HomeMy WebLinkAbout20040541.tiff STATE OF COLORADO
Bill Owens,Governor
Douglas H.Benevento,Executive Director ,,-'ao
Dedicated to protecting and improving the health and environment of the people of Colorado y! o
4300 Cherry Creek Dr.S. Laboratory and Radiation Services Division
Denver,Colorado 80246-1530 8100 Lowry Blvd. Ar 1 /
Phone(303)692-2000 Denver,Colorado 80230-6928 a�6'
TDD Line(303)691-7700 (303)692-3090 Colorado Department
Located in Glendale,Colorado of Public Health
http://www.cdphe.state.co.us and Environment
February 5, 2004
Robert E. Roberts
Regional Administrator
United States Environmental -:-I
Protection Agency -Region 8
999 18th Street, Suite 300
Denver, CO. 80202-2466
Subject: Proposed 8-hour Ozone Standard Nonattainment Boundary
Dear Mr. Roberts:
Governor Owens has asked me to respond to your December 3, 2003 letter on this issue. Due to
our commitment to excellent air quality, as of Spring 2003, all areas of the State of Colorado had
achieved attainment with all National Air Quality Standards, including the 1-hour ozone
standard.
The Colorado Department of Public Health and Environment (CDPHE) has been tracking trends
from its monitors for years and realized in 2002 that the Denver metropolitan area was in danger
of exceeding the new, more restrictive 8-hour ozone standard. Accordingly, on December 31,
2002,before the new standard had been violated, CDPHE, the Colorado Department of
Transportation, the Denver Regional Council of Governments (DRCOG),the Air Quality
Control Commission(AQCC), and the Regional Air Quality Commission (RAQC) entered into
an agreement with EPA that provides for early action by the state to bring the Denver
metropolitan area into attainment with the new standard.
As you note in your letter, the parties to the Early Action Compact have made substantial
progress in meeting the requirements and milestones in that agreement and I look forward to
submitting the State Plan to you later this year, after approval by the General Assembly.
As part of the plan preparation, CDPHE and the RAQC have engaged in substantial gathering
and analysis of source and meteorological data and state-of-the-art modeling of future trends in
ozone formation. The EPA has provided both technical and financial support for these efforts,
for which we thank you. The analysis and modeling is on-going and continues to be refined,
with the input of a diverse group of stakeholders that includes local government, industry,
academic, and environmental group representatives.
7 2004-0541
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Robert E. Roberts
February 5, 2004
Page 2
The Clean Air Act defines a nonattainment area as any area that does not meet or that contributes
to ambient air quality in a nearby area that does not meet a national air quality standard. It is
important that the boundary of the area capture those areas that are experiencing or significantly
contributing to the problem.
It is not clear from the information developed to date that all of the areas EPA is proposing need
to be within the nonattainment area under those criteria. In particular, there are areas within the
proposed boundary that do not contain significant sources of ground-level ozone precursors, or
that due to topography, meteorology, or other factors do not contribute to the problem. Areas
that do not contribute to the problem should not be subject to the burdens of a possible
nonattainment designation. Therefore, I am suggesting that the 11-county nonattainment
boundary described in your December 3 letter be modified to include all of Broomfield, Boulder,
Denver, Douglas, and Jefferson counties, and portions of Adams, Arapahoe, Larimer, and Weld
counties, and none of Morgan and Elbert counties. The attachment to this letter provides a more
detailed explanation.
Please have the appropriate staff person contact Margie Perkins, Director of the Air Pollution
Control Division, at(303) 692-3101 to schedule a discussion of the data that addresses the
criteria for designation.
Sincerely,
Douglas H. Benevento
Executive Director
Attachment
cc: Margie Perkins, Director, Air Pollution Control Division, CDPHE
Richard Long, EPA Region 8
Enclosure:
Recommended Boundary for the 8-hour Ozone Nonattainment Area
Colorado Department of Public Health and Environment
February 6, 2004
On December 3, 2003, EPA recommended that the Denver/Front Range ozone nonattainment
boundary include all 8 counties of the Denver-Boulder-Weld Consolidated Metropolitan
Statistical Area(CMSA). This CMSA includes all of Adams, Arapahoe, Boulder, Broomfield,
Denver, Douglas,Jefferson, and Weld Counties. EPA also recommends that all of Elbert,
Larimer, and Morgan Counties be included in the nonattainment area. It is EPA's position that
this area comprises on airshed where ozone precursor emissions sources either cause or
contribute to high ozone levels measured throughout the area. Monitoring sites in Jefferson and
Douglas Counties have violated EPA's 8-hour ozone National Ambient Air Quality Standard,
and monitors in Arapahoe, Larimer, and Weld Counties are in danger of measuring violations of
the standard.
Upon review of the topography, meteorology, and locations of emissions sources in the region,
CDPHE concurs that much of this area should be included within the nonattainment area
boundary when EPA publishes a final rulemaking in the Federal Register by April 15, 2004.
However, CDPHE suggests that portions of Adams, Arapahoe, Larimer, and Weld Counties, and
all of Elbert County and Morgan County not be included as part of the nonattainment area.
For Larimer County, the northern and western portions of the county should be excluded from
the nonattainment area due to the lack of sources that emit ozone precursor emissions, and due to
terrain features that logically exclude these areas from being considered as part of the airshed. In
summary, the mountainous part of the county north of Rocky Mountain National Park (north of
40°33'17.4"North Latitude and west of 105°29'40.0" West Longitude), and the northern, rural
portion of the county above the town of Wellington and east to the Weld county line (north of
40°42'47.1"North Latitude) should not be included in the nonattainment boundary. The
elevated terrain features of the Rocky Mountains (which runs through the western portion of the
county), and the Cheyenne Ridge (which runs through the northern portion of the county),
coupled with the lack of significant volatile organic compound (VOC) and nitrogen oxide(NOx)
emission sources,justify the exclusion of this area from the nonattainment boundary.
For Weld County, the Division recommends that the northern portion of the county be excluded
from the nonattainment area due to the lack of sources that emit ozone precursor emissions, and
due to terrain features that logically exclude this area from being considered as part of the
airshed. In summary, the northern, rural portion of the county north of Highway 14 (north of
40°42'47.1"North Latitude) and east to the Logan county line should not be included in the
nonattainment boundary. The elevated terrain feature of the Cheyenne Ridge (which runs
through the northern portion of the county), coupled with the lack of significant VOC and NOx
emission sources,justify the exclusion of this area from the nonattainment boundary.
For Elbert County, the entire county should be excluded from the nonattainment area due to the
lack of sources that emit ozone precursor emissions, and due to terrain features that logically
exclude this area from being considered as part of the airshed. In summary, the entire county
should not be included in the nonattainment boundary. The elevated terrain feature of the Palmer
Divide (which runs through the entire county), coupled with the lack of significant VOC and
NOx emission sources,justify the exclusion of this area from the nonattainment boundary.
For Weld, Adams and Arapahoe Counties, the eastern portions of these counties should be
eliminated from the boundary. Regarding Morgan County, if a portion of Morgan County must
be included in the boundary, the eastern portion of this county should be eliminated. Eliminating
this area from the recommended boundary is based on the extended distance that precursor
emissions would have to travel in order to cause or contribute to high ozone concentrations. This
boundary line should be drawn north-south through Morgan County west of Ft. Morgan (Ft.
Morgan is not included in the boundary) along 103°53'00" West Longitude. The boundary
extends directly north into Weld County, where it intersects the boundary line described above
(40°42'47.1"North Latitude), and south through Adams and Arapahoe Counties, where it
intersects the Elbert County Line north of the Town of Agate.
For Boulder, Broomfield, Denver, Douglas, and Jefferson Counties, all portions of these counties
should be included in the nonattainment area as recommended by EPA.
The attached map illustrates the proposed 8-hour ozone nonattainment area boundary.
Ozone Nonattainment Area
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