40 C.F.R. § 81.306
Current through September 30, 2024
Colorado-1971 Sulfur Dioxide NAAQS
[Primary and Secondary]
| Designated Area | Does not meet primary standards | Does not meet secondary standards | Cannot be classified | Better than national standards |
| Entire State | X |
Colorado-2010 Sulfur Dioxide NAAQS
[Primary]
| Designated area1 | Designation | |
| Date3 | Type | |
| Colorado Springs, CO | 9/12/16 | Unclassifiable. |
| 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, CO | 9/12/16 | Unclassifiable. |
| 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 02 | Attainment/Unclassifiable. | |
| Larimer County | ||
| Weld County | ||
| State AQCR 03 | Attainment/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 05 | Attainment/Unclassifiable. | |
| Cheyenne County | ||
| Elbert County | ||
| Kit Carson County | ||
| Lincoln County | ||
| State AQCR 06 | Attainment/Unclassifiable. | |
| Baca County | ||
| Bent County | ||
| Crowley County | ||
| Kiowa County | ||
| Otero County | ||
| Prowers County | ||
| State AQCR 07 | Attainment/Unclassifiable. | |
| Huerfano | ||
| Las Animas | ||
| Pueblo | ||
| State AQCR 08 | Attainment/Unclassifiable. | |
| Alamosa County | ||
| Conejos County | ||
| Costilla County | ||
| Mineral County | ||
| Rio Grande County | ||
| Saguache County | ||
| State AQCR 09 | Attainment/Unclassifiable. | |
| Archuleta County2 | ||
| Dolores | ||
| La Plata2 | ||
| Montezuma2 | ||
| San Juan | ||
| State AQCR 10 | Attainment/Unclassifiable. | |
| Delta County | ||
| Gunnison County | ||
| Hinsdale County | ||
| Montrose County | ||
| Ouray County | ||
| San Miguel County | ||
| State AQCR 11 | Attainment/Unclassifiable. | |
| Garfield County | ||
| Mesa County | ||
| Moffat County | ||
| Rio Blanco County | ||
| State AQCR 12 | Attainment/Unclassifiable. | |
| Eagle County | ||
| Grand County | ||
| Jackson County | ||
| Pitkin County | ||
| Routt County | ||
| Summit County | ||
| State AQCR 13 | Attainment/Unclassifiable. | |
| Chaffee County | ||
| Custer County | ||
| Fremont County | ||
| Lake County | ||
| Southern Ute Indian Reservation | Attainment/Unclassifiable. | |
1 Includes 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.
2 Does not include the Southern Ute Indian Reservation, which is being designated separately.
3 This date is April 9, 2018, unless otherwise noted.
Colorado-Carbon Monoxide
| Designated Area | Designation | Classification | ||
| Date1 | Type | Date1 | Type | |
| Colorado Springs Area: | October 25, 1999 | Attainment | ||
| 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 52 | January 14, 2002 | Attainment | ||
| 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, 2003 | Attainment | ||
| 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 Area | Nov. 23, 1999 | Attainment | ||
| 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 1 | Unclassifiable/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 county | Unclassifiable/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 5-13 | Unclassifiable/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 | ||||
1 This 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 Creek | 10/11/01 | Attainment | ||
| Arapahoe County (part) | ||||
| West of Kiowa Creek | Attainment | |||
| Boulder County (part) excluding Rocky Mountain National Park | Attainment | |||
| Denver County | Attainment | |||
| Douglas County | Attainment | |||
| Jefferson County | Attainment | |||
| State AQCR 01 | Unclassifiable/Attainment | |||
| Logan County | ||||
| Morgan County | ||||
| Phillips County | ||||
| Sedgwick County | ||||
| Washington County | ||||
| Yuma County | ||||
| State AQCR 02 | Unclassifiable/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 11 | Unclassifiable/Attainment | |||
| Garfield County | ||||
| Mesa County | ||||
| Moffat County | ||||
| Rio Blanco County | ||||
| Rest of State | Unclassifiable/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 | ||||
1 This date is October 18, 2000, unless otherwise noted.
2 An 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.
3 This date is January 16, 2001.
4 The 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 Area | 8/14/01 | Attainment | ||
| Township 35N-Range 2W: Sections 13, 14, 15; Section 23 NE, N 1/2 SE; Section 24 all except SWSW; Section 25 N 1/2NE, NENW. | ||||
| Township 35N-Range 1W: Section 18 W 1/2 | ||||
| Adams, Denver, and Boulder Counties | ||||
| Denver Metropolitan area | 10/16/02 | Attainment | ||
| 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 | ||||
| Telluride | 8/14/01 | Attainment | ||
| 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.36'00" W. 292.70 Feet; Thence S 04 deg.05'12" W. 538.63 Feet; Thence N 03 deg.29'42" W. 780.19 Feet; Thence N 22 deg.15'00" E. 3344.16 Feet; Thence S 51 deg.51'49" E. 570.44 Feet; Thence S 03 deg.15'36" E. 1106.22 Feet; Thence S 45 deg.24'42" E. 546.96 Feet; Thence S 28 deg.41'12" W. 549.62 Feet; Thence S 29 deg.40'09" E. 169.68 Feet; Thence S 44 deg.30'03" W. 649.51 Feet; Thence S 85 deg.54'00" E. 660.00 Feet; Thence S 04 deg.06'00" W. 660.00 Feet; Thence N 89 deg.56'00" 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 | ||||
| Lamar | 12/27/05 | Attainment | ||
| 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, 2643-26 | 7/14/03 | Attainment. | ||
| Fremont County | ||||
| Canon City Area | 7/31/00 | Attainment | ||
| Township 18S-Range 70W: All of sections 21, 22, 27, 28, 33, and 34; the E 1/2, NENW, NESW, SENW, SESW quarters of sections 20, 29, 32; and the W 1/2 of sections 23, 26, and 35; Township 19S-Range 70W: All of sections 3, 4, 9, 10; E 1/2, NENW, NESW, SENW, SESW quarters of sections 5 and 8; W 1/2 of sections 2 and 11. | ||||
| Routt County (part): | ||||
| Steamboat Springs | 11/24/04 | Attainment. | ||
| 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 1 | 11/15/90 | Unclassifiable | ||
| AQCR 2 | 11/15/90 | Unclassifiable | ||
| AQCR 3 (excluding the Denver Metropolitan PM-10 nonattainment area) | 11/15/90 | Unclassifiable | ||
| AQCR 4 | 11/15/90 | Unclassifiable | ||
| AQCR 5 | 11/15/90 | Unclassifiable | ||
| AQCR 6 (excluding the Lamar PM-10 nonattainment area) | 11/15/90 | Unclassifiable | ||
| AQCR 7 | 11/15/90 | Unclassifiable | ||
| AQCR 8 | 11/15/90 | Unclassifiable | ||
| AQCR 9 (excluding the Pagosa Springs PM-10 nonattainment area) | 11/15/90 | Unclassifiable | ||
| AQCR 10 (excluding the Telluride PM-10 nonattainment area) | 11/15/90 | Unclassifiable | ||
| AQCR 11 | 11/15/90 | Unclassifiable | ||
| AQCR 12 (excluding the Aspen/Pitkin County and Steamboat Springs Area Airshed PM-10 nonattainment areas) | 11/15/90 | Unclassifiable | ||
| AQCR 13 (excluding the Canon City PM-10 nonattainment area) | 1/15/90 | Unclassifiable | ||
Colorado-1997 Annual PM2.5 NAAQS
[Primary and Secondary]
| Designated area | Designationa | Classification | ||
| Date1 | Type | Date | Type | |
| Denver-Boulder Area: | ||||
| Adams County (part) West of Kiowa Creek | Unclassifiable/Attainment | |||
| Arapahoe County (part) West of Kiowa Creek | Unclassifiable/Attainment | |||
| Boulder County (part) Excluding Rocky Mountain National Park | Unclassifiable/Attainment | |||
| Broomfield County | Unclassifiable/Attainment | |||
| Denver County | Unclassifiable/Attainment | |||
| Douglas County | Unclassifiable/Attainment | |||
| Jefferson County | Unclassifiable/Attainment | |||
| State AQCR 01: | ||||
| Logan County | Unclassifiable/Attainment | |||
| Morgan County | Unclassifiable/Attainment | |||
| Phillips County | Unclassifiable/Attainment | |||
| Sedgwick County | Unclassifiable/Attainment | |||
| Washington County | Unclassifiable/Attainment | |||
| Yuma County | Unclassifiable/Attainment | |||
| State AQCR 02: | ||||
| Larimer County | Unclassifiable/Attainment | |||
| Weld County | Unclassifiable/Attainment | |||
| State AQCR 03 (remainder of): | ||||
| Adams County (remainder) | Unclassifiable/Attainment | |||
| Arapahoe County (remainder) | Unclassifiable/Attainment | |||
| Boulder County (remainder) | Unclassifiable/Attainment | |||
| Clear Creek County | Unclassifiable/Attainment | |||
| Gilpin County | Unclassifiable/Attainment | |||
| State AQCR 04: | ||||
| El Paso County | Unclassifiable/Attainment | |||
| Park County | Unclassifiable/Attainment | |||
| Teller County | Unclassifiable/Attainment | |||
| State AQCR 05: | ||||
| Cheyenne County | Unclassifiable/Attainment | |||
| Elbert County | Unclassifiable/Attainment | |||
| Kit Carson County | Unclassifiable/Attainment | |||
| Lincoln County | Unclassifiable/Attainment | |||
| State AQCR 06: | ||||
| Baca County | Unclassifiable/Attainment | |||
| Bent County | Unclassifiable/Attainment | |||
| Crowley County | Unclassifiable/Attainment | |||
| Kiowa County | Unclassifiable/Attainment | |||
| Otero County | Unclassifiable/Attainment | |||
| Prowers County | Unclassifiable/Attainment | |||
| State AQCR 07: | ||||
| Huerfano County | Unclassifiable/Attainment | |||
| Las Animas County | Unclassifiable/Attainment | |||
| Pueblo County | Unclassifiable/Attainment | |||
| State AQCR 08: | ||||
| Alamosa County | Unclassifiable/Attainment | |||
| Conejos County | Unclassifiable/Attainment | |||
| Costilla County | Unclassifiable/Attainment | |||
| Mineral County | Unclassifiable/Attainment | |||
| Rio Grande County | Unclassifiable/Attainment | |||
| Saguache County | Unclassifiable/Attainment | |||
| State AQCR 09: | ||||
| Archuleta County | Unclassifiable/Attainment | |||
| Dolores County | Unclassifiable/Attainment | |||
| La Plata County | Unclassifiable/Attainment | |||
| Montezuma County | Unclassifiable/Attainment | |||
| San Juan County | Unclassifiable/Attainment | |||
| State AQCR 10: | ||||
| Delta County | Unclassifiable/Attainment | |||
| Gunnison County | Unclassifiable/Attainment | |||
| Hinsdale County | Unclassifiable/Attainment | |||
| Montrose County | Unclassifiable/Attainment | |||
| Ouray County | Unclassifiable/Attainment | |||
| San Miguel County | Unclassifiable/Attainment | |||
| State AQCR 11: | ||||
| Garfield County | Unclassifiable/Attainment | |||
| Mesa County | Unclassifiable/Attainment | |||
| Moffat County | Unclassifiable/Attainment | |||
| Rio Blanco County | Unclassifiable/Attainment | |||
| State AQCR 12: | ||||
| Eagle County | Unclassifiable/Attainment | |||
| Grand County | Unclassifiable/Attainment | |||
| Jackson County | Unclassifiable/Attainment | |||
| Pitkin County | Unclassifiable/Attainment | |||
| Routt County | Unclassifiable/Attainment | |||
| Summit County | Unclassifiable/Attainment | |||
| State AQCR 13: | ||||
| Chaffee County | Unclassifiable/Attainment | |||
| Custer County | Unclassifiable/Attainment | |||
| Fremont County | Unclassifiable/Attainment | |||
| Lake County | Unclassifiable/Attainment | |||
a Includes 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 area1 | Designation | Classification | ||
| Date2 | Type | Date2 | Type | |
| State AQCR 01: | ||||
| Logan County | Unclassifiable/Attainment | |||
| Morgan County | Unclassifiable/Attainment | |||
| Phillips County | Unclassifiable/Attainment | |||
| Sedgwick County | Unclassifiable/Attainment | |||
| Washington County | Unclassifiable/Attainment | |||
| Yuma County | Unclassifiable/Attainment | |||
| State AQCR 02: | ||||
| Larimer County | Unclassifiable/Attainment | |||
| Weld County | Unclassifiable/Attainment | |||
| State AQCR 03: | ||||
| Adams County | Unclassifiable/Attainment | |||
| Arapahoe County | Unclassifiable/Attainment | |||
| Boulder County | Unclassifiable/Attainment | |||
| Broomfield County | Unclassifiable/Attainment | |||
| Clear Creek County | Unclassifiable/Attainment | |||
| Denver County | Unclassifiable/Attainment | |||
| Douglas County | Unclassifiable/Attainment | |||
| Gilpin County | Unclassifiable/Attainment | |||
| Jefferson County | Unclassifiable/Attainment | |||
| State AQCR 04: | ||||
| El Paso County | Unclassifiable/Attainment | |||
| Park County | Unclassifiable/Attainment | |||
| Teller County | Unclassifiable/Attainment | |||
| State AQCR 05: | ||||
| Cheyenne County | Unclassifiable/Attainment | |||
| Elbert County | Unclassifiable/Attainment | |||
| Kit Carson County | Unclassifiable/Attainment | |||
| Lincoln County | Unclassifiable/Attainment | |||
| State AQCR 06: | ||||
| Baca County | Unclassifiable/Attainment | |||
| Bent County | Unclassifiable/Attainment | |||
| Crowley County | Unclassifiable/Attainment | |||
| Kiowa County | Unclassifiable/Attainment | |||
| Otero County | Unclassifiable/Attainment | |||
| Prowers County | Unclassifiable/Attainment | |||
| State AQCR 07: | ||||
| Huerfano County | Unclassifiable/Attainment | |||
| Las Animas County | Unclassifiable/Attainment | |||
| Pueblo County | Unclassifiable/Attainment | |||
| State AQCR 08: | ||||
| Alamosa County | Unclassifiable/Attainment | |||
| Conejos County | Unclassifiable/Attainment | |||
| Costilla County | Unclassifiable/Attainment | |||
| Mineral County | Unclassifiable/Attainment | |||
| Rio Grande County | Unclassifiable/Attainment | |||
| Saguache County | Unclassifiable/Attainment | |||
| State AQCR 09: | ||||
| Archuleta County | Unclassifiable/Attainment | |||
| Dolores County | Unclassifiable/Attainment | |||
| La Plata County | Unclassifiable/Attainment | |||
| Montezuma County | Unclassifiable/Attainment | |||
| San Juan County | Unclassifiable/Attainment | |||
| State AQCR 10: | ||||
| Delta County | Unclassifiable/Attainment | |||
| Gunnison County | Unclassifiable/Attainment | |||
| Hinsdale County | Unclassifiable/Attainment | |||
| Montrose County | Unclassifiable/Attainment | |||
| Ouray County | Unclassifiable/Attainment | |||
| San Miguel County | Unclassifiable/Attainment | |||
| State AQCR 11: | ||||
| Garfield County | Unclassifiable/Attainment | |||
| Mesa County | Unclassifiable/Attainment | |||
| Moffat County | Unclassifiable/Attainment | |||
| Rio Blanco County | Unclassifiable/Attainment | |||
| State AQCR 12: | ||||
| Eagle County | Unclassifiable/Attainment | |||
| Grand County | Unclassifiable/Attainment | |||
| Jackson County | Unclassifiable/Attainment | |||
| Pitkin County | Unclassifiable/Attainment | |||
| Routt County | Unclassifiable/Attainment | |||
| Summit County | Unclassifiable/Attainment | |||
| State AQCR 13: | ||||
| Chaffee County | Unclassifiable/Attainment | |||
| Custer County | Unclassifiable/Attainment | |||
| Fremont County | Unclassifiable/Attainment | |||
| Lake County | Unclassifiable/Attainment | |||
1 Includes areas of Indian country located in each county or area, except as otherwise specified.
2 This date is April 15, 2015, unless otherwise noted.
Colorado-1997 24-Hour PM2.5 NAAQS
[Primary and Secondary]
| Designated area | Designationa | Classification | ||
| Date1 | Type | Date | Type | |
| Denver-Boulder Area: | ||||
| Adams County (part) West of Kiowa Creek | Unclassifiable/Attainment | |||
| Arapahoe County (part) West of Kiowa Creek | Unclassifiable/Attainment | |||
| Boulder County (part) Excluding Rocky Mountain National Park | Unclassifiable/Attainment | |||
| Broomfield County | Unclassifiable/Attainment | |||
| Denver County | Unclassifiable/Attainment | |||
| Douglas County | Unclassifiable/Attainment | |||
| Jefferson County | Unclassifiable/Attainment | |||
| State AQCR 01: | ||||
| Logan County | Unclassifiable/Attainment | |||
| Morgan County | Unclassifiable/Attainment | |||
| Phillips County | Unclassifiable/Attainment | |||
| Sedgwick County | Unclassifiable/Attainment | |||
| Washington County | Unclassifiable/Attainment | |||
| Yuma County | Unclassifiable/Attainment | |||
| State AQCR 02: | ||||
| Larimer County | Unclassifiable/Attainment | |||
| Weld County | Unclassifiable/Attainment | |||
| State AQCR 03 (remainder of): | ||||
| Adams County (remainder) | Unclassifiable/Attainment | |||
| Arapahoe County (remainder) | Unclassifiable/Attainment | |||
| Boulder County (remainder) | Unclassifiable/Attainment | |||
| Clear Creek County | Unclassifiable/Attainment | |||
| Gilpin County | Unclassifiable/Attainment | |||
| State AQCR 04: | ||||
| El Paso County | Unclassifiable/Attainment | |||
| Park County | Unclassifiable/Attainment | |||
| Teller County | Unclassifiable/Attainment | |||
| State AQCR 05: | ||||
| Cheyenne County | Unclassifiable/Attainment | |||
| Elbert County | Unclassifiable/Attainment | |||
| Kit Carson County | Unclassifiable/Attainment | |||
| Lincoln County | Unclassifiable/Attainment | |||
| State AQCR 06: | ||||
| Baca County | Unclassifiable/Attainment | |||
| Bent County | Unclassifiable/Attainment | |||
| Crowley County | Unclassifiable/Attainment | |||
| Kiowa County | Unclassifiable/Attainment | |||
| Otero County | Unclassifiable/Attainment | |||
| Prowers County | Unclassifiable/Attainment | |||
| State AQCR 07: | ||||
| Huerfano County | Unclassifiable/Attainment | |||
| Las Animas County | Unclassifiable/Attainment | |||
| Pueblo County | Unclassifiable/Attainment | |||
| State AQCR 08: | ||||
| Alamosa County | Unclassifiable/Attainment | |||
| Conejos County | Unclassifiable/Attainment | |||
| Costilla County | Unclassifiable/Attainment | |||
| Mineral County | Unclassifiable/Attainment | |||
| Rio Grande County | Unclassifiable/Attainment | |||
| Saguache County | Unclassifiable/Attainment | |||
| State AQCR 09: | ||||
| Archuleta County | Unclassifiable/Attainment | |||
| Dolores County | Unclassifiable/Attainment | |||
| La Plata County | Unclassifiable/Attainment | |||
| Montezuma County | Unclassifiable/Attainment | |||
| San Juan County | Unclassifiable/Attainment | |||
| State AQCR 10: | ||||
| Delta County | Unclassifiable/Attainment | |||
| Gunnison County | Unclassifiable/Attainment | |||
| Hinsdale County | Unclassifiable/Attainment | |||
| Montrose County | Unclassifiable/Attainment | |||
| Ouray County | Unclassifiable/Attainment | |||
| San Miguel County | Unclassifiable/Attainment | |||
| State AQCR 11: | ||||
| Garfield County | Unclassifiable/Attainment | |||
| Mesa County | Unclassifiable/Attainment | |||
| Moffat County | Unclassifiable/Attainment | |||
| Rio Blanco County | Unclassifiable/Attainment | |||
| State AQCR 12: | ||||
| Eagle County | Unclassifiable/Attainment | |||
| Grand County | Unclassifiable/Attainment | |||
| Jackson County | Unclassifiable/Attainment | |||
| Pitkin County | Unclassifiable/Attainment | |||
| Routt County | Unclassifiable/Attainment | |||
| Summit County | Unclassifiable/Attainment | |||
| State AQCR 13: | ||||
| Chaffee County | Unclassifiable/Attainment | |||
| Custer County | Unclassifiable/Attainment | |||
| Fremont County | Unclassifiable/Attainment | |||
| Lake County | Unclassifiable/Attainment | |||
a Includes 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 area | Designationa | Classification | ||
| Date1 | Type | Date | Type | |
| Denver-Boulder Area: | ||||
| Adams County (part) West of Kiowa Creek | Unclassifiable/Attainment. | |||
| Arapahoe County (part) West of Kiowa Creek | Unclassifiable/Attainment. | |||
| Boulder County (part) Excluding Rocky Mountain National Park | Unclassifiable/Attainment. | |||
| Broomfield County | Unclassifiable/Attainment. | |||
| Denver County | Unclassifiable/Attainment. | |||
| Douglas County | Unclassifiable/Attainment. | |||
| Jefferson County | Unclassifiable/Attainment. | |||
| State AQCR 01: | ||||
| Logan County | Unclassifiable/Attainment. | |||
| Morgan County | Unclassifiable/Attainment. | |||
| Phillips County | Unclassifiable/Attainment. | |||
| Sedgwick County | Unclassifiable/Attainment. | |||
| Washington County | Unclassifiable/Attainment. | |||
| Yuma County | Unclassifiable/Attainment. | |||
| State AQCR 02: | ||||
| Larimer County | Unclassifiable/Attainment. | |||
| Weld County | Unclassifiable/Attainment. | |||
| State AQCR 03 (remainder of): | ||||
| Adams County (remainder) | Unclassifiable/Attainment. | |||
| Arapahoe County (remainder) | Unclassifiable/Attainment. | |||
| Boulder County (remainder) | Unclassifiable/Attainment. | |||
| Clear Creek County | Unclassifiable/Attainment. | |||
| Gilpin County | Unclassifiable/Attainment. | |||
| State AQCR 04: | ||||
| El Paso County | Unclassifiable/Attainment. | |||
| Park County | Unclassifiable/Attainment. | |||
| Teller County | Unclassifiable/Attainment. | |||
| State AQCR 05: | ||||
| Cheyenne County | Unclassifiable/Attainment. | |||
| Elbert County | Unclassifiable/Attainment. | |||
| Kit Carson County | Unclassifiable/Attainment. | |||
| Lincoln County | Unclassifiable/Attainment. | |||
| State AQCR 06: | ||||
| Baca County | Unclassifiable/Attainment. | |||
| Bent County | Unclassifiable/Attainment. | |||
| Crowley County | Unclassifiable/Attainment. | |||
| Kiowa County | Unclassifiable/Attainment. | |||
| Otero County | Unclassifiable/Attainment. | |||
| Prowers County | Unclassifiable/Attainment. | |||
| State AQCR 07: | ||||
| Huerfano County | Unclassifiable/Attainment. | |||
| Las Animas County | Unclassifiable/Attainment. | |||
| Pueblo County | Unclassifiable/Attainment. | |||
| State AQCR 08: | ||||
| Alamosa County | Unclassifiable/Attainment. | |||
| Conejos County | Unclassifiable/Attainment. | |||
| Costilla County | Unclassifiable/Attainment. | |||
| Mineral County | Unclassifiable/Attainment. | |||
| Rio Grande County | Unclassifiable/Attainment. | |||
| Saguache County | Unclassifiable/Attainment. | |||
| State AQCR 09: | ||||
| Archuleta County | Unclassifiable/Attainment. | |||
| Dolores County | Unclassifiable/Attainment. | |||
| La Plata County | Unclassifiable/Attainment. | |||
| Montezuma County | Unclassifiable/Attainment. | |||
| San Juan County | Unclassifiable/Attainment. | |||
| State AQCR 10: | ||||
| Delta County | Unclassifiable/Attainment. | |||
| Gunnison County | Unclassifiable/Attainment. | |||
| Hinsdale County | Unclassifiable/Attainment. | |||
| Montrose County | Unclassifiable/Attainment. | |||
| Ouray County | Unclassifiable/Attainment. | |||
| San Miguel County | Unclassifiable/Attainment. | |||
| State AQCR 11: | ||||
| Garfield County | Unclassifiable/Attainment. | |||
| Mesa County | Unclassifiable/Attainment. | |||
| Moffat County | Unclassifiable/Attainment. | |||
| Rio Blanco County | Unclassifiable/Attainment. | |||
| State AQCR 12: | ||||
| Eagle County | Unclassifiable/Attainment. | |||
| Grand County | Unclassifiable/Attainment. | |||
| Jackson County | Unclassifiable/Attainment. | |||
| Pitkin County | Unclassifiable/Attainment. | |||
| Routt County | Unclassifiable/Attainment. | |||
| Summit County | Unclassifiable/Attainment. | |||
| State AQCR 13: | ||||
| Chaffee County | Unclassifiable/Attainment. | |||
| Custer County | Unclassifiable/Attainment. | |||
| Fremont County | Unclassifiable/Attainment. | |||
| Lake County | Unclassifiable/Attainment. | |||
a Includes Indian Country located in each county or area, except as otherwise specified.
1 This date is 30 days after November 13, 2009, unless otherwise noted.
Colorado-NO2 (1971 Annual Standard)
| Designated area | Better than national standards |
| Entire State | X |
Colorado-NO2 (2010 1-Hour Standard)
| Designated area | Designationa | |
| Date1 | Type | |
| State AQCR 01: | ||
| Logan County | Unclassifiable/Attainment. | |
| Morgan County | Unclassifiable/Attainment. | |
| Phillips County | Unclassifiable/Attainment. | |
| Sedgwick County | Unclassifiable/Attainment. | |
| Washington County | Unclassifiable/Attainment. | |
| Yuma County | Unclassifiable/Attainment. | |
| State AQCR 02: | ||
| Larimer County | Unclassifiable/Attainment. | |
| Weld County | Unclassifiable/Attainment. | |
| State AQCR 03: | ||
| Adams County | Unclassifiable/Attainment. | |
| Arapahoe County | Unclassifiable/Attainment. | |
| Boulder County | Unclassifiable/Attainment. | |
| Broomfield County | Unclassifiable/Attainment. | |
| Clear Creek County | Unclassifiable/Attainment. | |
| Denver County | Unclassifiable/Attainment. | |
| Douglas County | Unclassifiable/Attainment. | |
| Jefferson County | Unclassifiable/Attainment. | |
| Gilpin County | Unclassifiable/Attainment. | |
| State AQCR 04: | ||
| El Paso County | Unclassifiable/Attainment. | |
| Park County | Unclassifiable/Attainment. | |
| Teller County | Unclassifiable/Attainment. | |
| State AQCR 05: | ||
| Cheyenne County | Unclassifiable/Attainment. | |
| Elbert County | Unclassifiable/Attainment. | |
| Kit Carson County | Unclassifiable/Attainment. | |
| Lincoln County | Unclassifiable/Attainment. | |
| State AQCR 06: | ||
| Baca County | Unclassifiable/Attainment. | |
| Bent County | Unclassifiable/Attainment. | |
| Crowley County | Unclassifiable/Attainment. | |
| Kiowa County | Unclassifiable/Attainment. | |
| Otero County | Unclassifiable/Attainment. | |
| Prowers County | Unclassifiable/Attainment. | |
| State AQCR 07: | ||
| Huerfano County | Unclassifiable/Attainment. | |
| Las Animas County | Unclassifiable/Attainment. | |
| Pueblo County | Unclassifiable/Attainment. | |
| State AQCR 08: | ||
| Alamosa County | Unclassifiable/Attainment. | |
| Conejos County | Unclassifiable/Attainment. | |
| Costilla County | Unclassifiable/Attainment. | |
| Mineral County | Unclassifiable/Attainment. | |
| Rio Grande County | Unclassifiable/Attainment. | |
| Saguache County | Unclassifiable/Attainment. | |
| State AQCR 09: | ||
| Archuleta County | Unclassifiable/Attainment. | |
| Dolores County | Unclassifiable/Attainment. | |
| La Plata County | Unclassifiable/Attainment. | |
| Montezuma County | Unclassifiable/Attainment. | |
| San Juan County | Unclassifiable/Attainment. | |
| State AQCR 10: | ||
| Delta County | Unclassifiable/Attainment. | |
| Gunnison County | Unclassifiable/Attainment. | |
| Hinsdale County | Unclassifiable/Attainment. | |
| Montrose County | Unclassifiable/Attainment. | |
| Ouray County | Unclassifiable/Attainment. | |
| San Miguel County | Unclassifiable/Attainment. | |
| State AQCR 11: | ||
| Garfield County | Unclassifiable/Attainment. | |
| Mesa County | Unclassifiable/Attainment. | |
| Moffat County | Unclassifiable/Attainment. | |
| Rio Blanco County | Unclassifiable/Attainment. | |
| State AQCR 12: | ||
| Eagle County | Unclassifiable/Attainment. | |
| Grand County | Unclassifiable/Attainment. | |
| Jackson County | Unclassifiable/Attainment. | |
| Pitkin County | Unclassifiable/Attainment. | |
| Routt County | Unclassifiable/Attainment. | |
| Summit County | Unclassifiable/Attainment. | |
| State AQCR 13: | ||
| Chaffee County | Unclassifiable/Attainment. | |
| Custer County | Unclassifiable/Attainment. | |
| Fremont County | Unclassifiable/Attainment. | |
| Lake County | Unclassifiable/Attainment. | |
a Includes Indian Country located in each county or area, except as otherwise specified.
1 This date is 90 days after October 31, 2011, unless otherwise noted.
Colorado-1997 8-Hour Ozone NAAQS
[Primary and Secondary]
| Designated area | Designationa | Category/classification | ||
| Date1 | Type | Date1 | Type | |
| Denver-Boulder-Greeley-Ft. Collins-Loveland, CO: | ||||
| Adams County | 2 | Nonattainment | 6/13/12 | Subpart 2/Marginal. |
| Arapahoe County | 2 | Nonattainment | 6/13/12 | Subpart 2/Marginal. |
| Boulder County (includes part of Rocky Mtn. Nat. Park) | 2 | Nonattainment | 6/13/12 | Subpart 2/Marginal. |
| Broomfield County | 2 | Nonattainment | 6/13/12 | Subpart 2/Marginal. |
| Denver County | 2 | Nonattainment | 6/13/12 | Subpart 2/Marginal. |
| Douglas County | 2 | Nonattainment | 6/13/12 | Subpart 2/Marginal. |
| Jefferson County | 2 | Nonattainment | 6/13/12 | Subpart 2/Marginal. |
| Larimer County (part) | 2 | Nonattainment | 6/13/12 | Subpart 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) | 2 | Nonattainment | 6/13/12 | Subpart 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 01 | Unclassifiable/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 11 | Unclassifiable/Attainment | |||
| Garfield County | ||||
| Mesa County | ||||
| Moffat County | ||||
| Rio Blanco County | ||||
| Rest of State | Unclassifiable/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 | ||||
a Includes Indian Country located in each county or area, except as otherwise specified.
1 This date is June 15, 2004, unless otherwise noted.
2 Effective November 20, 2007.
Colorado-2008 8-Hour Ozone NAAQS
[Primary and Secondary]
| Designated area | Designation | Classification | ||
| Date1 | Type | Date1 | Type | |
| Denver-Boulder-Greeley-Ft. Collins-Loveland, CO:2 | Nonattainment | 11/7/22 | Severe. | |
| 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 Reservation3 | Unclassifiable/Attainment | |||
| Rest of State and Rest of Indian Country | Unclassifiable/Attainment | |||
1 This date is July 20, 2012, unless otherwise noted.
2 Excludes Indian country located in each area, unless otherwise noted.
3 Includes 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 area1 | Designation | Classification | ||
| Date2 | Type | Date2 | Type | |
| Denver Metro/North Front Range, CO | Nonattainment | 7/24/24 | Serious. | |
| 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 | 12/30/21 | |||
| Alamosa County | 1/16/18 | Attainment/Unclassifiable | ||
| Archuleta County | 1/16/18 | Attainment/Unclassifiable | ||
| Baca County | 1/16/18 | Attainment/Unclassifiable | ||
| Bent County | 1/16/18 | Attainment/Unclassifiable | ||
| Chaffee County | 1/16/18 | Attainment/Unclassifiable | ||
| Cheyenne County | 1/16/18 | Attainment/Unclassifiable | ||
| Clear Creek County | Attainment/Unclassifiable | |||
| Conejos County | 1/16/18 | Attainment/Unclassifiable | ||
| Costilla County | 1/16/18 | Attainment/Unclassifiable | ||
| Crowley County | 1/16/18 | Attainment/Unclassifiable | ||
| Custer County | 1/16/18 | Attainment/Unclassifiable | ||
| Delta County | 1/16/18 | Attainment/Unclassifiable | ||
| Dolores County | 1/16/18 | Attainment/Unclassifiable | ||
| Eagle County | 1/16/18 | Attainment/Unclassifiable | ||
| Elbert County | Attainment/Unclassifiable | |||
| El Paso County | Attainment/Unclassifiable | |||
| Fremont County | 1/16/18 | Attainment/Unclassifiable | ||
| Garfield County | Attainment/Unclassifiable | |||
| Gilpin County | Attainment/Unclassifiable | |||
| Grand County | Attainment/Unclassifiable | |||
| Gunnison County | 1/16/18 | Attainment/Unclassifiable | ||
| Hinsdale County | 1/16/18 | Attainment/Unclassifiable | ||
| Huerfano County | 1/16/18 | Attainment/Unclassifiable | ||
| Jackson County | Attainment/Unclassifiable | |||
| Kiowa County | 1/16/18 | Attainment/Unclassifiable | ||
| Kit Carson County | 1/16/18 | Attainment/Unclassifiable | ||
| Lake County | 1/16/18 | Attainment/Unclassifiable | ||
| La Plata County | 1/16/18 | Attainment/Unclassifiable | ||
| Larimer County (part remainder) | Attainment/Unclassifiable | |||
| Las Animas County | 1/16/18 | Attainment/Unclassifiable | ||
| Lincoln County | 1/16/18 | Attainment/Unclassifiable | ||
| Logan County | 1/16/18 | Attainment/Unclassifiable | ||
| Mesa County | 1/16/18 | Attainment/Unclassifiable | ||
| Mineral County | 1/16/18 | Attainment/Unclassifiable | ||
| Moffat County | Attainment/Unclassifiable | |||
| Montezuma County | 1/16/18 | Attainment/Unclassifiable | ||
| Montrose County | 1/16/18 | Attainment/Unclassifiable | ||
| Morgan County | 1/16/18 | Attainment/Unclassifiable | ||
| Otero County | 1/16/18 | Attainment/Unclassifiable | ||
| Ouray County | 1/16/18 | Attainment/Unclassifiable | ||
| Park County | Attainment/Unclassifiable | |||
| Phillips County | 1/16/18 | Attainment/Unclassifiable | ||
| Pitkin County | 1/16/18 | Attainment/Unclassifiable | ||
| Prowers County | 1/16/18 | Attainment/Unclassifiable | ||
| Pueblo County | 1/16/18 | Attainment/Unclassifiable | ||
| Rio Blanco County | Attainment/Unclassifiable | |||
| Rio Grande County | 1/16/18 | Attainment/Unclassifiable | ||
| Routt County | 1/16/18 | Attainment/Unclassifiable | ||
| Saguache County | 1/16/18 | Attainment/Unclassifiable | ||
| San Juan County | 1/16/18 | Attainment/Unclassifiable | ||
| San Miguel County | 1/16/18 | Attainment/Unclassifiable | ||
| Sedgwick County | 1/16/18 | Attainment/Unclassifiable | ||
| Summit County | 1/16/18 | Attainment/Unclassifiable | ||
| Teller County | Attainment/Unclassifiable | |||
| Washington County | 1/16/18 | Attainment/Unclassifiable | ||
| Yuma County | 1/16/18 | Attainment/Unclassifiable | ||
1 Includes 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.
2 This date is August 3, 2018, unless otherwise noted.
Colorado-2008 Lead NAAQS
| Designated area | Designation for the 2008 NAAQSa | |
| Date1 | Type | |
| Whole State | Unclassifiable/Attainment. | |
a Includes Indian Country located in each county or area, except as otherwise specified.
1 December 31, 2011 unless otherwise noted.
40 C.F.R. §81.306
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.