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Electronic Code of Federal Regulations

e-CFR data is current as of December 3, 2019

Title 40Chapter ISubchapter CPart 81Subpart C → §81.306


Title 40: Protection of Environment
PART 81—DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES
Subpart C—Section 107 Attainment Status Designations


§81.306   Colorado.

Colorado—1971 Sulfur Dioxide NAAQS

[Primary and Secondary]

Designated AreaDoes not meet primary standardsDoes not meet secondary standardsCannot be classifiedBetter than national standards
Entire StateX

Colorado—2010 Sulfur Dioxide NAAQS

[Primary]

Designated area1Designation
Date3Type
Colorado Springs, CO9/12/16Unclassifiable.
El Paso County (part)
Manitou Springs
Colorado Springs (and certain unincorporated areas) as follows; Areas east of the western city limits of Colorado Springs, north of the southern city limits of Colorado Springs with the addition of the area termed “Stratmoor” bounded on the south by South Academy Boulevard, west of Powers Blvd, and south of East Woodman Blvd (east of Academy Blvd. N) and the northern city limits of Colorado Springs (west of Academy Blvd. N).
Eastern Morgan County, CO9/12/16Unclassifiable.
Morgan County (part)
Circle with a 12-kilometer radius centered on the Pawnee Power Plant
State AQCR 01 (remainder)Attainment/Unclassifiable.
Logan County
Morgan County (part) (remainder)
Phillips County
Sedgwick County
Washington County
Yuma County
State AQCR 02Attainment/Unclassifiable.
Larimer County
Weld County
State AQCR 03Attainment/Unclassifiable.
Adams County
Arapahoe County
Boulder County
Broomfield County
Clear Creek County
Denver County
Douglas County
Gilpin County
Jefferson County
State AQCR 04 (remainder)Attainment/Unclassifiable.
El Paso County (part) (remainder)
Park County
Teller County
State AQCR 05Attainment/Unclassifiable.
Cheyenne County
Elbert County
Kit Carson County
Lincoln County
State AQCR 06Attainment/Unclassifiable.
Baca County
Bent County
Crowley County
Kiowa County
Otero County
Prowers County
State AQCR 07Attainment/Unclassifiable.
Huerfano
Las Animas
Pueblo
State AQCR 08Attainment/Unclassifiable.
Alamosa County
Conejos County
Costilla County
Mineral County
Rio Grande County
Saguache County
State AQCR 09Attainment/Unclassifiable.
Archuleta County2
Dolores
La Plata2
Montezuma2
San Juan
State AQCR 10Attainment/Unclassifiable.
Delta County
Gunnison County
Hinsdale County
Montrose County
Ouray County
San Miguel County
State AQCR 11Attainment/Unclassifiable.
Garfield County
Mesa County
Moffat County
Rio Blanco County
State AQCR 12Attainment/Unclassifiable.
Eagle County
Grand County
Jackson County
Pitkin County
Routt County
Summit County
State AQCR 13Attainment/Unclassifiable.
Chaffee County
Custer County
Fremont County
Lake County
Southern Ute Indian ReservationAttainment/Unclassifiable.

1Includes any Indian country in each county or area, unless otherwise specified. EPA is not determining the boundaries of any area of Indian country in this table, including any area of Indian country located in the larger designation area. The inclusion of any Indian country in the designation area is not a determination that the state has regulatory authority under the Clean Air Act for such Indian country.

2Does not include the Southern Ute Indian Reservation, which is being designated separately.

3This date is April 9, 2018, unless otherwise noted.

Colorado—Carbon Monoxide

Designated AreaDesignationClassification
Date1TypeDate1Type
Colorado Springs Area:October 25, 1999Attainment
Urban Transportation Planing Study Area as defined in 1989.
Beginning near the Town of Palmer Lake, at the Northwest corner of the Study Area at a point on the El Paso/Douglas County line, also on the Pike National Forest boundary, then:
east along the County line to Elbert Road; south on Elbert Road to Judge Orr Road; east on Judge Orr Road to Ellicott Highway; south on Ellicott Highway to Squirrel Creek Road; west on Squirrel Creek Road to Williams Creek; south along Williams Creek to the confluence of Williams and Fountain Creeks; south along Fountain Creek to the El Paso/Douglas County line; west on the County line to I-25; north on I-25 to Exit 132; west on McGrath to 35th; south on 35th to Specker; northwest on Specker to Titus Blvd.; west on Titus Blvd. to SH-115;
south on SH-115 to Rock Creek;
northwest along Rock Creek to the Pike National Forest boundary; north along the Forest boundary to Old Stage Road; southwest on Old Stage Road to Gold Camp Road; north on Gold Camp Road to High Drive; north on High Drive to Lower Gold Camp Road; north on Lower Gold Camp Road to the Pike National Forest boundary; west along the Forest boundary, following the boundary north, then east to US-24; northwest on US-24 to the Pikes Peak Toll Road; west on the Toll Road to the El Paso/Teller County line;
north along the County line to Crystola Creek; west on Crystola Creek to County Road 282, north on Road 282 to US-24; northeast on US-24 to Trout Creek Road; northwest on Trout Creek Road to Trout Creek; north along Trout Creek to the confluence of Trout and Mule Creeks; north along Mule Creek to Long Gulch; east along Long Gulch to White Gulch; east along White Gulch to Rampart Range Road; southeast on Rampart Range Road to the Pike National Forest Boundary; north along the Forest boundary to the El Paso/Douglas County line, to the point of origin.
El Paso County (part)
Teller County (part)
Denver-Boulder Area:
The boundaries for the Denver nonattainment area for carbon monixide (CO) are described as follows: Start at Colorado Highway 52 where it intersects the eastern boundary of Boulder County; Follow Highway 52 west until it intersects Colorado Highway 119; Follow northern boundary of Boulder city limits west to the 6,000-ft. elevation line; Follow the 6000-ft. elevation line south through Boulder and Jefferson Counties to US 6 in Jefferson County; Follow US 6 west to the Jefferson County-Clear Creek County line; Follow the Jefferson County western boundary south for approximately 16.25 miles; Follow a line east for approximately 3.75 mile to South Turkey Creek; Follow South Turkey Creek northeast for approximately 3.5 miles; Follow a line southeast for approximately 2.0 miles to the junction of South Deer Creek Road and South Deer Creek Canyon Road; Follow South Deer Creek Canyon Road northeast for approximately 3.75 miles; Follow a line southeast for approximately five miles to the northern-most boundary of Pike National Forest where it intersects the Jefferson County-Douglas County line; follow the Pike National forest boundary southeast through Douglas County to the Douglas County-El Paso County line; Follow the southern boundary on Douglas County east to the Elbert County line; Follow the eastern boundary of Douglas County north to the Arapahoe County line; Follow the southern boundary of Araphoe County east to Kiowa Creek; Follow Kiowa Creek northeast through Arapahoe and Adams Counties to the Adams-Weld County line; Follow the northern boundary of Adams County west to the Boulder County line; Follow the eastern boundary of Boulder County north to Highway 52January 14, 2002Attainment
Adams County (part)
Arapahoe County (part)
Boulder County (part)
Denver County
Douglas County (part)
Jefferson County (part)
Fort Collins Area:
Larimer County (part)Sept. 22, 2003Attainment
Fort Collins Urban Growth Area Boundary as adopted by the City of Fort Collins and the Larimer County Commissioners and in effect as of July 30, 1991.
Greeley Area:Attainment
Weld County (part)May 10, 1999
Urban boundaries as defined in the North Front Range Regional Transportation Plan, May, 1990.
Longmont AreaNov. 23, 1999Attainment
Hwy 52 west from the Boulder/Weld County line to 95th Street/Hoover Road, then north on 95th Street/Hoover Road to the intersection of Plateau Road and SH 119, then west on Plateau Road to the intersection of Hygiene Road, then due north to the Boulder/Larimer County line, then due east to the intersection of the Boulder/Larimer/Weld County lines, then south along the Boulder/Weld County line to Hwy 52, plus the portion of the City of Longmont east of the Boulder/Weld County line in Weld County.
Boulder County (part):
Weld County (part):
State AQCR 1Unclassifiable/Attainment
Logan County
Morgan County
Phillips County
Sedgwick County
Washington County
Yuma County
State AQCR 2 (Remainder of)
Larimer County (part)Unclassifiable/Attainment
Area outside Fort Collins Urban Growth Area Boundary
Weld County (part)
Remainder of countyUnclassifiable/Attainment
State AQCR 3 (Remainder of)Unclassifiable/Attainment
Adams County (part)
Remainder of County
Arapahoe County (part)
Remainder of County
Boulder County (part)
Remainder of County
Clear Creek County
Douglas County (part)
Remainder of County
Gilpin County
Jefferson County (part)
Remainder of County
State AQCR 4 (Remainder of)Unclassifiable/Attainment
El Paso County (part)
Area other than Urban Transportation Planning Study Area as defined in 1989
Park County
Teller County (part)
Remainder of County
State AQCR's 5-13Unclassifiable/Attainment
Alamosa County
Archuleta County
Baca County
Bent County
Chaffee County
Cheyenne County
Conejos County
Costilla County
Crowley County
Custer County
Delta County
Dolores County
Eagle County
Elbert County
Fremont County
Garfield County
Grand County
Gunnison County
Hinsdale County
Huerfano County
Jackson County
Kiowa County
Kit Carson County
La Plata County
Lake County
Las Animas County
Lincoln County
Mesa County
Mineral County
Moffat County
Montezuma County
Montrose County
Otero County
Ouray County
Pitkin County
Prowers County
Pueblo County
Rio Blanco County
Rio Grande County
Routt County
Saguache County
San Juan County
San Miguel County
Summit County

1This date is November 15, 1990, unless otherwise noted.

Colorado—Ozone (1-Hour Standard)4

Designated area Designation Classification
Date1 Type Date1 Type
Denver-Boulder Area:
Adams County (part)
West of Kiowa Creek10/11/01Attainment
Arapahoe County (part)
West of Kiowa CreekAttainment
Boulder County (part) excluding Rocky Mountain National ParkAttainment
Denver CountyAttainment
Douglas CountyAttainment
Jefferson CountyAttainment
State AQCR 01Unclassifiable/Attainment
Logan County
Morgan County
Phillips County
Sedgwick County
Washington County
Yuma County
State AQCR 02Unclassifiable/Attainment
Larimer County
Weld County
State AQCR 03 (Remainder of)Unclassifiable/Attainment
Adams County (part) East of Kiowa Creek
Arapahoe County (part) East of Kiowa Creek
Boulder County (part) Rocky Mtn. National Park Only
Clear Creek County
Gilpin County
State AQCR 11Unclassifiable/Attainment
Garfield County
Mesa County
Moffat County
Rio Blanco County
Rest of StateUnclassifiable/Attainment
Alamosa County
Archuleta County
Baca County
Bent County
Chaffee County
Cheyenne County
Conejos County
Costilla County
Crowley County
Custer County
Delta County
Dolores County
Eagle County
El Paso County
Elbert County
Fremont County
Grand County
Gunnison County
Hinsdale County
Huerfano County
Jackson County
Kiowa County
Kit Carson County
La Plata County
Lake County
Las Animas County
Lincoln County
Mineral County
Montezuma County
Montrose County
Otero County
Ouray County
Park County
Pitkin County
Prowers County
Pueblo County
Rio Grande County
Routt County
Saguache County
San Juan County
San Miguel County
Summit County
Teller County

1This date is October 18, 2000, unless otherwise noted.

2An area designated as an ozone nonattainment area as of the date of enactment of the CAAA of the 1990 that did not violate the ozone NAAQS during the period of 1987-1989.

3This date is January 16, 2001.

4The 1-hour ozone standard is revoked effective June 15, 2005 for all areas in Colorado except the Denver (Denver-Boulder-Greeley-Ft. Collins-Love) area where it is revoked effective November 20, 2008.

Colorado—PM-10

Designated area Designation Classification
Date Type Date Type
Archuleta County
Pagosa Springs Area8/14/01Attainment
Township 35N-Range 2W: Sections 13, 14, 15; Section 23 NE, N 12 SE; Section 24 all except SWSW; Section 25 N 12 NE, NENW.
Township 35N-Range 1W: Section 18 W 12
Adams, Denver, and Boulder Counties
Denver Metropolitan area10/16/02Attainment
All of Denver, Jefferson, and Douglas Counties, Boulder County (excluding the Rocky Mountain National Park) and the Colorado automobile inspection and readjustment program portions of Adams and Arapahoe Counties
San Miguel County
Telluride8/14/01Attainment
The Telluride attainment/maintenance area begins at the intersection of Colorado State Highway 145 and the Telluride service area boundary, as it existed in 1991. The western edge of the nonattainment area until it meets Remine Creek is defined as follows: A tract of land located in a portion of the west one-half of Section 28 and the east one-half of Section 29, Township 43 North, Range 9 west, of New Mexico Principal Meridian, County of San Miguel, State of Colorado, described as follows: Beginning at the southwest corner of the said Section 28; Thence N 89 deg.3600 W. 292.70 Feet; Thence S 04 deg.0512 W. 538.63 Feet; Thence N 03 deg.2942 W. 780.19 Feet; Thence N 22 deg.1500 E. 3344.16 Feet; Thence S 51 deg.5149 E. 570.44 Feet; Thence S 03 deg.1536 E. 1106.22 Feet; Thence S 45 deg.2442 E. 546.96 Feet; Thence S 28 deg.4112 W. 549.62 Feet; Thence S 29 deg.4009 E. 169.68 Feet; Thence S 44 deg.3003 W. 649.51 Feet; Thence S 85 deg.5400 E. 660.00 Feet; Thence S 04 deg.0600 W. 660.00 Feet; Thence N 89 deg.5600 E. 1318.68 Feet; to the true point of beginning containing 11249 acres as described above. Then, at Remine Creek, the attainment/maintenance boundary follows the service area boundary for 9.65 miles to the 9,200 foot contour line. The boundary then intersects Bear Creek. Here the attainment/maintenance boundary diverges from the service area boundary (9,200 foot contour line). The attainment/maintenance boundary continues in a west, southwest direction for 0.92 miles from the intersection of the 9,200 foot contour line and Bear Creek to the top of ski lift number 9 in the Telluride Ski Area at an elevation of about 11,900 feet. The boundary then shifts and runs in a north-westerly direction for 0.83 miles from the top of lift 9 to the top of lift 7, which is located at an elevation of 10,490 feet. From the top of lift 7, the attainment/maintenance boundary continues in a north-westerly direction for 0.5 miles to the intersection of lift 3 with the 10,000 foot control line. The attainment/maintenance boundary follows the 10,000 foot contour line in a south, south-west direction for 3.2 miles, until it intersects Skunk Creek. Here the boundary diverges from the 10,000 foot contour line and follows Skunk Creek in a northerly direction for 2.25 miles. At the intersection of Skunk Creek and Colorado State Highway 145, the attainment/maintenance boundary leaves the creek and follows Highway 145 in a northerly direction until it meets the service area boundary as it existed prior to changes adopted in 1991.
Prowers County
Lamar12/27/05Attainment
Pitkin County:
Aspen/Pitkin County Area—The area encompassed by the following Parcel ID numbers, as defined by the Pitkin County Planning Department: 2337-29, 2737-28, 2737-21, 2737-20, 2737-19, 2737-18, 2737-17, 2737-08, 2737-07, 2737-06, 2735-22, 2735-15, 2735-14, 2735-13, 2735-12, 2735-11, 2735-10, 2735-03, 2735-02, 2735-01, 2641-31, 2643-36, 2643-35, 2643-34, 2643-27, 2643-267/14/03Attainment.
Fremont County
Canon City Area7/31/00Attainment
Township 18S—Range 70W: All of sections 21, 22, 27, 28, 33, and 34; the E 12 , NENW, NESW, SENW, SESW quarters of sections 20, 29, 32; and the W 12 of sections 23, 26, and 35; Township 19S—Range 70W: All of sections 3, 4, 9, 10; E 12 , NENW, NESW, SENW, SESW quarters of sections 5 and 8; W 12 of sections 2 and 11.
Routt County (part):
Steamboat Springs11/24/04Attainment.
On the East—The Routt National Forest.
On the South—The southern border of sections 19, 10, 21, T4N, R84W of the 6th P.M. and the southern border of sections 23, 24, T4N, R85W of the 6th P.M.
On the West—Beginning at the southwestern corner of section 23, T4N, R85W of the 6th P.M. North along the western border of sections 23, 14, 11, T4N, R85W. Thence, along the ridge which bisects sections 35, 36, 25, 24, 13, 14, 11, 12, 1, T5N, R85W, and sections 36, 25, 24, T6N, R85W. Thence heading northwest along the ridge which bisects sections 23, 15, 10, 9, 4, T6N, R85W of 6th P.M. Thence, heading northeast along the ridge which bisects sections 33, 34, 35, 36, 25, T7N, R85W and sections 30 and 10 of T7N, R84W. Thence, north along the N 1/2 of the western edge of section 19, to the NW corner of section 18, T7N, R84W.
On the North—The northern boundary of sections 16, 17, 18, T7N, R84W of 6th P.M.
AQCR 111/15/90Unclassifiable
AQCR 211/15/90Unclassifiable
AQCR 3 (excluding the Denver Metropolitan PM-10 nonattainment area)11/15/90Unclassifiable
AQCR 411/15/90Unclassifiable
AQCR 511/15/90Unclassifiable
AQCR 6 (excluding the Lamar PM-10 nonattainment area)11/15/90Unclassifiable
AQCR 711/15/90Unclassifiable
AQCR 811/15/90Unclassifiable
AQCR 9 (excluding the Pagosa Springs PM-10 nonattainment area)11/15/90Unclassifiable
AQCR 10 (excluding the Telluride PM-10 nonattainment area)11/15/90Unclassifiable
AQCR 1111/15/90Unclassifiable
AQCR 12 (excluding the Aspen/Pitkin County and Steamboat Springs Area Airshed PM-10 nonattainment areas)11/15/90Unclassifiable
AQCR 13 (excluding the Canon City PM-10 nonattainment area)1/15/90Unclassifiable

Colorado—1997 Annual PM2.5 NAAQS

[Primary and Secondary]

Designated areaDesignationaClassification
Date1TypeDateType
Denver-Boulder Area:
Adams County (part) West of Kiowa CreekUnclassifiable/Attainment
Arapahoe County (part) West of Kiowa CreekUnclassifiable/Attainment
Boulder County (part) Excluding Rocky Mountain National ParkUnclassifiable/Attainment
Broomfield CountyUnclassifiable/Attainment
Denver CountyUnclassifiable/Attainment
Douglas CountyUnclassifiable/Attainment
Jefferson CountyUnclassifiable/Attainment
State AQCR 01:
Logan CountyUnclassifiable/Attainment
Morgan CountyUnclassifiable/Attainment
Phillips CountyUnclassifiable/Attainment
Sedgwick CountyUnclassifiable/Attainment
Washington CountyUnclassifiable/Attainment
Yuma CountyUnclassifiable/Attainment
State AQCR 02:
Larimer CountyUnclassifiable/Attainment
Weld CountyUnclassifiable/Attainment
State AQCR 03 (remainder of):
Adams County (remainder)Unclassifiable/Attainment
Arapahoe County (remainder)Unclassifiable/Attainment
Boulder County (remainder)Unclassifiable/Attainment
Clear Creek CountyUnclassifiable/Attainment
Gilpin CountyUnclassifiable/Attainment
State AQCR 04:
El Paso CountyUnclassifiable/Attainment
Park CountyUnclassifiable/Attainment
Teller CountyUnclassifiable/Attainment
State AQCR 05:
Cheyenne CountyUnclassifiable/Attainment
Elbert CountyUnclassifiable/Attainment
Kit Carson CountyUnclassifiable/Attainment
Lincoln CountyUnclassifiable/Attainment
State AQCR 06:
Baca CountyUnclassifiable/Attainment
Bent CountyUnclassifiable/Attainment
Crowley CountyUnclassifiable/Attainment
Kiowa CountyUnclassifiable/Attainment
Otero CountyUnclassifiable/Attainment
Prowers CountyUnclassifiable/Attainment
State AQCR 07:
Huerfano CountyUnclassifiable/Attainment
Las Animas CountyUnclassifiable/Attainment
Pueblo CountyUnclassifiable/Attainment
State AQCR 08:
Alamosa CountyUnclassifiable/Attainment
Conejos CountyUnclassifiable/Attainment
Costilla CountyUnclassifiable/Attainment
Mineral CountyUnclassifiable/Attainment
Rio Grande CountyUnclassifiable/Attainment
Saguache CountyUnclassifiable/Attainment
State AQCR 09:
Archuleta CountyUnclassifiable/Attainment
Dolores CountyUnclassifiable/Attainment
La Plata CountyUnclassifiable/Attainment
Montezuma CountyUnclassifiable/Attainment
San Juan CountyUnclassifiable/Attainment
State AQCR 10:
Delta CountyUnclassifiable/Attainment
Gunnison CountyUnclassifiable/Attainment
Hinsdale CountyUnclassifiable/Attainment
Montrose CountyUnclassifiable/Attainment
Ouray CountyUnclassifiable/Attainment
San Miguel CountyUnclassifiable/Attainment
State AQCR 11:
Garfield CountyUnclassifiable/Attainment
Mesa CountyUnclassifiable/Attainment
Moffat CountyUnclassifiable/Attainment
Rio Blanco CountyUnclassifiable/Attainment
State AQCR 12:
Eagle CountyUnclassifiable/Attainment
Grand CountyUnclassifiable/Attainment
Jackson CountyUnclassifiable/Attainment
Pitkin CountyUnclassifiable/Attainment
Routt CountyUnclassifiable/Attainment
Summit CountyUnclassifiable/Attainment
State AQCR 13:
Chaffee CountyUnclassifiable/Attainment
Custer CountyUnclassifiable/Attainment
Fremont CountyUnclassifiable/Attainment
Lake CountyUnclassifiable/Attainment

aIncludes Indian Country located in each county or area, except as otherwise specified.

1This date is 90 days after January 5, 2005, unless otherwise noted.

Colorado—2012 Annual PM2.5 NAAQS

[Primary]

Designated area1DesignationClassification
Date2TypeDate2Type
State AQCR 01:
Logan CountyUnclassifiable/Attainment
Morgan CountyUnclassifiable/Attainment
Phillips CountyUnclassifiable/Attainment
Sedgwick CountyUnclassifiable/Attainment
Washington CountyUnclassifiable/Attainment
Yuma CountyUnclassifiable/Attainment
State AQCR 02:
Larimer CountyUnclassifiable/Attainment
Weld CountyUnclassifiable/Attainment
State AQCR 03:
Adams CountyUnclassifiable/Attainment
Arapahoe CountyUnclassifiable/Attainment
Boulder CountyUnclassifiable/Attainment
Broomfield CountyUnclassifiable/Attainment
Clear Creek CountyUnclassifiable/Attainment
Denver CountyUnclassifiable/Attainment
Douglas CountyUnclassifiable/Attainment
Gilpin CountyUnclassifiable/Attainment
Jefferson CountyUnclassifiable/Attainment
State AQCR 04:
El Paso CountyUnclassifiable/Attainment
Park CountyUnclassifiable/Attainment
Teller CountyUnclassifiable/Attainment
State AQCR 05:
Cheyenne CountyUnclassifiable/Attainment
Elbert CountyUnclassifiable/Attainment
Kit Carson CountyUnclassifiable/Attainment
Lincoln CountyUnclassifiable/Attainment
State AQCR 06:
Baca CountyUnclassifiable/Attainment
Bent CountyUnclassifiable/Attainment
Crowley CountyUnclassifiable/Attainment
Kiowa CountyUnclassifiable/Attainment
Otero CountyUnclassifiable/Attainment
Prowers CountyUnclassifiable/Attainment
State AQCR 07:
Huerfano CountyUnclassifiable/Attainment
Las Animas CountyUnclassifiable/Attainment
Pueblo CountyUnclassifiable/Attainment
State AQCR 08:
Alamosa CountyUnclassifiable/Attainment
Conejos CountyUnclassifiable/Attainment
Costilla CountyUnclassifiable/Attainment
Mineral CountyUnclassifiable/Attainment
Rio Grande CountyUnclassifiable/Attainment
Saguache CountyUnclassifiable/Attainment
State AQCR 09:
Archuleta CountyUnclassifiable/Attainment
Dolores CountyUnclassifiable/Attainment
La Plata CountyUnclassifiable/Attainment
Montezuma CountyUnclassifiable/Attainment
San Juan CountyUnclassifiable/Attainment
State AQCR 10:
Delta CountyUnclassifiable/Attainment
Gunnison CountyUnclassifiable/Attainment
Hinsdale CountyUnclassifiable/Attainment
Montrose CountyUnclassifiable/Attainment
Ouray CountyUnclassifiable/Attainment
San Miguel CountyUnclassifiable/Attainment
State AQCR 11:
Garfield CountyUnclassifiable/Attainment
Mesa CountyUnclassifiable/Attainment
Moffat CountyUnclassifiable/Attainment
Rio Blanco CountyUnclassifiable/Attainment
State AQCR 12:
Eagle CountyUnclassifiable/Attainment
Grand CountyUnclassifiable/Attainment
Jackson CountyUnclassifiable/Attainment
Pitkin CountyUnclassifiable/Attainment
Routt CountyUnclassifiable/Attainment
Summit CountyUnclassifiable/Attainment
State AQCR 13:
Chaffee CountyUnclassifiable/Attainment
Custer CountyUnclassifiable/Attainment
Fremont CountyUnclassifiable/Attainment
Lake CountyUnclassifiable/Attainment

1Includes areas of Indian country located in each county or area, except as otherwise specified.

2This date is April 15, 2015, unless otherwise noted.

Colorado—1997 24-Hour PM2.5 NAAQS

[Primary and Secondary]

Designated areaDesignationaClassification
Date1TypeDateType
Denver-Boulder Area:
Adams County (part) West of Kiowa CreekUnclassifiable/Attainment
Arapahoe County (part) West of Kiowa CreekUnclassifiable/Attainment
Boulder County (part) Excluding Rocky Mountain National ParkUnclassifiable/Attainment
Broomfield CountyUnclassifiable/Attainment
Denver CountyUnclassifiable/Attainment
Douglas CountyUnclassifiable/Attainment
Jefferson CountyUnclassifiable/Attainment
State AQCR 01:
Logan CountyUnclassifiable/Attainment
Morgan CountyUnclassifiable/Attainment
Phillips CountyUnclassifiable/Attainment
Sedgwick CountyUnclassifiable/Attainment
Washington CountyUnclassifiable/Attainment
Yuma CountyUnclassifiable/Attainment
State AQCR 02:
Larimer CountyUnclassifiable/Attainment
Weld CountyUnclassifiable/Attainment
State AQCR 03 (remainder of):
Adams County (remainder)Unclassifiable/Attainment
Arapahoe County (remainder)Unclassifiable/Attainment
Boulder County (remainder)Unclassifiable/Attainment
Clear Creek CountyUnclassifiable/Attainment
Gilpin CountyUnclassifiable/Attainment
State AQCR 04:
El Paso CountyUnclassifiable/Attainment
Park CountyUnclassifiable/Attainment
Teller CountyUnclassifiable/Attainment
State AQCR 05:
Cheyenne CountyUnclassifiable/Attainment
Elbert CountyUnclassifiable/Attainment
Kit Carson CountyUnclassifiable/Attainment
Lincoln CountyUnclassifiable/Attainment
State AQCR 06:
Baca CountyUnclassifiable/Attainment
Bent CountyUnclassifiable/Attainment
Crowley CountyUnclassifiable/Attainment
Kiowa CountyUnclassifiable/Attainment
Otero CountyUnclassifiable/Attainment
Prowers CountyUnclassifiable/Attainment
State AQCR 07:
Huerfano CountyUnclassifiable/Attainment
Las Animas CountyUnclassifiable/Attainment
Pueblo CountyUnclassifiable/Attainment
State AQCR 08:
Alamosa CountyUnclassifiable/Attainment
Conejos CountyUnclassifiable/Attainment
Costilla CountyUnclassifiable/Attainment
Mineral CountyUnclassifiable/Attainment
Rio Grande CountyUnclassifiable/Attainment
Saguache CountyUnclassifiable/Attainment
State AQCR 09:
Archuleta CountyUnclassifiable/Attainment
Dolores CountyUnclassifiable/Attainment
La Plata CountyUnclassifiable/Attainment
Montezuma CountyUnclassifiable/Attainment
San Juan CountyUnclassifiable/Attainment
State AQCR 10:
Delta CountyUnclassifiable/Attainment
Gunnison CountyUnclassifiable/Attainment
Hinsdale CountyUnclassifiable/Attainment
Montrose CountyUnclassifiable/Attainment
Ouray CountyUnclassifiable/Attainment
San Miguel CountyUnclassifiable/Attainment
State AQCR 11:
Garfield CountyUnclassifiable/Attainment
Mesa CountyUnclassifiable/Attainment
Moffat CountyUnclassifiable/Attainment
Rio Blanco CountyUnclassifiable/Attainment
State AQCR 12:
Eagle CountyUnclassifiable/Attainment
Grand CountyUnclassifiable/Attainment
Jackson CountyUnclassifiable/Attainment
Pitkin CountyUnclassifiable/Attainment
Routt CountyUnclassifiable/Attainment
Summit CountyUnclassifiable/Attainment
State AQCR 13:
Chaffee CountyUnclassifiable/Attainment
Custer CountyUnclassifiable/Attainment
Fremont CountyUnclassifiable/Attainment
Lake CountyUnclassifiable/Attainment

aIncludes Indian Country located in each county or area, except as otherwise specified.

1This date is 90 days after January 5, 2005, unless otherwise noted.

Colorado—2006 24-Hour PM2.5 NAAQS

[Primary and Secondary]

Designated areaDesignationaClassification
Date1TypeDateType
Denver-Boulder Area:
Adams County (part) West of Kiowa CreekUnclassifiable/Attainment.
Arapahoe County (part) West of Kiowa CreekUnclassifiable/Attainment.
Boulder County (part) Excluding Rocky Mountain National ParkUnclassifiable/Attainment.
Broomfield CountyUnclassifiable/Attainment.
Denver CountyUnclassifiable/Attainment.
Douglas CountyUnclassifiable/Attainment.
Jefferson CountyUnclassifiable/Attainment.
State AQCR 01:
Logan CountyUnclassifiable/Attainment.
Morgan CountyUnclassifiable/Attainment.
Phillips CountyUnclassifiable/Attainment.
Sedgwick CountyUnclassifiable/Attainment.
Washington CountyUnclassifiable/Attainment.
Yuma CountyUnclassifiable/Attainment.
State AQCR 02:
Larimer CountyUnclassifiable/Attainment.
Weld CountyUnclassifiable/Attainment.
State AQCR 03 (remainder of):
Adams County (remainder)Unclassifiable/Attainment.
Arapahoe County (remainder)Unclassifiable/Attainment.
Boulder County (remainder)Unclassifiable/Attainment.
Clear Creek CountyUnclassifiable/Attainment.
Gilpin CountyUnclassifiable/Attainment.
State AQCR 04:
El Paso CountyUnclassifiable/Attainment.
Park CountyUnclassifiable/Attainment.
Teller CountyUnclassifiable/Attainment.
State AQCR 05:
Cheyenne CountyUnclassifiable/Attainment.
Elbert CountyUnclassifiable/Attainment.
Kit Carson CountyUnclassifiable/Attainment.
Lincoln CountyUnclassifiable/Attainment.
State AQCR 06:
Baca CountyUnclassifiable/Attainment.
Bent CountyUnclassifiable/Attainment.
Crowley CountyUnclassifiable/Attainment.
Kiowa CountyUnclassifiable/Attainment.
Otero CountyUnclassifiable/Attainment.
Prowers CountyUnclassifiable/Attainment.
State AQCR 07:
Huerfano CountyUnclassifiable/Attainment.
Las Animas CountyUnclassifiable/Attainment.
Pueblo CountyUnclassifiable/Attainment.
State AQCR 08:
Alamosa CountyUnclassifiable/Attainment.
Conejos CountyUnclassifiable/Attainment.
Costilla CountyUnclassifiable/Attainment.
Mineral CountyUnclassifiable/Attainment.
Rio Grande CountyUnclassifiable/Attainment.
Saguache CountyUnclassifiable/Attainment.
State AQCR 09:
Archuleta CountyUnclassifiable/Attainment.
Dolores CountyUnclassifiable/Attainment.
La Plata CountyUnclassifiable/Attainment.
Montezuma CountyUnclassifiable/Attainment.
San Juan CountyUnclassifiable/Attainment.
State AQCR 10:
Delta CountyUnclassifiable/Attainment.
Gunnison CountyUnclassifiable/Attainment.
Hinsdale CountyUnclassifiable/Attainment.
Montrose CountyUnclassifiable/Attainment.
Ouray CountyUnclassifiable/Attainment.
San Miguel CountyUnclassifiable/Attainment.
State AQCR 11:
Garfield CountyUnclassifiable/Attainment.
Mesa CountyUnclassifiable/Attainment.
Moffat CountyUnclassifiable/Attainment.
Rio Blanco CountyUnclassifiable/Attainment.
State AQCR 12:
Eagle CountyUnclassifiable/Attainment.
Grand CountyUnclassifiable/Attainment.
Jackson CountyUnclassifiable/Attainment.
Pitkin CountyUnclassifiable/Attainment.
Routt CountyUnclassifiable/Attainment.
Summit CountyUnclassifiable/Attainment.
State AQCR 13:
Chaffee CountyUnclassifiable/Attainment.
Custer CountyUnclassifiable/Attainment.
Fremont CountyUnclassifiable/Attainment.
Lake CountyUnclassifiable/Attainment.

aIncludes Indian Country located in each county or area, except as otherwise specified.

1This date is 30 days after November 13, 2009, unless otherwise noted.

Colorado—NO2 (1971 Annual Standard)

Designated areaBetter than national standards
Entire StateX

Colorado—NO2 (2010 1-Hour Standard)

Designated areaDesignationa
Date1Type
State AQCR 01:
Logan CountyUnclassifiable/Attainment.
Morgan CountyUnclassifiable/Attainment.
Phillips CountyUnclassifiable/Attainment.
Sedgwick CountyUnclassifiable/Attainment.
Washington CountyUnclassifiable/Attainment.
Yuma CountyUnclassifiable/Attainment.
State AQCR 02:
Larimer CountyUnclassifiable/Attainment.
Weld CountyUnclassifiable/Attainment.
State AQCR 03:
Adams CountyUnclassifiable/Attainment.
Arapahoe CountyUnclassifiable/Attainment.
Boulder CountyUnclassifiable/Attainment.
Broomfield CountyUnclassifiable/Attainment.
Clear Creek CountyUnclassifiable/Attainment.
Denver CountyUnclassifiable/Attainment.
Douglas CountyUnclassifiable/Attainment.
Jefferson CountyUnclassifiable/Attainment.
Gilpin CountyUnclassifiable/Attainment.
State AQCR 04:
El Paso CountyUnclassifiable/Attainment.
Park CountyUnclassifiable/Attainment.
Teller CountyUnclassifiable/Attainment.
State AQCR 05:
Cheyenne CountyUnclassifiable/Attainment.
Elbert CountyUnclassifiable/Attainment.
Kit Carson CountyUnclassifiable/Attainment.
Lincoln CountyUnclassifiable/Attainment.
State AQCR 06:
Baca CountyUnclassifiable/Attainment.
Bent CountyUnclassifiable/Attainment.
Crowley CountyUnclassifiable/Attainment.
Kiowa CountyUnclassifiable/Attainment.
Otero CountyUnclassifiable/Attainment.
Prowers CountyUnclassifiable/Attainment.
State AQCR 07:
Huerfano CountyUnclassifiable/Attainment.
Las Animas CountyUnclassifiable/Attainment.
Pueblo CountyUnclassifiable/Attainment.
State AQCR 08:
Alamosa CountyUnclassifiable/Attainment.
Conejos CountyUnclassifiable/Attainment.
Costilla CountyUnclassifiable/Attainment.
Mineral CountyUnclassifiable/Attainment.
Rio Grande CountyUnclassifiable/Attainment.
Saguache CountyUnclassifiable/Attainment.
State AQCR 09:
Archuleta CountyUnclassifiable/Attainment.
Dolores CountyUnclassifiable/Attainment.
La Plata CountyUnclassifiable/Attainment.
Montezuma CountyUnclassifiable/Attainment.
San Juan CountyUnclassifiable/Attainment.
State AQCR 10:
Delta CountyUnclassifiable/Attainment.
Gunnison CountyUnclassifiable/Attainment.
Hinsdale CountyUnclassifiable/Attainment.
Montrose CountyUnclassifiable/Attainment.
Ouray CountyUnclassifiable/Attainment.
San Miguel CountyUnclassifiable/Attainment.
State AQCR 11:
Garfield CountyUnclassifiable/Attainment.
Mesa CountyUnclassifiable/Attainment.
Moffat CountyUnclassifiable/Attainment.
Rio Blanco CountyUnclassifiable/Attainment.
State AQCR 12:
Eagle CountyUnclassifiable/Attainment.
Grand CountyUnclassifiable/Attainment.
Jackson CountyUnclassifiable/Attainment.
Pitkin CountyUnclassifiable/Attainment.
Routt CountyUnclassifiable/Attainment.
Summit CountyUnclassifiable/Attainment.
State AQCR 13:
Chaffee CountyUnclassifiable/Attainment.
Custer CountyUnclassifiable/Attainment.
Fremont CountyUnclassifiable/Attainment.
Lake CountyUnclassifiable/Attainment.

aIncludes Indian Country located in each county or area, except as otherwise specified.

1This date is 90 days after October 31, 2011, unless otherwise noted.

Colorado—1997 8-Hour Ozone NAAQS

[Primary and Secondary]

Designated area DesignationaCategory/classification
Date1Type Date1Type
Denver-Boulder-Greeley-Ft. Collins-Loveland, CO:
Adams County2Nonattainment6/13/12Subpart 2/Marginal.
Arapahoe County2Nonattainment6/13/12Subpart 2/Marginal.
Boulder County (includes part of Rocky Mtn. Nat. Park)2Nonattainment6/13/12Subpart 2/Marginal.
Broomfield County2Nonattainment6/13/12Subpart 2/Marginal.
Denver County2Nonattainment6/13/12Subpart 2/Marginal.
Douglas County2Nonattainment6/13/12Subpart 2/Marginal.
Jefferson County2Nonattainment6/13/12Subpart 2/Marginal.
Larimer County (part)2Nonattainment6/13/12Subpart 2/Marginal.
(includes part of Rocky Mtn. Nat. Park). That portion of the county that lies south of a line described as follows: Beginning at a point on Larimer County's eastern boundary and Weld County's western boundary intersected by 40 degrees, 42 minutes, and 47.1 seconds north latitude, proceed west to a point defined by the intersection of 40 degrees, 42 minutes, 47.1 seconds north latitude and 105 degrees, 29 minutes, and 40.0 seconds west longitude, thence proceed south on 105 degrees, 29 minutes, 40.0 seconds west longitude to the intersection with 40 degrees, 33 minutes and 17.4 seconds north latitude, thence proceed west on 40 degrees, 33 minutes, 17.4 seconds north latitude until this line intersects Larimer County's western boundary and Grand County's eastern boundary.
Weld County (part)2Nonattainment6/13/12Subpart 2/Marginal.
That portion of the county that lies south of a line described as follows: Beginning at a point on Weld County's eastern boundary and Logan County's western boundary intersected by 40 degrees, 42 minutes, 47.1 seconds north latitude, proceed west on 40 degrees, 42 minutes, 47.1 seconds north latitude until this line intersects Weld County's western boundary and Larimer County's eastern boundary.
State AQCR 01Unclassifiable/Attainment
Logan County
Phillips County
Sedgwick County
Washington County
Yuma County
State AQCR 03 (remainder of)Unclassifiable/Attainment
Clear Creek County
Gilpin County
State AQCR 11Unclassifiable/Attainment
Garfield County
Mesa County
Moffat County
Rio Blanco County
Rest of StateUnclassifiable/Attainment
Alamosa County
Archuleta County
Baca County
Bent County
Chaffee County
Cheyenne County
Conejos County
Costilla County
Crowley County
Custer County
Delta County
Dolores County
Eagle County
El Paso County
Elbert County
Fremont County
Grand County (includes portion of W. Rocky Mtn. Nat. Park)
Gunnison County
Hinsdale County
Huerfano County
Jackson County
Kiowa County
Kit Carson County
La Plata County
Lake County
Larimer County (part) remainder
Las Animas County
Lincoln County
Mineral County
Montezuma County
Montrose County
Morgan County
Otero County
Ouray County
Park County
Pitkin County
Prowers County
Pueblo County
Rio Grande County
Routt County
Saguache County
San Juan County
San Miguel County
Summit County
Teller County
Weld County (part) remainder

aIncludes Indian Country located in each county or area, except as otherwise specified.

1This date is June 15, 2004, unless otherwise noted.

2Effective November 20, 2007.

Colorado—2008 8-Hour Ozone NAAQS

[Primary and Secondary]

Designated areaDesignationClassification
Date1TypeDate1Type
Denver-Boulder-Greeley-Ft. Collins-Loveland, CO:2Nonattainment6/3/16Moderate.
Adams County
Arapahoe County
Boulder County
Broomfield County
Denver County
Douglas County
Jefferson County
Larimer County (part)
That portion of the county that lies south of a line described as follows: Beginning at a point on Larimer County's eastern boundary and Weld County's western boundary intersected by 40 degrees, 42 minutes, and 47.1 seconds north latitude, proceed west to a point defined by the intersection of 40 degrees, 42 minutes, 47.1 seconds north latitude and 105 degrees, 29 minutes, and 40.0 seconds west longitude, thence proceed south on 105 degrees, 29 minutes, 40.0 seconds west longitude to the intersection with 40 degrees, 33 minutes and 17.4 seconds north latitude, thence proceed west on 40 degrees, 33 minutes, 17.4 seconds north latitude until this line intersects Larimer County's western boundary and Grand County's eastern boundary
Weld County (part)
That portion of the county that lies south of a line described as follows: Beginning at a point on Weld County's eastern boundary and Logan County's western boundary intersected by 40 degrees, 42 minutes, 47.1 seconds north latitude, proceed west on 40 degrees, 42 minutes, 47.1 seconds north latitude until this line intersects Weld County's western boundary and Larimer County's eastern boundary
Southern Ute Indian Tribe of the Southern Ute Reservation3Unclassifiable/Attainment
Rest of State and Rest of Indian CountryUnclassifiable/Attainment

1This date is July 20, 2012, unless otherwise noted.

2Excludes Indian country located in each area, unless otherwise noted.

3Includes Indian country of the tribe listed in this table located in the identified area. Information pertaining to areas of Indian country in this table is intended for CAA planning purposes only and is not an EPA determination of Indian country status or any Indian country boundary. EPA lacks the authority to establish Indian country land status, and is making no determination of Indian country boundaries, in this table.

Colorado—2015 8-Hour Ozone NAAQS

[Primary and Secondary]

Designated area1DesignationClassification
Date2TypeDate2Type
Denver Metro/North Front Range, CONonattainmentMarginal.
Adams County.
Arapahoe County.
Boulder County.
Broomfield County.
Denver County.
Douglas County.
Jefferson County.
Larimer County (part):
Including the portion of Rocky Mountain National Park therein and that portion of the county that lies south of a line described as follows: Beginning at a point on Larimer County's eastern boundary and Weld County's western boundary intersected by 40 degrees, 42 minutes, and 47.1 seconds north latitude, proceed west to a point defined by the intersection of 40 degrees, 42 minutes, 47.1 seconds north latitude and 105 degrees, 29 minutes, and 40.0 seconds west longitude, thence proceed south on 105 degrees, 29 minutes, 40.0 seconds west longitude to the inter-section with 40 degrees, 33 minutes and 17.4 seconds north latitude, thence proceed west on 40 degrees, 33 minutes, 17.4 seconds north latitude until this line intersects Larimer County's western boundary and Grand County's eastern boundary.
Weld County (part):
That portion of the county that lies south of a line described as follows: Beginning at a point on Weld County's eastern boundary and Logan County's western boundary intersected by 40 degrees, 42 minutes, 47.1 seconds north latitude, proceed west on 40 degrees, 42 minutes, 47.1 seconds north latitude until this line intersects Weld County's western boundary and Larimer County's eastern boundary.
Alamosa County1/16/18Attainment/Unclassifiable
Archuleta County1/16/18Attainment/Unclassifiable
Baca County1/16/18Attainment/Unclassifiable
Bent County1/16/18Attainment/Unclassifiable
Chaffee County1/16/18Attainment/Unclassifiable
Cheyenne County1/16/18Attainment/Unclassifiable
Clear Creek CountyAttainment/Unclassifiable
Conejos County1/16/18Attainment/Unclassifiable
Costilla County1/16/18Attainment/Unclassifiable
Crowley County1/16/18Attainment/Unclassifiable
Custer County1/16/18Attainment/Unclassifiable
Delta County1/16/18Attainment/Unclassifiable
Dolores County1/16/18Attainment/Unclassifiable
Eagle County1/16/18Attainment/Unclassifiable
Elbert CountyAttainment/Unclassifiable
El Paso CountyAttainment/Unclassifiable
Fremont County1/16/18Attainment/Unclassifiable
Garfield CountyAttainment/Unclassifiable
Gilpin CountyAttainment/Unclassifiable
Grand CountyAttainment/Unclassifiable
Gunnison County1/16/18Attainment/Unclassifiable
Hinsdale County1/16/18Attainment/Unclassifiable
Huerfano County1/16/18Attainment/Unclassifiable
Jackson CountyAttainment/Unclassifiable
Kiowa County1/16/18Attainment/Unclassifiable
Kit Carson County1/16/18Attainment/Unclassifiable
Lake County1/16/18Attainment/Unclassifiable
La Plata County1/16/18Attainment/Unclassifiable
Larimer County (part remainder)Attainment/Unclassifiable
Las Animas County1/16/18Attainment/Unclassifiable
Lincoln County1/16/18Attainment/Unclassifiable
Logan County1/16/18Attainment/Unclassifiable
Mesa County1/16/18Attainment/Unclassifiable
Mineral County1/16/18Attainment/Unclassifiable
Moffat CountyAttainment/Unclassifiable
Montezuma County1/16/18Attainment/Unclassifiable
Montrose County1/16/18Attainment/Unclassifiable
Morgan County1/16/18Attainment/Unclassifiable
Otero County1/16/18Attainment/Unclassifiable
Ouray County1/16/18Attainment/Unclassifiable
Park CountyAttainment/Unclassifiable
Phillips County1/16/18Attainment/Unclassifiable
Pitkin County1/16/18Attainment/Unclassifiable
Prowers County1/16/18Attainment/Unclassifiable
Pueblo County1/16/18Attainment/Unclassifiable
Rio Blanco CountyAttainment/Unclassifiable
Rio Grande County1/16/18Attainment/Unclassifiable
Routt County1/16/18Attainment/Unclassifiable
Saguache County1/16/18Attainment/Unclassifiable
San Juan County1/16/18Attainment/Unclassifiable
San Miguel County1/16/18Attainment/Unclassifiable
Sedgwick County1/16/18Attainment/Unclassifiable
Summit County1/16/18Attainment/Unclassifiable
Teller CountyAttainment/Unclassifiable
Washington County1/16/18Attainment/Unclassifiable
Weld County (part) remainderAttainment/Unclassifiable
Yuma County1/16/18Attainment/Unclassifiable

1Includes any Indian country in each county or area, unless otherwise specified. EPA is not determining the boundaries of any area of Indian country in this table, including any area of Indian country located in the larger designation area. The inclusion of any Indian country in the designation area is not a determination that the state has regulatory authority under the Clean Air Act for such Indian country.

2This date is August 3, 2018, unless otherwise noted.

Colorado—2008 Lead NAAQS

Designated areaDesignation for the 2008 NAAQSa
Date1Type
Whole StateUnclassifiable/Attainment.

aIncludes Indian Country located in each county or area, except as otherwise specified.

1December 31, 2011 unless otherwise noted.

[43 FR 8964, Mar. 3, 1978]

Editorial Note: For Federal Register citations affecting §81.306, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.govinfo.gov.

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