40 CFR 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 State X

Colorado—2010 Sulfur Dioxide NAAQS

[Primary]

Designated area 1 Designation

Date 3 Type

Colorado Springs, CO 9/12/2016 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 9/12/2016 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 County 2

Dolores

La Plata 2

Montezuma 2

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

Date 1 Type Date 1 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

Date 1 Type Date 1 Type

Denver-Boulder Area:

Adams County (part)

West of Kiowa Creek 10/11/2001 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 8/14/2001 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 10/16/2002 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 8/14/2001 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 12/27/2005 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 7/14/2003 Attainment.

Fremont County

Canon City Area 7/31/2000 Attainment

Township 18S—Range 70W: All of sections 21, 22, 27, 28, 33, and 34; the E1⁄2, NENW, NESW, SENW, SESW quarters of sections 20, 29, 32; and the W1⁄2 of sections 23, 26, and 35; Township 19S—Range 70W: All of sections 3, 4, 9, 10; E1⁄2, NENW, NESW, SENW, SESW quarters of sections 5 and 8; W1⁄2 of sections 2 and 11.

Routt County (part):

Steamboat Springs 11/24/2004 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 11/15/1990 Unclassifiable

AQCR 2 11/15/1990 Unclassifiable

AQCR 3 (excluding the Denver Metropolitan PM-10 nonattainment area) 11/15/1990 Unclassifiable

AQCR 4 11/15/1990 Unclassifiable

AQCR 5 11/15/1990 Unclassifiable

AQCR 6 (excluding the Lamar PM-10 nonattainment area) 11/15/1990 Unclassifiable

AQCR 7 11/15/1990 Unclassifiable

AQCR 8 11/15/1990 Unclassifiable

AQCR 9 (excluding the Pagosa Springs PM-10 nonattainment area) 11/15/1990 Unclassifiable

AQCR 10 (excluding the Telluride PM-10 nonattainment area) 11/15/1990 Unclassifiable

AQCR 11 11/15/1990 Unclassifiable

AQCR 12 (excluding the Aspen/Pitkin County and Steamboat Springs Area Airshed PM-10 nonattainment areas) 11/15/1990 Unclassifiable

AQCR 13 (excluding the Canon City PM-10 nonattainment area) 1/15/1990 Unclassifiable

Colorado—1997 Annual PM2.5 NAAQS

[Primary and Secondary]

Designated area Designation a Classification

Date 1 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 90 days after January 5, 2005, unless otherwise noted.

Colorado—2012 Annual PM2.5 NAAQS

[Primary]

Designated area 1 Designation Classification

Date 2 Type Date 2 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 Designation a Classification

Date 1 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 90 days after January 5, 2005, unless otherwise noted.

Colorado—2006 24-Hour PM2.5 NAAQS

[Primary and Secondary]

Designated area Designation a Classification

Date 1 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 Designation a

Date 1 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 Designation a Category/classification

Date 1 Type Date 1 Type

Denver-Boulder-Greeley-Ft. Collins-Loveland, CO:

Adams County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.

Arapahoe County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.

Boulder County (includes part of Rocky Mtn. Nat. Park) 2 Nonattainment 6/13/2012 Subpart 2/Marginal.

Broomfield County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.

Denver County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.

Douglas County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.

Jefferson County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.

Larimer County (part) 2 Nonattainment 6/13/2012 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 6/13/2012 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

Date 1 Type Date 1 Type

Denver-Boulder-Greeley-Ft. Collins-Loveland, CO: 2 Nonattainment 11/7/2022 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 Reservation 3 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 area 1 Designation Classification

Date 2 Type Date 2 Type

Denver Metro/North Front Range, CO Nonattainment 7/24/2024 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 12/30/2021

Alamosa County 1/16/2018 Attainment/Unclassifiable

Archuleta County 1/16/2018 Attainment/Unclassifiable

Baca County 1/16/2018 Attainment/Unclassifiable

Bent County 1/16/2018 Attainment/Unclassifiable

Chaffee County 1/16/2018 Attainment/Unclassifiable

Cheyenne County 1/16/2018 Attainment/Unclassifiable

Clear Creek County Attainment/Unclassifiable

Conejos County 1/16/2018 Attainment/Unclassifiable

Costilla County 1/16/2018 Attainment/Unclassifiable

Crowley County 1/16/2018 Attainment/Unclassifiable

Custer County 1/16/2018 Attainment/Unclassifiable

Delta County 1/16/2018 Attainment/Unclassifiable

Dolores County 1/16/2018 Attainment/Unclassifiable

Eagle County 1/16/2018 Attainment/Unclassifiable

Elbert County Attainment/Unclassifiable

El Paso County Attainment/Unclassifiable

Fremont County 1/16/2018 Attainment/Unclassifiable

Garfield County Attainment/Unclassifiable

Gilpin County Attainment/Unclassifiable

Grand County Attainment/Unclassifiable

Gunnison County 1/16/2018 Attainment/Unclassifiable

Hinsdale County 1/16/2018 Attainment/Unclassifiable

Huerfano County 1/16/2018 Attainment/Unclassifiable

Jackson County Attainment/Unclassifiable

Kiowa County 1/16/2018 Attainment/Unclassifiable

Kit Carson County 1/16/2018 Attainment/Unclassifiable

Lake County 1/16/2018 Attainment/Unclassifiable

La Plata County 1/16/2018 Attainment/Unclassifiable

Larimer County (part remainder) Attainment/Unclassifiable

Las Animas County 1/16/2018 Attainment/Unclassifiable

Lincoln County 1/16/2018 Attainment/Unclassifiable

Logan County 1/16/2018 Attainment/Unclassifiable

Mesa County 1/16/2018 Attainment/Unclassifiable

Mineral County 1/16/2018 Attainment/Unclassifiable

Moffat County Attainment/Unclassifiable

Montezuma County 1/16/2018 Attainment/Unclassifiable

Montrose County 1/16/2018 Attainment/Unclassifiable

Morgan County 1/16/2018 Attainment/Unclassifiable

Otero County 1/16/2018 Attainment/Unclassifiable

Ouray County 1/16/2018 Attainment/Unclassifiable

Park County Attainment/Unclassifiable

Phillips County 1/16/2018 Attainment/Unclassifiable

Pitkin County 1/16/2018 Attainment/Unclassifiable

Prowers County 1/16/2018 Attainment/Unclassifiable

Pueblo County 1/16/2018 Attainment/Unclassifiable

Rio Blanco County Attainment/Unclassifiable

Rio Grande County 1/16/2018 Attainment/Unclassifiable

Routt County 1/16/2018 Attainment/Unclassifiable

Saguache County 1/16/2018 Attainment/Unclassifiable

San Juan County 1/16/2018 Attainment/Unclassifiable

San Miguel County 1/16/2018 Attainment/Unclassifiable

Sedgwick County 1/16/2018 Attainment/Unclassifiable

Summit County 1/16/2018 Attainment/Unclassifiable

Teller County Attainment/Unclassifiable

Washington County 1/16/2018 Attainment/Unclassifiable

Yuma County 1/16/2018 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 NAAQS a

Date 1 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.