of UFP Measurements Numerous methods have been developed to measure the ambient concentrations and composition of UFPs. The var- ious sampling and analysis techniques offer possibilities to analyze ambient particles in different ways, each with its own advantages and disadvantages. Given their sim- plicity and potential biological relevance, measurements of total NC have been the most common method used to measure UFPs, although as interest grows in the health rel- evance of particular size fractions, the use of methods that provide size -specific count data is increasing. Since studies often report measurements or exposures for "ultrafines" or UFPs regardless of the specific measure- ment and sampling techniques that have been used, care should be taken when comparing, synthesizing, and inter- preting results across studies. Emission factors and charac- teristics for UFPs should always be given with reference to the sampling conditions and procedure utilized. Other- wise, inconsistent findings in concentrations, size distri- butions and chemical composition are likely to exist and can complicate comparison of results. SOURCES OF AMBIENT UFPs Ambient UFPs have numerous sources. Most are related to combustion processes that include the burning of wood and other forms of biomass, and the combustion of fossil fuels for transportation, home heating, and cooking. UFPs may be emitted directly or may be formed secondarily through chemical reactions or particle —gas interactions in the atmosphere. This section focuses on primary emissions and briefly mentions the secondary formation of aerosol by a number of dynamic processes that occur in the seconds, minutes, hours, and days after an emission occurs. Emissions Inventories Emissions inventories, estimated from pollutant emis- sions factors for individual source categories, have long been used in air pollution studies to provide a regional perspective on the relative contribution of different sources to overall emissions of pollutants. However, few emissions inventories have been created for UFPs. Three are summarized in this section: one in California, one in the United Kingdom, and one in continental Europe. Though constructed using different approaches, they each point to a similar set of source categories, but the relative importance of particular sources has varied by location and time. The one emissions inventory identified in the United States was conducted for California's South Coast Air Basin using PM:" mass emissions data from 1996 (Figure 2); it estimated that on -road vehicles and other mobile sources (mostly off -road diesel) accounted for about 53% of UFP emissions (Cass et al. 2000). The emissions inventory from the United Kingdom is based on UFP mass emissions data for 1970 to 2007 from that country's National Atmospheric Other Industrial Processes (7%) Waste Burring — (1%) Surface Coating (0-50%1 i Stationary Fuel Use (32%) Petroleum Industry 415°41 MiscelEanous Processes / (5%) On -Road Vehicles (43°/a) Figure 2. Source contributions to UFP emissions in California's south coast air basin (1996) that surrounds Los Angeles. Total PM0.1 emissions were 13.25 metric tons per clay. (Adapted from Cass et al. 2000, Figure 3a, with permission from the Royal Society.) 14 HEI Perspectives 3 Emissions Inventory and is illustrated in Figure 3 (Kuhl- busch and Asbach 2011). It shows an overall decline in the total anthropogenic emissions of UFP mass over time, but shows traffic accounting for about 40% of total emissions in 2007, followed by industrial sources at 30%. The third emissions inventory, illustrated in Figure 4, is based on particle number emissions factors (for particles < 300 nm) for Europe in 2005 (Denier van der Gon et al. 2010; Kulmala et al. 2011). It suggests that road and nonroad transport together accounted for 51% of particle number emissions, followed by residential and commercial heating (21%), and various industrial processes (16%) accounting for most of the remainder (Denier van der Gon et al. 2010). Although these inventories suggest similar source con- tributions, limitations of these inventories are that they are typically region specific, not verified with field measure- ments, and need to be updated over time as changes in emissions occur. Source Apportionment A second category of methods, source apportionment, has been used to estimate more directly the contribution of different sources to ambient UFP concentrations. These methods rely primarily on different statistical models (for example, chemical mass balance, principal components, and factor analysis) to infer the contribution of different 0) 0 M a 50 45- 40 35 30- 25 20- 15 10 5- 0 Z Other ❑ Domestic combined Agriculture • Traffic other H Street traffic • Industry 1970 1980 1990 2000 2007 Figure 3. Emission inventory of PM9,1 emissions in the United Kingdom from 1970 to 2007. Basic data from the National Atmospheric Emission Inventory (NAEI 2007). (Source: Kuhlbusch and Asbach 2011, reprinted with permission from John Wiley and Sons). sources from the chemical composition of particles mea- sured at a given location. Several source -apportionment studies of PM0.1 mass alongside larger size fractions (PM0.18) have been con- ducted at an urban location downwind of Los Angeles and in urban and rural locations of central California (Kleeman et al. 2009; Ham and Kleeman 2011), in the vicinity of major ports (Minguillon et al. 2008), and adjacent to road- sides (Riddle et al. 2008). Such studies have traced PM0.1 to a variety of sources including diesel and gasoline engines, residential wood burning, and cooking from fast food restaurants, among others (Martin et al. 2009; Ham and Kleeman 2011). Data from the same and related studies have also shown that the chemical signature of traffic sources can be estimated for the PM0.1 size fraction several meters from major freeways (Kleeman et al. 2008a, 2009; Riddle et al. 2008) and that the relative contribution of different engine types and sources may vary with distance from roadways, by season, by time of day and by location (Kleeman et al. 2008a; Ham and Kleeman 2011). Figure 5 illustrates such variations by juxtaposing results of source -apportionment analyses based on the OC content of PM0.1 from those studies. The chemical signature of the organic material in the PM0.1 size fraction is altered by atmospheric chemical reactions as these particles age for several days in the atmosphere, making it difficult to link these particles to their emissions Residential, Commercial and Other Combustion (21%) Agriculture (3%) ---__— Industrial—_ Combustion (2%) Industrial Processes (16%) Waste Treatment / and Disposal (5%) Energy Transformation (2%) Non -Road Transport (15%) Figure 4. Source sector contributions in 2005 to European particle number emissions < 300 nm. (Total number of particles = 1.9 x 1027). The estimated contribution from fossil fuel production was negligible. (Adapted from Denier van der Gon et al. 2010, using data provided by the author.) 15 Understanding the Health Effects of Ambient Ultrafine Particles A) Roadside (44 ± 5%) B) Community Motor oil (2 ± 1%) Meal cook (67±.6x) C) Rural Unknown (53 ± 22%) Other (11%) Road dust (4 ± 4%) Diesel (8 ± 2%) Diesel {15 ± f0%) Gasoline (4+1°t) Wood burning (8±5%) Gasoline (1 ± 0%) Wood burning (12 ± 6%) Meal cook (26 ± 14%) Figure 5. Predicted source contributions to PMe,1 OC at varying dis- tances from roadways. A: Roadside sampling site was 37 m downwind of Interstate 5 in San Diego, CA in summer; PMo.1 OC concentration was 1.1 µg/m3. B: Community sampling site was an urban site 400 m from a busy regional highway in Fresno, CA during the winter; PM01 OC concen- tration was 0.07 pg/m3. C: Rural sampling site was a rural site in Westside, CA in winter; PMo.1 OC concentration was 0.09 p.g/m3. (Sources: Ham and Kleeman 2011, reprinted with permission from Elsevier; Riddle et al. 2008, reprinted with permission from the American Chemical Society.) source using methods such as chemical mass balance that rely on the conserved chemical fingerprint of emissions. Studies that analyze numerous measurements at a recep- tor site without the benefit of known emission chemistry pro- files have generally yielded results that are consistent with the chemical mass analysis for UFPs. Kim and colleagues (2004) identified four dominant sources of UFPs in Seattle over a one-year study involving over 1000 measurements of particle size distributions. The lack of chemical fingerprint information made definite source identification impos- sible, but circumstantial evidence suggested contributions from traffic, wood burning, and secondary aerosol produc- tion from atmospheric chemical reactions. Ogulei and colleagues (2006, 2007a,b) used a similar technique to identify primary PM0.1 source contributions from traffic and industrial point sources in Baltimore, Maryland (2006); Buffalo, New York (2007b); and Roch- ester, New York (2007a), confirming that point sources can be important in regions downwind of industrial activities. In a further analysis of the Rochester data, Wang and col- leagues (2011) measured a —50% reduction in UFP con- centrations when a local coal-fired power plant was converted to natural gas. Two European studies have identified road traffic as a dominant source in Europe, using different methods to apportion sources. Pey and colleagues (2009) in Barcelona, Spain, used factor analysis and multilinear regression analysis to analyze PM2.5 and particle number measure- ments (0.013 pm -0.800 pm). They attributed between 54% and 86% of UFP numbers in the 0.030-0.2 pm size range to road traffic. Lonati and colleagues (2011) used factor anal- ysis and other methods to analyze the daily patterns of par- ticle number size distributions in Milan, Italy; they concluded from their results that fresh traffic exhaust emis- sions were the primary source of UFPs in the city and were a strong contributor to their concentrations at urban back- ground sites as well. These studies have been important in extending source - apportionment methods to the UFP size fraction and com- paring the source contributions to different particle size fractions. However, they also illustrate that the same sources contribute to multiple size fractions at the same lo- cations, which can complicate exposure and health stud- ies focused on UFPs. Particle Number Counts by Location A third, more general approach to illustrating the effect of traffic has been to report and compare the particle concentra- tions observed in different locations presumed to be differen- tially affected by traffic. Morawska and colleagues (2008) conducted a meta -analysis of 71 studies of NCs in multiple 16 HEI Perspectives 3 geographic locations and showed that particle counts were progressively higher as the potential for traffic effects became greater. These findings are summarized in Figure 6 and show that mean NCs ranged from 2,600 particles/cm3 in clean back- ground areas to 10,760 particles/cm3 in urban areas, to 48,180 particles/cm3 at roadsides, and to 167,700 particles/cm3 in- side traffic tunnels where ventilation is relatively low. The relative contribution of other sources to the number concen- tration in urban areas cannot be assessed in these studies. Summary of Ambient UFP Sources Ambient UFPs have many sources, most related to com- bustion processes. They may be emitted directly or may also be formed from multiple precursors as part of sec- ondary atmospheric processes. In urban areas, motor vehi- cles are often the leading source, particularly in proximity to roads. Source -apportionment studies indicate that other point sources may be important contributors to UFP con- centrations at increasing distances from roads, and that the relative contribution may vary by geographic location, season, and time of day. EMISSIONS OF UFPs FROM MOTOR VEHICLES This section of the report seeks to provide an under- standing of emissions of UFPs from the major classes of engine technologies, the characteristics of these particles, 103 Particles/cm3 1000- 100- 10- Tunnel (3) 167.64 71.45 99.09 — 48.18 47.00 34.58 II Street Canyon (7) Urban (24) On Road Road Side (2) (18) 42.07 — 39.13 and how they may change over time as new technology is introduced. In recent decades, attention has focused on the emis- sions associated with diesel engines. Figure 7 helps explain why. For the transport sector of the 2005 European particle number emissions inventory shown earlier in Figure 4, it shows a breakdown by engine type (Denier van der Gon et al. 2010). In almost every particle size category, diesel engines including both light -duty (passenger and light commercial vehicles) and heavy-duty (trucks, buses) accounted for a large portion of the total particle number emissions from the transport sector. Contributions to total emissions from other engine types and to a much lesser extent, from non -exhaust sources (tire and brake wear) are also projected. However, the relative contribution of diesel engines to total and transport -related particle number emissions is likely to vary locally or regionally depending on the com- position of the vehicle fleet. The work in southern Cali- fornia that was discussed in the previous section (Kleeman et al. 2008b; Ham and Kleeman 2011) illustrated how the source contributions to UFP concentrations can differ depending on the type of vehicles dominant on particular roads. On a regional scale, Keogh and colleagues (2009) modeled emissions contributions to PN emissions for urban southeast Queensland in Australia where they estimated that 93% of the vehicle kilometers traveled were accounted to light -duty, gasoline -powered vehicles and about 6% to 10.76 8.83 7.29 8.10 4.83 1 Urban Background (4) Measurement Location ■ Mean ❑ Median 2.61 2.91 iT Rural (8) Clean Background (5) Figure 6. Mean and median particle number concentration (log scale) for different environments. The number of sites for each environment are in parentheses (e.g., 3 tunnel studies). (Source: Morawska et al. 2008, reprinted with permission from Elsevier.) 17 Understanding the Health Effects of Ambient Ultrafine Particles Particle Number Emissions (x 102') 80,000 70,000 60,000 50,000 40,00D 30,000 20,000 10,000 10▪ -13 13-16 16-20 ... MD 20-25 26-32 32-41 41-51 ▪ Diesel exhaust, road transport Diesel exhaust, nun -road transport • Other exhaust (including 2 -stroke) w Brake and tire wear i i in • 51--65 65-81 01-102 102-129 120-162 162-205 205-258.258-325 Particle Number Size Ranges (rasa) Figure 7. Estimated particle number emissions from road transport and non -road transport (railway, inland navigation, and mobile machinery) in Europe for 2005, excluding international shipping. The diesel exhaust emissions were based on the diesel fleet composition in 2005. (Adapted from Denier van der Gon et al. 2010.) heavy-duty diesel vehicles. In that example, heavy-duty diesel engines still accounted for more than 50% of daily particle number emissions (3 to 1000 nm) but light -duty vehicles also contributed 45%. Particle number emissions from diesel and compressed natural gas (CNG) buses were comparatively much lower. Equivalent inventories of number emissions for the United States were not identified. Generation and Characterization of UFPs in Engine Emissions UFPs emitted from motor vehicles are primarily a product of the combustion process. They are formed in the engine during the combustion process itself as well as during the journey of the exhaust as it moves through the exhaust line and then through aftertreatment devices to the tailpipe from which it is released to the atmosphere. As the exhaust gradually cools during this journey, volatile and semivolatile materials such as organic components and ions may nucleate, thus forming new particles. This pro- cess produces UFPs in the few nanometer size range that may coagulate to form larger particles, may gradually grow in size as material condenses on their surface, or if com- posed solely of volatile species, may evaporate completely. However, particles formed from nucleation — sometimes called nucleation mode particles — are almost fully con- fined within the UFP size range (Kittelson 1998). The formation and subsequent physical and chemical changes in UFPs prior to their release from the tailpipe is a function of engine characteristics and aftertreatment tech- nology, fuel type, engine operating conditions (including state of maintenance), and ambient conditions. This section provides an overview of the typical number, size, and mass ranges of UFPs from compression -ignition (diesel -powered) and spark -ignition (gasoline -powered) vehicles, giving spe- cial emphasis to the formation characteristics of nucleation mode particles and the effects of aftertreatment technology such as diesel particle filters (DPFs) on particle numbers and composition. It also reflects on differences in emissions from light -duty and heavy-duty engines, on the effects of DPF regeneration, and finally on the implications of new fuel and technology specifications for future emissions. Diesel Engines Particle emissions from diesel engines have been studied and characterized extensively; indeed, a large part of our understanding about the physicochemical and toxicologic properties of PM is based on studies that have used diesel emissions. Although several general con- clusions can be reached about the nature of PM emissions 18 HEI Perspectives 3 from earlier generations of diesel engines, diesel engine technology has undergone radical changes during the last decade. Improvements in engine design and operating conditions, a combination of low -sulfur diesel fuel, and the use of highly efficient aftertreatment systems have led to significantly reduced diesel PM emissions. New diesel engines currently being sold in the industrialized coun- tries are contributing to an important and noteworthy shift in the composition of the diesel fleet in these regions. However, during this transition, many older technology engines will remain on the road both in industrialized countries and particularly in developing countries where the introduction of the newer technology has not yet occurred. Consequently we discuss emissions from old - and new -technology engines and also describe differences between their exhaust emissions. Emissions from Old -Technology Diesel Engines Diesel ultrafine PM is one of the most well analyzed components of vehicular PM. David Kittelson (1998) first introduced the concept of a trimodal exhaust size distribution, illustrated in Figure 1. Results from that study are representative of emissions from the older heavy-duty diesel vehicles. In particular, it showed that a large number of particles in the size range below 50 nm may be formed by nucleation, espe- cially from engines that produce a high concentration of volatile and semivolatile components. The concentration of nucleation mode particles measured in the on -road exhaust plume can reach 109/cm3 with a mean size around 10 nm (Giechaskiel et al. 2005; Kittelson et al. 2006). Such nucleation mode particles have since been observed by measurements on a number of different vehicles and sam- pling conditions; the many mechanisms proposed for the formation of such volatile particles have been summarized in a review by Seigneur (2009) of key studies reported in the period between 1998, when the Kittelson paper was published, and 2007. The majority of accumulation mode particles (> 50 nm) also fall well within the UFP size range on the basis of number but not mass (see Figure 1); this distinction between size and mass distribution is particularly impor- tant to keep in mind. Particles in this mode consist of a nonvolatile agglomerate core on which volatile and semi - volatile material adsorbs or condenses. The size distribu- tion curve for typical accumulation mode particles from diesel engines without DPFs has a lognormal shape with a mean particle size of approximately 60 nm and a tail extending down to the 20-30 nm range. Peak concentra- tions on the order of 108 particles/cm3 have been observed at the tailpipe or nearby on the road (Kittelson et al. 2006; Giechaskiel et al. 2009). While nonvolatile particles have generally been associ- ated with the accumulation mode, a growing body of evi- dence suggests that they may also appear in the nucleation mode. This phenomenon has primarily been observed during engine idling (Kittelson et al. 2006) and has been attributed to metallic ash formation, primarily from lubrica- tion oil. More recently, the presence of a combustion - generated nonvolatile solid core in the size range below 10 nm has been recorded in emissions from heavy-duty diesel vehicles (Lande et al. 2010) and light -duty diesel vehi- cles (De Filippo and Maricq 2008). There are indications from one study that such particles can be formed by spark - ignition combustion as well (Sgro et al. 2008). The exact origin of these particles, the conditions favoring their pro- duction and the frequency of appearance in vehicle exhaust are not yet identified. However, the concern is that these may act as condensation sites for the formation of UFPs before or while the exhaust is diluted in the ambient air. Emissions from New -Technology Diesel Engines In view of health and other concerns about emissions of PM from diesel engines, the United States and other industrialized countries have mandated stringent regulations to control emissions. One of the first regulatory steps taken was to reduce the levels of sulfur in diesel fuel from about 2000 ppm to 500 ppm in 1995, with further reduction to 15 parts per million (ppm) in the United States by 2006; equivalent reductions were made in diesel fuels in Europe by 2010. These changes reduced the levels of particulate sulfate emitted. In combination with the low -sulfur diesel fuel, DPFs have now been introduced. DPFs are made from ceramic or other porous materials and are generally coated with metallic catalysts; in some cases a diesel oxidation catalyst device is also positioned upstream of the DPF to enhance effectiveness (HEI 2011). DPFs have been a piv- otal factor in emission reductions; they have been shown to be effective in practically eliminating particle emissions across the size spectrum, including the UFPs (Coordi- nating Research Council 2009; Tzamkiozis et al. 2010; Khalek et al. 2011). However, because the DPF technology is relatively new, and also because the numbers and mass of particles emitted are extremely low, relatively few studies have been done to characterize the PM emissions in detail. Although DPFs have been highly effective at reducing particulate emissions, two issues related to the use of DPFs deserve further attention. First, several studies now sug- gest that under certain conditions, DPFs contribute to the formation of nucleation mode UFPs with a high fraction of sulfate (Tzamkiozis et al. 2010; Herner et al. 2011). In a detailed study, Herner and colleagues (2011) report that the emission of nucleation mode particles depends on the 19 Understanding the Health Effects of Ambient Ultrafine Particles condition and configuration of the aftertreatment system, engine operating conditions (particularly exhaust temper- ature in the aftertreatment system), and the sulfur content of fuel and lubrication oil (see also Hesterberg et al. 2011). Secondly, high -efficiency particle filters can become loaded with soot particles, which must be removed to pre- vent plugging. Removal is done by oxidizing the collected soot particles in place in a process called regeneration. During regeneration, transient high UFP emissions have been observed (Bergmann et al. 2009; Khalek et al. 2009, 2011). For example, in the testing of new -technology diesel engines described above, most of the UFP emissions were confined to the regeneration phase which generally lasted 30 to 45 minutes (Khalek et al. 2011). Still, the use of modern aftertreatment technologies represents a very important advance in reducing diesel emissions and are expected to improve air quality. Comparison of Emissions from Old -Technology vs. New - Technology Diesel Engines As mentioned above, the PM emissions from old- and new -technology diesel engines are different in several respects; these differences are dis- cussed below and summarized in Figure 8. Moss: The PM mass emitted from the new -technology engines is far lower than that from the old engines. For example, comparing the results of two series of tests, with 2004 engines (Coordinating Research Council 2007) and Mass Emissions 0.07 - 0.06 0.05 o.oa 003 0.02 0.01 0 004 2007 Engine Year Particle Numbers Ave re e brake -specific particle number emissions (particleslhp-hr) 3.5E+1a .. 3E*14 - $E414 . 2E+14 - 1.5Et14 - 1E+14 - 5E * 13 - 0 2004 FTP tno DPE} ■ 2007 new -technology engines (Khalek et al. 2011), the mass of emitted total PM is reduced by 89% (Coordinating Research Council 2009). Other authors have reported sim- ilar reductions. Number emissions: Based on a comparison of two series of tests reported in Coordinating Research Council 2007 and 2009, the number of particles emitted by the new -tech- nology (2007 model year) vs. the old -technology (2004) engines is lower by more than 100 -fold; during regenera- tion events, when most of the PM is emitted, the particle numbers are still 10 -fold lower as compared to the 2004 engine tests. Chemical Composition: New -technology diesel engines also have a significant effect on the chemical composition of diesel emissions (Maricq 2007; Biswas et al. 2009; Coor- dinating Research Council 2009, Hesterberg et al. 2011). PM from old -technology engines contains significant amounts of both OC and EC (with the latter being in excess), along with sulfate, metals and other ions. DPFs reduce the mass of EC present in solid particles, reduce volatile components that contribute to OC, and render the proportion of OC greater than EC. Also, the relative pro- portion of sulfate in the particles is now higher than it is in old -technology engine emissions. DPFs also effectively (> 95%) reduce the metal content of PM exhaust over typ- ical driving cycles (Hu et al. 2009; Cheung et al. 2010). PM Composition - 50 -laid reduction in mess; shift from carbonaceousio sullale composition 2007 16 -hr, 12407 FTP. ❑PF, with DPF, wilh4ut actwe regen active regen 1998 EC (soot and ash) oc • so, 2007 411. Figure 8. Comparison of the mass, numbers, and composition of emissions from old -technology and new -technology diesel engines. (Sources: 1998 data from Khalek, Personal Communication 2012; 2007 and 2009 data from Coordinating Research Council 2007, 2009.) 20 HEI Perspectives 3 To meet the stringent 2010 nitrogen oxides (NOx) stan- dards established by the EPA and similar rules in Europe, manufacturers of diesel vehicles have developed methods for selective catalytic reduction (SCR) of NO„ compounds. Some SCRs use vanadium (as V2O5) in the catalytic formu- lation. However Hu and colleagues (2009) have shown that vanadium -containing SCR systems, may release vanadium in the UFP size range if the temperature of the exhaust is too high. In the United States, vanadium -based SCR are used for agricultural and other nonroad applications, but on -road vehicles use copper-zeolite catalyst, which is stable at higher temperatures. In Europe for heavy-duty applications (and increasingly in developing countries), vanadium -based catalysts are more common. Spark -Ignition Engines Gasoline spark -ignition engines, provided that they are well maintained, produce only small amounts of PM under normal operating conditions. Recently, in response to the call for increased fuel efficiency, gasoline direct injection or direct injection spark ignition (DISI) tech- nology is being widely adopted. While helping to boost fuel economy, however, DISI engines produce increased numbers of UFPs. Concern about the increased UFP emissions from DISI technology has led to the development of alternative fuel injector designs; the spray -guided, center mounted injector appears to be particularly promising in reducing particulate mass and number emissions. Conventional Gasoline Engines The dominant method used to introduce fuel in the combustion chamber of gaso- line engines has been port injection. Under normal oper- ating conditions in modern gasoline engines, negligible numbers of UFPs are formed. Conditions do exist, some transient and some longer term, under which these engines may be significant contributors to UFP emissions. During start up under cold temperature conditions (cold starts), UFP emissions can increase, as can emissions of other gaseous pollutants. For example, Mathis and col- leagues (2005) showed that gasoline particle number may reach diesel -like levels in tests at --7°C and --23°C. Such emissions are clearly of greater concern in colder climates where they may be important contributors to UFP concen- trations under certain conditions. Poor engine maintenance can also lead to increased emis- sions of UFPs. Light -duty gasoline vehicles with visible smoke emitted from their tail pipes due to engine malfunc- tion (so-called smokers) may be significant contributors due to emissions from partial combustion of lubrication oil. Robert and colleagues (2007) estimated the UFPs emitted by smokers to be 10 mg/km compared with 0.05 mg/km for modern gasoline cars operating on mild driving cycles, and with 2 mg/km for cars operating on more aggressive driving cycles. In gasoline PM, OC dominates the mass of UFPs, fol- lowed by EC with traces of ions, including calcium, ammo- nium, sulfate, and various metals (Geller et al. 2006; Robert et al. 2007). Typically, gasoline UFPs contain a higher fraction of heavy polycyclic aromatic hydrocarbons (PAHs) than diesel exhaust (DE) which may have implica- tions for the differential toxicity of these particles (Geller et al. 2006; Cheung et at 2010). Gasoline Direct Injection Engines The direct injection of fuel into the cylinders of gasoline engines is increasingly being used because it improves fuel efficiency and perfor- mance. The gasoline DISI provides better control of the air - to -fuel ratio, especially while starting an engine and during warm up. Another important feature of the DISI is that it allows the use of a higher engine compression ratio, made possible because of cooling of the contents of the combus- tion cylinder as the direct -injected fuel spray evaporates. Because of the less complete mixing of fuel vapor and air, however, the particulate emissions of the engine increase, including the number of UFPs (HEI 2011). Studies have shown the size distribution of particles emitted by DISI engines is similar to that emitted from non- DPF diesel engines (Harris and Maricq 2001), and the parti- cle numbers emitted can sometimes be only 4-5 times lower than typical non-DPF diesel cars (Ntziachristos et al. 2004). The high particle number of DISI vehicles has raised ques- tions about the need to install particle filters in DISI vehi- cles; it has also led to an intense interest in fine tuning the injection —combustion control system that can reduce the UFP emissions problem. The development of spray -guided fuel injectors shows a great deal of promise in this regard. Other Types of Combustion Engines Small gasoline en- gines, in particular two-stroke engines installed in mopeds and scooters, are a significant source of particle emissions. In such engines, rich combustion, early scavenging of com- bustion products, in -cylinder injection of lubricant oil, and poor maintenance lead to elevated hydrocarbon emissions which may condense to form UFPs. UFP emissions from such engines have been shown to exceed typical diesel en- gines by more than one order of magnitude (Ntziachristos et al. 2005). The air quality implications of such high UFP emissions are of particular importance in developing coun- tries where a significant population of such vehicles is still in operation (Begum et al. 2006). Off -road machinery, such as construction equipment, diesel power generators (especially those used in devel- oping countries), lawn mowers, and marine engines, has been a significant source of pollution in certain locations. Among the industrialized countries, regulations are gradu- ally being introduced to control such sources. However, 21 Understanding the Health Effects of Ambient Ultrafine Particles the smaller of such sources — such as lawn mowers and other gardening equipment used by large numbers of con- sumers — are still not well controlled and may be a source of PM exposure. The situation in developing countries also deserves much attention. Non -Exhaust Sources Vehicles also generate PM through mechanical pro- cesses, namely wear on tires and brakes, abrasion of road surfaces, and resuspension of road dust. The particle number emissions inventory, displayed in Figure 7, proj- ects a contribution to total 2005 UFP emissions from tire and brake wear (but not including road -surface wear or resuspension) that is substantially smaller than that from exhaust, on the order of a few percent at most depending on particle size (Denier van der Gon et al. 2010). A laboratory study of debris released during braking events found that mechanical processes generally resulted in a distribution of particles with mean diameters in the range of a few micrometers but with tails extending to the UFP range; the number and size distribution varied with brake materials and other factors (Sanders et al. 2003). In addition to mechanically -generated particles, there has been some evidence of thermal particle formation due to the heat produced in cornering and braking (Dahl et al. 2006; Kukutschova et al. 2011). These particles have not been well studied to date. Vehicles contribute to an increase in ambient PM through abrasion of road surfaces and resuspension of road dust in the vehicle wake. However, the particles that accumulate on the road are in the micrometer size -range or larger. Smaller particles are not likely to settle on the road sur- face, but they are scavenged out of the atmosphere by pre- cipitation or by photochemical reactions. Hence, the contribution of particle resuspension to UFP concentra- tions is likely to be negligible, although measurements to confirm this assumption are necessary. Finally, in old engines, crankcase emissions have also been a source of UFPs (Rim et al. 2008; Tatli and Clark 2009). These should have been effectively addressed with the post -2007 emission standards that have implicitly called for closed -type crankcase breathing systems. Potential Effects of Other New Fuels and Technologies The development of new fuels and technologies is pro- gressing rapidly in response to various pressures for alterna- tive fuels, the need for greater fuel economy, and efforts to reduce air pollution. Such changes in fuels and technologies are likely to affect both overall emissions and the relative contributions from different vehicle classes. However, these effects are not yet well characterized. Buses Powered by CNG UFP emissions from CNG buses have been studied in some detail in an effort to understand whether CNG buses can be a successful alternative to diesel buses with advanced aftertreatment systems. Par- ticle number emissions of CNG buses are typically one order of magnitude lower than those of diesel buses without DPFs at low loads, but the CNG bus emissions can reach diesel -like concentrations during acceleration and at high load (e.g., Nylund et al. 2004; Jayaratne et al. 2009, 2010). In all cases, particle mass is a fraction of total PM emissions, implying that these particles are in the UFP size range. It appears that emissions largely result from lubri- cating oil consumption and are affected by catalyst loca- tion and the engine type (lean -burn versus stoichiometric). It has also been shown that, similar to spark -ignition engines, OC dominates the mass of particles from CNG buses; EC and inorganic species make up some 30% of the total mass (Okamoto et al. 2006). Biodiesel Use of biodiesel is seen as one part of a multi - pronged approach to reducing greenhouse gas emissions from transport, but the implications for UFP emissions de- serve some attention. Biodiesel is a synthetic fuel derived from plant or animal products and blended with fossil die- sel fuel at low percentages (10% to 20% by volume, some- times lower in Europe). These blends generally produce lower emissions of total PM mass. Under certain conditions, however, and even in low blending ratios, biodiesel may en- hance the formation of nucleation mode particles (Heikkila et al. 2009; Fontaras et al. 2010; Chuepeng et al. 2011). The UFPs produced contain reduced amounts of EC as a result of decreased soot formation and enhanced in -cylinder oxi- dation of any particles formed (Jung et al. 2006; Hoekman et al. 2009). Ethanol Gasoline containing 10% ethanol is widely sold in the United States, and the use of ethanol is poised to increase in the coming years with higher blend levels. The blending of ethanol in fuel can lead to higher volatility of the blended fuel. To compensate for this, lower volatility base gasoline is usually used, which could contribute to less homogeneous mixing of fuel and air in the combustion chamber and poor evaporation, and in turn to higher UFP emissions. Data concerning the effect of ethanol on UFP emissions is limited; however, no substantial variations of the already low UFP emissions of gasoline -powered vehi- cles appear likely (Lee et al. 2009). After extensive mod- eling, the U.S. EPA (2010) concluded that the use of ethanol blends will lead to only minor changes in annual or daily PM10 or PM2 5 concentrations; the effects on UFPs were not specifically evaluated. Emissions of PM may also arise from poor maintenance of vehicles (e.g., erroneous 22 HEI Perspectives 3 recognition of the petroleum/ethanol blend ratio could lead to nonstoichiometric combustion with significant effects on releases of UFPs). Electric Drive Technologies Hybrid electric vehicles, plug-in hybrid electric vehicles, battery electric vehicles, and fuel cell vehicles have started to be marketed in many countries during the last few years. With tailpipe emis- sions at least comparable to the cleanest available gasoline engines (in the case of hybrid electric vehicles and plug-in hybrid electric vehicles) to zero emissions (in the case of battery electric vehicles and fuel cell vehicles), the increasing employment of such vehicles in the market should eventually have a net beneficial effect on all traffic - related emissions, including those of UFPs. Summary of Motor Vehicle UFP Emissions UFPs from motor vehicles are emitted primarily in exhaust from internal combustion engines. Non -exhaust sources such as mechanical wear on tire and brakes, abra- sion of road surfaces, and resuspension of road dust have begun to receive some attention, but their contributions to emissions of UFPs have not been extensively studied. Diesel engine technology, in particular, has historically favored the formation of particles in the ultrafine range, so their emissions and the factors giving rise to them have been extensively characterized. Changes in the sulfur con- tent of diesel fuels, optimization of engine design and operating conditions, and the use of modern aftertreatment technologies have led to substantial reductions in diesel engine UFP emissions as well as to significant changes in their chemical composition. However, emissions of UFPs during DPF regeneration events and under other engine operating conditions deserve further attention. Well -maintained gasoline spark -ignition engines using conventional port injection technology produce little UFP or other PM emissions under normal operating conditions. Newer fuel -efficient gasoline engines using DISI tech- nology have been found to release UFPs in similar size ranges as diesel engines, but at a lower rate of emissions. Optimization of engine design and operating conditions to reduce emissions are being pursued, and the need for DPFs is being considered. These two engine technologies, while they currently dominate the automotive fleet and consequently receive the most focus, are not the only types of combustion engines that contribute to UFP emissions. Rapid changes are occurring in fuels and in technologies that are likely to affect overall emissions, the relative contributions from different vehicle classes, and the relative importance of non -exhaust sources. The collective impact of all these changes on either overall emissions or ambient concentra- tions has not been thoroughly explored and is likely to vary regionally depending on the rate and extent to which they are deployed in different parts of the world. CHARACTERIZING HUMAN EXPOSURE TO AMBIENT UFPs The characterization of the sources and emissions of UFPs is an important first step. However, understanding the potential implications of these emissions for human health requires characterization of potential human expo- sures — how the concentrations and composition of UFPs vary over time and in the different locations where people live, travel, and work. Such information helps inform the design of relevant exposures for use in experimental set- tings with animal and human subjects (Chapter 3). Epide- miologic study designs take advantage of these variations in ambient concentrations to explore their implications for human health (Chapter 4). In the case of PM10 and PM2.5, such studies have played key roles in determining the numerical levels at which ambient standards are set. Providing a comprehensive characterization of UFP concentrations is challenging because no networks of UFP monitors currently exist. Instead, studies often provide a snapshot of specific locales at particular points in time, often relying on different monitoring methods. They may, or may not, include measurements of other pollutants, including other particulate size fractions and gaseous cop ollutants, that may ultimately be needed to understand more specifically the role of UFPs and their sources on health. To augment measurement data, various efforts to model UFP concentrations are also under development. This section of the document provides an overview of what these studies tell us about how ambient UFP concen- trations vary over time and space, in particular in relation to traffic in urban areas. Like the majority of studies, this summary focuses variation in measures of NC with some data on differences in particle mass and composition. Factors Affecting Concentrations and Composition of Ambient UFPs Numerous processes influence the concentrations and composition of ambient UFPs over different spatial and temporal scales. At a very local scale, Figure 9 schemati- cally illustrates the typical evolution of an exhaust aerosol packet immediately before and after it leaves the tailpipe of a diesel vehicle not equipped with DPFs. It describes the processes leading to changes in the size distribution and dilution ratio with increasing distance from the tailpipe until particles merge into the urban background. 23 Understanding the Health Effects of Ambient Ultrafine Particles Once emitted directly to the atmosphere or nucleated in the cooled exhaust from combustion sources such as motor vehicles, UFPs undergo coagulation and gas —particle exchange with the surrounding atmosphere (Zhang et al. 2004). Coagulation (particle collision and adherence) favors the transfer of the smallest UFPs to the larger size fractions, usually with diameters > 100 nm, over timescales of a few hours. This process can be an effective atmo- spheric removal mechanism for primary UFPs, which have very low settling velocities (Herner et al. 2006). Gas — particle exchange (condensation or evaporation) favors the growth or shrinkage of particles in the cooled combustion exhaust depending on the concentration of the sur- rounding gas -phase material over timescales of seconds to minutes (Zhang et al. 2004). As dilution with ambient air cools the exhaust, the gas -phase material initially becomes supersaturated, leading to nucleation and growth of semi - volatile organic compounds. Continued dilution reduces the gas -phase concentration below the saturation level, causing the nucleated particles to evaporate completely or leaving the solid primary cores of UFPs that previously acted as condensation sites. UFP concentrations beside busy roadways also depend strongly on emissions patterns, but the diurnal or seasonal cycle of temperature can strongly modify UFP NCs (Charron and Harrison 2003; Kuhn et al. 2005). Lower ambient temperatures favor the formation of greater num- bers of the smallest particles (< 50 nm) in the roadside envi- ronment (although these particles may evaporate completely within 300 meters downwind of roadways (Zhu et al. 2004; also discussed below). Relatively low tempera- ture and high humidity are associated with higher rates of new particle formation and slower atmospheric dispersion, indicating that UFP concentrations will generally be higher in the winter than in the summer (Sioutas et al. 2005). Lower temperatures near the ground at night also con- tribute to the formation of stable atmospheric layers that trap primary pollutants near their emissions source (Herner et al. 2006); this effect can dominate UFP concentrations in regions that are not heavily influenced by photochemistry. As an example, the highest concentrations of UFP number and mass during a winter pollution event in the San Joa- quin Valley were measured during the evening hours, with lower concentrations measured during the day (Herner et al. 2005). When photochemistry is important at a location, the opposite diurnal pattern is often observed. Numerous studies have observed that total NCs are positively corre- lated with ozone (O3) concentrations during the summer period, suggesting that the highest number concentrations occur on the warmest days (Sioutas et al. 2005). dNldlogDp (cm') 1a° 1 10= 10' 1O5 10° Scale: Temporal: ll III IV V 100 nm 100 nm 100 nm 1 hr 0.15 15 1m3n 1:1 10:1 10'',1 10:1 1 day Spatial, Tailpipe 1-10m Tensor Hundreds Urban Meters of Meters Background Dilution Ratio Figure 9. Typical evolution of an exhaust aerosol packet immediately before and after it leaves the tailpipe of a diesel vehicle not equipped with DPF. The initial size distribution is engine and operation condition dependent. Also, the exact time evolution of the size distribution (illus- trated in columns I through V) and the dilution ratio (red line) will depend on the exhaust, traveling, and ambient conditions. In general, five phases are observed: I) A lognormal distribution of nonvolatile particles is produced in the engine and leaves the tailpipe. II) Rapid dilution with ambient air takes place that decreases the concentration of non-volatile particles. Depending on traveling speed, dilution ratio can reach 102:1 up to 104:1 during the first second after emission. In parallel, a nucleation mode of volatile particles forms in the sub -50 nm size range. III) Further dilution downwind of emission production takes place that decreases concentration of volatiles and leads to mild evaporation of volatile nanoparticles. IV) Particle concentration almost reaches background levels and nanoparticles have almost completely disappeared. V) A new (secondary) nanoparticle mode may be formed as a result of photochem- ical reactions. Physical geography, such as topography and altitude also influence dispersion; low-lying valleys collect PM, and high elevations have greater atmospheric dispersion (Sardar et al. 2004; Zhou and Levy 2007). Urban street can- yons are subject to low wind speeds and poor mixing during most times of the day, so UFP concentrations at these locations are dominated by a diurnal cycle of traffic emissions. The higher concentrations in street canyons rel- ative to those near roads or in urban background sites were evident in the meta -analysis by Morawska and colleagues (2008) discussed earlier (see Figure 6). Scientists have expressed increasing interest in regional - scale nucleation events where large numbers of particles can be formed across distances of hundreds of kilometers through nucleation processes similar to those discussed in the context of vehicle exhaust as it cools near roadways. 24 HEI Perspectives 3 Nucleation events and their potential contribution to ambient UFP number concentration levels and human exposures have not been a focus of this issue of HEI Per- spectives. They are discussed briefly in Sidebar 1. Spatial Variation of Ambient UFP Concentrations As the schematic illustration of the fate of a diesel aerosol packet in Figure 9 would suggest, observed spatial gradients of UFPs in the atmosphere are sharp, with the highest con- centrations generally observed in the immediate proximity of combustion sources followed by a rapid decay. Zhu and colleagues (2002) were among the earliest investigators to monitor the change in UFP numbers and size distributions with distance from major freeways. UFP measurements were taken near a major interstate highway (freeway 710) in Los Angeles, California, where approximately 25% of the traffic came from heavy-duty diesel trucks. Figure 10 illus- trates the highest NCs of the smallest sized UFPs nearest the road, followed by a rapid drop-off in concentration, transi- tion to larger particles with increasing distance, and blend- ing into background levels at approximately 300 meters. Subsequent studies by these investigators and others have shown that these gradients can show diurnal and seasonal patterns, for example, with the distance required to reach background extending to 500 meters or more under night- time conditions (Zhu et al. 2006). Kerner and colleagues (2010) have now conducted a meta -analysis of 41 studies that evaluated gradients in UFPs and other traffic -related pollutants as a function of distance from roadways. Their analysis is notable because of their efforts to normalize concentrations to account for differences among studies in background concentrations (background normalization) and the distances from the edge of road at which measurements are made (edge -of - road normalization). Furthermore, the authors analyze and compare the concentration gradients for several particulate size fractions (UFPs > 3nm [UF1], > 15 nm [UF2], PM2.5, and PM10) as well as for several other traffic -related pollut- ants measured in the same studies (carbon monoxide [CO], EC, benzene, nitric oxide [NO], nitrogen dioxide [NO2], NON, and VOCs). 3.0E+5 O 2.0E+5 61 O 1 z D 1.0E+5 17 m 30 m._ k I \1 Upwind ry rl 90 m 150m ---300 m 10 100 Particle Diameter, Dp (rim) 1000 Figure 10. Ultrafine particle size distribution at different sampling loca- tions near the 710 freeway in Los Angeles, CA. (Source: Zhu et al. 2002, reprinted with permission from Elsevier.) Sidebar 1. Regional Nucleation Events Regional nucleation events differ from near -roadway nucleation events because the super saturation of semivolatile compounds across the regional events is driven by the buildup of chemical reaction products rather than by the cooling of hot exhaust gases near the roadway. On a global basis, particle nucleation events are best known as an important source of cloud condensation nuclei that influence cloud properties and climate. On a regional and urban scale, nucle- ation can significantly increase the NC over large population centers (Stanier et al. 2004; Cheung et al. 2012). In the Sta- nier study for example, conducted in Pittsburg, Pennsylvania, nucleation events were observed on —30% of the days during an extended study period. Despite the common occurrence of regional nucleation events, the mechanisms that control nucleation rates and the chemical composition of nucleated particles are poorly understood. Venkatachari and colleagues (2007) have studied nucleation events in Flushing, New York, and suggest that concentrations of reactive oxidative species were higher in the submicron fractions relative to larger particles. Recent results from the European Integrated project on Aerosol Cloud Climate and Air Quality suggest that sulfuric acid plays a central role in most nucleation events, although some other stabilizing compound such as ammonia or amines must also play a role. Since most epidemiologic studies have assessed associations between total ambient UFP NC and health, the specific implications of regional nucleation events, independent from other ambient UFP sources, for public health are not yet known. No epidemiologic studies have been done to isolate the effect of nucleation events on short- or long-term expo- sures and on health. 25 Understanding the Health Effects of Ambient Ultrafine Particles Figure 11 displays their results, which essentially show the percentage decrease in the concentrations of several pol- lutants from the roadway edge to various distances up to 500 meters. It confirms the rapid decline in the concentra- tions of the smallest UFP size fraction (UF1) within the first 100 meters with a more gradual decline in the UF2 size frac- tion to near background levels at distances of over 500 meters. The comparisons with other pollutants are useful for indicating those pollutants whose decay patterns are sim- ilar to those of UFPs and therefore are more likely to be correlated with one another. Like the different UFP size fractions, several of the other pollutants (CO, EC, NO, NO2, NON, VOCs) showed steep declines in the first 100 meters from the road. PM2.5 and PM10 appear somewhat elevated nearer to roads, but generally appear to be much less spa- tially variable and more representative of background levels. Correlations between pollutants that show similar patterns of decay are thus higher than between those that are distributed differently (see, for example, Kaur and col- leagues' study [2005] of personal exposure to UFPs, CO, and PM2.5 at an urban intersection in London). Given the steep gradients in UFP concentrations near sources like traffic, substantial spatial variation in UFPs can exist across a single city. In a study designed specifically to compare variation in different particle metrics, Puustinen and colleagues (2007) measured PM10, PM2.5, and total NC (using CPC) outdoors and indoors at a total of about 150 home sites spread across four European cities (Athens, Amsterdam, Birmingham, and Helsinki). Figure 12 compares variation in 24 -hour average total NC and PM2.5. 1.0 6.5 0.4 02 0.0 Although variation was observed in both total NC and PM2.5 across sites in the individual cities, the degree of variation tended to be greater for total NC than for PM2.5. The high degree of spatial variation in UFP concentra- tions poses both an opportunity and a challenge for scien- tists trying to represent population exposure to UFPs for health studies, particularly for longer -term average expo- sures. On the one hand, variation in concentrations of a pollutant is essential to investigate whether pollutant exposures may be related to variations in health outcomes. On the other hand, the high spatial variability makes it more difficult to rely on measurement strategies that have been adequate for more spatially homogenous particulate fractions like PM2.5. PM2.5 measurements taken at dif- ferent locations around a city are usually better correlated with one another than are measurements of spatially heter- ogenous particulate fractions; exposure can therefore more reliably be represented by a city-wide average or by a cen- tral site monitor over the longer term. For example, when the correlations between the central site and residential outdoor 24 -hour concentrations of PM2.5 and NC were compared for all sites within each of the four cities shown in Figure 12, the correlations for PM2.5 were generally higher (city medians: 0.79-0.98) and less variable across the sites than those for total NC (city medians: 0.67-0.76) (Figure 13). For total NC, median cor- relations varied considerably by residential site. The greater variability in correlations for total NC measurements sug- gests the potential for greater error in the degree to which central site measurements represent individual exposures for UPFs relative to PM2.5. This greater measurement error Rapid: }5D% drop by 150 to Less rapid or gradual decay No trend CO (32) - - - EC (49) NO (67) NOx (30) --UF1 Particle no. (76( 1, - — - — UF2 Particle no. (93) ',',..•,‘ VoC1 (BO) Benzene (33) - - - NO2 (125) PM2 a (61) ti' — — • - r • — _ _ -•�•••• = ,-,-� Fine particle no (19( - - - PMiO {57) VOC2(32) 0 100 200 300 400 0 100 200 300 400 0 Distance from Road Edge (m) 100 200 300 400 Figure 11. Local regression of road -edge normalized concentrations on distance from the edge of road. The horizontal black lines indicate reductions of 50% (0.5) and 90% (0.1) from the concentrations measured at the edge of the road. The regression sample size, it, is given in parentheses after each pol- lutant. (Source: Kamer et al. 2010, reprinted with permission from the American Chemical Society.) 26 HEI Perspectives 3 can limit the statistical strength of epidemiologic studies to observe any true associations that might exist. Either many more monitoring sites, or a reliable modeling strategy, would be necessary to characterize the UFP con- centrations experienced in a population across a city, par- ticularly over the longer term. Total NC (numberlcm3) 100,9CD - 90,000 - 80,00D - 70,000 - 60,000 - 50,00D - 40.000 - 30,000 20,00D - 10,000 0 • i Total NC t I - Helsinki Athens Amsterdam Birmingham City Temporal Variations Even in the case of strong differ- ences in absolute concentrations among sites (i.e., spatial variability), particular geographic locations are influenced by common diurnal patterns and meteorological influ- ences. Consequently, measurements at those locations may be temporally correlated. High temporal correlations among 120 100- - 80 0- 40 60 20 - 0- 1I i Helsinki PM, i • • • 4 t . i It r Athens Amsterdam Birmingham City Figure 12. Distribution of 24 -hour average central site (left box plot) and residential outdoor concentrations (right box plot) of total NC and PM2 5. The center line of the box is the median, the dotted line is the mean. The outer lines of the box represent the 25th and 75th percentiles, and the whiskers repre- sent the lath and 90th percentiles. (Source: Puustinen et al. 2007, reprinted with permission from Elsevier.) Pearson Correlation TotaL NC I • i • • • • Helsinki Athens Amsterdam Birmingham • • • PM2.5 • • • Helsinki Athens Amsterdam Birmingham Figure 13. Distribution of individual Pearson correlation coefficients of 24 -hour central site and residential outdoor concentrations for total NC and PM2 5. The center line of the box is the median, the outer lines of the box represent the 25th and 75th percentiles, and the whiskers represent the 10th and 90th percentiles. (Source: Puustinen et al. 2007, reprinted with permission from Elsevier.) 27 Understanding the Health Effects of Ambient Ultrafine Particles monitoring sites indicate that ambient fixed -site monitoring may be adequate for estimation of population exposure in study designs that examine the effect of short-term changes in air quality. The study by Puustinen and colleagues again provides a good example of high temporal correlations between sites using data from one of their study sites, a residence at an urban background site in Helsinki. Figure 14 compares the hourly variation in total number concentrations measured outdoors and indoors at their study site with those mea- sured at the central monitoring site over the course of one week in January 2004. Other studies also suggest that cor- relations between monitoring sites can vary more from location to location. Cyrys and colleagues (2008) reported high correlation coefficients (r> 0.8) for site -to -site hourly average measurements among four traffic -affected sites in Augsburg, Germany. However, Moore and colleagues (2009), who measured total NC over a period of about one year at 14 sites in the Los Angeles area of the United States, found that the median hourly correlation coefficient across all sites varied from 0.3-0.56. They reported a 10 -fold vari- ability in hourly UFP count measurements (10,000- 90,000) calculated by month. Tuch and colleagues (2006) reported a correlation of 0.31 between two locations (one roadside, one mixed industrial area) that are 1.5 km apart, across all days, in Leipzig, Germany. Given the site -specific nature of these correlations, and their implications for how well human exposure may be 10[.000• E m 1[,000• r1r14 • 141 1'•• ,-tip tea:`, }1_ Ji1I moo• 1.7 — Central MOEN --- Outdoor 11 iia 1 S �ytf.• ••a r} ! .�1 j 1 j .. �r 20 21 22 23 24 25 26 Date (January 2004) Figure 14. Illustrative example of hourly total NC measured indoors, outdoors, and at a central site for one week in January 2004 for an urban background study site in Helsinki, Finland. The correlation between hourly residential outdoor and central site concentrations was 0.99, although the concentrations were lower at the home than at the central site (ratio 0.37). (Source: Puustinen et al. 2007, reprinted with permission from Elsevier.) measured, such correlations need to be carefully evaluated when designing studies and when reporting and inter- preting study results. Copollutant Concentrations Given their sources, UFPs are typically found in the presence of a number of other pollutants of interest to human health (e.g., CO, NO, NON, NO2, EC, PM2.5, PM10,) as illustrated in Figure 11. Under- standing the spatial and temporal relationships between UFPs and the other pollutants with which they may co - vary is critical for efforts to assess their independent effects. However, copollutant exposures have not been consistently measured or reported in studies. Some authors have suggested that NO2 may be acting as a surrogate for other harmful pollutants in the traffic pollu- tion mixture, including UFPs, based on associations of within -city NO2 concentrations and adverse health effects in some epidemiologic studies (Seaton and Dennekamp 2003; WHO 2006). There is some evidence to suggest rela- tively high correlations between UFPs and NOx (Sardar et al. 2004; Vinzents et al. 2005; Andersen et al. 2008b). While the recent HEI Special Report on Traffic (2010) cau- tioned that none of the traffic -related pollutants evaluated (including NO2, UFP, CO, EC, or black carbon [BC]) met all the criteria for an ideal surrogate for traffic), it is possible that observed associations between health effects and spa- tial patterns in NO2 related to traffic also reflect spatial patterns in traffic -related UFPs. Consistent with the evidence provided by Kamer and col- leagues (2010), results from several studies seem to suggest that UFPs and PM2.5 can be governed by different processes, so their concentrations are less likely to be well correlated. Investigators interested in the impact of local traffic restric- tions on air quality in New York City found that, in contrast to PM2 5, near -road NC (for particles 5-560 nm in diameter) varied linearly with measures of traffic flow, suggesting that they were highly influenced by traffic sources (Whitlow et al. 2011). Atmospheric processing may lead to inverse correlations between UFP concentrations and PM2 5 concentrations, as coagulation and condensational growth moves material from the UFP size range to the accumulation mode size range over time (Chung et al. 2001; Herner et al. 2006). PM2.5 concentrations increased by a factor of three during a winter stagnation event in cen- tral California, but UFP number and PM01 mass concen- trations remained relatively constant (Herner et al. 2005; Kelly et al. 2011). Microenvironmental Exposures to UFPs The preceding sections have focused on how well spa- tial and temporal patterns in ambient concentrations of 28 HEI Perspectives 3 UFPs, often measured at some central location, represent those that individuals might experience at their homes. Such central site ambient measurements are the most common indicators of exposure used in epidemiologic studies. However, scientists know that an individual's total personal exposure to any air pollutant is actually a function of microenvironments, the places where people spend time during the day in which the air pollutant con- centrations may differ (e.g., at home, at work, during a commute). It is also well known that concentrations in individual microenvironments can have origins both in ambient air and within the microenvironment. Though sources or precursors of UFPs within microenvironments can be substantial (Abt et al. 2000; Diapouli et al. 2008; Guo et al. 2010; Wang et al. 2010; Hovorka and BraniS 2011), and may themselves merit evaluation in health studies, they are not the focus of this document. We have focused this discussion on whether concentrations mea- sured outdoors are in fact a good representation of human exposure to particles of ambient origin and the circum- stances under which they may fall short. Such insights are important for the interpretation of health studies that may rely solely on outdoor measurements. Ambient Contributions to Indoor Concentrations of UFPs Indoor microenvironments (e.g., home, work, schools, stores, etc.) are some of the most important deter- minants of personal exposure simply by virtue of the time we spend in them. Most people in the United States and in Europe spend a large fraction (90% or more) of their time indoors. One broad approach to understanding how well ambient measurements may represent indoor exposures to particles of ambient origin is to evaluate whether the variations in ambient air concentrations are temporally or spatially correlated with those of indoor concentrations. A study by Hoek and colleagues (2008) is one of the few studies that has systematically examined such relationships for UFPs, along with other pollutants, inside a large number of homes in multiple cities. Using the same dataset as Puustinen and colleagues (2007) for 152 homes in four European cities (Amsterdam, Athens, Birmingham, and Helsinki), Hoek and colleagues analyzed the 24 -hour corre- lations between indoor and central site concentrations for particle number, PM2.5, soot, and sulfate over a one -week period. They reported that correlations were lower on average for particle number (0.18-0.45) than they were for the other pollutants (PM2.5 [0.40-0.801, soot [0.64-0.921, and sulfate (0.91-0.991), a finding that the authors sug- gested might be related to the higher spatial variability in ambient UFPs discussed earlier, as well as to the lower infiltration of UFPs and to the presence of indoor sources. The results of Hoek and colleagues (2008) can be inter- preted with the help of a number of other studies that have evaluated indoor and outdoor particle NC relationships, including estimating infiltration and the effect of indoor sources. These studies have reported moderately high infil- tration fractions for UFPs and have noted that infiltration varies with particle size. Zhu and colleagues (2005) mea- sured indoor UFPs in four apartments near a major freeway in Los Angeles and reported low (0.1-0.4) infiltration frac- tions for the smallest (10-20 nm) particles but moderate to high infiltration fractions (0.6-0.9) for 70-100 nm particles. Sarnat and colleagues (2006a) described a similar size - related pattern of infiltration fractions in 17 homes of non- smokers in Los Angeles. These results are consistent with a study in 4 homes of nonsmokers in Boston, where Abt and colleagues (2000) reported Spearman correlations between home indoor and outdoor concentrations of 0.67 for 20-100 nm particles, 0.90 for 100-500 nm particles, and 0.83 for 700-2500 nm particles. The indoor:outdoor UFP ratios estimated from measurements in seven primary schools in Athens, Greece, ranged from 0.33 to 0.74 and were lower in general that those for PM10 and PM2.5 (Diapouli et al. 2008). Studies have also suggested that the composition of particles that infiltrate to the indoors may also differ from that of outdoor particles (Sarnat et al. 2006a; Polidori et al. 2007). Other factors can strongly influence estimated UFP infiltration rates including: air exchange or ventilation rates within buildings, presence of local outdoor sources, wind speed, season, numbers of occupants, and time of day (which may be related to indoor activities that gen- erate particles, like cooking) (Koponen et al. 2001; Sarnat et al. 2006a; Polidori et al. 2007; Guo et al. 2008; Hoek et al. 2008; Parker et al. 2008; Weichenthal et al. 2008; Wang et at 2010). Collectively, these factors help explain why the relation- ships between outdoor and indoor concentrations of UFPs are more variable and the correlations generally lower than they are for PM2.5 and other pollutants. They need to be considered carefully when interpreting the results of epi- demiologic studies based on ambient measurements. In -Vehicle Exposures Given the high concentrations of UFPs reported on or near roads, a large number of studies have evaluated concentrations in vehicles and as a function of mode of transport. For example, Westerdahl and col- leagues (2005) reported in -vehicle total NC measurements in Los Angeles of 55,000-200,000 on freeways, 40,000 on arterial roads, and 14,000-27,000 in residential areas (back- ground) averaged over several hours. Concentrations mea- sured while following diesel vehicles resulted in peak concentrations of up to 800,000. In -vehicle concentrations 29 Understanding the Health Effects of Ambient Ultrafine Particles were also strongly dependent on the number of vehicles in front of the measurement vehicle at intersections. Based on these and other measurements, Fruin and col- leagues (2008) conducted a microenvironmental analysis and estimated that 33%-45% of total UFP exposure for Los Angeles residents was due to time spent traveling in vehicles (Fruin et al. 2008). In another study of Los Angeles freeway exposures, Zhu and colleagues (2007) estimated that a 1 -hour commute accounted for 10%-50% of daily exposure to traffic -generated UFPs. Further evalu- ation is required to determine whether these study results of the importance of commuting exposures in the high - traffic areas around Los Angeles are representative of com- muting exposures in areas with less traffic or shorter com- muting times. In -vehicle UFP concentrations can be affected by a number of factors, including temperature, wind speed, traffic counts, and numbers of passengers (Gong et al. 2009; Knibbs et al. 2011) as well as vehicle ventilation (and filtration). Standard automobile filters result in reductions of between approximately 30% and 60% in in - vehicle UFP concentrations (Zhu et al. 2007; Pui et al. 2008; Qi et al. 2008), while these percentages can be increased with advanced filters (Burtscher et al. 2008). Zhu and colleagues (2007) found that the lowest in -vehicle concentrations were observed (—85% reduction) when fans were operated on recirculation mode, and that stan- dard filters provided reductions of —50% for the smallest particles (7-40 nm), but that this decreased to —20%-30% for particles in the 40-200 nm size range. In a study in the Netherlands designed to examine the effects of transport method (car, bus, bicycle), route (high and low traffic), and fuel type (gasoline, diesel, and elec- tric) on commuter exposures to total particle numbers and other pollutants, Zuurbier and colleagues (2010) reported no significant differences between concentrations of par- ticle numbers inside diesel and gasoline automobiles. They suggested that this result may be a reflection of the ambient environment surrounding the automobiles and infiltration of UFPs rather than self -pollution. Commuter exposures to total particle NC in this study were lowest among those riding electric buses. Exposures via all modes of transport were elevated when following high -traffic routes relative to when travelling low -traffic routes. Knibbs and colleagues (2011) conducted a meta -analysis of 47 in -transit studies to assess the differences in microen- vironmental exposures experienced using different modes of transit (e.g., travel by bicycle, automobile, walking, ferry, rail, automobile tunnel). They reported overall trip - weighted mean UFP concentrations to be lowest for bicy- clists (34,000 particles/cm3) and highest when riding in an automobile in a traffic tunnel (300,000 particles/cm3). Implications for Other Countries Most of the studies of UFP concentrations reported above have been performed in locations in the United States or Europe; they may not be representative of concentrations in other countries where the mixture of vehicle type, emission controls, and fuel composition are different. For example, Lung and colleagues (unpublished data, 2005) measured exposures of pedestrians standing at intersections in Taiwan and found variable, but much higher concentrations (123,639 particles/cm3) than reported elsewhere. Recently, Apte and colleagues (2011) studied PM levels on the roads of Delhi, India, which have a large number of auto -rick- shaws. Trip -averaged concentrations were about 280,000 particles/cm3, which corresponded to about eight times the ambient levels. Peak concentrations of 800,000 parti- cles/cm3 were measured over a 10 -second interval. Modeling UFP Concentrations In the absence of extensive monitoring networks for UFPs, investigators have begun to augment the limited monitoring data with mathematical modeling approaches for predicting spatial and temporal concentrations of UFPs over broader areas. Two methods have been explored: regional transport models and land -use regression models. In theory, numerous regional advection and dispersion models could be used to study the fate of primary UFPs (as discussed, for example, in the review by Holmes and Morawska [20061), but special care must be exercised to specify the correct emissions rate, coagulation rate, and nucleation rate in order to represent ambient UFP NCs. Regional transport models that have incorporated these additional parameters, like the Community Multiscale Air Quality Model used the by U.S. EPA for regulatory analyses, have not been able to accurately predict UFP NCs (Elleman and Covert 2009, 2010). As of this writing, two groups have explored land -use regression methods to model UFP concentrations in urban areas. Land -use regression models predict pollutant con- centrations using relationships with land -use features such traffic intensity, building density, industrial develop- ment, and the amount of green space. Hoek and colleagues (2011) developed a land -use regression model with which they were able to explain 67% of the variability in mea- sured total particle NC in Amsterdam. Terms in the model included the product of traffic intensity and the inverse distance to the nearest road squared (as measured in field observations), address density, and location near the port. When the variables obtained from field observations were removed, substantially less variability was explained (R2 = 44%). The median temporal correlation between concentrations at the central site and the outdoor locations 30 HEI Perspectives 3 was fairly high (r = 0.72). At the urban background loca- tion, there was a very low temporal correlation between PM2.5 and particle NC (r = 0.19) and between particle NC and soot (r = 0.38). Abernethy (2012) developed a land -use regression model for UFPs using one -hour particle NC measurements (using CPC) at 80 locations and 135 geo- graphic predictors in Vancouver, Canada. The strongest model predicted NC on the basis of length of truck routes within 50 meters, density of fast food locations within 200 meters, and natural log of the distance to the nearest port, but accounted for only half the variability in mea- sured particle NC (R2 = 0.48). Hourly median particle NCs were highly variable across the city; two-week average number concentrations were well -correlated with NO2, NO, and NOx concentrations at the same sites (r = 0.64, 0.65, and 0.70 respectively). Broader application of these models has been limited by sufficient UFP measurements with which to develop models. Summary of Evidence Characterizing Human Exposure to Ambient UFPs Several factors acting on the emission, transformation, and dispersion of UFPs contribute to the substantial spa- tial variability that exists in NCs within urban areas. This high degree of spatial variability presents an opportunity to study the potential related health effects but also sug- gests that epidemiologic studies of long-term exposures would require detailed spatial characterization of UFP concentrations. Despite this spatial variability, NCs within an urban area have been shown to be reasonably correlated over time. In other words, a central monitoring site, while not accu- rately characterizing the concentration of UFPs elsewhere in the city, can be a reasonable measure of within- and between -day changes in UFP concentrations throughout the urban area. However, variation in the degree of correla- tion between sites over time may vary by city and should be confirmed before reliance on a central site monitor can be uniformly advised. Analysis of UFP exposures by microenvironments indi- cates that, while indoor sources of UFPs can contribute to high indoor concentrations, contributions from outdoor sources can be substantial. Infiltration of UFPs from out- door air varies with particle size but is relatively efficient for particles in the 70-100 nm size range. In the absence of major indoor sources, ambient UFP concentrations are moderately correlated with indoor concentrations. Where reasonably high correlations between indoor and outdoor concentrations exist, central monitoring sites may be ade- quate to characterize changes in personal exposure to UFPs in studies that rely on temporal variability. Microenvironmental exposure analyses suggest that time spent in proximity to motor vehicles is a major con- tributor to personal exposure to ambient UFPs (NC) in urban areas. Depending upon commuting mode, route type, and duration, exposures during commuting may account for as much as 50% of an individual's daily UFP exposure. Land -use regression and other approaches to modeling ambient UFP concentrations may eventually provide an important alternative to or complement of intensive mea- surement campaigns. However, further work is necessary to assess the accuracy of the models' predictions in more locations and under different conditions. Adequate mea- surement data will still be necessary to build models and to evaluate their performance. CHAPTER 3. Do UFPs Affect Health? What Is the Evidence from Experimental Studies in Animals and Humans? Concern about the possible role of UFPs in air pollution health effects was originally driven by a greater under- standing of the unique physical and chemical properties of UFPs. This concern was supported by laboratory animal exposure studies suggesting that UFPs are more toxic than larger particles at an equivalent mass dose. More recently, with the development of systems for concentrating and delivering ambient particles in the UFP size range, studies to investigate the effects of human exposure to UFPs in clinical settings have become possible. This chapter will first address the unique physical prop- erties of UFPs, summarizing what is known about their deposition, clearance, and translocation. The physical characteristics of particles in the UFP size range pro- foundly affect their behavior after inhalation into the respiratory system. These characteristics are hypothesized to account in part for potential differences in toxicity in comparison with larger particles in the accumulation mode or fine particle (PM2.5) size range. We will then review the key findings of experimental studies in laboratory animals and humans. Our primary focus will be on studies considered most relevant to effects of ambient UFPs, defined as 100 nm in diameter. We will discuss some studies of deposition, clearance, and translocation that have used model UFPs, and some toxi- cologic studies involving exposures to concentrated ambient particles in the quasi-UFP range (particles < 150- 180 nm). Our focus on inhalation studies reflects our emphasis on evaluating the effects of exposure to ambient UFPs via the 31 Understanding the Health Effects of Ambient Ultrafine Particles normal, physiological route. For this reason, we have not taken into account studies that have exposed laboratory animals via different routes of exposure, in particular, by intratracheal instillation. Although the dose administered by this method can be controlled, particle distribution in the lung is less uniform and far from physiological (Oberdorster 2010). In addition, intratracheal instillation administers particles in a bolus, so the dose -rate is much higher than via inhalation. Furthermore, we have chosen not to review the growing body of in vitro UFP toxicology research, while nevertheless recognizing the importance of such studies in understanding specific mechanisms. We do cite select studies that help in understanding UFP dis- position after inhalation. Along with the experimental studies with humans in laboratory settings, we also discuss real -world panel studies of human exposures to ambient environments rich in UFPs (for example, in areas with heavy traffic), as long as the study design included a control exposure with reduced concentrations of UFPs. Particle Deposition Fraction 1 0 - 0.0 - fatal 06- 04- 02- 0 8 - extra- p.4 _ thoracic 02- O,A - 0,2 — bronchi a4- 0,2bronchioli 0.s - 0s- 0,4 - 0.2 - 0-01 0.1 atveoJI 1 10 Particle Diameter (pm) DEPOSITION, CLEARANCE, AND TRANSLOCATION OF UFPs To fully understand the deposition of particles entering the human body, it is useful to review the relevant anatomy of the human respiratory tract, illustrated in Figure 15. Upon inhalation, air moves through the upper respiratory tract: first through the nasal or oral cavities, then into the pharynx, or throat, and then into the larynx and upper trachea. These constitute the extra -thoracic air- ways. The trachea enters the thorax and splits into the two tubular bronchi, which lead to the left and right lungs. Inside the lungs, the bronchi divide repeatedly into pro- gressively smaller tubes that end in the bronchioli, the smallest subdivision of the bronchi. Attached to the end of the bronchioli are the alveoli, tiny air sacks covered with capillaries where gas exchange takes place. UFP deposition in the respiratory tract differs impor- tantly from that of larger particles and can be affected by such factors as exercise, oral versus nasal breathing, dis- ease status, and age (Daigle et al. 2003; Chalupa et al. 2004; Particle density: 1 g cm 3 Respiratory flaw rate: 300 cm3 s ' Mouth breathing at rest, cycle period: 5 s Figure 15. Total and regional deposition of inhaled particles in the adult human respiratory tract during mouth breathing at rest according to "Human Respiratory Tract Model" of the ICRP. Note particle diameter > 0.5 um relates to the aerodynamic diameter and a particle diameter < 0.5 um relates to the thermodynamic diameter. (Source: Kreyling et al. 2006a, Figure 2, reprinted with permission from Springer Science+Business Media.) 32 HEI Perspectives 3 Geiser and Kreyling 2010). Unlike larger particles that either settle with the help of gravity or impact directly onto airway walls, UFP deposition depends largely on dif- fusion (Brown et at 2002; Kreyling et al. 2006a; Moller et al. 2008). The ICRP and others have developed models to predict the respiratory deposition fractions of inhaled particles based on particle characteristics and lung anatomy and physiology (ICRP 1994; Kreyling et at 2006a,b). As shown in Figure 15, UFPs are predicted to deposit with highest efficiency in the bronchioles and alveoli, whereas larger particles (1 to 10 pm) preferentially deposit in the extra - thoracic region and bronchi. A large fraction of very small particles (in the 1 to 15 nm range) also deposits in the extrathoracic airways, including the nose. The diffusional deposition probability of inhaled UFPs for the alveolar region peaks at 20-30 nm. For UFPs < 20 nm, alveolar dif- fusional deposition decreases, in part because increasing numbers of these small particles have already deposited in the upper airways. Furthermore, due to their ability to move via diffusion, UFPs deposit more homogeneously onto the epithelia of the various regions than fine particles or coarse particles (PM2.5_10), and they can diffuse into nonventilated air volumes within the alveolar region. Particle Clearance and Retention in the Respiratory Tract Inhaled particles of all size ranges are generally cleared from different regions of the airways via both physical and chemical clearance processes (reviewed in detail in Oberdorster et al. 2005). In the bronchioles and alveoli, the major clearance mechanism results from particle phagocy- tosis by alveolar macrophages. If particles are not cleared from the lung, they may be retained over prolonged periods, which results in their accumulation in airway tissue. UFPs appear to be cleared less quickly and completely from the lung than larger particles. Moller and colleagues (2008) studied the deposition of radiolabeled 100 nm parti- cles in humans, using a shallow bolus inhalation technique that targeted deposition in the distal airways and alveoli. There was negligible particle clearance from the peripheral regions of the lung 24 hours after exposure. Findings in air- ways of dogs are similar (Kreyling et al. 1999). The reasons for the slower clearance and hence pro- longed retention of UFPs remain unclear. Mucociliary clearance may be less effective for UFPs, either because the particles penetrate through the mucus deep into the peri- ciliary phase, a continuous aqueous layer of relatively low viscosity surrounding the cilia (Schiirch and Gehr 1990), or they deposit in areas with a lung -lining layer in which mucous is reduced or absent. Whatever the mechanism, the lack of UFP clearance may lead to accumulation, furthering interaction of particles with lung cells, and par- ticle translocation beyond the epithelial barrier. Particle TransIocation UFPs have been hypothesized to have unique effects because of their potential for translocation into the blood via the lung, with subsequent transport to other organs, including the heart and brain. The mechanisms for translo- cation of UFPs into tissues are not well understood. Evi- dence suggests that UFPs may either be transported by endocytotic and exocytotic mechanisms or they may dif- fuse across membranes into airway cells (Geiser and Krey- ling 2010); similar evidence has not been reported for fine particles. UFPs are not only taken up by macrophages but are endocytosed by epithelial lining cells to a greater extent than are larger particles (Geiser et al. 2008; Takenaka et al. 2012). In contrast to fine particles that deposit on the surface of epithelial cells, UFPs enter these cells rapidly; in this case they are no longer accessible for phagocytosis by alveolar macrophages (Rothen-Rutishauser et al. 2007). UFPs, by virtue of their small size, may form complexes with proteins in the epithelial lining fluid of the lung that enhance their movement into cells (Cedervall et al. 2007; Kreyling et al. 2007; Lynch et al. 2007). This is likely a complex process, involving protein adsorption and desorption to UFPs, and the kinetics may differ with dif- ferent body and cellular fluids, organs, and tissues in ways that are not yet understood. We will briefly review the evidence from laboratory animal and human studies for translocation of UFPs (also see Geiser and Kreyling 2010). Laboratory Animal Studies Several experimental stud- ies in animals have provided evidence for the translocation across the air —blood barrier of model UFPs such as gold, sil- ver, TiO2, polystyrene, and carbon, in the 5-100 nm size range. UFPs were found in the pulmonary vasculature and blood (Figure 16) (Berry et al. 1977; Kapp et al. 2004; Geiser et al. 2005) and in extrapulmonary organs, includ- ing the liver, spleen, kidneys, heart, brain, and reproduc- tive organs (Takenaka et al. 2001, 2006; Kreyling et al. 2002, 2009; Oberdorster et al. 2002; Semmler et al. 2004; Semmler-Behnke et al. 2007). Estimates of the total trans - located fraction of UFP range from 1%-2% of 50 nm poly- styrene particles (Chen et al. 2006) to as much as 10% of 20-nm diameter radiolabeled iridium UFPs when translo- cation to connective tissue and bone were included (Kreyling et al. 2009). Furthermore, 20-nm iridium UFPs were poorly cleared from secondary target organs. Six months after a single one -hour UFP inhalation exposure, the total UFP fraction in all secondary target organs was 33 Understanding the Health Effects of Ambient Ultrafine Particles EN EP AL Figure 16. Images of particles (arrows) in the lung parenchyma (using energy -filtering transmission electron microscopy). Image A shows an 81 nm par- ticle in the cytoplasm of a capillary endothelial cell (EN). Image B shows a 41 nm particle within an erythrocyte (EC) in the capillary lumen. (Source: Geiser et al. 2005, reproduced with permission from Environmental Health Perspectives.) still close to 0.1% of the initial UFPs deposited in the lungs, and all organs studied still contained UFPs (Semmler et al. 2004; Semmler-Behnke et al. 2007). Inhaled UFPs may translocate to the brain (Elder and Oberdorster 2006). UFPs that deposit in the olfactory turbi- nates of the nose may enter the olfactory nerve and be transported to the olfactory bulb of the brain. While UFPs may access the brain via this pathway, their effects on the central nervous system have not been evaluated in great detail (see Neurological Responses in the Experimental Studies section). Human Studies We know from histopathologic evidence in studies of long-term, heavy particle exposure in smokers, coal miners, and asbestos workers (showing par- ticle or fiber accumulation in the liver and other organs of the reticuloendothelial system) (Auerbach et al. 1980; LeFevre et al. 1982) that particles can be found in organs beyond the lung. However, these studies offer little insight as to the importance of particle size or the relative impor- tance of inhalation and ingestion pathways and have ques- tionable relevance to the inhalation of ambient UFPs. Comprehensive biokinetic analysis of particle transloca- tion is not feasible in humans for ethical and technical reasons. Thus to date, very little direct evidence of UFP accumulation and retention in organs and tissues is avail- able from experimental human studies. A paper by Nemmar and colleagues (2002) has been widely cited as direct evidence for UFP translocation from the airways into the circulation. However, subsequent work has failed to confirm their findings. In this study, Nemmar and colleagues exposed young volunteers to an aerosol of 5-10 nm carbon UFPs labeled with 99technetium. They detected the tracer in the blood within minutes after the exposure and in the liver and stomach within an hour. They interpreted their findings to indicate that insoluble UFPs passed rapidly into the blood, and were circulated to organs throughout the body. These investigators subsequently developed a pharmacokinetic model of inhaled UFP distribution to blood and other organs based on these findings (Pery et al. 2009). However, other investigators (Mills et al. 2006; Wiebert et al. 2006a) have repeated these studies with similarly sized carbon UFPs and were unable to find evidence for particle translo- cation into the blood. Mills and colleagues (2006) found 34 HEI Perspectives 3 that radioactive technetium leached off 4-20 nm carbon UFPs when they entered the airways, and that the radioac- tive moiety, rather than the particle itself, was detected rapidly in circulating blood. Moller et al. (2006) also found that the radiolabel is rapidly leached off unless it has been stabilized on the carbon UFPs. Wiebert and colleagues (2006a) did not find evidence of significant translocation of inhaled 35 nm radiolabeled carbon UFPs into the sys- temic blood circulation over a 24 -hour period. These human studies suggest that under these specific experi- mental conditions, less than 1% of the inhaled dose of UFPs enters the blood and is available for translocation beyond the lung. It remains unknown what extrapulmo- nary burden of UFP is required to elicit health effects, and indeed whether translocation of UFPs beyond the lung is responsible for any of the health effects associated with PM exposure (Brown et at 2002; Mills et at 2006; Wiebert et at 2006a,b; Moller et al. 2008). Summary of Particle Deposition, Clearance, and Transloc ation Compared with larger particles, UFPs deposit with higher efficiency, are cleared more slowly, and are retained longer. This raises the concern that chronic or repeated exposure to UFPs may lead to more accumulation within the lung of UFPs than of larger particles. Laboratory animal studies demonstrate that inhaled UFPs, but not fine or coarse particles, can translocate across the lung epithelium into the circulatory system and then be transported throughout the body where they have the potential to affect directly the cardiovascular system and other organs. UFPs depositing in the nose may also translocate via the olfactory nerve to the brain. These studies in animals also suggest that UFPs, to a greater degree than fine or coarse particles, may accumulate in organs and tissues under normal physi- ological conditions with the potential for long-term adverse effects. However, human studies to date have been limited and have failed to find substantial translocation of inhaled UFPs beyond the lung. It is unknown whether translocated UFPs cause or contribute to the adverse effects of PM expo- sure that have been observed in humans. EXPERIMENTAL STUDIES OF ADVERSE EFFECTS OF EXPOSURE TO UFPs IN ANIMALS AND HUMANS Experimental studies provide insight to the effects of exposure to any toxicant. The nature and level of exposure can be carefully controlled and the health endpoints chosen and evaluated against specific scientific hypotheses. For this issue of HEI Perspectives, we have focused primarily on experimental studies that involve exposures to laboratory animals and humans via inhalation, the most physiologi- cally relevant route for exposure to ambient air pollution. We have focused our discussion on studies of exposures to UFPs that are relevant to ambient, and especially combustion - related, UFPs in the < 100 nm size fraction. In particular: • Carbon UFPs. The rationale for using these particles is that most combustion -generated particles have a carbon core, and so are representative of a major combustion - derived component of particles in ambient air, particu- larly those derived from diesel engines. Carbon UFPs are generated by a spark discharge of graphite elec- trodes; 95% of those produced consist of EC and have a median diameter of approximately 25 nm. Experiments with these particles have provided useful information about the effects of pure ultrafine carbon particles, but these particles lack the other components that are typi- cally adsorbed to UFPs found in ambient air. • Ambient UFPs. Some studies have compared the effects of exposures in contrasting environments with high ver- sus low concentrations of ambient UFPs. A very few studies, conducted in New York State, have examined the effects of animal exposure to on -road emissions. • Concentrated ambient UFPs. In order to study expo- sures to UFPs separately from other size fractions and at concentrations that are higher than those in ambient air, investigators have relied on UFP concentrators. These devices concentrate UFPs first by growing the particles in a supersaturated chamber, concentrating them using virtual impaction, and then drying them to their original size distribution. This technology becomes less efficient for particle sizes below 35-40 nm. They also usually includes a portion of particles > 100 nm, and conse- quently are considered quasi-UFPs. It should also be noted that an intrinsic limitation of UFP concentrator technology is the potential for chemical reactions with the condensed water, which may change the physico- chemical properties of the original UFPs. Finally, we acknowledge an entire class of experimental studies of inhalation exposures to DE in laboratory ani- mals and in humans. Because DE from older engines has been an important source of UFP emissions, these studies are often taken to represent the effects of UFPs themselves. However, whole DE is a complex mixture of both gases and particulates, and few studies have attempted to account for the role of the various components in the health effects observed. In addition, few of those studies measured par- ticle number. Like others who have reviewed this litera- ture (U.S. EPA 2009; Hesterberg et al. 2011), we view the findings from this body of work to provide supportive but not direct evidence on the role of UFPs and have therefore summarized them in Sidebar 2. 35 Understanding the Health Effects of Ambient Ultrafine Particles Our evaluation of the studies in this chapter has focused on the set of health effects with which PM has been associ- ated more generally in the scientific literature and for which UFPs have also been hypothesized to play a partic- ular role given their physical and chemical characteristics: • effects on the respiratory system, including increases in lung inflammation and allergic responses, and decreased lung function; • effects on the cardiovascular system, including progres- sion or exacerbations of cardiovascular disease (CVD); and • effects on the neurological system, including increases in inflammatory responses and adverse effects on cellular function in the brain. There are multiple pathways by which PM in general is hypothesized to exert adverse effects on various organ sys- tems (Brook et al. 2010), but some pathways may be espe- cially relevant for UFPs, for example, effects on the brain via translocation from the nose. Figure 17 provides a sche- matic of the multiple pathways via which inhaled UFPs are hypothesized to cause effects, directly or indirectly, in dif- ferent organ systems. As we described in earlier sections, inhaled UFPs and their chemical constituents may act directly on the airways, the first point of contact for the particles. The indirect pathways involve mechanisms by which inhaled particles or their chemical constituents may trigger a series of responses in airway cells, in particular the synthesis of reactive oxygen species and induction of oxi- dative stress that may in turn result in inflammatory responses in the lungs, blood, or remote tissues. These inflammatory responses may themselves have adverse effects, including changes in the balance of the autonomic nervous system, which governs critical body functions like heart rate (HR) and respiration rate. Finally, particles may translocate from the airways to other organs and directly induce effects at sites such as the heart, liver, or brain. The animal and human studies discussed in this chapter evalu- ated the evidence that UFPs may be exerting influence via these various pathways using a variety of measures. Laboratory Animal Studies Experimental studies in animals offer certain advantages over studies in humans. Exposures can be conducted, and the toxicologic endpoints followed, over longer periods than in human studies. Endpoints can include sampling of tissues and organs. Animal studies can also include expo- sures during sensitive life stages such as fetal development and the extremes of age. Furthermore, special animal Sidebar 2. Diesel Engine Exhaust — Components and Health Effects in Clinical and Animal Studies Several controlled -exposure studies in human volunteers and rodents have examined the effects of inhaling whole diesel engine exhaust, in particular on the cardiopulmonary system. These studies are of some relevance to this issue of HET Perspectives, because the particulate emissions from diesel engines include UFPs. Diesel particulate emissions vary in composition and in how they were formed. Nuclei mode particles are composed largely of volatile organic and sulfur compounds with smaller amounts of solid material (carbon and metallic compounds), and are generally less than 30 nm in diameter. They are the major contributor to particle number. The accumulation mode particles range in size between 30 and 500 nm and consist largely of soot (solid carbonaceous material and ash) and of adsorbed organic and sulfur compounds. These particles straddle the ultrafine and fine ranges and contribute to some extent to the UFP number (Kittelson et al. 2002). DE also contains many gases, including NOx (primarily NO and NO2) and carbon dioxide. The relative proportion and composition of the two particle modes and of the gaseous compounds depends on a number of factors, including testing conditions, engine type and operating condition, and fuel type. Human clinical studies of DE have been conducted primarily in two research centers: at the University of Umea, Sweden (using either a 1990 or 1991 4 -cylinder 4.5 liter Volvo diesel engine), and at the University of Washington, in Seattle (using a 2002 5.9 liter Cummins diesel engine). Details about these studies can be found in Hesterberg and col- leagues (2010, 2011). The studies investigated the effects of short-term exposure (1-2 hours) to DE on pulmonary function and immuno- logic and inflammatory endpoints in healthy individuals, as well as those with cardiopulmonary conditions, including asthma, metabolic syndrome, and post -myocardial infarction. Exposures were conducted at PM mass con- centrations between 100 and 300 pg/m3, but particle number or UFP concentrations were generally not reported. These studies used differing exposure protocols and outcome measures. Nonetheless, they provide evidence that DE can cause airway inflammation and changes in systemic vascular endothelial function and thrombus formation — physio- logic endpoints with relevance to both acute respiratory and cardiovascular effects. One study (Continued next page) 36 HEI Perspectives 3 models of diseases such as asthma or atherosclerosis can be used to test hypotheses about disease -related suscepti- bility. The major weaknesses of these studies are the failure of many animal models to replicate all aspects of disease states and the difficulty in extrapolating findings in animals to humans. We have limited our review to studies of inhalation exposure, to studies that provide exposures specifically to UFPs, with appropriate charac- terization of the UFPs and, where possible, to studies that compare the effects of UFPs to other particle size ranges. Respiratory Responses Experimental inhalation of spe- cific kinds of model UFPs can cause airway inflammation in rats, which can be more intense than with larger (fine) particles at equal mass concentrations (Elder et al. 2000a,c; Oberdorster et al. 2000). However, inhalation in mice of carbon UFPs at concentrations considerably higher than ambient (380 pg/m3, < 100 nm) did not cause an increase of inflammatory cells in bronchoalveolar lavage fluid (Andre et al. 2006; Maier et al. 2008). Similarly, Elder and col- leagues (2004b) found no airway inflammation in response to 6 -hour inhalation of carbon UFPs at 150 pg/m3. A higher concentration (1.7 mg/m3 UFP, median diameter 114 nm) did produce clear signs of lung inflammation (Gilmour et Sidebar 2 (Continued) al. 2004). In rodent models of respiratory compromise, such as aging rats and rats with respiratory infection, short- term inhalation of carbon UFPs enhanced pulmonary inflammation and oxidative stress (Elder et al. 2000a,c). The lab -generated carbon UFPs used in these studies are likely to be less toxic than ambient UFPs at an equivalent concentration because ambient UFPs contain reactive organic and other chemical species. However, Elder and colleagues (2000a,b) exposed aged rats, with or without pretreatment with lipopolysaccharide or influenza virus, to freshly generated on -road aerosols for 6 to 18 hours. In general, on -road particles (which were predominantly UFPs) did not cause airway inflammation, or significantly enhance the background airway inflammation caused by the priming agents. Several studies from investigators at University of California —Davis have explored the effects of exposure to UFPs in neonatal rats — a critical period of lung develop- ment (Pinkerton et al. 2004, 2008; Zhong et at 2010). Specif- ically, the investigators evaluated the effects on neonatal lungs of exposures to combinations of laboratory -generated ultrafine iron and soot particles (20 nm in diameter, com- prising both EC and OC), which were intended to model components of combustion -source —derived emissions. found alterations of electroencephalogram signals in the frontal cortex of the brain during and up to one hour after exposure, suggesting possible effects on the central nervous system, although this has not yet been confirmed. Both long- and short-term DE inhalation studies have also been conducted in laboratory animals, particularly rodents. Long-term exposure (up to 24 months) to high concentrations of DE (1 mg/m3 or higher) resulted in an increase in lung tumor incidence in rats, but generally not in mice. However, long-term exposure to high levels of particles other than DE (such as carbon black and titanium dioxide) can also increase lung tumor incidence in rats, but not in other spe- cies. For this reason, the increase in carcinogenicity in the DE exposure studies has been attributed to a rat -specific particle overload response in the lung, rather than to a response specific to DE. Shorter exposures to DE, particularly in animal models of cardiovascular conditions such as the ApoE knockout mouse, suggest effects on cardiovascular function, such as cardiac ischemia. Several cautions should be noted about the extrapolation of the results of these controlled human and laboratory animal studies to real -world exposures to UFPs. First, in all these studies, the particle concentrations were above those encountered in typical ambient exposures, even in heavy -traffic situations; in several rodent studies the particle concentrations were orders of magnitude higher. Second, only a few of the studies reported particle numbers, so the contribution of particles in the ultrafine range to the effects detected is uncertain. Indeed, because DE contains mul- tiple components that may be toxic, it is not possible to conclude from these studies that effects were caused by ultra - fine or larger particles, by gaseous components, or by some combination of particles and gases. Finally, regulations introduced in the United States to take effect in 2007 and beyond have mandated reductions in diesel engine emis- sions; the technologies developed by engine manufacturers (as well as the use of low -sulfur fuel) have substantially reduced the number and mass of particles produced by these newer engines. The health effects of these emissions, currently being investigated in HEI's Advanced Collaborative Emissions Study (ACES) program (Coordinating Research Council 2009; ACES 2012; Mauderly and McDonald 2012), are likely to differ from those of older engine emissions. 37 Understanding the Health Effects of Ambient Ultrafine Particles Ambient UFP — Deposition in the respiratory tract I ' rankocatk m through circulation. Sensory Nerves, Ganglia Autonomic Nervous System Respiratory Tract Effects Effects on: Epithelial Cells Endothelial Cells Macrophages • Increased ROS ■ Inflammation Endothelial Dysfunction Acute Phase Response Extrapulmonary Tissues • Heart * Brain • Liver • Bone marrow, etc. Platelet Activation Blood Coagulability i Cardiovascular and Respiratory Health Effects Nose Tra nslocra tion vta olfactory nerve to olfactory bulb Brain Effects Figure 17. Hypothesized pathways via which inhalation of UFPs may lead to effects on cardiovascular and respiratory systems and on the brain. With exposures of 243 ± 34 pg/m3 for six hours per day for three days, cell proliferation in the alveolar region of the lung decreased, and there was evidence of oxidative injury and increases in some markers of inflammation. Lee and colleagues (2010) found changes in the architecture of the airways of adult rats that had been exposed as neonates to combustion -generated 73 nm UFP with a high OC/EC ratio; changes in lung architecture were not found after exposures to fine particles (212 nm diameter) generated with a similar OC/EC ratio. In summary, animal studies suggest that UFPs at high concentrations have the potential to induce airway inflam- mation, but the concentration of ambient UFPs necessary to induce an inflammatory response is not known and may exceed the relatively high concentrations found on a busy roadway. Responses in different species may vary and may also differ by age of the animal. For example, some evidence suggests that neonatal exposures to UFPs may alter lung development, with the potential for lifelong consequences. Allergic Responses The potential for UFP exposure to enhance respiratory allergic responses has been of partic- ular interest because several early studies had shown that instillation or injection of diesel particles into animals could enhance characteristics of the allergic response (Muranaka et al. 1986; Takafuji et al. 1987; Fujimaki et al. 1997; Takano et al. 1997). A series of studies has been conducted in California using concentrated quasi-ultrafine and fine particles collected using the versatile aerosol concentrator enrichment system (VACES). In considering the results, it is important to note that when the VACES system is used to concentrate fine par- ticles, it includes all particles < 2.5 pm and so also includes particles in the quasi-UFP range (0.01 to < 0.18 pm). Kleinman and colleagues used VACES in several studies of the effects of inhaling concentrated UFPs collected near roadways in a mouse model of allergy — the sensitization and challenge of BALB/c mice with the allergen, ovalbumin (OVA). In the first such study (Kleinman et at 2005), mice 38 HEI Perspectives 3 were exposed (4 hours/day, 5 days/week for 2 weeks) to either concentrated quasi-UFPs (< 150 nm) or concen- trated fine particles (< 2.5 pm) collected at different dis- tances (50 m or 150 m) from a roadway used by many diesel trucks. Particle mass in both quasi-UFP and fine particle groups averaged approximately 400 pg/m3, and particle counts averaged 200,000/cm3. No differences in effects were found between exposure to concentrated fine particles (including UFPs) or to UFPs alone. However, mice exposed to either size fraction of concentrated parti- cles at 50 meters from the roadway showed greater increases in markers of inflammation and of the allergic response (immunoglobulin [Ig]E, IgG1 [the mouse equivalent of human IgG4, which is elevated in allergic responses], inter- leukin [IL] -5, and eosinophils) compared to mice exposed at 150 meters from the roadway. Similar results were found in a follow-up study by the same investigators (Kleinman et al. 2007); IL -5 and IgG1 levels were increased in mice exposed nearest to the road (50 m) but not at the greater distance (150 m) from the road. These increases were associated with EC and OC components of both fine particles and UFPs, suggesting the importance not just of particle size but of particle com- position. Li and colleagues (2010) also found that exposure to concentrated ambient quasi-UFPs, (< 180 nm) collected close to a freeway in Los Angeles, enhanced the secondary or memory -type response in this animal model: exposure to UFPs increased features of the allergic response (influx of eosinophils into the airways, increased levels OVA - specific IgE and IgG1, and enhanced expression of the cytokine genes IL -5 and IL -13 in the lung). Exposure to UFPs in this study also enhanced inflammatory -type responses (enhanced expression of IL -17a and influx of neutrophils in the lung). In addition, in a similar OVA mouse model of allergy, several studies have shown that 24 -hour exposures to carbon UFPs (< 100 nm) potentiated the effects of lung allergic inflammation (Alessandrini et al. 2006, 2008; Maier et al. 2008). Alessandrini and colleagues (2006) showed that 24 -hour exposure to 526 pg/m3 35 nm carbon UFPs up to 96 hours before OVA challenge enhanced bron- choalveolar lavage inflammatory cell infiltrate and IL -4, IL -5, and IL -13 levels, as well as mucus production in the airways. Exposure to the same concentration of carbon UFPs 24 or 72 hours after OVA challenge had much milder effects on airway inflammation, suggesting that sensitized animals are more sensitive to the effects of exposure to UFPs if exposed before allergen challenge. Evaluating par- ticle deposition in the BALB/c OVA sensitization and challenge mouse model, Alessandrini and colleagues (2008) found that compared to nonsensitized mice, OVA -sensitized mice exposed for one hour to ultrafine iridium particles radiolabeled with192Ir (UF-Ir) before OVA challenge showed a 21% relative increase in the total OF-Ir deposited fraction. When inhalation of UF-Ir was performed after allergen challenge, no differences in total deposited fraction or extrathoracic deposition or regional particle deposition were detected between sensitized and nonsensitized mice. Alessandrini and colleagues (2009) confirmed that 24 -hour exposure to 504 pg/m3 35 nm carbon UFPs before OVA challenge enhanced the markers of inflammation they had detected previously, but also found that levels of 8-isoprostane, a marker of lipid peroxidation and oxida- tive stress, and NF -KB, a transcription factor that activates genes involved in inflammatory and other responses, were also enhanced. These studies provide support for the hypothesis that UFP exposure may enhance components of the allergic response, perhaps by facilitating the entry or processing of allergen that has deposited in the airway. However, the exposure concentrations in these studies were quite high, and it is uncertain whether these effects occur at concentrations more relevant to ambient levels. Cardiovascular Responses The relatively few animal studies that have evaluated cardiovascular responses pro- vide some evidence of UFP effects on the cardiovascular system but differ in the types of UFP exposures used and the outcomes examined. Two studies have found that rodents exposed to carbon UFPs at concentrations relevant to ambient levels (100- 200 pg/m3, 1-5 X 106 particles/cm3) for as little as 24 hours showed changes in cardiovascular endpoints. Exposure to carbon UFPs (median diameter 72-74 nm; aggregate: 80% mass < 100 nm) for 24 hours showed thrombogenic effects in the microcirculation of healthy mice without any signifi- cant sign of inflammation in the respiratory tract (Khandoga et al. 2010). Furthermore, a mild but consistent increase in HA and a significant decrease in HA variability were found during inhalation of carbon UFPs (median diameter 38 nm) (Harder et al. 2005). Araujo and colleagues (2008) have conducted one of the few studies designed to compare directly the effects of exposure to UFPs (albeit quasi-UFP < 180 nm) and PM2.5 (containing concentrated UFPs). It is also one of the few animal studies of cardiovascular outcomes to compare the composition of the two size fractions. Using particles con- centrated by the VACES from ambient air close to a Los Angeles freeway, Araujo and colleagues (2008) compared the effects of exposures to quasi-UFPs and fine PM at 39 Understanding the Health Effects of Ambient Ultrafine Particles approximately the same NC (-5 X 105 particles/cm3). Apo E knockout mice — a strain that develops atheroscle- rosis more rapidly than normal mice (particularly if fed on a high -fat chow) — developed 25% and 55% larger athero- sclerotic lesions when exposed to concentrated UFPs (5 hr/day, 3 days per week for 5 weeks) compared with PM2.5 and with filtered air, respectively (see Figure 18). Exploring the possible mechanisms by which particles might affect the development of atherosclerosis, the inves- tigators found that, compared with exposure to PM2.5, exposure to the quasi-UFPs resulted in a decrease in the anti-inflammatory capacity of plasma high -density lipopro- tein and in increased measures of systemic oxidative stress. It remains unclear whether differences in particle compo- sition could at least partially explain these findings. Figure 19 summarizes the percentage contribution by mass of metals, nitrates, sulfates, EC, and OC in each size fraction. The quasi-UFP fraction was enriched in OC, and to a lesser degree in EC, compared with the PM2.5 fraction. Further exploration of the implications of composition is needed. Elder and colleagues (2004a; 2007) have conducted the only studies of rats exposed by inhalation to ambient Aortic Lesion Area (µm2/section) 70,000 - 60,000 - 50,000 - 40,000 - 30,000 - 20,000 • 10,000 - 0 0 O O 8 P = 0.002 P = 0.04 0 9 • • • • • • Filtered Air PM25 PMc.ts - 5000 3.88 X 105 5.59 X 105 Number of sub -0.18 pm (particles/cm3) Figure 18. Mouse model of atherosclerosis: Near -roadway concentrated fine particulate matter (PM2.5) and quasi-ultrafine particles (< PM0.18) compared with filtered air. (Source: Araujo et al. 2008, reprinted with permission from Wolters Kluwer Health.) particles, predominantly UFPs, while being driven along a major highway (I-90 in New York State). They studied both pulmonary and cardiovascular endpoints. Elder and colleagues (2004a) found that a 6 -hour on -road exposure (1-3 X 105 particles/cm3) of older rats (21 months), with and without prechallenges using either endotoxin (lipo- polysaccharide) or influenza virus, was associated with enhanced plasma endothelin-2, which causes constriction of arteries and increases in blood pressure (BP). Elder and colleagues (2007) later evaluated a similar 6 -hour on -road exposure (count median diameter 15-20 nm) on the HR and heart -rate variability (HRV) of spontaneously hyper- tensive rats. Rats exposed to the highway aerosol had a lower HR compared to rats exposed to clean air, an effect that persisted after exposure. In addition, exposure to the highway aerosol affected several HRV parameters that sug- gested an effect on the autonomic nervous system, with a shift from parasympathetic to sympathetic (fight or flight) influences. This collection of animal studies provides evidence of cardiovascular effects associated with UFPs of different size fractions; the study by Araujo and colleagues (2008) suggests that particles in the quasi-UFP fraction alone have a greater effect than an equivalent number of fine particles on the progression of atherosclerosis. However, the animal data are insufficient to provide clear evidence that UFPs have cardiovascular effects that differ from those of fine particles. ® Unknown ❑ Metals II Nitrates ® Sulfates • EC ❑ Oc 0 20 40 60 80 100 Percentage Composition by Mass Figure 19. Comparison of the chemical composition of concentrated quasi-ultrafine (PM0.18) and fine particulate matter (PM2.5) in the pre- vious study of mouse atherosclerosis in Figure 18. (Source: Araujo et al. 2008, adapted with permission from Wolters Kluwer Health.) 40 HEI Perspectives 3 Neurological Responses A small number of studies have looked at neurological responses in rodents after expo- sures to ambient UFPs or more specifically, to concen- trated quasi-UFPs (< 180 nm). As discussed earlier, a limitation of these studies from the standpoint of this issue of HEI Perspectives is that they involve exposures to parti- cles that are larger than the < 100 nm definition for UFPs. However, a strength is that at least some of these studies also conducted direct comparisons with particles in the PM2.5 size range. Collectively, these studies provide some indication that, compared with filtered air, exposure to quasi-UFPs in the vicinity of major freeways induces aller- genic responses, inflammatory responses, or both in the brain. However, in studies with parallel exposures to fine particles, similar inflammatory responses were observed. Campbell and colleagues (2005), studied the brains of the OVA -sensitized BALB/c mice that had been exposed to filtered air, concentrated quasi-UFPs, or the fine particles collected at varying distances from the roadway in the study by Kleinman and colleagues (2005) (discussed earlier in the Allergic Responses section). The brains of these mice showed increased levels of mediators associated with the induction of inflammatory responses — interleukin-1 alpha (IL -1a) and tumor necrosis factor alpha (TNFa), and of the transcription factor NF -KB. Increases in levels of IL -1a and TNFa were also detected by Campbell and col- leagues (2009) in the brains of ApoE knockout mice after exposure to either quasi-UFPs or fine PM. Kleinman and colleagues (2008) found that Apo E knockout mice exposed to concentrated UFPs (4- or 15 -fold) from ambient air close to a freeway in central Los Angeles for 5 hours/day, 3 days/week for 5 weeks showed changes in brain cell function compared to cells from filtered air controls. Changes included a dose -related increase in nuclear translocation of NF -KB and in another transcrip- tion factor, AP -1, that are associated with the induction of immune and inflammatory responses. Exposure to quasi- UFPs also activated NF -KB and AP -1 in the brains of the ApoE knockout mice reported by Campbell and colleagues (2009). Kleinman and colleagues (2008) also found that the lower concentration of concentrated UFPs also increased the activation of a kinase, JNK, which participates in one of the intracellular cascades that leads to the activation of these transcription factors. In addition, UFP-exposed mice showed increased expression of glial fibrillary acidic pro- tein, a molecule expressed on the surface of glial cells. These findings suggest that exposure to concentrated ambient UFPs near a roadway has the potential to induce inflammation in the brain. Summary of Animal Studies These studies suggest that traffic -related UFPs may enhance allergic responses in allergen -sensitized animals. Furthermore, quasi-UFPs may enhance the progression of atherosclerosis in ApoE knockout mice, and may influence autonomic control of the heart in aged rats. Markers of inflammation in the brain increased after exposure to concentrated traffic -related quasi-UFPs, but similar increases were also observed with exposure to concentrated PM2.5. These are intriguing find- ings, suggesting that there may be extrapulmonary effects of traffic -related UFPs. However, the findings must be con- sidered preliminary; they require confirmation in other models and laboratories. Experimental Human Exposures to UFPs Human exposure studies of various designs have consti- tuted an important set of experiments for understanding the health effects of air pollution and have played an important role in establishing rational ambient air pollu- tion standards. Human clinical studies, studies of human exposure to controlled atmospheres usually performed within a specially designed exposure facility or chamber, have several strengths and weaknesses that have been dis- cussed at length in previous reviews (Frampton 2006; Langrish et al. 2011). A major strength, of course, is that humans are the species of most interest. They can be exposed to particles via a physiologically relevant route such as oral or oro-nasal breathing using exposure atmo- spheres that can be carefully controlled and characterized. Different exposure scenarios can be designed to compare effects, in the same person, of exposure to particles of dif- ferent size ranges when the individual is engaged in dif- ferent levels of activity. Exercise for example, increases breathing and can therefore affect particle intake, and deposition (see section, Deposition, Clearance, and Trans - location of UFPs). Under carefully controlled conditions, the effects of exposures can be evaluated in potentially susceptible subpopulations, such as those with cardiore- spiratory diseases, asthma, and diabetes. However, such experiments are generally limited to short-term exposures (a few hours maximum) and so do not provide insight into potential chronic effects. Ethical and safety considerations prevent the study of those most susceptible to pollutant health effects, such as people with severe airway constriction or with CVD, and limit the use of invasive outcome measures. Clinical studies of UFPs have involved unique technical challenges. Prior to the development of UFP concentrators 10-15 years ago, there was no way to study ambient expo- sures to UFPs that did not include other particles and gases. As indicated earlier, because UFPs have so little 41 Understanding the Health Effects of Ambient Ultrafine Particles mass even the current generation of UFP concentrators does not efficiently concentrate UFPs smaller than about 35-40 nm. UFPs can be generated in the laboratory, but cannot be collected and resuspended for later exposure because the UFPs agglomerate into larger particles. For these reasons, there have been relatively few human con- trolled -inhalation studies of UFP exposure, and the expo- sure atmospheres of those studies are not entirely representative of ambient UFPs. Nonetheless, with these caveats in mind, the limited number of such studies has provided valuable information. To move beyond some of the limitations of clinical studies, we have broadened our discussion of experimental studies of controlled human exposure to include panel studies of exposures to real -world environments, such as walking along a busy street. We have included the latter studies provided they included both an assessment of expo- sure to UFPs, such as particle number counts, and a cleaner air exposure as a control. These study designs involve other challenges but can also offer additional insights. Respiratory Responses Respiratory outcome measures include pulmonary function (in particular, forced expira- tory volume in 1 second [FEVI], forced vital capacity [FVC], and peak expiratory flow [PEF]). Pulmonary function testing is used to diagnose and monitor respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD), and reductions in FEVI correlate with impairments in physical functional status. Even transient reductions in lung function, if accompanied by symptoms, are considered to be adverse health effects (American Thoracic Society 2000). Other respiratory measures include an influx of inflammatory cells into the airways and markers of airway injury or inflammation in exhaled air. Respiratory responses of UFPs have been studied in clinical chamber studies using both laboratory -generated UFPs and UFP concentrators, as well as in real -world exposure settings enriched in UFPs. While real -world expo- sures have shown some respiratory effects, most chamber studies have not. Chamber Studies — Carbon UFPs A group in Rochester, New York, led by Drs. Frampton and Utell, has published a series of studies (Frampton et al. 2004; Pietropaoli et al. 2004a,b; Stewart et al. 2010) that focus on the effects of controlled inhalation via mouthpiece of laboratory - generated carbon UFPs. These experiments provided use- ful information about the effects of pure carbon UFPs, but in the absence of adsorbed components that would be at- tached to UFPs found in ambient air. In aggregate, these studies show little evidence for acute effects of carbon UFPs on lung function. One study of exposure to 50 pg/m3 carbon UFPs for two hours with intermittent exercise found small, marginally significant reductions in the max- imal midexpiratory flow rate (about —5% relative to fil- tered air), suggesting mild obstructive or small airways effects (Pietropaoli et al. 2004a). However, there were no significant effects on FEVI, and none of the other carbon UFP inhalation studies showed lung function effects (Stewart et al. 2010). Similarly, there was no evidence for increased airway inflammation, assessed by a lack of changes in markers in induced sputum or in the level of exhaled NO. In a comparative study of ultrafine and fine particles, the investigators exposed resting healthy subjects to clean air, to 500 pg/m3 of ultrafine zinc oxide particles, and to 500 pg/m3 of ultrafine zinc oxide particles that were allowed to agglomerate in an aging chamber to the fine par- ticle size range (Beckett et al. 2005). Zinc oxide particles can be generated by welding processes, and in occupa- tional settings their inhalation can lead to a systemic inflammatory response known as metal fume fever. How- ever, no effects were detected in any of the physiological, airway or systemic inflammatory, or cardiac endpoints examined for exposure to particles of either size range. Chamber Studies — Concentrated UFPs Only a few studies have utilized concentrated ambient UFPs to exam- ine health effects in humans. As with chamber studies of exposure to carbon UFPs, they have provided weak evi- dence of UFP effects on respiratory outcomes. Gong and colleagues (2008) exposed healthy and asth- matic volunteers to filtered air or to 7- to 8 -fold concen- trated quasi-UFPs (mean particle count 145,000/cm3, mean mass concentration 100 pg/m3, and diameter < 180 nm) for two hours with intermittent exercise in a chamber. The UFPs were collected in a Los Angeles suburb that has heavily -traveled roadways. Exposure to UFPs was associated with a 0.5% mean reduction in arterial oxygen saturation and a 2% mean reduction in FEVI the morning after exposure, estimated across all subjects. However, there was no evidence for increased airway inflammation by analysis of induced sputum or exhaled air. Responses in healthy and asthmatic subjects were similar. Samet and colleagues (2007, 2009) compared the effects of concentrated ambient quasi-UFPs (PMT 0.16 pm), PM2.5, and coarse particles (PM2.5-10) delivered to young, inter- mittently exercising human volunteers at the U.S. EPA lab in Chapel Hill, North Carolina. These studies used the Harvard particle concentrator systems which, in contrast to the VACES system, delivers fine and coarse particles that do not include UFPs. Concentrated quasi-UFPs (1.52 X 105 ± 1.65 X 105 particles/cm3) had no effect on pulmonary function or on the influx of inflammatory cells 42 HEI Perspectives 3 in bronchoalveolar lavage fluid 18 hours after the exposure, whereas fine and coarse particles caused a modest degree of airway inflammation. Both the Gong and Samet studies also examined multiple cardiovascular endpoints, which are summarized in a later section on cardiovascular responses. Real -World Ambient Air Studies A series of panel studies compared health responses in individuals exposed to high numbers of UFPs (e.g., high traffic intensity) with those in individuals exposed to cleaner air (e.g., low traffic inten- sity). An advantage of the study design is the use of real- istic exposures to ambient UFPs. However, these exposures necessarily involve mixtures of pollutants, making it difficult to attribute effects to any single pol- lutant type. Such exposures cannot be blinded, so expecta- tions on the part of subjects or investigators could confound the results. Furthermore, the exposure settings likely differ in ways other than pollutant concentrations. For example, traffic noise, odor, and visual stimuli may differ between the experimental and control exposure set- tings, with unpredictable results on outcome measures. Two publications examined the results of a study of lung function and inflammatory responses in 60 subjects with mild or moderate asthma who walked for two hours on separate occasions on Oxford Street and on Hyde Park in London (McCreanor et al. 2007; Zhang et al. 2009). Oxford Street is a busy street on which only diesel vehi- cles are allowed. Exposures were characterized in real time, including total particle number counts using a CPC. The Oxford Street exposures had higher particle counts compared with the Hyde Park exposures, and they were associated with greater declines in FEV1 and FVC, increased markers of airway inflammation in induced sputum, and a decline in the pH of exhaled breath conden- sate. These findings indicate that the Oxford Street expo- sures worsened markers of asthma in these subjects, although self -reported symptoms of asthma did not change (Zhang et al. 2009). Respiratory changes were sta- tistically most strongly associated with UFP exposures, although there were also significant associations with exposure to NO2. However, in multiple -pollutant models, particle number counts and EC concentrations were most consistently associated with effects. Rundell and colleagues (2007, 2008) have studied lung function and markers of inflammation in healthy young vol- unteers exercising in environments with contrasting total NCs (NC0.02-1.0 as measured by CPC). In the 2008 study, subjects performed vigorous 30 minute running trials, either on an inner campus loop free of vehicle traffic with low par- ticle counts (mean 7382 particles/cm3), or on a soccer field and trail within 50 meters of a major highway with high particle counts (mean 252,290 particles/cm3). Concentra- tions of CO, NO2, and O3 were comparable in the two envi- ronments. The near -traffic exposures were associated with statistically significant airway effects, including reduc- tions in lung function, alveolar NO concentrations, and nitrate, and with increased levels of malondialdehyde, a marker of oxidative stress in exhaled breath condensate. These findings were interpreted as suggesting pollutant - induced airway effects, but the changes cannot be attrib- uted specifically to UFPs. Similar studies have been conducted by Strak and col- leagues (2010) with bicyclists in Europe and have detected little evidence of an UFP effect on lung function or mea- sures of inflammation. These investigators evaluated a marker of airway inflammation (exhaled NO), and lung function (FEV1, FVC, and PEF) in 12 healthy adults who cycled on a low- and a high -traffic intensity route in Utrecht, the Netherlands. As expected, particle number counts were higher on the high -traffic intensity route (41,097 particles/cm3) than on the low -traffic intensity route (27,028 particles/cm3); however, the PM10 concentra- tions were similar on both routes. There were no statisti- cally significant relationships between the exposures and the outcome measures. In a study in Antwerp with a larger number of healthy volunteers (38), Jacobs and colleagues (2010) compared the effects of bicycling in traffic (28,867 particles/cm3) and bicycling in a laboratory with fil- tered air (496 particles/cm3). There was no effect of expo- sure on exhaled NO, which is considered a measure of airway inflammation. Bicycling in traffic was associated with an increase in blood neutrophils, but no change was observed in the other blood markers tested. A recent study of cyclists in Ottawa, Canada did not find strong associations of total NC or BC, NO2, or O3 with respiratory outcomes; associations with exhaled NO and pulmonary function measures were inconsistent across endpoints, lags, and pollutants (Weichenthal et al. 2011). In another recent series of studies of commuters' expo- sures to air pollution in traffic, Zuurbier and colleagues found various associations of total NC with effects on lung function (FEV1, PEF), exhaled NO, and airway resistance in 34 healthy nonsmoking adults directly after and 6 -hours after (depending on the endpoint measured) 2 -hour com- mutes by bus, car, or bicycle; select associations with PM10 and soot were also observed (Zuurbier et al. 2010, 2011b). Estimated effects were not consistent for other lung func- tion parameters, respiratory symptoms, and blood markers of inflammation and coagulation (Zuurbier et al. 2011a,b). Potential confounding by stress, noise, or both was not assessed in these studies. 43 Understanding the Health Effects of Ambient Ultrafine Particles Klepczynska Nystrom and colleagues (2010) examined the respiratory effects of exposure for two hours in a subway tunnel in Stockholm, Sweden, using an office environment as a clean -air control. Blood sampling and bronchoscopy were performed 14 hours after exposure. Pollutants measured in the tunnel and in the control envi- ronment included not only UFPs (mean NC,100 nm), but also PM2.5, PM10, NO, and NO2. The NC,100 nm in tunnels was 110,000 particles/cm3 versus 8,283 particles/cm3 in the control environment. The investigators found no effects on lung function or airway inflammation associated with exposures in the subway. However, they did observe statis- tically significant increases in levels of blood fibrinogen and regulatory T -lymphocytes after the subway exposure. Summary of Human Respiratory Responses Experimen- tal studies with human subjects include a spectrum of ex- posures, from laboratory -generated model UFPs and concentrated ambient particles delivered in specially de- signed chambers, to ambient exposures in real -world set- tings. Relatively few studies have compared the effects of particles of different size fractions or accounted for the presence of other copollutants. The small number of experimental studies conducted to date show a range of findings on respiratory outcomes, from reductions in lung function and increases in airway inflammation to no effects. In the one study that compared respiratory responses to UFPs, fine particles, and coarse particles, pulmonary inflammation was observed with fine and coarse particles but not with UFPs; no changes were observed in lung function for any exposure. Similarly, the laboratory -generated carbon UFP studies found no evi- dence for airway inflammatory effects and no convincing effects on lung function. In contrast, some of the real - world studies found changes in lung function and airway inflammatory markers, particularly in subjects with asthma, while others did not. While these diverse findings may reflect some of the inherent limitations of these study designs (e.g., small sample size, short durations of expo- sure, subjects who are not blinded to the type of exposure they receive), they raise additional questions about the potential importance of the overall mixture in which UFP exposures occur. Cardiovascular Responses The role of exposures to PM in the development or exacerbation of CVD and in cardio- vascular mortality in humans has been of considerable research interest (see, for example, the review by Brook et al. 2010). The following section provides a summary of the contributions from experimental, controlled human expo- sure studies to the base of evidence on UFPs. Chamber Studies — Carbon UFPs The studies of labora- tory -generated carbon UFP inhalation have suggested effects on both pulmonary and systemic vascular function in both healthy and asthmatic people. Inhalation of 10 or 25 pg/m3 of carbon UFPs (-2 X 106 and —7 X 106 particles/cm3, respectively) during intermittent exercise showed concen- tration -related attenuation of the exercise -induced increase in the peripheral blood leukocyte surface expression of adhesion molecules (Frampton et al. 2004, 2006). This finding was considered consistent with transient pulmo- nary vascular effects of carbon UFP exposure. It was also supported by studies of 50 pg/m3 carbon UFPs showing reductions in the diffusing capacity for CO approximately 24 hours after a 2 -hour exposure (Pietropaoli et al. 2004a). Taken together with the blood leukocyte findings, these results suggest that carbon UFP exposure transiently reduces pulmonary capillary blood volume, and thus affects pulmonary circulatory function. Although the sig- nificance of this finding is unknown, such an effect, if repeated and persistent, could contribute to remodeling of the pulmonary circulation and the development of pulmo- nary hypertension. With regard to effects on the systemic circulation, a study in healthy exercising people inhaling carbon UFPs at 50 pg/m3 (Shah et al. 2008) found that carbon UFPs completely inhibited the expected exercise -associated increase in peak hyperemic forearm blood flow (a measure of systemic vascular responsiveness with relevance for cardiac coronary artery disease) 3.5 hours after exposure. One potential mechanism for reduction in vascular responsiveness is a reduction in the circulatory bioavail- ability of endogenous NO, which causes relaxation of vas- cular smooth muscle. The investigators observed reduced plasma nitrate concentrations (a product of NO oxidation) in comparison with a control filtered air exposure. These findings support the hypothesis that inhalation of carbon UFPs impairs systemic vascular function and reduces NO bioavailability. A study of people with type 2 diabetes, exposed at rest to 50 pg/m3 carbon UFPs, showed changes in markers associated with enhanced blood coagulation — an increase in plasma von Willibrand factor and an increase in markers of platelet activation (Stewart et al. 2010). A recent study from the same research group focused on cardiac changes measured by electrocardiogram (ECG) in young healthy adults after exposure to 10 and 25 pg/m3 carbon UFPs (Zareba et al. 2009). Changes were generally small and not significant, but the authors felt that there was a trend in HRV that indicated an increase in parasym- pathetic tone, the arm of the autonomic nervous system involved in slowing down the HR. The health implications of transient changes in HRV in young healthy people are not clear. 44 HEI Perspectives 3 Chamber Studies — Concentrated UFPs The studies of Samet and colleagues (2007, 2009) comparing the effects of exposure to concentrated UFPs, fine particles, and coarse particles on respiratory endpoints also examined several indicators of cardiovascular function. As illustrated in Figure 20, exposure to concentrated UFPs increased D-dimer in blood, indicating activation of coagulation, and also transiently increased blood lipids. Continuous ECG monitoring revealed increases in markers of HRV and vari- ance in duration of the QT interval (Samet et al. 2009). HRV was also measured in the study by Gong and col- leagues (2008) in which healthy and asthmatic volunteers were exposed to concentrated UFPs in a Los Angeles suburb (for exposure details, refer to the discussion in the Respiratory Responses section). Exposure to UFPs was associated with a transient slight decrease in low - frequency power, without changes in other measures of HRV. Responses in people with asthma were similar to responses in people without asthma. A recent study (Mills et al. 2011b) was designed to deter- mine whether the effects of DE exposure on systemic vascu- lar endothelial function were caused by UFPs or by the gaseous component of DE; 16 healthy volunteers inhaled 4 different atmospheres: diluted DE (particle concentration of 300 pg/m3), laboratory generated carbon UFPs (< 100 nm, 4 X 106 particles/cm3), filtered DE, or filtered air. After each exposure, forearm blood flow was measured in response to infusion of vasoconstrictors and vasodilators; Figure 21 pro- vides illustrative results for the vasodilator, acetylcholine. The impairment of vascular responsiveness with exposure to whole DE that had been observed in an earlier study (Mills et al. 2005) was confirmed (panel A). However, nei- ther filtered exhaust (panel B) nor pure carbon UFPs (re- sults not shown, but were the same as for filtered exhaust) affected endothelial function measured by forearm blood flow. These experiments indicate that the particulate com- ponent of DE was responsible for the vascular effects, and that carbon UFPs alone do not reproduce the effect. Thus, it appears that particle size is not the only factor determining the vascular effects of DE. The findings do not exclude the possibility that some aspect of the gas —particle mixture is responsible. Real -World Ambient Air Studies Brauner and colleagues (2008) performed an intervention study in 21 nonsmoking couples, ranging in age from 60 to 75 years, in their homes in Copenhagen, Denmark. Investigators installed high - efficiency particle filters in their homes, and the study con- sisted of consecutive 48 -hour periods living with either fil- tered or unfiltered indoor air. The exposures were double - blinded and randomized, and monitoring included tPA - vWF - D-dimer - CRP - PAI1 - Fibrinogen - Plasminogen - Factor IX - Factor VII - - m- Post - 0- Follow up r-i---rte -80 -60 -40 -20 0 2D 40 % Change per 100,000 particleslcm3 Figure 20. Effects of concentrated quasi-ultrafine particles (<PMais pm) on D-dimer in blood and other markers of coagulation. (Source: Samet et al. 2009, reprinted with permission of the American Thoracic Society.) particle counts and fine and coarse mass concentrations. Filtering reduced mean particle counts from 10,016 to 3,206 particles/cm3 and reduced mean PM2.5 mass from 12.6 to 4.7 pg/m3. Microvascular function, measured by digital peripheral artery tone after arm ischemia, improved by 8.1% during air filtration. However, this effect was more strongly related to the PM2.5 mass concentration than to particle number, suggesting that reductions in UFPs were not the driving influence in improving vascular function. As part of the study discussed earlier, Rundell and col- leagues (2007) also assessed systemic vascular effects of exercise in outdoor environments with high versus low ambient particle counts. Higher particle count exposures were associated with markedly reduced systemic vascular function (measured by reduced flow -mediated dilatation of the forearm) and reduced reperfusion of small vessels of the forearm (measured by near -infrared spectrometry). A recent study of cyclists in Ottawa, Canada found sug- gestive associations of total NC with reduced HRV parame- ters within four hours of the start of cycling, although some results were sensitive to outliers; select associations with other pollutants (e.g., BC, NO2, and O3) were also observed with HRV endpoints (Weichenthal et al. 2011). Laumbach and colleagues (2010) piloted a protocol for assessing the effects of car commuting on HRV measures. The authors recruited 21 subjects with type 2 diabetes to participate in 90- to 110 -minute car rides on a busy 45 Understanding the Health Effects of Ambient Ultrafine Particles Forearm Blood Flow (mLJ100 mL of tissue/min) 25- 20- 15 10- 5- 0- A • • DE O Filtered DE Filtered air Irfused Nonirifused NoninfuSed e • 5 10 Acetylcholine (pglmin) 20 25- B 20- 15- 10- 5- 0 - Filtered DE Air 5 114 20 Acetylcholine (pgfmin) Figure 21. Endothelial function and exposure to diesel exhaust particulates after acetylcholine infusion. Forearm blood flow was measured in healthy subjects 0-8 hours after exposure to DE, filtered DE, or filtered air — either during acetylcholine infusion or without any infusion. Significant dose - dependent increases in blood flow were observed with infusion (P < 0.0001) versus without infusion. This effect was significantly attenuated with expo- sure to DE (panel A; P = 0.008), but not with filtered DE (panel B; P < 0. 05). Results using carbon UFP were similar to those for filtered DE (not shown). (Source: Mills et al. 2011b, by permission of Oxford University Press.) highway in New Jersey. Changes in HRV parameters (e.g., reduced high -frequency HRV) relative to pre -ride levels were observed post -ride and on the next day, and while not statistically significant, the authors linked these with in - vehicle pollutant concentrations (total NC, PM2.5, CO, NO2). Potential confounding by perceived stress and anx- iety was considered in this study using a stress question- naire that was administered at four time points during each sampling session. Observed results were indepen- dent of stress or anxiety in sensitivity analyses that excluded subjects with high stress or anxiety scores. Noise levels, however, were not measured in this study. Summary of Human Cardiovascular Responses As noted for respiratory responses, there are a small number of studies examining cardiovascular endpoints, with dif- fering approaches and a range of findings. Human expo- sure studies to carbon UFPs in Rochester, New York, suggested small, transient effects on both pulmonary and systemic vascular function. However, the study by Mills and colleagues (2011b) examining the components of DE found that inhalation of carbon UFPs did not reproduce the vascular effects of whole DE. Indoor air filtration in the homes of older subjects improved microvascular function, but the effect was more strongly related to PM mass than to particle number, implicating the larger particles in the indoor air mix. With regard to cardiac ECG monitoring, both the Roch- ester and Chapel Hill studies, using carbon UFPs and con- centrated UFPs respectively, suggested effects on cardiac repolarization and increases in high -frequency and low - frequency power, without substantial effects on time - domain variables of HRV. However, the study by Gong and colleagues (2003, 2008) in Southern California showed reductions, rather than increases, in low frequency power. Thus, the effects of UFP inhalation on cardiac autonomic function remain unclear. There is evidence that carbon UFP exposure activates platelets in people with diabetes, and that concentrated ambient UFPs activate coagulation, an effect not seen with concentrated fine and coarse particles. However these studies require confirmation. Thus, there is evidence in some studies for UFP effects on vascular function, HRV, cardiac repolarization, and coagula- tion, all findings that support adverse cardiovascular influ- ences of exposures to UFPs, especially for people with underlying heart or vascular disease. However, there are 46 HEI Perspectives 3 inconsistencies among studies. There remains insufficient evidence from human studies for definitive conclusions about cardiovascular effects of inhalation exposure to UFPs. Other Responses One study (Vinzents et al. 2005) looked at measures of oxidative and mutagenic activity (level of DNA purine oxidation and strand breaks) in 15 healthy nonsmoking subjects who bicycled in traffic on five occa- sions and in the laboratory on one occasion, with personal monitoring of total particle number counts. Cumulative outdoor and indoor exposures to UFPs were each indepen- dent predictors of the level of DNA purine oxidation, but not of strand breaks. Other outdoor pollutants, including PM10, NON, CO, and urban background UFP concentra- tions were not significant predictors of oxidative or muta- genic activity. Summary and Conclusions for Experimental Studies UFPs have unique physical properties that determine their deposition and disposition in the respiratory tract. These characteristics indicate that, with repeated or pro- longed exposures, UFPs have a greater potential than fine particles for retention in the lung. Studies in animals have suggested that UFPs can enter the blood and move beyond the lung, although the extent to which this happens in humans remains unknown. These properties indicate a potential for adverse effects in the lung and in other organs. Animal studies indicate that inhalation of UFPs at con- centrations relevant to ambient air does not cause substan- tial lung inflammation. However, UFPs have been shown to enhance responses to allergens in allergen -sensitized and challenged animals, increase the progression of ath- erosclerosis in susceptible animal models, and influence the autonomic control of the heart. UFPs have been shown to translocate from the nose to the brain via the olfactory nerve, and there is evidence for increased inflammatory markers in the brain of exposed rodents. Human chamber studies with exposure to carbon UFPs and to concentrated ambient UFPs have been fairly consis- tent in finding no effects on lung function or airway inflammation. Some chamber studies found UFP effects on vascular function, cardiac repolarization, HRV, and blood coagulation, suggesting that UFPs may have effects outside the lung in the absence of lung inflammation. Other chamber studies, however, have shown conflicting data. One real -world study showed declines in lung function and increased airway inflammatory markers in subjects with asthma. Both animal and human studies provide evidence for respiratory and cardiac effects, and animal exposure studies suggest the possibility of effects on the brain. However, the ability to draw definitive conclusions is limited by the absence of long-term animal exposure studies and by somewhat inconsistent findings in human clinical studies. Human clinical exposure studies remain limited by the technology available to generate exposures relevant to ambient UFPs: laboratory -generated particles are not com- pletely representative of ambient UFPs, and concentrator studies are limited to the larger, quasi-UFPs. Real -world ambient exposure studies arguably offer the most realistic exposures to ambient UFPs, and some adverse respiratory and cardiovascular responses associ- ated with those exposures have been observed. However, such studies always involve exposures to complex mix- tures, and even with appropriate study designs, with cur- rent statistical methods it is challenging to separate completely the effects of UFPs from those of other pollut- ants. The results of these studies contribute to the traffic - related air pollution and health literature by suggesting high exposure to traffic -related pollutants (and associated factors, such as noise and stress or anxiety) during com- muting may be relevant for human health. Collectively, the studies reviewed in this chapter do not provide strong evidence that short-term exposures to UFPs have effects that are dramatically different from those of larger particles; the effects of long-term, repeated experi- mental exposures to UFPs are unknown. CHAPTER 4. Do UFPs Affect Human Health at Environmental Concentrations? What Is the Evidence from Epidemiologic Studies? In the previous chapters, we have explored the sources and environments which could result in human exposure to UFPs, and the evidence for possible health effects deriving from controlled animal and human exposure studies. In this section, we examine the evidence base from epidemiologic studies that attempt to address directly the most central question of this issue of HEI Per- spectives: Does ambient UFP exposure have an adverse effect on human health? Our evaluation of the literature in this chapter considers this question from two angles: 1) an evaluation of the evi- dence for specific endpoints, with an assessment of the consistency and coherence of observed associations, and 2) an evaluation of the evidence with respect to key study design and data issues, including UFP measurement, exposure assignment approaches, and consideration of potential cop ollutant confounding. In doing so, we attempt to address the overarching question as to whether any observed UFP effects are independent of those 47 Understanding the Health Effects of Ambient Ultrafine Particles observed for other particle sizes or for other combustion - or traffic -related pollutants. The intent of this document is to provide a broad survey of the state of the science on UFPs by describing the nature and scope of the current body of evidence. This survey summarizes the human health outcomes, exposure assess- ment approaches, and the ways that the studies account for the complex multipollutant exposure environment that often accompanies UFPs. In this chapter, we do not give an intensive quantitative meta -analysis or a more systematic, in-depth literature review. Instead, we will use this survey of studies to identify areas of investigation that are needed to more fully understand the specific effects of UFPs on human health, if any, and to guide recommendations for future exploration of human health and UFP exposure. EVIDENCE BASE We searched for all articles published through December 2011 that examined associations between UFPs and health using online databases (Web of Science and PubMed) and personal article collections. The U.S. EPA's 2009 Integrated Science Assessment for Particulate Matter (PM ISA; U.S. EPA 2009) was also used as a source for relevant articles. We included for consideration any epidemiologic (i.e., observational) study utilizing one or more relevant UFP metrics (Le., number, mass, or surface area concentrations) as the measure of exposure in the health model. For number concentration, while we focused on articles that assessed UFP NC for particles < 100 nm, we included some articles that measured total NC, where the size range is unspecified or varies between 3 and 1000 nm (but where the study authors expect that the total number of particles will be dominated by the number of particles in the < 100 nm range). Studies that measured only particles > 0.3 pm were excluded, as were studies with no particle count or par- ticle size measurements. For example, studies of traffic using only distance to roadway measures or pollutant mea- sures that were not specific to UFPs, such as PM2.5 EC, were excluded. We also focused on studies involving exposure to ambient UFPs or ambient UFP surrogates and therefore excluded articles focused on nanotechnology and exposures to workplace engineered nanoparticles. The following groups of articles were identified: 1) 8 rel- evant reviews published in the years 2009-2011; 2) an expert elicitation conducted to assess causality and con- centration —response functions for UFPs and health; and 3) over 75 articles presenting primary research on the rele- vant UFP metrics. Overall findings from the first two groups of articles, including the 2009 PM ISA (U.S. EPA 2009), were used as a starting point for examining whether ambient UFPs affect human health. Studies published since the 2009 PM ISA were evaluated together with prior evidence to determine whether recent findings further our understanding of whether ambient UFPs adversely affect human health. PREVIOUS REVIEWS The 2009 PM ISA reviewed over 40 primary research articles that examined the effects of UFPs on health (pub- lished in years 2000-2009) (U.S. EPA 2009). This report found that in a limited number of epidemiologic studies the investigators observed associations of UFPs and acute respiratory effects, such as respiratory symptoms in infants (Andersen et al. 2008a) and in adults with asthma (Von Klot et al. 2002) as well as hospitalizations and emer- gency department visits for asthma and pneumonia (Andersen et al. 2008b; Halonen et al. 2008). However, associations were not observed in all studies, such as in a study in Atlanta of emergency department visits and high UFP concentrations (38,000/cm3) (Peel et al. 2005). Simi- larly for cardiovascular outcomes, the 2009 PM ISA reviewed a small number of epidemiologic studies and found inconsistent evidence for an association between UFPs and CVD hospital admissions, although some posi- tive associations for subclinical cardiovascular measures (Le., arrhythmias and supraventricular beats) were cited. Taken together with toxicologic findings, the 2009 PM ISA concluded that evidence of a causal relationship between short-term UFP exposure and respiratory or cardiovascular effects is suggestive. Evidence of causal relationships between UFP exposure and other acute outcomes (e.g., mortality and central nervous system effects) and chronic outcomes (e.g., cardiovascular and respiratory effects, reproductive and developmental effects, cancer, genotox- icity, and mutagenicity) was deemed inadequate. An expert elicitation was also recently conducted to specifically assess the likelihood of causal relationships (separately and independently from effects of coarser par- ticle fractions or other components of the air pollution mix) and the likelihood of potential causal pathways for cardiac events (Knol et al. 2009). A panel of twelve Euro- pean experts (epidemiologists, toxicologists, and clini- cians) rated the causality of health effects of short-term UFP exposure as medium to very high for all -natural -cause mortality, low to high for cardiovascular and respiratory hospital admissions, very low to medium for cough, low to high for aggravation of symptoms in asthma patients, and low to very high for decrements in lung function. The experts rated the likelihood of a causal relationship between long-term UFP exposure and health effects as ranging from low to very high, with most evidence deemed 48 HEI Perspectives 3 as indirect. Of the causal pathways for cardiac events eval- uated, the pathway involving respiratory inflammation and subsequent thrombotic effects was rated as most likely; the pathway with the lowest ratings involved trans - location of particles affecting the autonomic nervous system and affecting HR, HRV, and arrhythmia endpoints. Lower ratings by experts were motivated by issues such as reliance of studies on limited UFP data, exposure misclas- sification, lack of evidence for the independent effects of UFPs, lack of correction for publication bias, and lack of data on long-term UFP exposures. These and other review articles struck similar themes regarding the limitations of available epidemiologic evi- dence for the effect of ambient UFPs on human health: 1. The reviews each noted an inadequate base of evidence with which to assess different facets of the UFP health effects field: that is, the lack of coherent studies assess- ing specific disease, organ or system -based endpoints that would lead to specific mechanistic hypotheses (Araujo and Nel 2009; Lotti et at 2009; U.S. EPA 2009), limited knowledge of the effect of exposures in specific microenvironments such as those related to commuting (Knibbs et at 2011) or in school environments (Mejia et al. 2011), and the lack of studies assessing the effects of long-term exposures (U.S. EPA 2009; Knol et al. 2009; Hoek et al. 2010). 2. Several of the reviews addressed the difficulties in as- sessing UFP effects in epidemiologic settings. UFP mon- itoring data are scarce. Also, assigning UFP exposures using data from single ambient monitoring sites results in a high likelihood of exposure misclassification due to the high spatial variability of UFP concentrations (Fan- ning et al. 2009; U.S. EPA 2009; Terzano et al. 2010). In the expert elicitation (Hoek et at 2010), exposure mis- classification was identified as a high source of uncer- tainty in epidemiologic investigations into UFPs. 3. High covariation of UFPs with other combustion -related pollutants, such as CO and NO2, makes it difficult to disentangle the independent effects of UFPs from these pollutants or the traffic -related mix in general (U.S. EPA 2009; Knol et al. 2009). For this document, we evaluated the primary research articles based on their ability to provide evidence that would help address these limitations. LONG-TERM EFFECTS There have been no studies that have examined long-term UFP exposure and health with the kinds of retrospective or prospective cohort study designs that have played influential roles in characterizing the chronic cardiorespiratory effects of PM10 and PM2 5. The absence of such studies is directly related to the limited monitoring of UFPs over time and with insufficient spatial resolution to identify the spatial contrasts in population exposures on which long- term studies typically rely. Instead, investigators have attempted to use cross- sectional study designs that assess the prevalence of chronic diseases in relation to concentrations of UFPs in different locations within a particular period (Lwebuga- Mukasa et al. 2005; Cahill et at 2011; Kim et at 2011). For example, Kim and colleagues (2011) reported results of a survey of over 1900 schoolchildren from 12 schools in Korea for which indoor and outdoor school environmental measurements were conducted over a 7 -day period in winter 2004. This study found associations of wheeze and asthma (in the previous year) with a number of home envi- ronment factors, such as water damage, visible mold growth, and indoor dampness. Among the outdoor mea- surements, associations of wheeze with NO2 and current asthma with total NC were observed. Lwebuga-Mukasa and colleagues (2005) examined total NC in relation to asthma prevalence among Buffalo, New York, neighbor- hoods using a cross-sectional survey of over 1600 house- holds. The authors found that total NC was highest in neighborhoods downwind of the Peace Bridge Complex, a commercial truck traffic corridor on Buffalo's west side; these neighborhoods also had the highest asthma preva- lence in the study. The cross-sectional design of these studies is a limita- tion. With no information on long-term personal expo- sures, it is not possible to attribute exposures to disease onset or progression. Nor is it possible to tease apart the potential effects of particle number from those of other potential causal factors (i.e., confounders) for asthma that may covary spatially with particle number. For example, in the article by Lwebuga-Mukasa and colleagues (2005), NCs were examined as one of several potential factors con- tributing to asthma prevalence or exacerbation; traffic - related pollution, distance to source, home environmental conditions, and socioeconomic differences among neigh- borhoods in this region. SHORT-TERM EFFECTS Studies of the health effects associated with short-term exposures (e.g., hourly or daily) are easier to conduct and are far more common. We reviewed over 75 articles and reports for studies assessing the short-term health effects of ambient UFPs, including over 25 articles from the 2009- 2012 period that were not included in the 2009 PM ISA (U.S. EPA 2009). In this section the articles reviewed presented UFP exposure that was represented by number 49 Understanding the Health Effects of Ambient Ultrafine Particles concentration data. A small number of studies that evalu- ated UFP mass concentration data are considered sepa- rately in a later section, Epidemiologic Studies Using Measures of UFP Moss. Figure 22 provides an overview of the geographic distri- bution of the studies reviewed. It indicates that the large majority of the short-term studies reviewed to date have been conducted in Europe and that several European cities (e.g., Erfurt and Copenhagen) have been studied repeatedly +A:. Number of Article s C 1-2 ::°3-4 5 Y-2 ! 15-16 * 17-18 9 in the literature. Moreover, European research activity on UFPs is concentrated primarily in western European coun- tries. More details on the study design features of the pri- mary short-term research studies reviewed, organized by the health endpoints and geographic location, are provided in Appendix Table B.1. The table includes more specificity on the UFP measurement methods and metrics used in the study (i.e., sized -differentiated number concentrations) than provided in this chapter. For simplicity, we have '`��r' I�� "t- r- : r *yam- _ rt -1T-i% .1:'.. f / y L 3 r. Figure 22. Geographic locations of epidemiologic investigations of the short-term exposures to UFPs discussed in this chapter. A number of populations in a given location have been the subject of multiple articles. 50 HEI Perspectives 3 reported results for total NC when that was the only mea- sure of UFP provided, and for UFP NC, representing the NC size fraction closest to the definition used in this docu- ment (e.g., NC < 100 nm). Mortality Several population -based studies examining the associa- tion between short-term exposure to total or UFP NC and mortality that were conducted over the past 10 years com- pared ambient central site particle measurements to various mortality outcomes (e.g., all -natural -cause, respiratory, car- diovascular, or stroke mortality) using time -series or case — crossover approaches (Appendix Table B.1). Most of these studies considered various particle and gaseous pollutant metrics in association with mortality. In general, associa- tions of NC and mortality were not consistently observed across the studies. Strong (significant) associations with NC were noted in the studies conducted in Erfurt, London, Rome, and Beijing and weak or no associations were observed in studies conducted in Helsinki and Prague. Closer evaluation of study designs and exposure character- istics in different study locations would be necessary to better understand sources of variability in the findings. The strongest associations with NC reported in most ¢/o Change I ICR Concentra-ton 10 5 0 5 AN Cardiovascular Mortality NC<0.8µm SC 0.1-0.3 pm . SC 0.3-0.8 µm - f O • Al ❑ 65 years and above MC 0-1-0-3 µm, MC 0.3-0.8 Nm• ■ MC<0.8µm- studies were largely for cardiovascular causes of death. Breitner and colleagues (2011) assessed associations of various particle size metrics (number, mass, and surface area concentrations) and cause -specific cardiovascular deaths in Beijing and reported that the strongest associa- tions were between all cardiovascular and ischemic heart disease mortality and UFP NC, with weaker or null associ- ations with larger size fractions and with other UFP met- rics (see Figure 23). In general, however, differences in the specific mortality outcomes and in the lag structure of the associations exam- ined in the various studies make it difficult to fully assess the consistency of the results. In Erfurt 1995-2001, for example, robust associations between UFP NC and total mortality and a combined cardiovascular and respiratory mortality grouping were found for a 4 -day lag (other lags in the 0-5 day range were not significant) (Stolzel et al. 2007) as well as for longer averaging periods (Le., 6- and 15 -day polynomial distributed lag models) (Breitner et al. 2009). In contrast, among the other studies that found associa- tions with NC, strongest associations were observed for shorter lags (lag 0, 1, or 2) (Forastiere et al. 2005; Kettunen et al. 2007; Atkinson et al. 2010; Breitner et al. 2011). Mortality Due to Ischemic Heart Diseases • E o � a o 7,1 ei V z z NCC08µrn- SC0.1-0.3µm" SC 0.3-08µm- E 0 U • All 65 years and above MC0.1-0.3µm • f MC 0.3-0.8 Nm MG<09µm. Figure 23. Percentage change (and 95% confidence interval) in cause- and age -specific cardiovascular mortality per an interquarlile increase in particle metrics in Beijing, from March 2004 to August 2005. The investigators measured particle number concentrations (NC) which they then converted into sur- face area concentrations (SC) and mass concentrations (MC) for the specific size ranges indicated (using assumptions found in the published paper). The interquartile ranges for the different metrics were: nucleation mode (NC < 0.03 pm), 10,203/cm3; Aitken mode (NC 0.03-0.1 pm), 6,250/cm3; NC < 0.8 pm, 13,790/cm3; SC 0.1-0.3 pm, 469.9 pmZ/cm3; SC 0.3-0.8, 486.7 pmZ/cm3; SC < 0.8 pm, 973.7 pmZ/cm3; MC 0.1-0.3 pm, 24.0 pg/m3; MC 0.3-0.8 pm, 57.9 pgim3; and MC < 0.8 pm, 81.8 pg/m3. (Source: Breitner et al. 2011, Figure 2, reprinted with permission from Elsevier.) 51 Understanding the Health Effects of Ambient Ultrafine Particles Moderate to high correlations between UFP NC and mobile -source related gases (CO, NO2) have also made it difficult to implicate UFPs, as opposed to more general mobile -source emissions, in observed associations with health endpoints (U.S. EPA 2009). Indeed, in most papers, authors implicate combustion sources, as opposed to UFPs specifically, as affecting mortality. For example, while the authors did not specifically assess the effects of traffic - related gases or particle components, Atkinson and col- leagues (2010) indicated that NC in London is largely influ- enced by nucleation -mode particles from diesel traffic that have a high OC component. In their analysis, NOx data were used to apportion PM measures into primary and nonpri- mary components; the authors observed a high correlation (r = 0.77) between total NC and primary PM10. In Rome, observed associations were strong for both total NC and CO, with a high correlation (r = 0.89) observed between these pollutants (Forastiere et al. 2005). In Helsinki, associations were suggestive for UFP NC and CO in the warm, but not the cold, season (UFP NC —CO warm season correlation, r = 0.39) (Kettunen et al. 2007). Breitner and colleagues (2011) did not include CO and NO„ in the Beijing analysis, but the authors indicated that UFP NC (30-100 nm) was highly influenced by local traffic emissions. Some studies have investigated multipollutant models of UFP NC with other particle or gaseous copollutants as a means of controlling for potential copollutant con- founding. In Erfurt, associations of UFP NC and total mor- tality for the 1995-2001 period appeared to be independent of those for mobile -source —related gases (CO, NO, NO2) (i.e., in two -pollutant models, the effects of UFP NC adjusted for individual gases were even slightly higher than those for UFP NC alone, as indicated in Figure 24, but did not change the interpretation of the UFP NC results); two - pollutant models of UFP NC and mass concentration met- rics (i.e., PM2 5 and PM10, which showed no association with mortality in this study) were not reported (Stolzel et al. 2007). In Erfurt, daily mean UFP NC were moderately correlated with daily mean CO (r = 0.57), NO2 (r = 0.65), PM2.5 (r = 0.51), and PM10 (r = 0.56). In Beijing, associa- tions of UFP NC and mortality were unchanged in models that included other NC or mass concentration metrics (e.g., nucleation mode NC in the 10-30 nm size range and accu- mulation mode mass concentration in the 100-800 nm size range); this study however did not consider CO or NO2 (Breitner et al. 2011). Cardiorespiratory Acute Morbidity Population -based studies assessing associations of NC and acute morbidity (using data on emergency department visits, hospital admissions, physicians' visits, or emer- gency service calls) have mainly been conducted in Europe RR per Interquartile Range 1-08 - 1.06 - 1.04 - 1.02 - 1.00 • • • UFP NC Lag 4 UFP NC Lag 4. Adjusted for NO UFP NC Lag 4, Adjusted for NO2 • UFP RFC Lag 4, AdjuSled 1orCO Figure 24. Relative risk of mortality per interquartile range of UFP NC (NC 0.01-0.1pm), adjusted for gaseous pollutants in two -pollutant models. Erfurt, Germany, September 1995 to August 2001. These results indicate that accounting for the presence of gaseous copollutants did not substantially change the UFP NC relative risks of mortality 4 days post exposure (lag 4) in this study. Significant associations of UFP NC with mortality were found at this lag but not generally with shorter lags in this study (Source: Stolzel et al. 2007, Figure 3, reprinted with permission from Macmillan Publishers Ltd: Journal of Exposure Science and Envi- ronmental Epidemiology.) (Appendix Table B.1). Similar to studies assessing mor- tality, daily ambient central site particle measurements were used in these studies in relation to measures of mor- bidity using time -series or case -crossover approaches. Most of these studies considered a variety of particle and gaseous pollutant metrics. A number of studies have been pub- lished since the 2009 PM ISA (U.S. EPA 2009); however, it is not clear that these later studies provide additional insight into the consistency of associations for specific end- points or clarity on the potential for UFPs to exert effects independent of copollutants. While many studies reported associations of morbidity with NC, observed associations within studies were generally outcome dependent, age -group dependent, or both, making it difficult to assess consistency across studies. For example, Andersen and colleagues (2008b) observed significant associ- ations of 5 -day mean total NC (6-700 nm) and respiratory dis- ease admissions, but not CVD admissions, in subjects 65 years or older in Copenhagen; associations with total NC were nonsignificant for pediatric asthma in this analysis and remained nonsignificant and weaker than associations with 52 HEI Perspectives 3 other PM and gaseous pollutants in a follow-up study in Co- penhagen that added four additional years of data (Iskandar et al. 2012). In a study in Helsinki, investigators also ob- served associations of 5 -day mean UFP NC (30-100 nm) with pneumonia and a combination of other respiratory dis- ease admissions in the population 65 years or older, but they found no associations with asthma or COPD admissions (Ha- lonen et al. 2009) or for emergency department visits (Ha- lonen et al. 2008) in this age group. Pediatric asthma emergency department visits, however, were associated with UFP NC (30-100 nm) at 3-5 day lags in Helsinki (Halonen et al. 2008). Differing study period lengths, daily outcome counts, and modeling choices also likely affect the pattern of observed associations by study and preclude attempts at meta -analysis. Moreover, for most studies in which UFP effects were observed, associations for other particle measures (PM mass concentration and/or accumulation mode NC) or gas- eous copollutants were also reported. Observed NC effects remained after controlling for PM10 or PM2.5 in several studies (Von Klot et al. 2005; Lanki et al. 2006; Belleudi et al. 2010), however, they were diminished in other studies (Andersen et al. 2008b). Only two studies found indepen- dent associations with NC after controlling for CO, NO2, or both (Andersen et al. 2010; Leitte et al. 2011). Leitte and colleagues (2011), however, indicated that NC associations were generally stronger when controlled for NO2 than when controlled for other pollutants in two -pollutant models. In other studies, adjustment for the gases reduced the observed NC effect (Andersen et al. 2008b; Halonen et al. 2008), or the gases were not included with NC in two - pollutant models (Von Klot et al. 2005; Lanki et al. 2006; Halonen et al. 2009). In some studies, traffic -related copol- lutants were not considered at all, making it difficult to draw conclusions about the independence of the observed NC effects (Atkinson et al. 2010; Belleudi et al. 2010; BraniS et al. 2010; Franck et al. 2011). Overall, similar to the acute mortality studies, most authors implicate parti- cles from traffic -related sources in the observed NC effects (Von Klot et al. 2005; Lanki et al. 2006; Andersen et al. 2008b, 2010; Halonen et al. 2008; Atkinson et al. 2010). Respiratory Effects In addition to population -based studies assessing mor- tality and morbidity outcomes, numerous panel -based and individual -level studies have been conducted that examine associations of UFPs and cardiorespiratory health end- points. In general, specific endpoints in these studies have been chosen to reflect and support hypothesized biological mechanisms of UFPs, as described in Chapter 3. In this sec- tion, we consider observational studies investigating respiratory -related endpoints; these have included mea- surements of respiratory symptoms (obtained through questionnaires) and pulmonary function (obtained through spirometry). Respiratory Symptoms Studies of respiratory symp- toms (e.g., wheeze, cough, phlegm, shortness of breath) in relation to total and UFP NC have been conducted in Europe (Appendix Table B.1). Study populations have varied by age group (children, adults, older adults) and pre-existing disease (asthma, other chronic conditions). Overall, the results of these studies are inconsistent, with some studies reporting significant NC effects and some not. Similar to the previous sections, in those studies in which NC effects were observed, most of these effects were not independent from those of other particle or gaseous measurements (Peters et al. 1997; Von Klot et al. 2002; Andersen et al. 2008a). Pulmonary Function A number of studies, also largely conducted in Europe, have assessed pulmonary function in relation to total and UFP NC (Appendix Table B.1). The results of these studies have again been inconsistent, with a majority of studies observing few effects of UFP NC spe- cifically. Many of these studies were conducted in the 1990s and considered ambient fixed -site particle measure- ments in relation to subjects' daily measurements of PEF, a measure of airflow obstruction during exhalation. One recent study adds to the literature in terms of the exposure assessment approach utilized, with effects esti- mated using several different exposure metrics. De Hartog and colleagues (2010) conducted a multicity study in four European cities (Helsinki, Finland; Athens, Greece; Amsterdam, the Netherlands; Birmingham, UK) with 135 subjects with mild to moderate asthma or COPD. This study was specifically designed to assess the effect of exposure assignment approaches on observed epidemio- logic results. The authors compared associations of total NC and lung function among different exposure metrics (ambient central site, home outdoor, and home indoor). Overall, no consistent associations were observed for any particle metric with lung function, even after various mod- eling specifications and controlling for medications use and lung function measurement time -of -day, or restricting the analysis to people with asthma. Furthermore, associa- tions were not stronger when exposures measured in the subjects' homes were used in the analyses. The authors cite several potential explanations for the null findings in this study; for example, stated limitations of this study were the 1 -week design (each subject monitored over just a 1 -week period), which did not allow for assessment of lags longer than 2 days for the home -based metrics, and that 53 Understanding the Health Effects of Ambient Ultrafine Particles 94% of subjects used respiratory medication. However, the detailed exposure characterization in this study mostly rules out exposure measurement error as a contributing factor to the null findings. Ultimately, the observed results could also be due to lack of a true association between UFPs and lung function. Allergy and Atopy While allergy is often considered in the context of respiratory responses, Song and colleagues (2011) recently conducted a panel study in Incheon to examine associations of UFPs and other pollutants, with atopic symptoms in 41 elementary school children (ages 8- 12) with atopic dermatitis. The authors reported a strong UFP NC effect that appeared to be independent of other pol- lutants: 1 -day lagged UFP NC was associated with skin itching, but other pollutants were not (PM1, PM2.5, PM10, NO2, SO2, and O3). Associations remained in two -pollutant models with PM mass metrics. A limitation of this study was that PM measurements were conducted on the roof of the school while the gaseous pollutants were collected at an ambient fixed site located two kilometers from the school. Because the UFPs were measured closer to the school, it is possible that there was less exposure misclas- sification for UFPs compared with the gases in this study. Distance from the collection site may be a reason for the lack of effects observed with the gaseous pollutants. Cardiovascular Effects In addition to respiratory endpoints, panel -based and individual -level studies have considered a number of car- diovascular endpoints, such as ECG -related outcomes (e.g., HRV, arrhythmias, ischemia), vascular reactivity, BP, and soluble blood (and urinary) markers of systemic inflammation, coagulation, and oxidative stress. These endpoints broadly relate to autonomic nervous system, inflammatory, and oxidative stress -related pathways hypothesized as routes of action for ultrafine as well as for other particle size fractions. Heart -Rate Variability A number of studies were found that examined associations of total NC or UFP NC with HRV, including time -domain (e.g., SDNN, r-MSSD) and frequency -domain (e.g., low -frequency [LF], high -fre- quency [HF], LF:HF ratio) endpoints obtained from anal- ysis of ECG measurements (Appendix Table B.1). These studies were conducted in cities across Europe, North America, and Asia and were largely repeated -measures panel studies in which multiple measurements were taken in the same individual over time. The one exception was an analysis conducted as part of the Normative Aging Study cohort for years 2000-2003, which provided outcome data for one sampling session per subject throughout the study period (Park et al. 2005). These six studies considered a range of different expo- sure measurements. Five studies used ambient fixed -site NC measurements (Park et al. 2005; Timonen et al. 2006; Barclay et al. 2009; Schneider et al. 2010; Rich et al. 2012). One study incorporated personal total NC (20-1000 nm range) monitoring (Chan et al. 2004), and the study by Barclay and colleagues (2009) estimated personal UFP NC exposures based on ambient fixed -site measurements. Associations of HRV effects with NC were not observed consistently: associations were observed in only three of the six studies (Chan et al. 2004; Timonen et al. 2006; Rich et al. 2012). A variety of factors may have contributed to the positive associations observed in these studies, such as the reduced uncertainty in exposure assignment due to the personal exposure characterization by Chan and col- leagues (2004) and the relatively high statistical power of the multicity study design (the ULTRA study) by Timonen and colleagues (2006). It should be noted, however, that these studies also reported similar effects associated with exposures to other particle size fractions and gases. Arrhythmia and Related Endpoints Studies of arrhyth- mias and total and UFP NC have also largely been con- ducted in Europe, with studies in Aberdeen, Augsburg, Erfurt, and London and one study conducted in the United States, in Boston (Appendix Table B.1). These studies have considered arrhythmias detected in individuals with implanted cardioverter defibrillators (ICDs), as well as arrhythmias detected in panel study subjects through anal- ysis of ECG recordings. The ICD studies focus on serious ventricular arrhyth- mias (e.g., ventricular tachycardia, ventricular fibrillation) that ICDs are designed to detect and treat (such as with pacing or shock). In a follow-up study of ICD patients living in eastern Massachusetts, Dockery and colleagues (2005a,b) found associations between ventricular arrhyth- mias and 2 -day mean PM2.5, BC, CO, NO2, and SOZ, but not for total NC or O3, with significant associations observed only when restricting analyses to arrhythmias occurring within three days of a previous arrhythmia. It should be noted that NC measurements were only available for one third of the study period; consequently, the null associations with NC may have been a function of limited data (and lower statistical power). The authors implicated traffic pollution in this study. In London, traffic -related pol- lutants (total NC, black smoke, CO, NO2) assessed at 0-5 day lags were not associated with ICD-detected arrhythmias, whereas there were associations with secondary pollutants (e.g., sulfate) (Anderson et al. 2010). Null results for UFP 54 HEI Perspectives 3 NC and other pollutants, assessed at 0-2 day lags, were also found in the Aberdeen panel study, in which ventric- ular and supraventricular arrhythmias were assessed through ECG recordings (Barclay et al. 2009). In Erfurt, Berger and colleagues (2006) observed associations of arrhythmias with 5 -day mean (and shorter single -day lags of) UFP NC, but also with accumulation mode NC, PM2.5, CO, and NO2. Two other panel studies conducted in Germany assessed ECG -derived measures of rep olarization abnormalities (e.g., QT duration, T -wave complexity, T -wave amplitude, T -wave amplitude variability), which may be linked with the onset of arrhythmias (Henneberger et al. 2005; Yue et al. 2007; Hampel et at 2010). The results of these studies have been mixed. No associations with total NC at 0-5 day lags were found in a panel of myocardial infarction survi- vors in Augsburg (Hampel et al. 2010). Henneberger and colleagues (2005) observed significant decreases in T -wave amplitude with exposures to UFP NC, accumulation mode NC, and PM2.5 in the previous 5 and 23 hours of ECG mea- surements in a panel study of males with ischemic heart disease in Erfurt. Further analysis of these data suggested that local traffic -related UFP NC and diesel traffic -related source factors showed the strongest associations with rep olarization parameters (Yue et al. 2007). Ischemia Several studies have been conducted to exam- ine the effects of particle exposure on myocardial ischemia using ST -segment changes from ECG recordings (Appen- dix Table B.1). These were conducted in panels of subjects with coronary artery disease in Helsinki and in Los Ange- les. The two Helsinki publications focused largely on the same subject data, but assessed different lag structures: 1) Pekkanen and colleagues (2002) observed strong associ- ations with 2 -day mean UFP NC (and accumulation mode NC, PM1, PM2.5, CO, NO2) and ST -segment depression during exercise tests; and 2) in an assessment of subdaily exposures, Lanki and colleagues (2008) observed associa- tions with 1- to 4 -hour lagged PM2.5, but not with UFP NC. In Los Angeles, Delfino and colleagues (2011) found ST - segment depression associated with home outdoor traffic - related pollutant measures (including PM2.5, PMo.25, BC, primary OC, CO, NO2) at various lags (including 1 -hr, 8 -hr, and 1-3 day means), but not for total NC (r = 0.36 between total NC and PM0.25) in a panel of older subjects living in a retirement community. Vascular Reactivity Only two studies have considered vascular reactivity in relation to exposure to particle count measures (Appendix Table B.1), and both studies have found little association with NC. In a panel of subjects with diabetes or at risk for diabetes in Boston, O'Neill and colleagues (2005) examined associations of ambient particle concentrations and two measures of vascular reactivity: non —endothelium -dependent nitroglycerin -mediated reactivity and endothelium -dependent flow -mediated reac- tivity. Total NC was associated with nonsignificant decreases in both measures, while other particle metrics (PM2.5, BC, and sulfate) showed significant inverse associa- tions. Dales and colleagues conducted a bus stop study in a panel of healthy subjects who were asked to sit at one of two bus stops in Ottawa, Canada, for two hours (Dales et al. 2007). Associations between PM2.5 and flow -mediated dilatation were observed, but not with NO2, total NC (s 1 pm), or traffic density. Blood Pressure A limited number of studies have con- sidered changes in HR and BP, which both reflect changes in autonomic tone, in relation to NC measures. These studies have been conducted in Europe as part of the mul- ticity ULTRA study (Amsterdam, Helsinki, and Erfurt), in Los Angeles, in Ottawa as part of the bus stop study, and in Taipei, Taiwan (Appendix Table B.1). The results to date have been inconsistent in regard to both the direction and significance of observed associations. In a small panel of subjects with lung function impair- ments, Chuang and colleagues (2005) observed positive asso- ciations between personal exposures to total NC (20-1000 nm) and HR and both systolic and diastolic BP in the 1-3 hours be- fore the BP measurement. In contrast, in the ULTRA multicity study of adults with coronary heart disease, small but sig- nificant inverse associations between particle measures (PM2.5, NCo.o1-0.1, and accumulation mode particles [NC0.1-1.01) at 0-2 day lags and systolic and diastolic BP were found in pooled analyses (Ibald-Mulli et al. 2004). In the panel study of older subjects with coronary heart dis- ease living in retirement homes in Los Angeles, outdoor home measurements of total NC, PM2.5, OC, BC, and gases were conducted (Delfino et al. 2010c). In overall analyses, the authors observed positive associations of systolic and diastolic BP with all particle measures, at 3-9 day mean concentrations, except for total NC. In effect modification analyses, associations with 1-8 hour lagged total NC were observed when subjects reported moderate to strenuous physical activity in the hour preceding the BP measure- ment. In the bus stop study, only NO2 was associated (pos- itively) with 2 -hour bus stop exposures (Dales et al. 2007). Soluble Markers A relatively large number of articles (n = 16) from eight different studies have considered total or UFP NC in relation to various blood (and urinary) markers of systemic inflammation, coagulation, and oxida- tive stress, pathways that are linked with processes of CVD and atherosclerosis (Appendix Table B.1). The large range 55 Understanding the Health Effects of Ambient Ultrafine Particles of specific markers examined across these studies makes it difficult to fully assess the consistency of effects. However, there have been a handful of common markers used across studies, including C -reactive protein (CRP) and inter- leukin-6 (IL -6) as markers of systemic inflammation, and fibrinogen as a marker of coagulation. Of the eight studies assessing endpoints for CRP, IL -6, or both, four studies observed associations with various mea- sures of number concentration: 1) a population -based cohort study in Germany (Hertel et al. 2010); 2) a European multicity study of myocardial infarction survivors in Athens, Greece; Augsburg, Germany; Barcelona, Spain; Helsinki, Finland; Rome, Italy; and Stockholm, Sweden (as part of the AIRGENE study) (Rucked et at 2007a); and two well -characterized panel studies in 3) Erfurt (Rnckerl et al. 2006; Rnckerl et al. 2007b; Yue et al. 2007) and in 4) Los Angeles (Delfino et al. 2008, 2009). The first of these studies (Hertel et at 2010) used a dispersion and chemical transport model to determine spatiotemporally-resolved total NC, but did not consider pollutants other than NC, PM2.5, and PM10 in the analysis. The other three studies, however, in addition to observed associations with NC metrics, found associations of CRP, IL -6, or both with accu- mulation mode NC, CO, NO2, or other traffic -related pol- lutants (such as EC in the Los Angeles study). Two - pollutant models of NC and other pollutants were not examined in these studies. The four studies in which no significant associations were found between NC metrics and CRP or IL -6 included panel studies of: 1) adults with a previous myocardial infarction in Augsburg (Kraus et al. 2011) (although this study did find an association with plasma Lp-PLA2, a marker of vascular inflammation [Briiske et al. 20111); 2) adult men with chronic pulmonary disease in Erfurt (Hildebrandt et al. 2009); 3) adults with stable chronic heart failure in Aberdeen (Barclay et al. 2009); and 4) adult men in the VA Normative Aging Study in Massachusetts (Zeka et al. 2006). It is difficult to generalize the differ- ences between the positive and null studies here. How- ever, the studies with null results for CRP were largely null not only with respect to particle number, but also with other pollutants examined. Such findings suggest that overall study design factors such as sample size or the exposure contrasts that were considered may have made detection of any underlying effect difficult. Seven of the eight studies also assessed fibrinogen levels or other blood markers of coagulation in relation to various NC measures. The results for these endpoints have been very inconsistent; only two studies observed associations between NC and fibrinogen effects (Zeka et al. 2006; Hil- debrandt et al. 2009), and studies that evaluated a range of coagulation endpoints have generally observed mixed results among the endpoints examined (Rnckerl et al. 2006; Delfino et al. 2008; Hildebrandt et al. 2009). In the Erfurt panel study, Rnckerl and colleagues (2006) examined multiple blood biomarkers in a panel of coro- nary heart disease patients and observed associations between ambient fixed -site PM10, UFP NC, accumulation mode NC, CO, and NO2, and increased markers of inflam- mation (CRP) and adhesion (ICAM-1) above the 90th per- centile, with the strongest associations using 2 -day lagged pollutant measures; results for markers of coagulation were inconsistent (e.g., factor VII, fibrinogen, D-dimer) (Rnckerl et at 2006). In a further analysis of this panel, the authors observed associations between 0-23 hours mean UFP NC and accumulation mode NC with plasma levels of sCD40L, a marker for platelet activation (Rnckerl et al. 2007b). In contrast, however, associations of 0-5 day lagged UFP NC with CRP and ICAM-1 were weak in another Erfurt panel study of male chronic pulmonary disease patients (Hildebrandt et al. 2009); in this study, associations of ambient UFP NC at 1- and 3 -day lags and 5 -day mean con- centrations were observed for fibrinogen. The differences in findings between these two studies may be due in part to the differences in underlying health status of the patient popu- lations examined, and may also point to limitations in the generalizability of results of small panel studies. Delfino and colleagues have published several articles describing associations of total NC and other pollutants on blood markers and other endpoints in a panel of subjects with a history of coronary artery disease recruited from four retirement homes in the Los Angeles air basin (Delfino et al. 2008, 2009, 2010c). Overall, this study has included the most detailed health and exposure character- ization of the studies published to date. The health end- points characterized have included biomarkers of inflammation, coagulation, and oxidative stress, and the exposure characterization has included unusually detailed home outdoor and indoor measurements of UFPs, includ- ing total NC, PM0.25, and PM0.25 components. (See section entitled Epidemiologic Studies Using Measures of UFP Moss for a discussion of PM0.25 epidemiologic results.) The results from this study have pointed to consistent as- sociations between UFPs measured as total NC and inflam- matory markers (IL -6, CRP, and sP-selectin); however, associations have also been strong for other traffic -related pollutants and components (e.g., EC, primary OC, CO, NO2), and the authors implicate traffic emissions in their findings (Delfino et al. 2008, 2009). In contrast to the ob- served strong associations with the inflammatory markers, however, the results for markers of coagulation have been mixed, and the results for a measure of oxidative stress 56 HEI Perspectives 3 (Cu, Zn-super oxide dismutase) have been internally in- consistent. For example, the authors observed negative and positive responder groups, with negative associations observed for certain subjects and positive associations ob- served for others (Delfino et al. 2008, 2009). EXPOSURE ASSESSMENT CONSIDERATIONS Our review of the epidemiologic literature identified several issues affecting the assessment of exposure to UFPs that are likely to have contributed to inconsistencies in observed results between studies as well as to uncertain- ties and limitations in assessing more specifically the con- tribution of UFPs to adverse health outcomes. CopoIIutant Confounding Previous reviews (e.g., U.S. EPA 2009), and many pri- mary research articles examined as part of this evaluation, indicate that high covariation of UFPs with other combus- tion -related pollutants, such as CO and NO2, makes it diffi- cult to disentangle the independent effects of UFPs from these pollutants or the traffic -related mix in general. To illustrate this point with the currently available literature, of 42 published articles that cited any significant NC -health associations, 37 articles also noted significant effects for other particle or traffic -related pollutants and 10 articles did not consider traffic -related gases at all in the analysis (see Appendix Table B.1). Two -pollutant models were considered in some studies to assess the inde- pendence of UFP effects from other pollutants. Observed effects of NC measures did hold in two -pollutant models with other particle measures (e.g., accumulation mode NC or PM) and CO or NO2 in some studies (8 and 3 studies, respectively). However, 5 studies reported that observed effects of NC measures did not hold in two -pollutant models with copollutants, and 23 of these studies did not consider NCs in two -pollutant models with copollutants. Multipol- lutant models are inherently difficult to interpret and may not be appropriate to implement with pollutants that are considered surrogates of the same source (e.g., traffic in this case). Thus, in most analyses to date, the indepen- dence of UFP effects cannot be clearly determined in the available observational study designs. Exposure Measurement Error Most studies assessing UFP health effects, especially the population -based studies of acute mortality and morbidity as well as many panel -based studies assessing clinical and subclinical endpoints, have utilized ambient fixed -site mea- surements of UFPs to represent exposures to individual study subjects. Depending on the study design and the nature of spatial and temporal variability in UFP concen- trations in a study area, this approach may lead to varying degrees of error in how well individual exposures are rep- resented (see related discussion in Chapter 2). These types of error in exposure measurement can, in turn, affect the ability of epidemiologic studies to detect associations with health outcomes. Population -Based (Time -Series) Studies For population - based studies of short-term exposures as in daily time -series studies, exposure contrasts are temporal and assessment of short-term average population exposure for the entire study area is necessary. In these studies, ambient fixed -site moni- toring data may be adequate as the measure of exposure if the temporal variability in UFP concentrations at the fixed site represents the temporal variability of concentrations over the study area. However, it is important that assess- ments of both spatial and temporal variability of UFPs at a range of locations within the study area be provided to assess the suitability of reliance on the fixed -site monitor for this purpose. How well exposures are characterized for the individ- uals in the study can affect the strength, and in some cases the direction, of the associations that can be observed in a study. Error in exposure estimates can often bias associa- tions between exposures and health outcomes to the null and can be one explanation for lack of observed positive associations in a study (Atkinson et al. 2010). In other cases, exposure measurement error can lead to spurious associations. Studies indicating strong temporal correlation among monitoring sites for NC, despite differences in absolute con- centrations among sites, might reassure us that the use of ambient fixed -site monitoring data in these studies is ade- quate for detecting underlying associations in time -series epidemiologic studies. For example, Cyrys and colleagues (2008) documented strong site -to -site temporal correlations (r> 0.80) for ambient UFP NC in Erfurt, Germany. However, study locations likely differ in the level of spatiotemp oral variability of UFPs, and need to be evaluated directly for each study location and period. In studies that observe associations only with larger particle measures, it is pos- sible that null findings for UFPs may be due to greater exposure error for the UFP measurements than for other size fractions (Pekkanen and Kulmala 2004). Panel Studies Assessment of exposure in panel studies that rely on ambient fixed -site monitoring data can be more complex than for population -based studies. Ambient fixed -site measurements in these studies are less likely to accurately describe the temporal variability of exposures 57 Understanding the Health Effects of Ambient Ultrafine Particles for each individual, depending on their time —activity pat- terns and proximity to local sources, and more precise measures of exposure may be needed. For PM2.5, results of detailed exposure assessment studies suggest that for many individuals an ambient monitoring site can ade- quately represent temporal variability in exposures to ambient PM2.5 (Ebelt et al. 2000; Janssen et al. 2000; Sarnat et al. 2000, 2006b). However, there have been no studies that have directly assessed the relationship between per- sonal exposures and ambient concentrations for UFPs. Hoek and colleagues (2008) have approached this ques- tion in their investigation of ambient (central site), outdoor home, and indoor home concentrations of total NC, PM2.5, PM10, soot, and sulfate for over 150 homes across four European cities. In their analysis of 24 -hour average data, correlations of central site to indoor concentrations were lower for total NC (r = 0.16-0.45) than for PM2.5 (r = 0.40- 0.80) and sulfate (r = 0.91-0.99). These analyses suggest that ambient fixed -site monitoring data for NCs may be less representative of individuals' exposures than they are for PM2.5. Addressing Potential Exposure Error To overcome some of the concerns of exposure error in both types of studies, some investigators have considered capture area analyses (O'Neill et al. 2005; Stolzel et al. 2007; Andersen et al. 2008a; Belleudi et al. 2010), where associations are reas- sessed in only the population that resides within a limited distance from the monitoring site. This restriction made a difference in the study by Andersen and colleagues (2008a): total NC was not significantly associated with dai- ly wheezing in infants in the overall analyses (i.e., includ- ing children living within a 15 -km radius of the monitor), but associations were significant when the analysis was limited to children living within a 5 -kilometer radius of the monitor (Andersen et al. 2008a). In panel studies, populations have also been chosen on the basis of their residence near the fixed -site monitor of interest — within 2 kilometers (Penttinen et al. 2001a,b; Song et al. 2011), 5 kilometers (Pekkanen et al. 2002; Lanki et al. 2008), or 10 kilometers (Anderson et al. 2010) — of the ambient monitoring site. It is difficult to assess the con- tribution of these geographical restrictions to detection of epidemiologic associations, however. Effects with NC measures were observed in only three of the six cited studies; these variable findings may be attributable to a range of factors other than exposure error (such as study population and outcome investigated). Other efforts have been made to improve UFP field mon- itoring campaigns for panel studies. Several of the more recent panel studies have utilized more comprehensive exposure characterization, including school -based out- door measurements (Song et al. 2011), home outdoor and indoor measurements (Delfino et al. 2008, 2009, 2010b,c; de Hartog et al. 2010), as well as personal exposure moni- toring of NCs (Chan et al. 2004; Chuang et al. 2005). Many, but not all, of these studies reported associations between NC measures and the respective outcomes of interest. Several of these articles allow for a comparison of epide- miologic results obtained from different exposure assess- ment approaches. In a European multicity study, de Hartog and colleagues (2010) found no consistent associations between total NC and pulmonary function, regardless of whether central site, home outdoor, or home indoor mea- surements were applied. Delfino and colleagues (2008), in their study of retirement home subjects, found stronger associations between total NC and markers such as IL -6 and CRP when using outdoor compared with indoor con- centrations (note that indoor UFPs may have different size and chemical composition than outdoor UFPs). Associa- tions using estimated indoor NC of outdoor origin, how- ever, were more similar to those observed for outdoor concentrations. Figure 25 compares, for example, the results for IL -6 using outdoor and indoor NC (including indoor NC of ambient origin). The authors suggest that measurements recorded at outdoor home locations may be adequate to capture outdoor air pollution —cardiovascular health associations. EpidemioIogic Studies Using Measures of UFP Mass Our review has until this point focused on studies that evaluated associations between UFPs characterized by number concentration measurements and health out- comes. As discussed in the Chapter 2 of this document, scientists have also characterized UFP concentrations using different measures of UFP mass. Measurements of reconstructed mass (PM0.1) that more specifically target UFPs in the size range of interest for this document have been used to study source -apportionment of UFPs. How- ever, these methods are only just beginning to be used in epidemiologic studies, and results have not yet been pub- lished. Some of the most detailed work done to date with PM mass has involved a larger particle size cut point, 250 nm, or PM0.25 which is included in the class of particles commonly referred to as quasi-UFPs. Although these studies are not ideal for shedding light on UFPs (< 100 nm), we discuss them here in part because the investigators have made reasonable efforts to include data on particle number count and other air pollutants in their analyses. This work is also notable for providing some data on the composition of these smaller particle size fractions. 58 HEI Perspectives 3 Pollutant Lag N Est Coef Outdoor Measurements PMvzs Lag 0 175 0.64 - 4 d ave. 205 0.63 - PMo25-25 Lag 0 216 -0.05 - 4 d ave_ 241 —0.46 - PM25,o Lag 0 189 0.43 - 4 d ave. 219 —0.09 - EC Lag 0 207 0.31 3 d ave. 241 0.48 - 9 d ave. 226 1.14 - CC Lag 0 207 0.03 3 d ave. 241 6.22 - 9 d ave. 226 0.28 - BC Lag 0 241 0.48 - 3 d ave. 241 0.42 - 9 d ave 241 6.66 - CCp Lag 0 207 0.34 - 3 d ave. 241 0.59 - 9 d ave 226 1.08 - SOA Lag 0 207 -0.06 -3 d ave. 241 —0.13 - 9 d ave. 226 —0.17 - PN Lag 0 216 0.50 - 3 d ave. 205 0.50 - 9 d ave. 195 0.76 - NO, Lag 0 241 0.61 - 3 d ave. 241 0.54 - 9 d ave. 241 0.61 - Co Lag 0 226 0.52 - 3 d ave 241 0.51 - 9 d ave. 216 0.50 - I.' • I • • • • • • • E _ • • • I •1 -1 5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 Figure 25. Comparison of the relationships of IL -6 (pg/mL), a biomarker of inflammation, to outdoor and indoor air pollutants. The figure plots the esti- mated change (adjusted coefficient and 65% CI) in IL -6 corresponding to an interquartile range change in the average air pollutant concentration for the pre- vious day (lag 0), or for the previous several days preceding the blood draw). (Est Coef signifies estimated coefficient. For indoor measurements of EC, primary OC (OCpri), secondary organic aerosol (SOA), and PN, the symbol oo signifies indoor concentrations of outdoor origin). (Source: Delfino et al. 2008, Figures 1 and 2, reproduced with permission from Environmental Health Perspectives.) (Figure 25 continues on next page.) 59 Understanding the Health Effects of Ambient Ultrafine Particles Pollutant Lag N Est Coef Indoor Measurements PMo zs Lag 0 164 0.02 - 4 d ave 197 -0 09 - P1\110_25-zs Lag 0 186 -0.12 - 4 d ave. 197 -0.46 - pM, s -a Lag 0 241 -0.05 4 d ave. 225 -0.24 - EC Lag D 195 -0 02 - 3 d ave. 167 0.30 9 d ave. 167 0.59 - EC o o Lag 0 195 0.20 - 3 d ave. 231 0.37 - 9 d ave. 193 0.76 - CO Lag D 195 -0 03 - 3 d ave. 167 0.10 9 d ave. 167 -0.40 - OCp+F 0_0 Lag 0 207 0.20 - 3 d ave. 241 0.30 - 9 d ave. 226 0.83 - SCA o0 Lag D 207 -0 07 - 3 d ave. 241 -0.12 - 9 d ave. 226 -0.17 - PN Lag 0 205 0.31 - 3 d ave_ 205 0 28 -- 9 d ave. 194 0.29 - PN o_o Lag O 161 0 50 - 3 d ave. 175 0.48 - 9 d ave. 154 0.72 - NCz Lag 0 241 0.40 - 3 d ave. 226 0 42 -- 9 d ave. 226 0.43 - CO Lag 0 241 0 54 - 3 d ave. 241 0.47 - 9 d ave. 241 0.77 - Figure 25 (Continued). F•1 • I F -•t1 I• H I • • • I • I I • I • I • • • 1 • I • I • 1,5 -1.0 -0.5 0 0 0.5 1.0 1.5 2.0 60 HEI Perspectives 3 Two panel studies have assessed PM0.25 mass concen- tration, either alone or alongside number concentration or other PM data. One is a study of patients with a previous myocardial infarction in Italy in which negative correla- tion was found between HRV and exposure to PM0.25 in a group of patients not taking beta-blockers. More severe ventricular arrhythmias were observed at the highest con- centrations of PM10 and PM2.5. Indexes of inflammation in either breath condensate or blood did not correlate with PM exposures (Folino et al. 2009). The other is a series of panel studies of retirement home subjects with a history of coronary artery disease by Delfino and colleagues in Los Angeles, which has included perhaps the most detailed work to date on quasi-UFPs in an epidemiologic setting (Delfino et al. 2008; 2009; 2010a,b; 2011). Overall, the authors have observed associations between outdoor and indoor home PM0.25 and ECG and blood marker outcomes. The group's recent analyses examined outdoor and indoor home measurements of PM0.25 and PM0.25 components (PAHs, hopanes, n-alkanes, organic acids, water-soluble A 0.6 J Ten Q. J 0.4 0.2 0.0 - 0.2 -0.4 - 0.6 • V Outdoor Indoor PMo 25 PAH Hopanes WSOC Organic Ads Mass POA Components SOA Components and Tracers and Tracers OC, and transition metals) (Delfino et al. 2010b). The authors reported that strong associations with inflamma- tory markers (IL -6 and sTNF-RII) were observed with PAHs, and that associations of total PM0.25 were con- founded by PM0.25 PAHs (see Figures 26 and 27). In a fur- ther analysis, the authors found both IL -6 and exhaled NO, a marker of pulmonary inflammation, were associated with PM0.25 oxidative potential, which was assessed via reactive oxygen species generation in the in vitro cellular assays (Delfino et al. 2010a). This study also included measurements of total NC, and therefore affords a comparison of results between the dif- ferent UFP metrics. For example, in examination of the inflammatory markers the authors found associations with outdoor home measurements of both total NC and PM0.25 (Delfino et al. 2009). In another analysis, however, the authors found ST -segment depression associated with out- door home measurements of PM0.25 (and other traffic - related pollutant measurements), but not with measure- ments of total NC (Delfino et al. 2011). B sTNF-RII (pglmL) 400 - 350 = 300 25Q 200 - 150 - 100 50 • Ouldoar v Indoor -50 - - 100 - — 150 - — 200 - _ PMo 25 PAH Hopanes WSOC Organic Accts Mass POA Components SOA Components and Tracers and Tracers Figure 26. Associations of biomarkers of inflammation with 5 -day average outdoor and indoor concentrations of PMa25 mass, and markers of primary organic aerosols (POAs) and secondary organic aerosols (SOAs) in subjects from a retirement community in Los Angeles, CA. The figure plots the expected change (adjusted coefficient and 65% CI) in A: IL -6 and B: sTNF-RII, corresponding to an IQR increase in the air pollutant concentration, adjusted for temperature. (Source: Delfino et al. 2010b, Figure 1, reproduced with permission from Environmental Health Perspectives.) 61 Understanding the Health Effects of Ambient Ultrafine Particles A 0.6 0.4 — S 0.2 — J E Q J 0.0 —0.2 —0_4 — 300 B sTNF-RII (pg1mL) • 200 — 100 — 0 - 100 - -200- - 300 PMazs PM0.25 PAH PAH Alone with PAH Alone with PM,„„ • • PM0 25 PM425 PAH PAH Alone with PAH Alone with PMO25 C 300 200 - -200 - 300 PM0.25 PM0.25 with Hopanes Hopanes Alone Hopanes Alone with PM425 Figure 27. Associations of circulating biomarkers of inflammation with outdoor PMo,25 mass coregressed with outdoor total PAHs and hopanes in PMo,25 for subjects in a retirement community in Los Angeles, CA. A: IL -6, PAHs, and PM0.25. B: sTNF-RII, PAHs, and PM0.25. C: sTNF-RII, hopanes, and PM0.25. Estimated change in the biomarker (adjusted coefficient and 95% CI) corresponds to an IQR increase in the air pollutant concentration, adjusted for temperature. (Source: Delfino et al 2010b, Figure 2, reproduced with permission from Environmental Health Perspectives.) 62 HEI Perspectives 3 SUMMARY AND CONCLUSIONS FROM EPIDEMIOLOGY For this issue of HEI Perspectives on UFPs, we reviewed both older summary reviews of the UFP epidemiologic lit- erature and relevant primary research articles that have been published in the interval after the compilation of the 2009 EPA PM ISA (U.S. EPA 2009). A growing number of studies have attempted to assess the health effects of UFPs, either as their main focus or as one of several pollutants of interest. However, for reasons summarized below, we have found that the evidence to date continues to lack consis- tency and coherence with regard to our overarching ques- tion of whether ambient UFPs affect human health differently or independently from the effects of other par- ticle or gaseous copollutants. Inconsistency of Results by Endpoint Previous review articles have noted that the current evi- dence base lacks a coherent set of studies designed to address specific hypotheses about the specific health end- points (Araujo and Nel 2009; Lotti et al. 2009). While a growing number of studies have considered the effects of short-term UFP exposure, the consistency of effects for any one endpoint is still lacking. For both respiratory and cardio- vascular outcomes that are assessed here, studies continue to show inconsistent results, with some studies reporting asso- ciations with UFP exposure (e.g., Von Klot et al. 2002; Andersen et al. 2008a; Song et at 2011) while others do not (e.g., de Hartog et at 2003, 2010; Timonen et al. 2004). The inconsistencies in observed associations and lag structures may be due to a number of factors, including differences in study designs, populations examined, data availability and UFP metric utilized, differential measure- ment error across studies, different model strategies and confounder control (e.g., weather), and possibly differ- ences in pollutant composition, concentration, or a combi- nation of composition and concentration that might influence health risk. Studies based on small panels of subjects are limited in their generalizability, which likely also contributes to the lack of consistent effects across the small but growing numbers of epidemiologic studies of UFPs. Ultimately, as in any study, one explanation that must be considered is that a true underlying association does not exist. However, the meta -analysis necessary to more fully test this hypothesis would be difficult to imple- ment, given the current study design differences across the available epidemiologic literature. Exposure Assessment While research on UFPs and human health effects appears to be improving over time with regard to the quality of exposure measurements (e.g., improved measurement equipment, exposure assessment with mul- tiple monitors), most studies lacked significant conclu- sions regarding the potential effect of exposure measurement error on study results. UFP concentrations are known to be highly spatially variable within cities, yet many city-wide assessments of UFPs do not account for this high variability. Short-term studies of UFPs and health effects may avoid the spatial error component by analyzing temporal variations, but the assumption that temporal variations within a city are spatially uniform is not explic- itly evaluated. As such, there is a concern that null find- ings for health effects of UFPs may be the result of exposure measurement error. In one study where investi- gators specifically attempted to improve the accuracy of the NC exposure assessment, however, associations between total NC and human health effects were still not observed, possibly due to other study design consider- ations (de Hartog et al. 2010). Assessment of the Independence of UFP Effects Where positive associations have been observed with UFPs, studies have not generally shown independent effects of UFPs, either in the absence of other exposures or in models adjusting for expected copollutant effects. While associations between UFPs and human health effects were observed for some outcomes, many studies did not account or adjust for the potential associations with gases or other particle metrics (even when effects of those other particle metrics or gases were observed), or potential copollutant exposures were not addressed or even included in the analysis. While proximity to traffic and other markers of traffic exposures imply exposure to UFPs, it is very chal- lenging to separate the potential health effects of UFP expo- sure from the potential health effects of other exposures associated with traffic such as NO2, CO, or noise. This survey of the literature was intended to assess the state of the literature with the regard to the health effects that are potentially associated with UFP exposure. Despite a growing evidence base of observational studies of UFPs and improving measurement and exposure assessment approaches, there remain inconsistencies in reported results between studies of the same or similar health end- points and suggestive, but not definitive, research find- ings. Research on the long-term exposure effects of UFPs is particularly absent from the literature. Given the emerging understanding of spatial and temporal exposure variation, the potential role of copollutants, evolving measurement methods and technology, and unclear physiologic mecha- nisms of action, the epidemiologic findings do not identify definitive, reproducible human health effects that are uniquely associated with UFP exposure. 63 Understanding the Health Effects of Ambient Ultrafine Particles CHAPTER 5. Summary and Conclusions SUMMARY Ever since the hazards of air pollution were first identi- fied, scientists and policy makers have sought to identify those constituents of the air pollution mixture that might explain, in whole or in part, the adverse effects that have been observed. Over two decades ago, epidemiologic studies began to find that PM was associated with increased mortality and morbidity, but the underlying bio- logical mechanisms for such relationships were the subject of much speculation. About the same time, researchers hypothesized that the components of PM, including UFPs, could be responsible for the adverse effects of PM and of the air pollution mixture in general. The motivation for research on these hypotheses was not just to understand the underlying mechanisms but to help ensure that efforts to control exposures to air pollution were targeted effectively on those components of most relevance to public health. A substantial body of literature has now been published on the sources and generation of UFPs, their spatial and temporal distribution in ambient air, their inhalation and fate in the body, their mechanisms of toxicity, and their adverse effects in animals and in humans. The purpose of this issue of HEI Perspectives on UFPs has been to provide a broad assessment of what has been learned and what remains poorly understood. We structured our assessment of this literature and its ability to inform an answer to the overall objective as responses to three questions: 1. Ambient UFPs — sources, emissions, and exposures: To what extent do motor vehicles contribute? As products of combustion and secondary atmospheric transformations, ambient UFPs have multiple sources whose relative contributions to ambient concentrations varies with location, season, and time -of -day. However, in urban areas, particularly in proximity to major roads, motor vehicle exhaust can be identified as the major con- tributor to UFP concentrations. Diesel vehicles have been found to contribute substantially, sometimes in dispropor- tion to their numbers in the vehicle fleet. However, the absolute and relative contributions of different vehicle types to motor vehicle emissions is changing rapidly with changes in fuels, engine, and exhaust aftertreatment tech- nology. The collective effect of all these changes has not been thoroughly explored and is likely to vary regionally, depending on the rate and extent to which they are deployed in different parts of the world. It has been more challenging to characterize human exposure to ambient UFPs than to the more regionally dispersed and routinely monitored pollutants, such as PM2.5. UFP concentrations are not routinely monitored, and most monitoring in studies relies primarily on measures of total NC and to a lesser extent on size -differentiated number concentrations. Particle number counts tell us little about other characteristics of UFPs, such as surface area, surface reactivity, or chemical composition, which may be of interest in understanding health effects. In addition, high covariation exists between UFPs and other combustion - related pollutants, such as CO and NON, near sources such as traffic. Furthermore, UFP NCs often differ substantially from one location to another in the same city. Conse- quently, reliance on measurements at central site monitors to represent broad population exposure, for example, across an entire metropolitan area — a central feature of epidemiologic of studies of long-term exposures to PM2.5 and other pollutants — is more likely to lead to misclassi- fication or errors in determining UFP exposure. However, UFP NCs measured at multiple locations within cities do tend to vary temporally in similar patterns over the course of a day. Moderately good temporal corre- lations between UFP concentrations at central monitors, outdoors at residences, and even indoors at residences have been observed in some but not all cities. The correla- tions are not always as strong as those observed for PM2.5, but in some locations they can be sufficient to support epi- demiologic studies of the effects of short-term variations of NCs on human health, with study designs that have been useful in studies of larger size fractions. However, the tem- poral variability in UFP NC is likely to be similar to that of other PM size fractions and gaseous pollutants, making it difficult to differentiate the effects of UFP NC in such study designs. 2. Do UFPs affect health? What is the evidence from experimental studies in animals and humans? Experimental studies have provided evidence to indi- cate that, as a result of their physical characteristics, inhaled UFPs differ from larger particles in their deposi- tion patterns in the lung, their clearance mechanisms, and in their potential for translocation from the lung to other tissues in the body. Some animal studies have also demon- strated translocation of UFPs via the olfactory nerve to the brain. Taken together, these findings provide a rationale for the hypothesis that the adverse health effects of exposure to UFPs differ from those of larger particles. Both animal and human studies provide evidence for respiratory and cardiovascular effects associated with 64 HEI Perspectives 3 exposure to UFPs. Observed effects in selected studies include lung function changes, airway inflammation, enhanced allergic responses, vascular thrombogenic effects, altered endothelial function, altered heart rate and heart rate variability, accelerated atherosclerosis, and increased markers of brain inflammation. With the excep- tion of brain effects, the findings are largely similar to those observed for exposures to fine particles. There are limitations and inconsistencies in the findings on UFP health effects. There are no long-term animal expo- sure studies of UFP health effects. Relatively few studies have directly compared UFPs with other particle size frac- tions. The somewhat inconsistent findings in human con- trolled exposure (chamber) and real -world studies discussed in Chapter 3 likely result in part from differing outcome measures, as well as limitations in measure- ments, study designs, and statistical power. Furthermore, clinical studies of exposure to UFP proxies, such as labora- tory -generated UFP or concentrated ambient UFP, may not accurately reflect the effects of exposure to actual ambient UFP under real -life conditions. On the other hand, the real -world studies of exposure to ambient UFPs face the challenges of disentangling the health effects of UFPs from other traffic -related pollutants. While selected studies show evidence for UFP effects, the current evidence, when considered together, is not suf- ficiently strong to conclude that short-term exposures to UFPs have effects that are dramatically different from those of larger particles. The limitations of the experi- mental data, and the absence of long-term exposure studies in animals or humans, constrain our ability to draw definitive conclusions about the consequences of exposure to UFPs. 3. Do UFPs affect human health at environmental concentrations? What is the evidence from epidemiologic studies? Epidemiologic studies have provided suggestive, but often inconsistent, evidence of adverse effects of short- term exposures to ambient UFPs on acute mortality and morbidity from respiratory and cardiovascular disease. One explanation that must be considered for the results to date is weakness in the true underlying relationship between UFP exposures and adverse effects — that the null hypothesis being tested by these studies is true. How- ever, limitations of the current studies are likely to play a role: UFPs have not been assessed routinely in larger epi- demiologic studies of air pollution health effects, in part because ambient monitoring of UFPs is not conducted in most locations; UFPs have been defined and measured in different ways; and the greater exposure measurement error for UFPs relative to PM2.5 and other pollutants makes it difficult to design epidemiologic studies with sufficient statistical power to test confidently for what may be small, but important health outcomes. The available observa- tional study designs have also not been able to clearly determine whether UFPs have effects independent of those for related pollutants. Where studies have measured UFPs, few have actually assessed whether the effects asso- ciated with UFPs are independent of other pollutants. When they have, the effects of UFPs have not been consis- tently discernible from those of other pollutants with which they often occur or share similar sources (e.g., traffic). Of 42 published articles that cited any significant health associations with UFPs measured as NC, 37 articles also noted significant effects for other particle size frac- tions or traffic -related pollutants, and 10 articles did not consider any traffic -related gases in the analysis. It should be noted that multipollutant models are inherently diffi- cult to interpret and may not be appropriate to implement with pollutants that are considered surrogates of the same source (e.g., traffic in this case). No epidemiologic studies of long-term exposures to ambient UFPs have been conducted, as the most common epidemiologic study designs are dependent on spatial con- trasts that are far more difficult to characterize for UFPs than for PM2.5• CONCLUSIONS Airborne PM has been the focus of extensive research and debate in the United States and around the world. At this point, considerable evidence from a broad array of experimental and epidemiologic studies has led to strong scientific consensus on the independent associations of airborne PM, in particular PM2 5 and PM10, with adverse respiratory and cardiovascular effects on human health (U.S. EPA 2009; Brook et al. 2010; CASAC 2010). This evi- dence has provided the foundation for many regulatory decisions to limit both PM emissions, particularly from motor vehicles, and ambient PM concentrations to which people might be exposed. What role have ambient concentrations of UFPs played in the adverse effects that have been observed in human populations exposed to ambient air pollution? In the years since investigators first became concerned about the potential adverse effects of exposure to the small- est of airborne particles, a considerable body of research has been conducted on the emissions, exposures, and health ef- fects of UFPs. Several factors — the unique physical proper- ties of UFPs, their interactions with tissues and cells, their potential for translocation beyond the lung — have led 65 Understanding the Health Effects of Ambient Ultrafine Particles scientists to expect that UFPs may have specific or en- hanced toxicity relative to other particle size fractions and may contribute to effects beyond the respiratory system. However, toxicologic studies in animals, human exposure studies, and epidemiologic studies to date have not provid- ed consistent findings of such effects with exposures to am- bient levels of UFPs, particularly in human populations. The evidence also does not support a conclusion that expo- sures to UFPs alone can account in substantial ways for the adverse effects that have also been associated with other ambient pollutants such as PM2.5. That the current database of experimental and epidemi- ologic studies does not support strong and consistent con- clusions about the independent effects of UFPs on human health does not mean that such effects can be ruled out. The limitations in the evidence base are attributable to un- derlying gaps in exposure data, to numerous challenges to comparison and synthesis of existing studies, and to the inherent complexity of the scientific task scientists have set out to accomplish. Similar kinds of issues face ongoing efforts to tease out the health significance of other compo- nents of the PM mixture (Brunekreef 2010; Bell 2012; Lippmann et al. in press; Vedal et al. in press). Fortunately, and irrespective of evidence for a specific role for UFPs, re- cent PM regulatory decisions affecting fuels, engine de- signs and exhaust aftertreatment in the United States, Europe, and Japan will result in the significant reduction in emissions of both fine and ultrafine particles. Where Do We Go From Here? There are many considerations beyond the scientific opinions expressed in this issue of HEI Perspectives that inform the level of confidence in the evidence necessary for policy makers to "ensure that resources spent in the future on control technology and regulatory compliance will have a reasonable probability of success" (U.S. National Research Council 1998). Among them is the need to weigh carefully the value to scientific understanding and to regulatory decisions of continuing to treat UFPs as an individual pol- lutant versus alternative approaches that focus on the health effects of exposure to traffic or to the broader air pollution mixture. As part of this discussion, however, steps to address some of the limitations of the current evidence on UFPs should be considered. Experimental Studies Even in the absence of broad -scale epidemiologic evi- dence, insight into the potential toxicologic implications of differences in the deposition and retention of inhaled UFPs may still be possible with well -designed experi- mental studies of controlled exposures to UFPs and related copollutants. Examples include: • Further animal studies of the potential for, and health effects of, translocation and accumulation of UFPs in tissues beyond the lung, including the central nervous system. This work should be extended to additional ani- mal species and to models of human disease. • Animal inhalation studies of long-term exposures to UFPs. Virtually all of the work to date has been with short-term exposures; the kind of evidence that has been so important for understanding the effects of long-term exposures to PM2.5 and PM10 does not exist for UFPs. • Further human studies of UFP health effects and mech- anisms. Such studies should include both controlled laboratory exposures and real -world panel studies that target UFPs of various sources and chemical composi- tion but also involve comparisons with various PM size fractions and copollutants. EpidemioIogic Studies • Studies of long-term exposure to ambient UFPs. The kinds of data that have provided broad support for epi- demiologic investigations of the public health implica- tions of long-term exposure to PM2 5 and PM10 — multiple years of monitoring data, using consistent methods, in major urban areas representing millions of people — have simply not existed for UFPs. Different approaches to characterizing exposure (discussed below in recommendations for characterization of ambient UFP exposures) need to be considered for long-term studies of UFP exposures to be possible. • Targeted study designs with sufficient contrasts in UFP exposure, but that improve the ability to characterize the independent effects of exposure to UFPs. These might include scripted activities, measurements in envi- ronments with unique UFP exposure features, and stud- ies of interventions that are specifically designed to control exposures to UFPs. Intervention study designs where investigators filter out exposures to UFPs or to particles of various size fractions, but not gases, may be informative here. • More consistent and comparable study designs. One of the factors that has limited comparisons and interpreta- tion of the epidemiologic studies conducted to date on the effects of short-term exposures to ambient UFPs is the variability in study designs, both in exposure meth- ods and measurements (including copollutants) and in the health outcomes across individual studies and cit- ies. The kinds of meta -analyses that have been used 66 HEI Perspectives 3 successfully to strengthen inferences from short-term studies of PM2.5 and PM10 in the United States, Europe, Asia, and Latin America are consequently challenging and, to our knowledge, have not been conducted. Even the more consistent multicity study designs desirable for meta -analyses, and that are beginning to be applied to the study of UFPs, may still yield equivocal results if they must rely primarily on central monitors or do not account appropriately for copollutants. Better Characterization of Ambient UFP Exposures Many of the underlying challenges posed by the existing evidence on ambient UFPs relate to differences in how they are measured across studies and how much data are available to assess exposures. In part, variation in ap- proaches reflects the exploratory stage of efforts to identify size and other characteristics that might predict toxicity of UFPs. However, it is one of the factors limiting comparison and synthesis of the studies that have been done to date. • Find ways to exploit the high spatial variability of ambient UFPs in health studies. As UFPs do show gra- dients in concentrations within urban areas that are related to traffic sources, spatial modeling approaches that have been used to assess health effects related to traffic pollution may be applicable to UFPs, although characterizing the role of UFPs within the traffic mix- ture will remain challenging. • Explore UFP metrics other than NC for these applica- tions. For example, UFP mass and chemical composi- tion are more difficult to measure at an individual location, but population exposure to these metrics may be easier to predict using a combination of statistical models and reactive chemical -transport models. Linked with source -apportionment methods, such data could assist in identifying sources and allow monitoring of how changes to those sources would affect these tempo- ral and spatial patterns in the future. • Consider the growing literature on new statistical and other analytic methods aimed at disentangling the sources, exposures, and health implications of PM com- ponents and other copollutants. Although not dis- cussed in this document, these methods are addressing many of the same basic issues as those faced in the study of UFPs. Ultimately, it will be important to monitor the effect on ambient UFPs of actions taken that target the emissions of PM and other pollutants that may directly or indirectly affect ambient UFP concentrations. 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Overview of HET Research Program on UFPs O Pet O ca 0 Hazi et al. 2003 o�� N NOn On N u'i a}i b El 04 CD k d 5' F o O 2 o� L --5.0 0 § a7 c0 v O$ w F. ao 'd y +r7 d O a0nc8,0 r�O Q+ V] O onooti O O �y 8q-vgaaD� �rdzcl'�U MO CD I V 0 '+i l ao N pa'd e� 0 ,d 4cDod.-cl, 00—I ..o� Foy g hfl opi 0 N ' o o O a)a� !ili a °' Z N ta, .PI1 amp F N 4 a] N yea ""0 rd O O O +.,:d o Aa5 1� 5 G O O -4 +o0 0 ai 40,:40 Jr o p n�� 0 al c ai'd yi�{P-I F1=1449 2:d cbc1� q a� -2 • a) 'd 0 0 -c- A 'J 4 a8i O+CD H "51 N m .d . O N cd ;MI 04 al CD nd G. w' la' Mr NI o Va] r' -d N V d F b F7 a) di eye O V O'd F V O F co g F G 44 V -+y , +' O y F�7 A V] . 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CD 04 ?r 0 i 2 'd G gl ++ O ' V a) cd G .b � d ° 5' _V - N `I cI N O d c0 0n CD Q A F coo c -)., 0o00,..0 cd cd y F O • 4+4 y F cd ++ cd o t b 40 O t181 ++ cd O 'd 0 a .,O 'd'dam b+0 0 a) O T a U O V a7 'b V �°C)�M il�0 '�'d"x op _ d_ ECU O in flECl-d 0 a a) 0 x —I H y p O a) ; V m a) d O m 4) 8 'd-' g El a049 c O q4 �1, v F O N, +� O O bE. 5'1 'd a �O.'�, . llD �, p, U cd 4''d°CD'd86a)�c +'b co PI p 0b ocC� w G d U 5 ca E d U c c N 0 O fiV F�tlyy -+.r� gnN T g O cy 'd co 4 p H Q.' 0 ,d 814dm 0 a) N d V ci 0 "CD 4c7, b"� c.) Fl�yy 4=i04,11, 94 Sagog 0 c O'd U+r � 0 x w c U 4 a � 0 I 2 0 b7c1P'd M;8a a�i O ,4 a) q m 0 0 ;� w CP OCO OP xFAa Table continues next page 89 Understanding the Health Effects of Ambient Ultrafine Particles 6▪ 6 a) Wes' 0 eig F I Q.) q l V V O 0 Xng1 2 0o O o F wroro p W p.'- H� -c;b°""yam-dad U O p 203 q U o V V V U O .G' O a rg .r51 Q F • -0 O y • . N +J Lti)PI al U CD • d U V E 0 • 0000 O .g cilW V Q1 on.94 F 14 ,+,�y1 a, p -d goy w N U a sai co V F FFyy M Fy co aAC' p Fy W V U API t co 4 cc00 aq CD 9) 22 I �,.40 = P 0 0 ,dcI �Q-dApg � U Oo0N-0p CD C.1 U �0 W Q N N U y flh �2�a)�aa)tl W F iq ' O aD 40 .-4 CD x c� ao"'•.d o� LyW'd�+OJcoVM0Vp CD Q1 .23 a0 co co , dLaLa go .36 c' 0 a a.. 0 o O o O iZ 2 or''d H. • 7., c4 .pp0 pai11Ii al 2 o.dn3vo00 X50 P'.ui .am M°A3 °'�oa,d,A boa 0 p ral • 0L4 t°i•0fiku N2-0hEs °9 p❑p 'd O .0 on o U "dq ' .d cI S� 4 '' Q7 U W 'al N 2 Lr q �j§ .t U7g No . co 04 a.,oco -1 p 'MIV U aa. -.. aa`no 2 Table continues next page 90 HEI Perspectives 3 o o ccl N Id P-2 CD 00 t . Te Q7 hUi A' N hiI 2 ` 3 ��" CD o 1- ..8 8C0 4 �"i 21 I q 5 0 0.1 O V F 0 r a i o V F Q7 W 1111111 V a 0 -0L 2 gl t0 o 0 +� 45 i O 0 0 b to 0 0 0 V �i c d al 1,1 qi co on -d y 00 p,d q o .0t 01 g - g Q. 'CI v_ 0 a O cC p b d- 4 Q V abi "2 a O S a� '4eaH�P'0itId8 i ��ow°n'm t H o b CD Fl OO a otoo �+ O Q] 04 F c a co cd�0a r 0 Ol.4 � � 3 a) Haiti O b� 44 0 O 0 co l o N C1 O CD 0 on cp '. V -F I.C1 CD a V b0 N ci5 .2 UI ap r814 .apq +y.+ aup0 on CD C CD 0 PI t ti F 0 �� .-Oyho-, F -d V W V d b N a-4=1 CI CD +b ;E O O 0 p p, .d P xCD a mto,-.° CEok WJ F" low U PI CD g d c b _v uo 4r" Ni.4 q" d U "0 dm Fy�E0`o�"aoo�°' , Op Q] W V b 049 U +'y H 'd �4 N V 'd ~ a) 0 b axi b R'i U 0 O N 91 Understanding the Health Effects of Ambient Ultrafine Particles APPENDIX B. Primary Research Articles i 7.3 o UU 'id O CA a if U Ix z z zz z Time series 2006 Brani6 et al. IIJ U Time series 2000-2005 Total NC z Time series 1998-2004 NC0.03_0.1 7.4n CCI xw Time series 1998-2004 NC<0.1 n 5 O N N a o zz o zz oo m .. CooO N y P4 C z O N N I zz o zz s ir' Sa Sza cp 0 cp CO, NO2, SO2, PM2.5 U CJ CJ CJ U CA CA Cf) CIO 4, Qom 144 000 zzz N N m tl a) a) Time series 1991-2002 NC0.01-0.1 s Time series 1995-1998 NC0.o1-0.1 Time series 1995-2001 NC0 01-0.1 a a :O O :O O CA N CA N Time series 1995-1998 NC0.01-0.1 Table continues next page o m g C may' S 01 kAA M g, .. g O 41 ii l'A i _ y •o li la O 9 Z P -0 t a g n II I 1 tt z° g o o 8 8 a � �� • V m la, 2Q v2 q 90 .4 2 OII o p 0 w I m h z" t p 4 IImm 1r0 II 8I �� LI o .-.9 1 m V m :4“....m F1 m" m �� .� 2 1111 M t04 g"o i'' 1 I' I' '' H. � I, ,,b $I42 .98 a�a .i 84 § b li w°gym �s�es I II 3, r, OOa :� 8 w u n 9� I:4 q v 92 HEI Perspectives 3 b i O co .10 O b .10 4+4 0.1 O ap cd Q7 Q7 a0 .H ail -48 d � •7O4 O F o co F4 p ti UCJ a c, En W CD CD Q P-3 U CDp El 0 UVA 0 V 0a° 1998-2000 Total NC z -d 2 0 Vn CD CJ a2 7.0 CCI cti CJ .003-0.03, co co co q NU 0.l O z PM2.5, NC32, 115, 365 CJ N 0 L O z N a) ti) +J co a0 0.l U U N 58 �a CCI 00 CF -8 O N N O ozza 2001-2004 a) ti) NON, CO, PM10 NON, CO, PM10 2003-2006 NC,0.1 0 N O • u, 0 N 2001— 2008 NC0.01-O.7 R1 0 CD U 2000-2005 Total NC N ao J I ad cad P H• Cl 'O N 2 N N 0F7 t I �t o m O W a Table continues next page 93 Understanding the Health Effects of Ambient Ultrafine Particles 0 ▪ ca CD CD W w b Ga co �UUUUUU co ap ri d fsa Q 1:4al a2 f 00.4 p� CJo 'al O C3 Cf) Py 410, Morbidity (Continued) NO2, CO, PM2.5 Cc;' a) a1 0 l o Pi v dd F. L71 y" F7 iri N N nd N Z p Fl id p 1998-2004 Time series 1998-2004 NC0.03-0.1 Time series el ul 00 zz 1997-2002 2001-2005 Total NC 0 O CO, NO2, O3, PM10 0 O CO, NO2, O3, PM10 U U Q o t CI) lit CI) lit Lip ot ▪ Li U o° U F CD F a1 1992-2000 Total NC Time series ca • 1992-2001 Total NC Time series 1993-2000 NC0.01-0.1 Time series 1993-2000 NC0.01-0.1 Time series Time series 1 0O F O LC1 cd n N P -I • N C# aj Table continues next page • Ou u g.9 8 m U ri. p a UM. G y qm II • iy a P 4 AI A A2 .9 .SEA .1I g Iii !I C4 [l'iW D7 II x] . U M • Z ° o wm b ii • b.2 g ... .E .2 a u 9 oag -..� m V UU 1 t 7▪ 5: ti 2 Al U zII m •aq u ti o mg Zr.,—F-; m III O m a i w M A II'° o II ° II 9 sp ''O m p m bA ° P. a b • <4 'O i II 1I 1 rQQo w 3fl at z q 0 � P a H:4 8 'mi p., .9 m 9,t-,1 A4 94 HEI Perspectives 3 O O oci 0 CD CD W P-� w C'Pm a0 oci U oo a O Qa cd F o a7 o (313 Ai 6 b (JO V 0 b�' O P- a v�q a) a) N CD El O .r U Q V 0 I- O oz z o2 V) o N U O4i Z 2004-2006 NC< 0.1 oci 07 P4 NO2, NOR, CO, PIStlio op d z p..l zzo 1998-2004 NC0.1-0.7 u, o O q 4 " z o U Q+ p i n z o a a oZ a an O o ill'I 1:14 '''J c; • iii N Go '''J z�9 za 0 o O eft e+ o o z I__ N WI O N O O Saa Sazz z NO2, SO2, CO m m Td.m o u V) ( .t,-.8 2...%) w w+b w§ b n 1996-1997 N V N V N aI &=i a a • O cp • N 0 pI t . oQ 000b 0000 g ad ZZZZ cti 1991-1992 O 0 • a� aEl 1996-1997 Table continues next page u II! g .9 II m▪ .t A 90 9° y q Acc so A E „ �q s i II i All 1 s g y JI. a II w ;M o VIII s0a Iii ° f5 0 LI F7 u II 8 U U G° o U I z o U II gin h' z z� s S. O O O rp0 pSI CD p O iAA� ▪ D)I I N Al V vm ii, II q.0 co .S t m q 111- I r. m d II m ▪ II 0 R,.m M 1 o p o P 0 0 .73 ✓ 8 8 N .5 ro ro 8 a0U z m� g 95 Understanding the Health Effects of Ambient Ultrafine Particles 0 0 as no -o P-� 0 44.4 0 I a0 O Qa Fa aj 04° �C7 NdA G O OVA a 0 z Nid 0 04 0 0o N Yes, not reported Total NC, PM2 5 �z z cn cn cn CO C) Nid 0 04 PMio, PMz.5, PMi Q1 N N id 0 ca ci) 04 CD V] V G cn NO2, NO, SO2 0 0 Cl.) CD 0 4 G ^ O I N m o ei N o M i N O 91 o 6+ m o ry o o o o zzzzzzm z C n ai m q m rl 0 PI 0 Table continues next page o lii mffi liE a AoI .9° N Io.. b a A0 A o 1 U i 1 II H 1 IJ i,my a •� Ng vj 'o pp a o.Eaz II g u d m 8u Uri II . gyp A II 09 • V 1 it r0 A glAg a II 8 x U�U G U 66 z o CIII U -W, A d � :5 41 II 2oa. co 8- m c4A c4 4 oo DO d 41 8 II .21 II -9 IH •figgI o 13 mom' II- " .0 VaA 1 I 1 8W 8 IUIJ g .c II u.m � S U C a 'a A P t (i.e., < 0.100 pm in 96 HEI Perspectives 3 O ap U CD CD os b oci co co .H d r=14 CCI Q aj Ai a 03 73 O OO 4 a, O A 410 V b co 7.3 O p., P.3a, a, e N O LI? p O N I '+O .6 � oz LI O ZZ 0 Z w8 a H on ; O , :≥iN P t 2 z ,. O O °z�q" N0cd o O °azz z ii! O 40 o 0 O 0 ad0 ad zzz zz 1996-1997 1996-1997 00 00IT 0.i 1991-1992 O z O a) CJ O z F .8 8 CJo'� 2002-2004 Total NC 00 00 F -z Fl Table continues next page 4 9 a. u 0U g.9 8 ° O R'� rg H a A�.� m a P s 4 AD AP- .9 II 'd g'gq c'1 [II W D7 a II C7 ,MM '�[ wm 8 b b.2 g .0 .1.4 V 9 q :a3g ~gy UU In 6 u6'11 V A' ti 2 U II z� m ti Or2 1' q u g z4 m ill .. .O GC co a w ii o - A II'° .8 o u ° •9 II ffi 0 ri q -6 q m o anti -g _0 ,�. d H. 101 vii -2 9 cci a3 Oat Al 1 Q ° II p .4 w 8fl at q 0 � P §ap°g Al �° A q a:-. 8 'mi p., .9 m u a+ 11 ro Li °� A 4 J b 97 Understanding the Health Effects of Ambient Ultrafine Particles b 0 0 0 N aV0 d p ri 0 F Q a Ai Ug 0 rd CD O7 tj CD rd o f) �a v]q m F Wes' 2 0 z PM2.5, PM10, soot 0 2007-2008 Total NC dleD O °z - O if) Lc? op 0 VI N dleD • aV crS i 0 z PM2.5, EC, OC U Cn 2000-2001 NC0.01-0.1 'd y N 0 s 0 z ii' 10 U �E 2003-2005 NC0.01-0.1 NO2, CO, O3, PM2.5 1998-1999 b N O • ,,rrGww N 'd CO 0 z 0 z U 2000-2003 Total NC Boston, MA Table continues next page .9 p u o. II n 0• U .9 u .B TA a p ;.4 1 n H-0 IA 0i .24 •l a 0 • a u -2 Z.2 ii p RI B.2 g B 1, o 0 9 IN 1II II 2 Fj z2 . U II R .' t 1:4 NEN A O m � P ' -. 11 II C , snore, M8 F1 m4 p oA l n U IU IS a 7311 .r.I II V HI H. F1 j i ▪ h :V P • c p 'O Cr, U 8 ✓ o V .9 2 ffi R p ce • 0 8 .9 I . ce N Q 'O 98 HEI Perspectives 3 i co co 0 co b O 4+4 O Po) aJ a) a) a) a0 a O Qa co F I• -1 • tb Ai 0 �C7 'al O Py 41,0 a v�q a) a) 0 z CO, NO2, PM2.5 0 CD p -I 0 0 0 z co p 7.0 a• t C z 0 z N 0 0 z PM2.5, NC0.1-0.5 Li? z Qi U Pp O O O 19 o L Sa 0 CD p -I CD 0 (\I CD 0 z 1995-2003 Total NC 2003-2004 Total NC Qi Table continues next page 99 Understanding the Health Effects of Ambient Ultrafine Particles P al 0 0 P al CD CD P al 0 w Caa ao ago a fit ;8 U q ri sv cd 24 8 F o al tb Ai O �C7 Pal Py 410 V] A N McD El O U Q V O I-1 z z z o zz 2000-2001 zz 2000-2001 NO2, NO, PM2.5, PM10 No ti cp En 2003-2005 NC0.01-0.1 co V co Q] y Q] y a CD a c a a 0 DI HT 09 Hg Pi m P H 'A os no in V H V Nco co G4 7YN [. Ti Pa N CL) t>4 N XI N cu 0 z z CJ 1995-2002 Total NC Eastern MA I PM2.5, PM1, NC0.1-1 1998-1999 co co 0914 " a O Table continues next page gu zg I. ": as t'iV c .9� m p, II . Aso gg .9 ti pi s 1 -.@. iti :t 41 ot i 1 DI 19 II R d i 73 w o ii V II 1 son y0 V El d PI II II $ P U U m o m arc; z0 p q r° i o o� 41 c� ▪ �.m LI 9 A A ▪ II 8 q II A 8 m • II , a m t r4 g r4 m i o 0.g m ▪ G° R, o 44 o mMd rs U m C 10 .m El F7 oIpp g . 1 i II I i 00 Z o oato,Il u:4 QO � p tt ri p p A 7 �°e sin 4 G ;o 100 HEI Perspectives 3 0 O 0 co -d 44.4 no no U no Fa aj F4 00 a) 0 z a)o� v a al U PU�a ,P, zN 2005-2007 id co cp 0 z u7 r0 C 1998-2002 Total NC 0 z 0 0.1 a OU 0 z O O CO, NO2, PM10 7 o a oTo on 0.1 PizU to 73 col Tj aa� a act 0 0 0 z z id • CD 2 co • cp • 4 OU Table continues next page t [i.o., < 0.100 pm in 101 Understanding the Health Effects of Ambient Ultrafine Particles z CO, NOR, O3, BC, OC 2005-2007 Total NC Delfino et al. rcl O N c▪ o" N N 6 0 PM2.5, NC0.1-0.5 cD UtzcD CD 0 F ll N H 4 UU Z id p � p I .ti. ▪ N V co 0z 2006-2009 z N H U (3c36.‘" U 4 1998-1999 2 al CD cD C N rya w ]� tion, Coagulation, and Oxidative Stress' Soluble Markers o z PM2.5, hopanes, PAHs II 2003-2004 2003-2004 Total NC 0� 0� Q) 0 W Q) 0 2 Cesa, aW a) ati a) Table continues next page t [i.e., < 0.100 pm in 2 o V 9 o I I m 102 HEI Perspectives 3 0 1 U CD CD cci 4, p4 a0o oa co co a rI d CCI F HI a a PI 8 O O 4 a2 O O 0 p., cp a) Soluble Markers of Inflammation, Coagulation, and Oxidative Stress (Coniinued)e 8 2001-2002 NO, PM2 5, PM10 ▪ a c En 'la qn o o o 2001-2002 2000-2001 2000-2001 2000-2001 NC0.01-0.1 plow PI P4 Oa, Pi I' M Pi I' M pi .ti pi pi aU t H • N 5- N pi N CD CD 44 N 44 CD Table continues next page �.9 a. .9A di § I o a � II 9 U v8' d 8 r�- m F m q •o V .9 .9 cc �a I m 103 Understanding the Health Effects of Ambient Ultrafine Particles vs 0 O co 0 CD CD P-� 4+4 a) a) a) ao a 0 Pa d coF • o • aj Ai 0 �C7 a2 . o (JO o � a cn V t ▪ qi b�' O 410 a cnq a) N�y W Soluble Markers of 0 z El -d q•rd Vn c o a� �- G4 d F 2000-2003 0 z 2003-2005 NC0.01-0.1 0 z PM2.5, PM10, soot 2007-2008 Total NC 1 z z 2003-2004 Total NC 2003-2004 Total NC o V o Q] 05 W Table continues next page II rEl mo pa.g n 90 9° 8 04 id y q 482 Aso A A I „ I a pa o a Ell tt Amy o na I I 111 R. s0a 1g ° p5 @0a:a co U0 U G° o t, al I z O U u 1 O q zj m 41 cot eo CO O O SI . rA DO .2 II -$ A 00 A< E.. ; a-$ gib d m� Ce W 0 id .5 i '.n $ g�Arm g o Id P 0 0 .73 rg ✓ 0 8 ✓ o ro 8 N ro a0U Da m� t g 104 HEI Perspectives 3 ✓ d U Jo co ✓ d co z F w O b co co co rl d Fa V F4 qO�� C7 O 0 J U C N U tea) CA A co jai CD o O Oa° U Soluble Markers of Inflammation, Coagulation, and Oxidative Stress (Continued)e z Z I c�1N IL /r Ow P., O-• 0 iri cs S°z z bd U U Cd CD ▪ O 2006-2008 2000-2004 on ca U � V a0 aCD 0 c N GAO IX • N N CD N PM2.5, NC0.1-0.5 a) CD dll 2006-2009 lb y z° z° PAHs, hopanes F '. '. F ▪ O O PI rd PI PI rd CJ .. Li CJ p Li 2005-2006 Li 2005-2007 2005-2007 Q)U ww Q) � wco• ,D4 co,D4 cow CD o o o N col m 0 II PA 6 -1 M II b �p a.ffi A I m Via -5 1,9 .~ IIti �.s-O ▪ O o n b .'4: LA m p m II I a dII N P4 r0 ig gg p R. m Q 'C II ti .� .5 .2 gi„ I Tol rn di U U m U II d q g zp., P , ' m 72 . 4 1 -ode II -+ m .m CO C r0 1 AAA erg 0 II o c� m 8 am -m4 o a. 9 8 cn .5.m mE 11 § ji 1 .B 8 9 m II 0 $ g m ti alpe q il G S g $V 4 9 m �oOa'Ih t [i.e., < 0.100 pm in 105 Understanding the Health Effects of Ambient Ultrafine Particles ABBREVIATIONS AND OTHER 1FRMS ACES Advanced Collaborative Emissions Study AMS aerosol mass spectrometer APC aerosol particle counter AS aerosol spectrometer BC black carbon BP blood pressure BS black smoke CAP concentrated ambient particles CASAC Clean Air Scientific Advisory Committee CNG compressed natural gas CO carbon monoxide COPD chronic obstructive pulmonary disease CPC condensation particle counter CRP C -reactive protein CVD cardiovascular disease DE diesel exhaust DISI direct injection spark ignition DMA differential mobility analyzers DMPS differential mobility particle sizer DPF diesel particle filters EAS electric aerosol spectrometer EC elemental carbon ECG electrocardiogram EEPS engine exhaust particle sizer ELPI electrical low pressure impactor FEV1 forced expiratory volume in 1 sec FMPS fast mobility particle sizer FVC forced vital capacity HR heart rate HRV heart -rate variability ICD implanted cardioverter defibrillator ICRP International Commission on Radiological Protection Ig immunoglobulin IL interleukin MAS mobile aerosol spectrometer MC mass concentration MOUDI micro -orifice uniform deposit impactor NAMS nanoaerosol mass spectrometer NC number concentration NF-icB DNA transcription factor NF -KB NOx NO NO2 NPACT O3 OC OVA PAHs PEF PM PM2.5 PM10 PM ISA PMF SCR SMPS TDMPS TNFa. UF1 UF2 UFP UFP NC nitrogen oxides nitric oxide nitrogen dioxide National Particle Component Toxicity ozone organic carbon ovalbumin polycyclic aromatic hydrocarbons peak expiratory flow particulate matter PM 2.5 pm in aerodynamic diameter PM s 10 pm in aerodynamic diameter Integrated Science Assessment for Particulate Matter positive matrix factorization selective catalytic reduction scanning mobility particle sizer twin differential mobility particle sizer tumor necrosis factor alpha UFPs > 3 nm UFPs > 15 nm ultrafine particle UFP number concentration ULTRA Exposure and risk assessment for fine & ultrafine particles in ambient air, a European Union -funded study U.S. EPA U.S. Environmental Protection Agency VACES versatile aerosol concentrator enrichment system WSOC water soluble organic carbon 106 HEI BOARD, COMMITTEES, and STAFF Board of Directors Richard F. Celeste, Chair President Emeritus, Colorado College Sherwood Boehlert Of Counsel, Accord Group; Former Chair, U.S. House of Representatives Science Committee Enriqueta Bond President Emerita, Burroughs Wellcome Fund Purnell W. Choppin President Emeritus, Howard Hughes Medical Institute Michael T. Clegg Professor of Biological Sciences, University of California —Irvine Jared L Cohon President Carnegie Mellon University Stephen Corman President, Corman Enterprises Gowher Rizvi Vice Provost of International Programs, University of Virginia Linda Rosenstock Dean Emerita and Professor of Health Policy and Management, Environmental Health Sciences and Medicine, University of California —Los Angeles Henry Schacht Managing Director, Warburg Pincus; Former Chairman and Chief Executive Officer, Lucent Technologies Warren M. Washington Senior Scientist National Center for Atmospheric Research; Former Choir, National Science Board Archibald Cox, Founding Chair 1980-200! Donald Kennedy,Vice Chair Emeritus Editor -in -Chief Emeritus, Science; President Emeritus and Bing Professor of Biological Sciences, Stanford University Health Research Committee David L Eaton, Chair Associate Vice Provost for Research and Director, Center for Ecogenetics and Environmental Health, School of Public Health, University of Washington —Seattle David Christiani Elkon Blout Professor of Environmental Genetics, Harvard School of Public Health David E. Foster Phil and Jean Myers Professor Emeritus, Department of Mechanical Engineering, Engine Research Center, University of Wisconsin Madison Uwe Heinrich Professor, Medical School Hannover; Executive Director; Fraunhofer Institute for Toxicology and Experimental Medicine, Hanover; Germany Grace LeMasters Professor of Epidemiology and Environmental Health, University of Cincinnati College of Medicine Sylvia Richardson Professor and Director; MRC Biostatistics Unit, Institute of Public Health, Cambridge, United Kingdom Allen L Robinson Professor; Departments of Atmospheric Science and Mechanical Engineering Colorado State University Richard L. Smith Director, Statistical and Applied Mathematical Sciences Institute, University of North Carolina —Chapel Hill James A Swenberg Kenan Distinguished Professor of Environmental Sciences, Department of Environmental Sciences and Engineering University of North Carolina —Chapel Hill 107 HEI BOARD, COMMITTEES, and STAFF Health Review Committee Homer A. Boushey, Chair Professor of Medicine, Deportment of Medicine, University of California —San Francisco Ben Armstrong Reader in Epidemiological Statistics, Public and Environmental Health Research Unit, Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, United Kingdom Michael Brauer Professor; School of Environmental Health, University of British Columbia, Canada Bert Brunekreef Professor of Environmental Epidemiology, Institute of Risk Assessment Sciences, University of Utrecht, the Netherlands MarkW. Frampton Professor of Medicine and Environmental Medicine, University of Rochester Medical Center Stephanie London Senior investigator,, Epidemiology Branch, National Institute of Environmental Health Sciences Armistead Russell Howard T Tellepsen Chair of Civil and Environmental Engineering School of Civil and Environmental Engineering Georgia Institute of Technology Lianne Sheppard Professor of Biostotistics, School of Public Health, University of Washington —Seattle Officers and Staff Daniel S. Greenbaum President Robert M. O'Keefe Vice President Rashid Shaikh Director of Science Barbara Gale Director of Publications Jacqueline C. Rutledge Director of Finance andAdministration Helen I. Dooley Corporate Secretary Kate Adams Senior Scientist Johanna Boogaard Staff Scientist Aaron J. Cohen Principal Scientist Maria G. Costantini Principal Scientist Philip J. DeMarco Compliance Manager Suzanne Gabriel Editorial Assistant Hope Green Editorial Assistant (part time) LVirgi Hepner Senior Science Editor Anny Luu Administrative Assistant Francine Marmenout Senior Executive Assistant Nicholas Moustakas Policy Associate Hilary Selby Polk Senior Science Editor Jacqueline Presedo Research Assistant Sarah Rakow Science Administrative Assistant Evan Rosenberg Staff Accountant Robert A. Shavers Operations Manager Geoffrey H. Sunshine Senior Scientist Annemoon M.M. van Erp Managing Scientist Katherine Walker Senior Scientist 108 1FF HEALTH EFFECTS INSTITUTE 101 Federal Street, Suite 500 Boston, MA 02110-1817, USA Phone +1-617-488-2300 Fax +1-617-488-2335 www.healtheffects.org HET PERSPECTIVES 3 January 2013 'No Safe Level of Exposure': EPA's Human Experiments With Particulate Matter Steve Milloy • Publisher, award -winning JunkScience.com • Senior Legal Fellow, Energy & Environment Legal Institute — Public interest, 501(c)(3), www.eelegal.org • Education — BA, Natural Sciences, Johns Hopkins University — MHS, Biostatistics, Johns Hopkins Univ. School of Public Health — JD, University of Baltimore, — LLM, Securities Regulation, Georgetown University • Consultant (environment/public health), author, former mutual fund manager & coal company executive • Bio at http://www.junkscience.com/about Dedicated to Haiyan `Nicole' Wan 1977-1996 EPA's Human Experiments • Substances experimented with: — Particulate matter (PM, PM2 5) — Diesel exhaust (95% PM2 5) — Ozone (smog) — Combinations of above — Chlorine gas and other substances Imagining PM HUMAN HAIR 50-70 J.1 m (microns) in diameter 90 p.m (microns) in diameter PM2,5 Combustion particles, organic com unc s, metals, etc_ < 2.5 p.m (microns) in diameter P IC Dust, pollen, mold, etc. <10 p.m (microns) in anieter Sources of PM — Natural Sources of PM - Manmade PM Lethality: Any Exposure Can Kill, Within Hours • From EPA's 2009 PM2 5 "Integrated Scientific Assessment": Summary of PMZ,5 Risk Estimates The risk estimates for all -cause mortality for all ages ranged from 0.29% Dominici et al. (2007, 097361) to 1.21% Franklin et al. (2007, 091257) per 10 µg/m3 increase in PM2.5 (Figure 6-26). An examination of cause -specific risk estimates found that PM2.5 risk estimates for cardiovascular deaths are similar to those for all -cause deaths (0.30-1.03%), while the effect estimates for respiratory deaths were consistently larger (1.01-2.2%), albeit with larger confidence intervals, than those for all -cause or cardiovascular deaths using the same lag/averaging indices. Figure 6-27 summarizes the PM2.5 risk estimates for all U.S.- and Canadian -based studies by cause -specific mortality. An examination of lag structure observed results similar to those reported for PMT° with most studies reporting either single day lags or two-day avg lags with the strongest effects observed on lag 1 or lag 0-1. In addition, seasonal patterns of PM2.5 risk estimates were found to be similar to those reported for PM10, with the warmer season showing the strongest association. An evaluation of regional associations found that in most cases the eastern U.S. had the highest PM2.5 mortality risk estimates, but this was dependent on the geographic designations made in the study. When grouping cities by climatic regions, similar PM2.5 mortality risk estimates were observed across the country except in the Mediterranean region, which included CA, OR, and WA. PM Lethality (cont'd): No Safe Exposure • Former EPA CASAC Chair Jonathan Samet in New England J. Med. (July 11, 2011). For ozone and particulate -matter pollution, because no thresholds have been identified below which there is no risk at all, the EPA is using scenarios of risk and ex- posure to gauge the effects of setting the standards at various concentrations and giving con- sideration to the burden of avoid- •ahlri flica,2cP Tti nrnrmilcritiricr thin PM Lethality (cont'd): Death from Any Exposure • Letter from then -EPA air chief Gina McCarthy to House Energy Committee (Feb. 3, 2012) EPA's approach for estimating benefits from reducing fine particle pollution is science -driven. Studies demonstrate an association between premature mortality and fine particle pollution at the lowest levels measured in the relevant studies, levels that are significantly below the NAAQS for fine particles. These studies have not observed a level at which premature mortality effects do not occur. The best scientific evidence, confirmed by independent, Congressionally -mandated expert panels, is that there is no threshold level of fine particle pollution below which health risk reductions are not achieved b7Iduced exposure, us, based on specific advice from scientific peer -review, we project benefits from reducing fine particle pollution below the level of the NAAQS and below the lowest levels measured in the studies. PM Lethality (cont'd): Death Within Hours of Exposure • From EPA 2004 Integrated Scientific Assessment for PM25: 9.2.2.7 Summary and Conclusions Epidemiological evidence can help to inform judgments about causality. The present discussion evaluated the epidemiologic evidence in relation to the first five criteria listed in the beginning of Section 9.2, including key considerations with regard to criteria such as the strength (magnitude, precision) and robustness of reported associations. Information related to last of the six criteria (coherence and biological plausibility of the evidence) is discussed in the following section. Overall, there is strong epidemiological evidence linking (a) short-term (hours, days) exposures to PM,; with cardiovascular and respiratory mortality and morbidity, and (b) long- term (years, decades) PM,5 exposure with cardiovascular and lung cancer mortality and respiratory morbidity. The associations between PMT; and these various health endpoints are positive and often statistically significant. There are fewer studies available for PM,,,., and the PM Lethality (cont'd): Just Death. No Sickness. • During a September 22, 2011 hearing of the Oversight and Investigations Subcommittee of the House Energy and Commerce Committee, Administrator Jackson testified: — "Particulate matter causes premature death. It doesn't make you sick. It's directly causal to dying sooner than you should." PM Lethality (cont'd): 1 Out of 5 Deaths Caused by PM • From September 22, 2011 House hearing (transcript): — REP. MARKEY: How would you compare it to the fight against cancer, reducing particulate matter? — MS. JACKSON: Yeah, I was briefed not long ago. If we could reduce particulate matter to healthy levels it would have the same impact as finding a cure for cancer in our country. — REP. MARKEY: Could you say that sentence one more time? — MS. JACKSON: Yes, sir. If we could reduce particulate matter to levels that are healthy we would have an identical impact to finding a cure for cancer. • Annual US cancer mortality — ^'570,000 — - 20+% of all US deaths annually PM Lethality (cont'd): Air in LA, NY & EPA Experiments May Kill • Declaration of clinical studies coordinator for EPA's CAPTAIN study: 14. I provide participants with information about fine particles (1)).4-, }, E say that 1'M, ; are particles so small that they are able past through your airways and go deep into your lungs, these Case 1:12-cv-01066-AJT-TCB Document 14-1 Filed 10/04/12 Page 10 of 135 PagelD# 320 particles are so small that your usual lining and cilia of your airways are not able to prevent these particles from passing into your lungs. Therefore, if you arc a person that for example lives in a large city like Los Angeles or New York, and it's been a very hot day, and you can see the haze in the air, and you happen to be someone that works outside, and if you have an underlying unknown health condition, or, you may be older in age; the chances arc that you could end up in the emergency room later on that night, wondering what's wrong, possibly having cardiac changes that could lead to a heart attack;, there is the possibility you may die from PM lethality (cont'd): Deadly Within Hours, No Safe Exposure American Heart Association Scientific Statement: Evidence Growing of Air Pollution's Link to Heart Disease, Death May 10.2010.18:45 ET from An cif, -,2• 2,•:._fciti:l.i: i "Particulate matter appears to directly increase risk by triggering events in susceptible individuals within hours to clays of an increased level of exposure, even among those who otherwise may have been healthy for years," said Robert D•Brook, ., ea au or o le statement. which was written after review of epidemiological, molecular and toxicological studies published during the past six years. M HEALTH SYSTEM UNIVERSITY OF MICHIGAN Find a Physician Conditions & Treatments UMHS Heallh Blogs I About Us I Maps & Dire. Locations Patient & Visitor Ho ra Robor. Camel Brook MD Robert Daniel Brook MD P ol_r;tr. 117'..=r tl IV' ino Specialties: Hypertension, Internal Medicine Clinical Interests: Hypertension clinic, resistant hwertensicn. secondary hypertensions. Lipid clinic. lipid discrders, crthostalic hypotensionlhypertension. Preventive cardiovascular medicine. "These studies also indicate that there is no 'safe' level of PM2„5 „5 exposure," he said. PM Lethality (Cont'd): EPA -Funded Researcher Renounces PM Experiments • After Brook's EPA -funded human experiments with PM were reported in the Detroit News (July 23, 2013): "I'm not going to do (these tests) because I don't believe in exposing people. I've shown PM2.5 is bad for you." EPA Regulates on the Basis that PM Kills The benefits of the Cross -State Air Pollution Rule far outweigh the costs of the rule. The final rule yields Si 20 to 5280 billion in annual health and environmental benefits in 201 4, including the value of 13 000 to 32- 000 remature deaths_ This far outweighs the estimated annual costs o e mi ion in annua projec ed costs of this rule in 201 4, along with the roughly 51 _6 billion per year in capital investments already under way as a result of CAIR, are improving air quality for over 240 million Americans- This rule will not disrupt a reliable flow of affordable electricity for American consumers and businesses_ Health benefits will be achieved at a very low cost, and while the effect on prices for specific regions or states I K.}i2S4tI J „Un,7i may vary, they are well within the range of normal electricity price fluctuations_ Any such costs cshl- cJw44 :i25v r thou. will be greatly outweighed by the benefits. CAINi .5L5,r.5I I h5 -f .I,I5i'1' I4 I$1 !I h I,',r PM Is Most Toxic Substance? As Lethal As A Bullet to the Brain? • EPA says any exposure to PM can kill in as little as hours — no safe exposure. • Even radiation and chemical carcinogens regulated on the basis of the linear no - threshold model (LNT) `only' have cancer as the health endpoint. • No known poison kills on an 'any exposure' basis. No Disclosure of the Nature of PM's lethality to IRBs • EPA staff researchers and EPA -funded university researchers did NOT provide any of this toxicity information or equivalent to any Institutional Review Board (IRB). - At most, occasional, vague, soft-pedaled and/or glancing mention of PM's correlation with 'mortality' — IRBs only given impression of `minimal risk.' (I) MinkTlef risk means that the probability and magnitude of harm or discomfort anticipated in the research are not greater in and of themselves than those ordinarily encountered in daily life or during the performance of routine physical or psychological examinations or tests. EPA's Human Experiments Exhaust from Idling Diesel Truck... Diesel Gas Piped into Chamber EPA Human Experiments (cont'd): ... Pumped Into Chamber Containing Study Subject ERA Gas Chamber Who Does EPA Say Are Most Vulnerable to The Effect of PM? You are here: !Y.A .iorre » Pa-iiculate Vette- p M) :7'o 'a: on • Hea-tand Env ronmental Effects of Pan:iculate Matter (PM) Health and Environmental Effects of Particulate Matter (PM) Health Effects The size of particles is directly linked to their potential for causing health problems. Small particles less than 10 micrometers in diameter pose the greatest problems, because they can get deep into your lungs, and some may even get into your bloodstream. Exposure to such particles can affect both your lungs and your heart. Numerous scientific studies have linked particle pollution exposure to a variety of problems, including: • premature death in people with heart or lung disease • nonfatal heart attacks a irregular heartbeat • aggravated asthma • decreased lung function • increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing. AIIIIN People with heart or lung diseases, children, and older adults are the most Ilkely to be affected by Who Are EPA's Human Subjects? The Elderly The US :Environmental Protection Agency is seeking Is your wais a - 00 big? Are your triglycerides, cholesterol, blood sugar or blood pressure a little high? If you can answer "yes" to any of these you may be one of 40 million Americans who might be especially sensitive to aft pollutant, We are looking for men whose waist size is larger than 40" and women larger than 35" for a research study about air pal€ution. The study •[Twelves 3 screening visits and 4 study visits for a total of about 26 hours You will receive payment for screening, the study, parkfng, and out of town travel. Call for more details! The Human Studies Facility is located on the LWAIC-CH campus Who Are EPA's Subjects? (cont'd): Even More Elderly The IBS Environmental Protection Agency is seeking TEEM. A. es 50 to 75 for Research This is a research study about genetics, diet supplementation and exposure to air pollution. We are looking for healthy older adults to study diet supplementation and the effects of air pollution exposure on heart and lung function. Total time coniniitmertt after screening is about 15 hours over 6 to 7 weeks. You will receive payment for screening, the study, an' out of town travel. Parking Is provided_ 1-888-279-9353 or 919.966-0804 www,epastudies.org 5�ya, '�r�S��I-• • • The Human Studies Facility is located on the UNC-CH campus Who Are EPA's Subjects? (cont'd): Even More Elderly Gericon The purpose of this study is to evaluate pulmonary and cardiac effects of exposure to air pollution particles in older adults ages 60 to 80. Time commitment includes one 24 hour screening period pus two 6 - hour test days with follow-up. Exposures are separated by several weeks. Volunteers will breathe concentrated Chapel Hill air during one exposure visit and clean air during the other. Tests include cardiac monitoring, blood draws, lung function tests, and brachial artery imaging. Who Are EPA's Subjects? (cont'd): Children Pmpnsal 403A1139 Review f ate .ory: E INSTITUTIONAL REVIEW BOAR]) HEALTH RESEARCI I ASSOCIATION AND INSTITUTIONAL REVIEW BOARD UNIVERSITY OF SOUTHERN CALIFORNIA SCHOOL OF .MEDICINE Date: 4/2/2004 To: Frank I? Gilliland, M.D. Associate Professor Preventive Medicine Center for Health Professions, #236 From: Vice Chair, IRB Robert Larsen, M.D. Interns Residence Dorm, Room #425 2020 Zonal Avenue Los Angeles, CA 90033 (323) 223-2340 TITLE OF PROPOSAL: CHILDREN'S ENVIRONMENTAL HEALTH CENTER Action Date: 3/30/2004 Action Taken: Noted Who Are EPA's Subjects? (cont'd) • Diesel exhaust particles sprayed up noses of children. PROCEDURES It yam voizmrexr to participate in imuly1 you will be :wed to do the [n Iuwn 1) Pimqad Clisileavre The nacral cba l 1V 1a vamtEral small niAnble of fluid into ibir masa1 cavity- Each c� tet-me will. i about three drops) of dd. applied ID'he nasal cavity through sprayer and will l froar a diet truck (iismel archaust fides). The I.�' � .: - . l t ' '1 •. • 4 •' - - Pin ble admirtistrzed in small mists of fluid conteirtiris . i ; ., s . i«-Ti 14- of pat -treks. ' 1! It beat ammult of panicles Tort be gar► is equal tD two & s arvcial5r urban in Los Acs_ This is !eve tb m you would reoriree fru= passing behind a diesel bas as it Maris iu engine, There have been no reported ad,vetse real:liona to Otis procedure, utlxtc than the ale uncomfortable feeling n( frig wed it*, yxumw Who Are EPA's Subjects? (cont'd) • How old were the children? a) Whit are the criteria for iodation and exclusion? agat ear 1.5 r214-* Oat, or 21 yours argil over. Who Are EPA's Subjects? (cont'd) • EPA -funded researchers described risk to Institutional Review Board as `minimal.' poltatutt tricsd calmed particles (DM in combination Ivilb ograi laraze. These fi'MritelIlltg argil involvorisk. We will then mem= the amount of aabosidans prockwal Who Are EPA's Subjects? (cont'd) • State of California determined in 1998 that diesel exhaust causes cancer and that there is no safe exposure. 20, Based on available scientific information, a level of diesel exhaust exposure below which no carcinogenic effects are anticipated has not been identified. Who Are EPA's Subjects? (cont'd) • EPA commenced the process to ban experimenting on children in 2003 and finalized the ban in 2006. Human Testing;Advance Notice of Proposed RuLemaking ing Environmental Protection Agency 05/07/2003 2U..OJ Prohibition of research conducted or supported by EPA involving intentional exposure of any human subject who is a pregnant woman (and therefore her fetus), a nursing woman, or child. Notwithstanding any other provision of this part under no circumstances shall EPA conduct or support research involving intentional exposure of any human subject who is a pregnant woman (and therefore her fetus), a nursing woman, or a child. [7' FR 36175, June 23, 2006] Who Are EPA's Subjects? (cont'd) • EPA -funded USC experiments on children occurred during 2004-2005. ProposaI #03A039 Re.vicw Gicugory: E INSTITUTIONAL REV] EW BOARD HEALTH HEALTH RESEARCIJ ASSOCIATION 1D INSTITUTIONAL REVIEW BOARD UNIVERSITY OF SOUTHERN CALIFORNIA SCHOOL OF MEDICINE Date: 4/2/2004 To: Frank I) Gilliland, M.D. Associatc Professor Preventive Medicine Center for Health Profe lions, #236 From: Vice Chair, IRB Robert Larsen, M.D. Interns Residence I)c)rm, Room #425 2020 Zonal Avenue Los Angeles, CA 90033 (323)223-2340 TITLE OF PROPOSAL.: CHILDREN'S ENVIRONMENTAL HEALTH CENTER ion Date: 3/30/2004 Action Taken: Noted EPA fails to explain deletion of kids diesel experiment on from data base • As reported on JunkScience.com (April 25, 2013): In February we FOIA-ed EPA for an explanation of why/how a report de- scribing an illegal experiment exposing children to diesel exhaust was deleted from its data base. EPA responded to our request today. You can read the EPA's response (collection of e -mails between technical staff) for yourself, but the bottom line appears to be: • JunkScience did not imagine the deletion. The deletion did in fact occur: • The deletion was unusual. It was the first deletion of its kind in the EPA databases's 13 years of existence; and • The miscreant remains undiscovered. Although the mechanics of the deletion are understood, no one knows what caused it to occur. • Cover-up? An EPA higher-up stated, "this situation is very disconcerting in that [EPA Research Triangle Park staff) as of yet has no idea what caused the problem to occur in the first place." Who Are EPA's Subjects? (cont'd): Unhealthy People —Metabolic Syndrome Do you have "fitletabo z Syndrome"' . 40 (33! ][foul Alit.s, o."ans do If so, you may qualify for a new research study about Metabolic Syndrome and Air Poliubon. People with Metabolic Syndrome experience. at least 3 of the following: Waist size greater than 40" for men or 35" for women OR BM!' greater than 30 • Blood Presawe greater then 130;35 OR BP controlled with medication (for this study blood pressure must en loss than 160/100) • Cholesterol: HCL less than 4.0 for men or less than 50 for women Fasting blood sugar greater than 113 but less than 126 • Triglycerides greater then 150 Cal! us If you think you qualify (we can calculate cur "Body Mass Index). This study involves 3 screening visits and 4 study visits for a total of about 25 htiurs.Ability t'o perform moderate exercise is required. You will be paid for <<�tir";, screening; tht: study, parking, end out or` town travel, c°` 9; Call for more details[ it LS69-965 llItt04..o I #46 - 7J 9 as '.ieww eaaetrnntl�a oret ... Who Are EPA's Subjects? (cont'd): Unhealthy - Older Asthmatics f it33'•�.y,' o-.�r� :�:�f'^�x`n"9 �fC"',i�•��" `:kf:{w�'°;t;,", �':�'fk,M„M,,:�r=��;k�� „�7 •'q��4Y r �E a 4'! J r� �-� � �i{ k� a� ri i �' 4 y ' p �+ J 1 � r iirttir! yu;'�f fy{s he U Envi�ronr ental�;Pro'Ireotipn, #gen + :f,:;y N! 'i,';�k�tts••�,!,..�•.Sr..tr ;+'.u:�-a=seJ §'.C,,�'� , �, Researcl kF! Now recruiting non-smoking adults ages 45 to 65 with mild asthma for a study about genetics and air pollution. Study requires screening and two exposures with follow up bronchoscopy. ., Payment forscreening and study 919-966-0604 or 1488-279-9353 fwr.epastudles,org A"`'' The Human Studies Facility is located on the UNC-CH campus Who Are EPA's Subjects? (cont'd): Unhealthy People - Diabetics 2. Inhalation of carbon UFP in diabetics We have completed our study of the effects of inhalation of ultrafine carbon particles in subjects with diabetes. D' • ■ othelial d sfunction which ma increase their risk fo ype ia.e ics, ag- i-. u, •• . ..... .. . - , o on s a In me.ica ions, were expose. o I ereair or 5U pg/m3 carbon UFP (count median diameter —30 nm, GSD 1.8) by mouthpiece for two hours, in a randomized double-blind cross- over study. Exposures were separated by at least two weeks. Nineteen subjects completed the study. Who Are EPA's Subjects? (cont'd): Unhealthy People: Heart Attack Waiting to Happen Case report: Supraventricular Arrhythmia Following Exposure to Concentrated Ambient Air Pollution Particles Andrew J. Ghio, Maryann Bassett, Tracey Montilla, Eugene H. Chung, Wayne E. Cascio, Martha Sue Carraway http://dx.doi.org/10.1289/ehp.1103877 Online 6 September 2011 Who Are EPA's Subjects? (cont'd): Unhealthy People: Heart Attack Waiting to Happen Abstract C0N'ET: Exposure to air pollution can result in the onset of arrhythmias. CASE PRESENTATION: We present a case of a 58 year old woman who volunteered to participate in a controlled exposure to concentrated ambient particles (CAPS). Twenty minutes into the exposure, telemetry revealed new onset of atrial fibrillation. The exposure was discontinued and she reverted to normal sinus rhythm approximately two hours later. No abnormality was evident on the volunteer's laboratory examination or echocardiography which could explain an increased risk for supraventricular arrhythmia. Who Are EPA's Subjects? (cont'd): Unhealthy People: Heart Attack Waiting to Happen On the day of exposure to CAPs, the volunteer had no symptoms. There was a history of osteoarthritis and hypertension treated with an angiotensin-converting enzyme inhibitor and a diuretic (lisinopril 10 rrig and hydrochlorothiazide 12,5 mg). Previous surgeries included a hernia repair, a cholecystectomy, and a total left knee arthroplasty. The family history was significant for her father dying at 57 years of age with a myocardial infarction. The volunteer was a lifetime non-smoker. On physical examination, she was 173 cm tall and weighed 104.4 kg (the body mass index was 34,9 and her waist was 45 inches). Her pulse was regular at 66 per minute and her blood pressure was 144/61. The baseline electrocardiogram showed normal sinus 4 Page 5 of 13 rhythm (Figure 1A). A hotter monitor was placed and this demonstrated evidence of increased supraventricular ectopy with 157 f 34 premature atrial contractions per hour during the 3 hours immediately preceding the exposure to CAPs. Twenty three minutes into the exposure to CAPs (with a filter weight revealing 112 µg/m3 and the particle number being 563912/cc), the telemetry monitor revealed that the subject Who Does EPA Say Are Most Vulnerable to Effects of PM? Particulate Matter (PM) Pollution Co" .=act Us 5 a e You are here: E7,A .lorre Pa-ticulate h"aTe ply') u. on Heat' and Eny-ronmental Effects of Particulate Matter (PM) Health and Environmental Effects of Particulate Matter (PM) Health Effects The size of particles is directly linked to their potential for causing health problems. Small particles less than 10 micrometers in diameter pose the greatest problems, because they can get deep into your lungs, and some may even get into your bloodstream. Exposure to such particles can affect both your lungs and your heart. Numerous scientific studies have linked particle pollution exposure to a variety of problems, including: • premature death in people with heart or lung disease • nonfatal heart attacks • irregular heartbeat • aggravated asthma 6 decreased lung function • increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing. People with heart or lung diseases, children, and older adults are the most likely to be affected by particle pollution exposure. How Much PM Did EPA Expose Study Subjects to? • Recall: There is no safe exposure to PM, according to EPA. • Average U.S. outdoor air has ^' 10 micrograms per cubic meter of PM25 according to EPA. — `Minimal risk' level for Common Rule purposes • EPA acute exposure standard to PM25 is 35 micrograms per cubic meter. — Exceeding standard violates the law How Much PM Did EPA Expose Study Subjects to? • 58 year -old woman spotlighted in the Case Report Twenty three minutes into the exposure to CAPs (with a filter weight revealing 112 gomfflia jag/m3 and the particle number being 563912/cc), the telemetry monitor revealed that the subject had non -sustained atrial fibrillation that quickly organized into atrial flutter. She was • 112 micrograms/m3 is: — 3.2 times greater than EPA acute PM standard -11 times greater than `minimal risk' How Much PM Did EPA Expose Study Subjects to? • Diesel exhaust experiments Procedures (methods): In the pilot study, subjects will have 3 sequential exposures to the diesel exhausts at concentrations approximately 100 iigim3, 200 lig/m3 and 300 m3 for 2 hours with Moil= weeks of interval between exposures. e main s u y, TM1 positive and GSTM1 • 300 micrograms/m3 is: — 8.5 times greater than EPA acute PM standard — 30 times greater than `minimal risk' How Much PM Did EPA Expose Study Subjects to? • Concentrated PM particles The concentration of particles delivered to the chamber will vary depending on the levels of naturally occurring particles in the Chapel Hill air. Although 24 hr averages seldom exceed 15- 20 ug/m3,. peak values in the summer can be as high as 50-60 ug/m3 with lower values during the rest of the year. A face mask is used to reduce the daily and seasonal variability of PM concentration. Our past experience provides a basis to expect the particle mass delivered to the mask will be up range between levels of 50 to ,600 ug/m3. ,The particle burden, on a mass basis • 600 micrograms/m3 is: — 17 times greater than EPA acute PM standard — 60 times greater than `minimal risk' How Much PM Did EPA Expose Study Subjects to? • `Oops!' exposure 1/5/2010 O MCO 19 11:02 13:02 1/6/2010 KCN112 9.34 11:34 2/912010 O MCO21 10:52 1.2:52 3/9/2010 O MCO2 3 10:45 11:03 205,27 153.58 442.49 No clinics N4 Clinic: No clinic: No clinics • 750 micrograms/m3 is: — 21 times greater than EPA acute standard - 75 times greater than `minimal risk' Are EPA's PM human experiments fundamentally unethical/illegal? • Nuremberg Code — 5. [An experiment] should not be conducted when there is any reason to believe that it implies a risk of death or disabling injury. • Principles adopted by California • Applied by Maryland Court to Appeals to EPA -funded experiments in Grimes v. Kennedy Krieger Institute (2001). • Common Rule — as adopted by EPA — No more than 'minimal risk' allowed (i.e., risk of harm no more than in ordinary life) • EPA Rule 1000.17 — 'Presumption' against studies with risk of 'substantial injury' or 'irreversible health effects.' • The EPA IG report never addressed whether the experiments are `fundamentally unethical/illegal.' Informed Consent • Instead of the `fundamentally unethical/ illegal' issue, EPA IG opted to focus on informed consent deficiency. • Informed consent required by — Nuremberg Code — Common Rule — State Law (applies EPA researchers who are state - licensed physicians) • Felony Recall what EPA tells the public and Congress about PM • Any exposure to PM can be lethal. • Lethality can occur within hours. • PM kills hundreds of thousands of people annually at current outdoor levels. • Old/sick are especially vulnerable. What did EPA tell study subjects? What are the possible risks_ or discomforts involved with ►ein ' in this study? This study might involve the following risks and/or discomforts to yo:u: if you have any tendency to become uncomfortable in small closed spaces, it is possible that you may become uncomfortable during this study. You will be taken to the exposure chamber when you are first evaluated for suitability for the study to allow you an opportunity to see where you will sit and what the chamber looks like. PM exposure: burin the ex osure to the concentrated air pollution particles, or u a experience some minor egree� ay irritation, cough, and shortness ofbreath or wheezing. These symptoms typically disappear 2 to 4 hours after exposure, but may lastlonger or particularly sensitive people. You 11 be rnonmtorea continuously during the exposure session Some EPA Guineas Pigs Received This Sort of 'Disclosure' Ultrafine particle exposure: During one of your exposure sessions you will be exposed to air containing mostly concentrated ultra -fine air pollution particles (this air may contain some larger particles as well). The risks associated with concentrated particle exposure in people with metabolic syndrome are unknown. Some studies suggest that elderly -people. D those with underlying cardiovascular disease are at increased r�s�r getting sick and even dying Turing episodes of high air ollution. At this time, no one understands exactly how these particles might cause peop e to ecome sick or die. While we cannot exclude the possibility that you have an adverse reaction to breathing these particles., you will only be exposed to them fora 2 hour period, and you will not be exposed to more than OQ,O00 particles/cc, which is less than or equal to what you would be exposed to driving along a heavily travelled highway in a large city such as Los Angeles. Alleged CAPTAIN Experiment Disclosure • EPA clinical studies coordinator claimed to orally state to study subjects, 'you may die from this.' • But Common Rule would require written disclosure for risk of death — if such an experiment were even permissible in the first place. Why Is EPA Experimenting With PM on Human Beings? • EPA claims `thousands' for studies support its regulation of PM (Source: EPA 'Fact Sheet') — Epidemiology — Animal toxicology — Human `clinical studies' -- i.e., human experiments EPA Admits PM Epidemiology Inadequate • From 2012 litigation with EPA about EPA's CAPTAIN human experiment: large-scale epidemiological studies. Epidemiological studies, the primary tool in the discovery At of risks to public health presented by ambient PM2.5, typically use data from large populations of people with varying susceptibility to PM2,5. They evaluate the relationship between changes in ambient levels of PM2.5 and changes in health effects. However epidemiological studies do not generally provide direct evidence of causation; instead they indicate the existence or absence of a statistical relationship. Large population studies cannot assess the biological mechanisms that could explain how inhaling ambient air pollution particles can cause illness or death in susceptible individuals. Devlin Decl. ¶¶ 6,7$. Animal Toxicology Not Helpful to EPA • No laboratory animal has ever died from mere PM exposure, despite extremely high exposures. [Source: EPA's 2009 ISA for PM] EPA's Last Resort: Human Guinea Pigs • EPA explanation for human experiments from 2012 litigation over EPA's CAPTAIN study: ¶¶ 8,9,10. The National Research Council of the National Academy of Science has recognized that controlled human exposure studies provide an opportunity to gain valuable scientific insights in the health effects of particulate matter. Devlin Decl. ¶ 8. Most of the controlled human exposure studies involving exposure to PM are in fact conducted by research institutions other than EPA. Declaration of Wayne Cascio ("Cascio Decl.") ¶ 11. This research has provided valuable information to help characterize and control risks to public health. See id. Exh. 1. These studies help to determine whether the mathematical associations between ambient (outdoor) levels of air pollutants and health effects seen in large-scale epidemiological studies are biologically plausible (or are not). They help to determine the mechanisms by which air SO... Is EPA doing these experiments to see... ...if incredibly high exposures to PM... can actually kill or... seriously harm someone... who is supposed to be especially vulnerable... all while claiming... there is only 'minimal risk' to study subjects? 'Fundamentally Unethical' • Letter from EPA Human Studies Review Board to EPA Science Advisor (October 26, 2009): a. With regard to determining whether or not a study is un amens y unet ica , t e Board's standard is to decide if the research was intended to seriously harm participants, or if it failed to obtain informed consent, or if it was fundamentally unethical for other reasons. EPA's Claimed Defense • Risks only occur in the population not study subjects. • From our human testing lawsuit, EPA writes: In evaluating the risk to research volunteers, it must be recognized that the risk to an individual is very different from the overall public health risk associated with exposures of large populations of people to typical ambient air levels of PM2.5. This is especially the case if the individual does not have the health conditions most at risk, such as a preexisting cardiovascular or respiratory illness. While small risks to individuals may evidence themselves as much larger overall public health risks when large populations are exposed to ambient levels of PM2.5, this does not change the fact that the risk for individuals that do not exhibit these health conditions will be small. Devlin Decl. ¶ 15. Breaking Down EPA's Claimed Defense • EPA admits PM kills people • EPA claims risk is large in the population, but small to individuals — Populations are made up of people • EPA says hundreds of thousands killed by PM annually • `Only' 31,000 killed in auto accidents annually — don't apply EPA rationale on your way home today — PM can kill hours after inhalation • Population doesn't collectively breathe — EPA researcher Dr. Robert Brook — stopped doing experiments because PM not safe • EPA claims risk small is unless you are old/sick — But old/sick are precisely who the study subjects are • EPA has already determined there is no safe exposure to PM and has regulated PM on the basis of lethality since 1997 — What is the purpose of the experiments? Beyond PM Toxicity: Danger to Study Subjects from Experimental Protocol • 19 -year -old college student Haiyan `Nicole' Wan killed during PM research (overdose of lidocaine administered for bronchoscopy). Massachusetts Institute of technology M ITnews engineering science management architecture planning humanities, arts, and social sciences today's news Student dies at Rochester in MIT -based study Carnera . Bronchi Light Trachca Fibeii'ic trunchomope • Many EPA experiments involve bronchoscopy — UNC college student told me she had 6 or 7 Are EPA's Experiments Scientific? • Examine spreadsheet of published human experiments in docket submitted by EPA (Summary Human Challenge Studies PM). • Experiments not systematically designed/conducted — Study sizes small (as few a n=4) — Myriad PM tested (diesel, wood smoke, concentrated PM) — Various exposure levels, times — All results for all study subjects published? — Misrepresentation of study results • Ghio et al. (EHP, Sep 2011), "Case Report:..." — No mention of other human study subjects, i.e., contrary results — Disregard actual cause of reported health effect Are EPA's Experiments Scientific? (cont'd) UNIVERSITY OF ROCHESTER — EPA PM Center Assessment of Ambient Z FF Health Effects: Linking Sources to Exposure and Respou.ses fu Exirapulittoitart' Organs Gunter Dberddrsterl; Alison Elden, Jack Finkelstein'; Mark Framptout; Phil Hopke'; Annette Peters' Kum Prather+; Erich Wichurwu3-5; Mark Utellt ( 'University of Rochester, 1Clarkson University; 'GSF, Germany i"UC-San Diego,'LMU-ISE, Germany) Rochester PM Center Report Grant EPA R827354 tlltrafarie partides: Characterstation, Health Effects and Pathophysia[ogicai hfeeharissrus 1999 - 2005 Are EPA's Experiments Scientific? (cont'd) • Utility of EPA's human experiments in doubt, admit EPA funded PM researchers: expected to produce only mild and transient responses. Furthermore, acute, transient responses seen in clinical studies cannot necessarily be used to predict health effects of chronic or repeated exposure. Endpoint assessment traditionally has included symptoms and pulmonary function, but Are EPA's Experiments Scientific? (cont'd) • Report from EPA's Science Advisory Board: United Stale EflYIronmenisI Pro1eelioa geri Seienee Ad YI5oot Board I1400A) Via shing1oa DG EPA SA 9 EC 00 017 S apsember2000 W W_ep9.g ovisaD aEPA COMMENTS ON THE USE OF DATA FROM THE TESTING OF HUMAN SUBJECTS A REPORT BY THE SCIENCE ADVISORY Y BOARD AND THE FIFRA SCIENTIFIC ADVISORY PANEL Are EPA's Experiments Scientific? (cont'd) Bad science is always unethical; research protocols that are fundamentally flawed, such as those with sample sizes inadequate to support reasonable inferences about the matter in question, are unjustifiable. Are EPA's Experiments Scientific? (cont'd) • Common Rule prohibits bad science: §26.102 Definitions. (a) Department or agency head means the head of any Federal department or agency and any other officer or employee of any department or agency to whom authority has been delegated. (b) Institution means any public or private entity or agency (including Federal, State, and other agencies) (c) Legally authorized representative means an individual or judicial or other body authorized under applicable law to consent on behalf of a prospective subject to the subject's participation in the procedure(s) involved in the research. (d) Research means a systematic investigation, ' cludina research development testing and evaluation designed to develop or contribute to enerallzable knowledge. ctivities Which meet this definition co c o ses o his policy, wheTher or not iney are Iona cted or supported under a program which is considered research for other purposes. For example, some demonstration and service programs may include research activities. • EPA human experiments are — Not systematic — Not generalizable `History of Regulatory Violations' • From internal EPA memo: Scientific Integrity and Human Research Ethics at EPA The Vulnerabilities Inherent in the Status Qua: • EPA's human research ethics program does not meet accepted standards in the bioethics community and is widely regarded as inadequate by knowledgeable individuals. • EPA's human studies rule is seriously flawed, contains barriers to ethically desirable human research, and impedes interagency collaborations. • EPA has a history of regulatory violations involving human research (details available). • If public scrutiny is brought to bear because of a new adverse event, EPA's inability to demonstrate that the Agency meets accepted standards could cause further harm to EPA's post -CHEERS reputation and thereby compromise the Agency's mission. • A current example is the allegation that the experimental building demolition carried out by EPA in Ft. Worth, TX in 2007 constituted human research without informed consent. Conclusion • Based on EPA -determined lethality of PM, the old/sick nature of study subjects, disclosure/ consent problems, and their non-scientific nature, EPA's PM human experiments are: — Fundamentally unethical, if not — Illegal. • EPA has withheld key information from IRBs, study subjects, and the NAS Committee. Implications of Conclusion • If PM is as deadly as EPA claims, then its experiments violated every law/regulation established for the protection of human study subjects since the Nuremberg Code. • The only way EPA does not have this legal culpability, is if PM is not as dangerous as EPA has told the public and Congress. • No third option. Thank you! • Contact me for more information: E-mail: milloy@me.com JunkScience.com/contact Twitter: @JunkScience LONG-TERM HEALTH EFFECTS OF PM2.5: RECENT FINDINGS May 16, 2002 Air Resources Board 0= California Environmental Protection Agency Thank you Mr. Kenny. Good morning Chairman Lloyd and members of the Board. Today I will present the results of a recent study regarding long-term exposure to fine particulate matter and associated mortality effects. OVERVIEW California PM standards under review Epidemiology studies support proposed PM standards Both short- and long-term exposures significant Recent findings on long-term exposure to fine particulate matter 0= As you are aware, staff have been reviewing the California air quality standards for particulate matter and will bring proposed recommendations to the Board in June. One of the key elements supporting the proposed recommendations are the results from epidemiology studies, which provide the link between exposure to particulate air pollution and adverse health effects. As you recall, you were briefed in March on a recent study on short-term exposure to fine particulate matter (defined as particulate matter of 2.5 micrometers or less) and heart disease, thus conveying the significance of short-term standards in protecting public health. Today I would like to present the results of a recent study on long-term exposure to fine particulate matter and associated mortality from cardiopulmonary disease and lung cancer. LONG-TERM PM STUDIES USING AMERICAN CANCER SOCIETY STUDY DATA ACS Study (1995)1 Reanalysis Study (2000)2 Follow-up Study (2002)3 0= 1Pope et al., 1995; 2Krewski et al., 2000; 3Pope et al., 2002 Over the past decade, several studies have evidenced the link between exposure to fine particulate matter and adverse health effects. One study, the 1995 American Cancer Society sponsored study or "ACS" study, concluded that annual mortality due to cardiopulmonary disease and lung cancer increased in association with an increase in fine particulate matter concentrations. Results from the 1995 ACS study came under intense scrutiny in 1997 when U.S. Environmental Protection Agency used it in support of new National Ambient Air Quality Standards for PM2.5. This study was labeled "controversial" because of uncertainty in the methodologies used in the analysis. As a result, and due to its significance in the standard setting process, an independent reanalysis was performed in 2000 which assured the quality of the data set and validated the findings of the 1995 ACS study. In March of this year, the primary authors of the 1995 ACS study published a follow-up study entitled "Lung Cancer, Cardiopulmonary Mortality, and long-term Exposure to Fine Particulate Air Pollution." The findings of this follow-up study are the focus of this health update. 2002 FOLLOW-UP STUDY • Design: - - 500,000 adults from 1981 through 1998 - ACS vital status & cause of death data • Advantages: doubled follow-up time (>16 years) expanded exposure data controlled potential confounders - individual risk factors - regional and spatial differences in measurements - co -pollutants robust evaluation of lung cancer mortality 0= The 2002 follow-up study evaluated approximately 500,000 adults, linking air pollution data from numerous metropolitan areas around the U.S. to vital statistics and death data from the American Cancer Society study database. It also had the following important advantages over its predecessor: 1) it doubled the follow-up time of the individuals being monitored to more than 16 years; 2) the exposure data was substantially expanded, including new PM2.5 data and gaseous co -pollutant data; 3) the analysis used advanced techniques for controlling potential "confounding" to ensure that reported associations were indeed due to exposure to fine particulate matter and not unduly influenced by individual risk factors, like smoking, alcohol consumption, body weight, diet, education and marital status; as well as potential differences in fine particulate matter concentrations within a region that may affect underlying exposure assumptions; and exposure to co -pollutants like coarse particles or gases; 4) Finally, the 2002 follow-up study had a better, more robust ability than the earlier study to evaluate mortality from lung cancer due to the inrrnocnrl fnlln,nr_i in fimc onrl ni imhor of rIoofhc 2002 FOLLOW-UP STUDY RESULTS • Each 10-Ng/m3 increase in PM2.5 was associated with increased risk of death: - 4% for all natural cause mortality - 6% for cardiopulmonary mortality - 8% for lung cancer mortality • Positive associations with sulfur - containing air pollution, not other gases • No consistent associations for coarse PM 0= The results of the 2002 follow-up study showed significant associations between PM2.5 and elevated risks for cardiopulmonary and lung cancer mortality. The study found that each 10 -microgram per -cubic -meter increase in long-term average PM2.5 concentrations was associated with approximately a 4% increased risk of death from all natural causes, a 6% increased risk of death from cardiopulmonary disease, and an 8% increased risk of death from lung cancer. Associations were also found with sulfur -containing air pollution but not other gaseous pollutants. On the other hand, measures of coarse particles were not consistently associated with mortality. As the study researchers indicated in the press release for this study, the lung cancer risk associated with exposure to fine particulate matter is comparable to that faced by nonsmokers who live with smokers, and are exposed long term to secondhand cigarette smoke. CONCLUSIONS • Significant associations between PM2.5 and elevated risks for cardiopulmonary and lung cancer mortality • Unprecedented opportunity to evaluate PM2.5 exposure and associated lung cancer mortality • Results validate those of previous studies and support a need for annual PM2.5 standard 0= In summary, this recent study provides the strongest evidence to date that long-term exposure to fine particulate matter or PM2.5 is an important risk factor in cardiopulmonary and lung cancer mortality. Also, the extended follow-up period provided the opportunity to determine, with greater confidence than the original study, a positive association between fine particulate matter air pollution and lung cancer related deaths. Of equal importance, the results of this recent validate results from earlier studies as well as supports the need for an annual or "long-term" PM2.5 standard. This concludes our presentation. Thank you --we will be glad to answer any questions. Reference: Pope, C., R. Burnett, M. Thun, E. Calle, D. Krewski, K. Ito, and G. Thurston, 2002. Lung Cancer, Cardiopulmonary Mortality, and long-term Exposure to Fine Particulate Air Pollution, Journal of the American Medical Association, 28(9):1132-1141. Hello