1. Regulations
  2. title 40
  3. chapter I-i19
  4. part 81
  5. subpart C
  6. § 81.306

View all text of Subpart C [§ 81.300 - § 81.356]

§ 81.306 - Colorado.

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 StateX

Colorado—2010 Sulfur Dioxide NAAQS

[Primary]

Designated area 1Designation Date 3Type 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 County 2Dolores La Plata 2Montezuma 2San 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.

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 Date 1Type Date 1Type 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

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

Colorado—Ozone (1-Hour Standard) 4

Designated area Designation Classification Date 1Type Date 1Type 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

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 Area8/14/01Attainment 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 1/2Adams, 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.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 Lamar12/27/05AttainmentPitkin 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 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 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 area Designation aClassification Date 1Type Date Type 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

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 area 1Designation Classification Date 2Type Date 2Type 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

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 Designation aClassification Date 1Type Date Type 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

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 Designation aClassification Date 1Type Date Type 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.

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 StateX

Colorado—NO2 (2010 1-Hour Standard)

Designated area Designation aDate 1Type 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.

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 Designation aCategory/classification Date 1Type Date 1Type 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

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 Date 1Type Date 1Type Denver-Boulder-Greeley-Ft. Collins-Loveland, CO: 2Nonattainment11/7/22Severe. 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 Reservation 3Unclassifiable/Attainment Rest of State and Rest of Indian CountryUnclassifiable/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 area 1Designation Classification Date 2Type Date 2Type Denver Metro/North Front Range, CONonattainment11/7/22Moderate. 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 County12/30/2021 3Alamosa 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 Yuma County1/16/18Attainment/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 NAAQS aDate 1Type Whole StateUnclassifiable/Attainment.

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

1 December 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.

AUTHORITY: 42 U.S.C. 7401,

SOURCE: 36 FR 22421, Nov. 25, 1971, unless otherwise noted.

CITE AS: 40 CFR 81.306