{"data":{"id":"us/40-cfr-81.306","jurisdiction":"us","citation":"40 CFR 81.306","heading":"Colorado.","body":"Colorado—1971 Sulfur Dioxide NAAQS\n[Primary and Secondary]\nDesignated Area Does not meet primary standards Does not meet secondary standards Cannot be classified Better than national standards\nEntire State X\nColorado—2010 Sulfur Dioxide NAAQS\n[Primary]\nDesignated area 1 Designation\nDate 3 Type\nColorado Springs, CO 9/12/2016 Unclassifiable.\nEl Paso County (part)\nManitou Springs\nColorado 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).\nEastern Morgan County, CO 9/12/2016 Unclassifiable.\nMorgan County (part)\nCircle with a 12-kilometer radius centered on the Pawnee Power Plant\nState AQCR 01 (remainder) Attainment/Unclassifiable.\nLogan County\nMorgan County (part) (remainder)\nPhillips County\nSedgwick County\nWashington County\nYuma County\nState AQCR 02 Attainment/Unclassifiable.\nLarimer County\nWeld County\nState AQCR 03 Attainment/Unclassifiable.\nAdams County\nArapahoe County\nBoulder County\nBroomfield County\nClear Creek County\nDenver County\nDouglas County\nGilpin County\nJefferson County\nState AQCR 04 (remainder) Attainment/Unclassifiable.\nEl Paso County (part) (remainder)\nPark County\nTeller County\nState AQCR 05 Attainment/Unclassifiable.\nCheyenne County\nElbert County\nKit Carson County\nLincoln County\nState AQCR 06 Attainment/Unclassifiable.\nBaca County\nBent County\nCrowley County\nKiowa County\nOtero County\nProwers County\nState AQCR 07 Attainment/Unclassifiable.\nHuerfano\nLas Animas\nPueblo\nState AQCR 08 Attainment/Unclassifiable.\nAlamosa County\nConejos County\nCostilla County\nMineral County\nRio Grande County\nSaguache County\nState AQCR 09 Attainment/Unclassifiable.\nArchuleta County 2\nDolores\nLa Plata 2\nMontezuma 2\nSan Juan\nState AQCR 10 Attainment/Unclassifiable.\nDelta County\nGunnison County\nHinsdale County\nMontrose County\nOuray County\nSan Miguel County\nState AQCR 11 Attainment/Unclassifiable.\nGarfield County\nMesa County\nMoffat County\nRio Blanco County\nState AQCR 12 Attainment/Unclassifiable.\nEagle County\nGrand County\nJackson County\nPitkin County\nRoutt County\nSummit County\nState AQCR 13 Attainment/Unclassifiable.\nChaffee County\nCuster County\nFremont County\nLake County\nSouthern Ute Indian Reservation Attainment/Unclassifiable.\n1 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.\n2 Does not include the Southern Ute Indian Reservation, which is being designated separately.\n3 This date is April 9, 2018, unless otherwise noted.\nColorado—Carbon Monoxide\nDesignated Area Designation Classification\nDate 1 Type Date 1 Type\nColorado Springs Area: October 25, 1999 Attainment\nUrban Transportation Planing Study Area as defined in 1989.\nBeginning 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:\neast 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;\nsouth on SH-115 to Rock Creek;\nnorthwest 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;\nnorth 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.\nEl Paso County (part)\nTeller County (part)\nDenver-Boulder Area:\nThe 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\nAdams County (part)\nArapahoe County (part)\nBoulder County (part)\nDenver County\nDouglas County (part)\nJefferson County (part)\nFort Collins Area:\nLarimer County (part) Sept. 22, 2003 Attainment\nFort 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.\nGreeley Area: Attainment\nWeld County (part) May 10, 1999\nUrban boundaries as defined in the North Front Range Regional Transportation Plan, May, 1990.\nLongmont Area Nov. 23, 1999 Attainment\nHwy 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.\nBoulder County (part):\nWeld County (part):\nState AQCR 1 Unclassifiable/Attainment\nLogan County\nMorgan County\nPhillips County\nSedgwick County\nWashington County\nYuma County\nState AQCR 2 (Remainder of)\nLarimer County (part) Unclassifiable/Attainment\nArea outside Fort Collins Urban Growth Area Boundary\nWeld County (part)\nRemainder of county Unclassifiable/Attainment\nState AQCR 3 (Remainder of) Unclassifiable/Attainment\nAdams County (part)\nRemainder of County\nArapahoe County (part)\nRemainder of County\nBoulder County (part)\nRemainder of County\nClear Creek County\nDouglas County (part)\nRemainder of County\nGilpin County\nJefferson County (part)\nRemainder of County\nState AQCR 4 (Remainder of) Unclassifiable/Attainment\nEl Paso County (part)\nArea other than Urban Transportation Planning Study Area as defined in 1989\nPark County\nTeller County (part)\nRemainder of County\nState AQCR's 5-13 Unclassifiable/Attainment\nAlamosa County\nArchuleta County\nBaca County\nBent County\nChaffee County\nCheyenne County\nConejos County\nCostilla County\nCrowley County\nCuster County\nDelta County\nDolores County\nEagle County\nElbert County\nFremont County\nGarfield County\nGrand County\nGunnison County\nHinsdale County\nHuerfano County\nJackson County\nKiowa County\nKit Carson County\nLa Plata County\nLake County\nLas Animas County\nLincoln County\nMesa County\nMineral County\nMoffat County\nMontezuma County\nMontrose County\nOtero County\nOuray County\nPitkin County\nProwers County\nPueblo County\nRio Blanco County\nRio Grande County\nRoutt County\nSaguache County\nSan Juan County\nSan Miguel County\nSummit County\n1 This date is November 15, 1990, unless otherwise noted.\nColorado—Ozone (1-Hour Standard)4\nDesignated area Designation Classification\nDate 1 Type Date 1 Type\nDenver-Boulder Area:\nAdams County (part)\nWest of Kiowa Creek 10/11/2001 Attainment\nArapahoe County (part)\nWest of Kiowa Creek Attainment\nBoulder County (part) excluding Rocky Mountain National Park Attainment\nDenver County Attainment\nDouglas County Attainment\nJefferson County Attainment\nState AQCR 01 Unclassifiable/Attainment\nLogan County\nMorgan County\nPhillips County\nSedgwick County\nWashington County\nYuma County\nState AQCR 02 Unclassifiable/Attainment\nLarimer County\nWeld County\nState AQCR 03 (Remainder of) Unclassifiable/Attainment\nAdams County (part) East of Kiowa Creek\nArapahoe County (part) East of Kiowa Creek\nBoulder County (part) Rocky Mtn. National Park Only\nClear Creek County\nGilpin County\nState AQCR 11 Unclassifiable/Attainment\nGarfield County\nMesa County\nMoffat County\nRio Blanco County\nRest of State Unclassifiable/Attainment\nAlamosa County\nArchuleta County\nBaca County\nBent County\nChaffee County\nCheyenne County\nConejos County\nCostilla County\nCrowley County\nCuster County\nDelta County\nDolores County\nEagle County\nEl Paso County\nElbert County\nFremont County\nGrand County\nGunnison County\nHinsdale County\nHuerfano County\nJackson County\nKiowa County\nKit Carson County\nLa Plata County\nLake County\nLas Animas County\nLincoln County\nMineral County\nMontezuma County\nMontrose County\nOtero County\nOuray County\nPark County\nPitkin County\nProwers County\nPueblo County\nRio Grande County\nRoutt County\nSaguache County\nSan Juan County\nSan Miguel County\nSummit County\nTeller County\n1 This date is October 18, 2000, unless otherwise noted.\n2 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.\n3 This date is January 16, 2001.\n4 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.\nColorado—PM-10\nDesignated area Designation Classification\nDate Type Date Type\nArchuleta County\nPagosa Springs Area 8/14/2001 Attainment\nTownship 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.\nTownship 35N-Range 1W: Section 18 W 1⁄2\nAdams, Denver, and Boulder Counties\nDenver Metropolitan area 10/16/2002 Attainment\nAll 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\nSan Miguel County\nTelluride 8/14/2001 Attainment\nThe 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.\nProwers County\nLamar 12/27/2005 Attainment\nPitkin County:\nAspen/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.\nFremont County\nCanon City Area 7/31/2000 Attainment\nTownship 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.\nRoutt County (part):\nSteamboat Springs 11/24/2004 Attainment.\nOn the East—The Routt National Forest.\nOn 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.\nOn 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.\nOn the North—The northern boundary of sections 16, 17, 18, T7N, R84W of 6th P.M.\nAQCR 1 11/15/1990 Unclassifiable\nAQCR 2 11/15/1990 Unclassifiable\nAQCR 3 (excluding the Denver Metropolitan PM-10 nonattainment area) 11/15/1990 Unclassifiable\nAQCR 4 11/15/1990 Unclassifiable\nAQCR 5 11/15/1990 Unclassifiable\nAQCR 6 (excluding the Lamar PM-10 nonattainment area) 11/15/1990 Unclassifiable\nAQCR 7 11/15/1990 Unclassifiable\nAQCR 8 11/15/1990 Unclassifiable\nAQCR 9 (excluding the Pagosa Springs PM-10 nonattainment area) 11/15/1990 Unclassifiable\nAQCR 10 (excluding the Telluride PM-10 nonattainment area) 11/15/1990 Unclassifiable\nAQCR 11 11/15/1990 Unclassifiable\nAQCR 12 (excluding the Aspen/Pitkin County and Steamboat Springs Area Airshed PM-10 nonattainment areas) 11/15/1990 Unclassifiable\nAQCR 13 (excluding the Canon City PM-10 nonattainment area) 1/15/1990 Unclassifiable\nColorado—1997 Annual PM2.5 NAAQS\n[Primary and Secondary]\nDesignated area Designation a Classification\nDate 1 Type Date Type\nDenver-Boulder Area:\nAdams County (part) West of Kiowa Creek Unclassifiable/Attainment\nArapahoe County (part) West of Kiowa Creek Unclassifiable/Attainment\nBoulder County (part) Excluding Rocky Mountain National Park Unclassifiable/Attainment\nBroomfield County Unclassifiable/Attainment\nDenver County Unclassifiable/Attainment\nDouglas County Unclassifiable/Attainment\nJefferson County Unclassifiable/Attainment\nState AQCR 01:\nLogan County Unclassifiable/Attainment\nMorgan County Unclassifiable/Attainment\nPhillips County Unclassifiable/Attainment\nSedgwick County Unclassifiable/Attainment\nWashington County Unclassifiable/Attainment\nYuma County Unclassifiable/Attainment\nState AQCR 02:\nLarimer County Unclassifiable/Attainment\nWeld County Unclassifiable/Attainment\nState AQCR 03 (remainder of):\nAdams County (remainder) Unclassifiable/Attainment\nArapahoe County (remainder) Unclassifiable/Attainment\nBoulder County (remainder) Unclassifiable/Attainment\nClear Creek County Unclassifiable/Attainment\nGilpin County Unclassifiable/Attainment\nState AQCR 04:\nEl Paso County Unclassifiable/Attainment\nPark County Unclassifiable/Attainment\nTeller County Unclassifiable/Attainment\nState AQCR 05:\nCheyenne County Unclassifiable/Attainment\nElbert County Unclassifiable/Attainment\nKit Carson County Unclassifiable/Attainment\nLincoln County Unclassifiable/Attainment\nState AQCR 06:\nBaca County Unclassifiable/Attainment\nBent County Unclassifiable/Attainment\nCrowley County Unclassifiable/Attainment\nKiowa County Unclassifiable/Attainment\nOtero County Unclassifiable/Attainment\nProwers County Unclassifiable/Attainment\nState AQCR 07:\nHuerfano County Unclassifiable/Attainment\nLas Animas County Unclassifiable/Attainment\nPueblo County Unclassifiable/Attainment\nState AQCR 08:\nAlamosa County Unclassifiable/Attainment\nConejos County Unclassifiable/Attainment\nCostilla County Unclassifiable/Attainment\nMineral County Unclassifiable/Attainment\nRio Grande County Unclassifiable/Attainment\nSaguache County Unclassifiable/Attainment\nState AQCR 09:\nArchuleta County Unclassifiable/Attainment\nDolores County Unclassifiable/Attainment\nLa Plata County Unclassifiable/Attainment\nMontezuma County Unclassifiable/Attainment\nSan Juan County Unclassifiable/Attainment\nState AQCR 10:\nDelta County Unclassifiable/Attainment\nGunnison County Unclassifiable/Attainment\nHinsdale County Unclassifiable/Attainment\nMontrose County Unclassifiable/Attainment\nOuray County Unclassifiable/Attainment\nSan Miguel County Unclassifiable/Attainment\nState AQCR 11:\nGarfield County Unclassifiable/Attainment\nMesa County Unclassifiable/Attainment\nMoffat County Unclassifiable/Attainment\nRio Blanco County Unclassifiable/Attainment\nState AQCR 12:\nEagle County Unclassifiable/Attainment\nGrand County Unclassifiable/Attainment\nJackson County Unclassifiable/Attainment\nPitkin County Unclassifiable/Attainment\nRoutt County Unclassifiable/Attainment\nSummit County Unclassifiable/Attainment\nState AQCR 13:\nChaffee County Unclassifiable/Attainment\nCuster County Unclassifiable/Attainment\nFremont County Unclassifiable/Attainment\nLake County Unclassifiable/Attainment\na Includes Indian Country located in each county or area, except as otherwise specified.\n1 This date is 90 days after January 5, 2005, unless otherwise noted.\nColorado—2012 Annual PM2.5 NAAQS\n[Primary]\nDesignated area 1 Designation Classification\nDate 2 Type Date 2 Type\nState AQCR 01:\nLogan County Unclassifiable/Attainment\nMorgan County Unclassifiable/Attainment\nPhillips County Unclassifiable/Attainment\nSedgwick County Unclassifiable/Attainment\nWashington County Unclassifiable/Attainment\nYuma County Unclassifiable/Attainment\nState AQCR 02:\nLarimer County Unclassifiable/Attainment\nWeld County Unclassifiable/Attainment\nState AQCR 03:\nAdams County Unclassifiable/Attainment\nArapahoe County Unclassifiable/Attainment\nBoulder County Unclassifiable/Attainment\nBroomfield County Unclassifiable/Attainment\nClear Creek County Unclassifiable/Attainment\nDenver County Unclassifiable/Attainment\nDouglas County Unclassifiable/Attainment\nGilpin County Unclassifiable/Attainment\nJefferson County Unclassifiable/Attainment\nState AQCR 04:\nEl Paso County Unclassifiable/Attainment\nPark County Unclassifiable/Attainment\nTeller County Unclassifiable/Attainment\nState AQCR 05:\nCheyenne County Unclassifiable/Attainment\nElbert County Unclassifiable/Attainment\nKit Carson County Unclassifiable/Attainment\nLincoln County Unclassifiable/Attainment\nState AQCR 06:\nBaca County Unclassifiable/Attainment\nBent County Unclassifiable/Attainment\nCrowley County Unclassifiable/Attainment\nKiowa County Unclassifiable/Attainment\nOtero County Unclassifiable/Attainment\nProwers County Unclassifiable/Attainment\nState AQCR 07:\nHuerfano County Unclassifiable/Attainment\nLas Animas County Unclassifiable/Attainment\nPueblo County Unclassifiable/Attainment\nState AQCR 08:\nAlamosa County Unclassifiable/Attainment\nConejos County Unclassifiable/Attainment\nCostilla County Unclassifiable/Attainment\nMineral County Unclassifiable/Attainment\nRio Grande County Unclassifiable/Attainment\nSaguache County Unclassifiable/Attainment\nState AQCR 09:\nArchuleta County Unclassifiable/Attainment\nDolores County Unclassifiable/Attainment\nLa Plata County Unclassifiable/Attainment\nMontezuma County Unclassifiable/Attainment\nSan Juan County Unclassifiable/Attainment\nState AQCR 10:\nDelta County Unclassifiable/Attainment\nGunnison County Unclassifiable/Attainment\nHinsdale County Unclassifiable/Attainment\nMontrose County Unclassifiable/Attainment\nOuray County Unclassifiable/Attainment\nSan Miguel County Unclassifiable/Attainment\nState AQCR 11:\nGarfield County Unclassifiable/Attainment\nMesa County Unclassifiable/Attainment\nMoffat County Unclassifiable/Attainment\nRio Blanco County Unclassifiable/Attainment\nState AQCR 12:\nEagle County Unclassifiable/Attainment\nGrand County Unclassifiable/Attainment\nJackson County Unclassifiable/Attainment\nPitkin County Unclassifiable/Attainment\nRoutt County Unclassifiable/Attainment\nSummit County Unclassifiable/Attainment\nState AQCR 13:\nChaffee County Unclassifiable/Attainment\nCuster County Unclassifiable/Attainment\nFremont County Unclassifiable/Attainment\nLake County Unclassifiable/Attainment\n1 Includes areas of Indian country located in each county or area, except as otherwise specified.\n2 This date is April 15, 2015, unless otherwise noted.\nColorado—1997 24-Hour PM2.5 NAAQS\n[Primary and Secondary]\nDesignated area Designation a Classification\nDate 1 Type Date Type\nDenver-Boulder Area:\nAdams County (part) West of Kiowa Creek Unclassifiable/Attainment\nArapahoe County (part) West of Kiowa Creek Unclassifiable/Attainment\nBoulder County (part) Excluding Rocky Mountain National Park Unclassifiable/Attainment\nBroomfield County Unclassifiable/Attainment\nDenver County Unclassifiable/Attainment\nDouglas County Unclassifiable/Attainment\nJefferson County Unclassifiable/Attainment\nState AQCR 01:\nLogan County Unclassifiable/Attainment\nMorgan County Unclassifiable/Attainment\nPhillips County Unclassifiable/Attainment\nSedgwick County Unclassifiable/Attainment\nWashington County Unclassifiable/Attainment\nYuma County Unclassifiable/Attainment\nState AQCR 02:\nLarimer County Unclassifiable/Attainment\nWeld County Unclassifiable/Attainment\nState AQCR 03 (remainder of):\nAdams County (remainder) Unclassifiable/Attainment\nArapahoe County (remainder) Unclassifiable/Attainment\nBoulder County (remainder) Unclassifiable/Attainment\nClear Creek County Unclassifiable/Attainment\nGilpin County Unclassifiable/Attainment\nState AQCR 04:\nEl Paso County Unclassifiable/Attainment\nPark County Unclassifiable/Attainment\nTeller County Unclassifiable/Attainment\nState AQCR 05:\nCheyenne County Unclassifiable/Attainment\nElbert County Unclassifiable/Attainment\nKit Carson County Unclassifiable/Attainment\nLincoln County Unclassifiable/Attainment\nState AQCR 06:\nBaca County Unclassifiable/Attainment\nBent County Unclassifiable/Attainment\nCrowley County Unclassifiable/Attainment\nKiowa County Unclassifiable/Attainment\nOtero County Unclassifiable/Attainment\nProwers County Unclassifiable/Attainment\nState AQCR 07:\nHuerfano County Unclassifiable/Attainment\nLas Animas County Unclassifiable/Attainment\nPueblo County Unclassifiable/Attainment\nState AQCR 08:\nAlamosa County Unclassifiable/Attainment\nConejos County Unclassifiable/Attainment\nCostilla County Unclassifiable/Attainment\nMineral County Unclassifiable/Attainment\nRio Grande County Unclassifiable/Attainment\nSaguache County Unclassifiable/Attainment\nState AQCR 09:\nArchuleta County Unclassifiable/Attainment\nDolores County Unclassifiable/Attainment\nLa Plata County Unclassifiable/Attainment\nMontezuma County Unclassifiable/Attainment\nSan Juan County Unclassifiable/Attainment\nState AQCR 10:\nDelta County Unclassifiable/Attainment\nGunnison County Unclassifiable/Attainment\nHinsdale County Unclassifiable/Attainment\nMontrose County Unclassifiable/Attainment\nOuray County Unclassifiable/Attainment\nSan Miguel County Unclassifiable/Attainment\nState AQCR 11:\nGarfield County Unclassifiable/Attainment\nMesa County Unclassifiable/Attainment\nMoffat County Unclassifiable/Attainment\nRio Blanco County Unclassifiable/Attainment\nState AQCR 12:\nEagle County Unclassifiable/Attainment\nGrand County Unclassifiable/Attainment\nJackson County Unclassifiable/Attainment\nPitkin County Unclassifiable/Attainment\nRoutt County Unclassifiable/Attainment\nSummit County Unclassifiable/Attainment\nState AQCR 13:\nChaffee County Unclassifiable/Attainment\nCuster County Unclassifiable/Attainment\nFremont County Unclassifiable/Attainment\nLake County Unclassifiable/Attainment\na Includes Indian Country located in each county or area, except as otherwise specified.\n1 This date is 90 days after January 5, 2005, unless otherwise noted.\nColorado—2006 24-Hour PM2.5 NAAQS\n[Primary and Secondary]\nDesignated area Designation a Classification\nDate 1 Type Date Type\nDenver-Boulder Area:\nAdams County (part) West of Kiowa Creek Unclassifiable/Attainment.\nArapahoe County (part) West of Kiowa Creek Unclassifiable/Attainment.\nBoulder County (part) Excluding Rocky Mountain National Park Unclassifiable/Attainment.\nBroomfield County Unclassifiable/Attainment.\nDenver County Unclassifiable/Attainment.\nDouglas County Unclassifiable/Attainment.\nJefferson County Unclassifiable/Attainment.\nState AQCR 01:\nLogan County Unclassifiable/Attainment.\nMorgan County Unclassifiable/Attainment.\nPhillips County Unclassifiable/Attainment.\nSedgwick County Unclassifiable/Attainment.\nWashington County Unclassifiable/Attainment.\nYuma County Unclassifiable/Attainment.\nState AQCR 02:\nLarimer County Unclassifiable/Attainment.\nWeld County Unclassifiable/Attainment.\nState AQCR 03 (remainder of):\nAdams County (remainder) Unclassifiable/Attainment.\nArapahoe County (remainder) Unclassifiable/Attainment.\nBoulder County (remainder) Unclassifiable/Attainment.\nClear Creek County Unclassifiable/Attainment.\nGilpin County Unclassifiable/Attainment.\nState AQCR 04:\nEl Paso County Unclassifiable/Attainment.\nPark County Unclassifiable/Attainment.\nTeller County Unclassifiable/Attainment.\nState AQCR 05:\nCheyenne County Unclassifiable/Attainment.\nElbert County Unclassifiable/Attainment.\nKit Carson County Unclassifiable/Attainment.\nLincoln County Unclassifiable/Attainment.\nState AQCR 06:\nBaca County Unclassifiable/Attainment.\nBent County Unclassifiable/Attainment.\nCrowley County Unclassifiable/Attainment.\nKiowa County Unclassifiable/Attainment.\nOtero County Unclassifiable/Attainment.\nProwers County Unclassifiable/Attainment.\nState AQCR 07:\nHuerfano County Unclassifiable/Attainment.\nLas Animas County Unclassifiable/Attainment.\nPueblo County Unclassifiable/Attainment.\nState AQCR 08:\nAlamosa County Unclassifiable/Attainment.\nConejos County Unclassifiable/Attainment.\nCostilla County Unclassifiable/Attainment.\nMineral County Unclassifiable/Attainment.\nRio Grande County Unclassifiable/Attainment.\nSaguache County Unclassifiable/Attainment.\nState AQCR 09:\nArchuleta County Unclassifiable/Attainment.\nDolores County Unclassifiable/Attainment.\nLa Plata County Unclassifiable/Attainment.\nMontezuma County Unclassifiable/Attainment.\nSan Juan County Unclassifiable/Attainment.\nState AQCR 10:\nDelta County Unclassifiable/Attainment.\nGunnison County Unclassifiable/Attainment.\nHinsdale County Unclassifiable/Attainment.\nMontrose County Unclassifiable/Attainment.\nOuray County Unclassifiable/Attainment.\nSan Miguel County Unclassifiable/Attainment.\nState AQCR 11:\nGarfield County Unclassifiable/Attainment.\nMesa County Unclassifiable/Attainment.\nMoffat County Unclassifiable/Attainment.\nRio Blanco County Unclassifiable/Attainment.\nState AQCR 12:\nEagle County Unclassifiable/Attainment.\nGrand County Unclassifiable/Attainment.\nJackson County Unclassifiable/Attainment.\nPitkin County Unclassifiable/Attainment.\nRoutt County Unclassifiable/Attainment.\nSummit County Unclassifiable/Attainment.\nState AQCR 13:\nChaffee County Unclassifiable/Attainment.\nCuster County Unclassifiable/Attainment.\nFremont County Unclassifiable/Attainment.\nLake County Unclassifiable/Attainment.\na Includes Indian Country located in each county or area, except as otherwise specified.\n1 This date is 30 days after November 13, 2009, unless otherwise noted.\nColorado—NO2 (1971 Annual Standard)\nDesignated area Better than national standards\nEntire State X\nColorado—NO2 (2010 1-Hour Standard)\nDesignated area Designation a\nDate 1 Type\nState AQCR 01:\nLogan County Unclassifiable/Attainment.\nMorgan County Unclassifiable/Attainment.\nPhillips County Unclassifiable/Attainment.\nSedgwick County Unclassifiable/Attainment.\nWashington County Unclassifiable/Attainment.\nYuma County Unclassifiable/Attainment.\nState AQCR 02:\nLarimer County Unclassifiable/Attainment.\nWeld County Unclassifiable/Attainment.\nState AQCR 03:\nAdams County Unclassifiable/Attainment.\nArapahoe County Unclassifiable/Attainment.\nBoulder County Unclassifiable/Attainment.\nBroomfield County Unclassifiable/Attainment.\nClear Creek County Unclassifiable/Attainment.\nDenver County Unclassifiable/Attainment.\nDouglas County Unclassifiable/Attainment.\nJefferson County Unclassifiable/Attainment.\nGilpin County Unclassifiable/Attainment.\nState AQCR 04:\nEl Paso County Unclassifiable/Attainment.\nPark County Unclassifiable/Attainment.\nTeller County Unclassifiable/Attainment.\nState AQCR 05:\nCheyenne County Unclassifiable/Attainment.\nElbert County Unclassifiable/Attainment.\nKit Carson County Unclassifiable/Attainment.\nLincoln County Unclassifiable/Attainment.\nState AQCR 06:\nBaca County Unclassifiable/Attainment.\nBent County Unclassifiable/Attainment.\nCrowley County Unclassifiable/Attainment.\nKiowa County Unclassifiable/Attainment.\nOtero County Unclassifiable/Attainment.\nProwers County Unclassifiable/Attainment.\nState AQCR 07:\nHuerfano County Unclassifiable/Attainment.\nLas Animas County Unclassifiable/Attainment.\nPueblo County Unclassifiable/Attainment.\nState AQCR 08:\nAlamosa County Unclassifiable/Attainment.\nConejos County Unclassifiable/Attainment.\nCostilla County Unclassifiable/Attainment.\nMineral County Unclassifiable/Attainment.\nRio Grande County Unclassifiable/Attainment.\nSaguache County Unclassifiable/Attainment.\nState AQCR 09:\nArchuleta County Unclassifiable/Attainment.\nDolores County Unclassifiable/Attainment.\nLa Plata County Unclassifiable/Attainment.\nMontezuma County Unclassifiable/Attainment.\nSan Juan County Unclassifiable/Attainment.\nState AQCR 10:\nDelta County Unclassifiable/Attainment.\nGunnison County Unclassifiable/Attainment.\nHinsdale County Unclassifiable/Attainment.\nMontrose County Unclassifiable/Attainment.\nOuray County Unclassifiable/Attainment.\nSan Miguel County Unclassifiable/Attainment.\nState AQCR 11:\nGarfield County Unclassifiable/Attainment.\nMesa County Unclassifiable/Attainment.\nMoffat County Unclassifiable/Attainment.\nRio Blanco County Unclassifiable/Attainment.\nState AQCR 12:\nEagle County Unclassifiable/Attainment.\nGrand County Unclassifiable/Attainment.\nJackson County Unclassifiable/Attainment.\nPitkin County Unclassifiable/Attainment.\nRoutt County Unclassifiable/Attainment.\nSummit County Unclassifiable/Attainment.\nState AQCR 13:\nChaffee County Unclassifiable/Attainment.\nCuster County Unclassifiable/Attainment.\nFremont County Unclassifiable/Attainment.\nLake County Unclassifiable/Attainment.\na Includes Indian Country located in each county or area, except as otherwise specified.\n1 This date is 90 days after October 31, 2011, unless otherwise noted.\nColorado—1997 8-Hour Ozone NAAQS\n[Primary and Secondary]\nDesignated area Designation a Category/classification\nDate 1 Type Date 1 Type\nDenver-Boulder-Greeley-Ft. Collins-Loveland, CO:\nAdams County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.\nArapahoe County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.\nBoulder County (includes part of Rocky Mtn. Nat. Park) 2 Nonattainment 6/13/2012 Subpart 2/Marginal.\nBroomfield County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.\nDenver County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.\nDouglas County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.\nJefferson County 2 Nonattainment 6/13/2012 Subpart 2/Marginal.\nLarimer County (part) 2 Nonattainment 6/13/2012 Subpart 2/Marginal.\n(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.\nWeld County (part) 2 Nonattainment 6/13/2012 Subpart 2/Marginal.\nThat 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.\nState AQCR 01 Unclassifiable/Attainment\nLogan County\nPhillips County\nSedgwick County\nWashington County\nYuma County\nState AQCR 03 (remainder of) Unclassifiable/Attainment\nClear Creek County\nGilpin County\nState AQCR 11 Unclassifiable/Attainment\nGarfield County\nMesa County\nMoffat County\nRio Blanco County\nRest of State Unclassifiable/Attainment\nAlamosa County\nArchuleta County\nBaca County\nBent County\nChaffee County\nCheyenne County\nConejos County\nCostilla County\nCrowley County\nCuster County\nDelta County\nDolores County\nEagle County\nEl Paso County\nElbert County\nFremont County\nGrand County (includes portion of W. Rocky Mtn. Nat. Park)\nGunnison County\nHinsdale County\nHuerfano County\nJackson County\nKiowa County\nKit Carson County\nLa Plata County\nLake County\nLarimer County (part) remainder\nLas Animas County\nLincoln County\nMineral County\nMontezuma County\nMontrose County\nMorgan County\nOtero County\nOuray County\nPark County\nPitkin County\nProwers County\nPueblo County\nRio Grande County\nRoutt County\nSaguache County\nSan Juan County\nSan Miguel County\nSummit County\nTeller County\nWeld County (part) remainder\na Includes Indian Country located in each county or area, except as otherwise specified.\n1 This date is June 15, 2004, unless otherwise noted.\n2 Effective November 20, 2007.\nColorado—2008 8-Hour Ozone NAAQS\n[Primary and Secondary]\nDesignated area Designation Classification\nDate 1 Type Date 1 Type\nDenver-Boulder-Greeley-Ft. Collins-Loveland, CO: 2 Nonattainment 11/7/2022 Severe.\nAdams County\nArapahoe County\nBoulder County\nBroomfield County\nDenver County\nDouglas County\nJefferson County\nLarimer County (part)\nThat 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.\nWeld County (part)\nThat 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.\nSouthern Ute Indian Tribe of the Southern Ute Reservation 3 Unclassifiable/Attainment\nRest of State and Rest of Indian Country Unclassifiable/Attainment\n1 This date is July 20, 2012, unless otherwise noted.\n2 Excludes Indian country located in each area, unless otherwise noted.\n3 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.\nColorado—2015 8-Hour Ozone NAAQS\n[Primary and Secondary]\nDesignated area 1 Designation Classification\nDate 2 Type Date 2 Type\nDenver Metro/North Front Range, CO Nonattainment 7/24/2024 Serious.\nAdams County.\nArapahoe County.\nBoulder County.\nBroomfield County.\nDenver County.\nDouglas County.\nJefferson County.\nLarimer County (part).\nIncluding 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.\nWeld County 12/30/2021\nAlamosa County 1/16/2018 Attainment/Unclassifiable\nArchuleta County 1/16/2018 Attainment/Unclassifiable\nBaca County 1/16/2018 Attainment/Unclassifiable\nBent County 1/16/2018 Attainment/Unclassifiable\nChaffee County 1/16/2018 Attainment/Unclassifiable\nCheyenne County 1/16/2018 Attainment/Unclassifiable\nClear Creek County Attainment/Unclassifiable\nConejos County 1/16/2018 Attainment/Unclassifiable\nCostilla County 1/16/2018 Attainment/Unclassifiable\nCrowley County 1/16/2018 Attainment/Unclassifiable\nCuster County 1/16/2018 Attainment/Unclassifiable\nDelta County 1/16/2018 Attainment/Unclassifiable\nDolores County 1/16/2018 Attainment/Unclassifiable\nEagle County 1/16/2018 Attainment/Unclassifiable\nElbert County Attainment/Unclassifiable\nEl Paso County Attainment/Unclassifiable\nFremont County 1/16/2018 Attainment/Unclassifiable\nGarfield County Attainment/Unclassifiable\nGilpin County Attainment/Unclassifiable\nGrand County Attainment/Unclassifiable\nGunnison County 1/16/2018 Attainment/Unclassifiable\nHinsdale County 1/16/2018 Attainment/Unclassifiable\nHuerfano County 1/16/2018 Attainment/Unclassifiable\nJackson County Attainment/Unclassifiable\nKiowa County 1/16/2018 Attainment/Unclassifiable\nKit Carson County 1/16/2018 Attainment/Unclassifiable\nLake County 1/16/2018 Attainment/Unclassifiable\nLa Plata County 1/16/2018 Attainment/Unclassifiable\nLarimer County (part remainder) Attainment/Unclassifiable\nLas Animas County 1/16/2018 Attainment/Unclassifiable\nLincoln County 1/16/2018 Attainment/Unclassifiable\nLogan County 1/16/2018 Attainment/Unclassifiable\nMesa County 1/16/2018 Attainment/Unclassifiable\nMineral County 1/16/2018 Attainment/Unclassifiable\nMoffat County Attainment/Unclassifiable\nMontezuma County 1/16/2018 Attainment/Unclassifiable\nMontrose County 1/16/2018 Attainment/Unclassifiable\nMorgan County 1/16/2018 Attainment/Unclassifiable\nOtero County 1/16/2018 Attainment/Unclassifiable\nOuray County 1/16/2018 Attainment/Unclassifiable\nPark County Attainment/Unclassifiable\nPhillips County 1/16/2018 Attainment/Unclassifiable\nPitkin County 1/16/2018 Attainment/Unclassifiable\nProwers County 1/16/2018 Attainment/Unclassifiable\nPueblo County 1/16/2018 Attainment/Unclassifiable\nRio Blanco County Attainment/Unclassifiable\nRio Grande County 1/16/2018 Attainment/Unclassifiable\nRoutt County 1/16/2018 Attainment/Unclassifiable\nSaguache County 1/16/2018 Attainment/Unclassifiable\nSan Juan County 1/16/2018 Attainment/Unclassifiable\nSan Miguel County 1/16/2018 Attainment/Unclassifiable\nSedgwick County 1/16/2018 Attainment/Unclassifiable\nSummit County 1/16/2018 Attainment/Unclassifiable\nTeller County Attainment/Unclassifiable\nWashington County 1/16/2018 Attainment/Unclassifiable\nYuma County 1/16/2018 Attainment/Unclassifiable\n1 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.\n2 This date is August 3, 2018, unless otherwise noted.\nColorado—2008 Lead NAAQS\nDesignated area Designation for the 2008 NAAQS a\nDate 1 Type\nWhole State Unclassifiable/Attainment.\na Includes Indian Country located in each county or area, except as otherwise specified.\n1 December 31, 2011 unless otherwise noted.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER C—AIR PROGRAMS","PART 81—DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES","Subpart C—Section 107 Attainment Status Designations"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"6387de1d1bf0daedcd3d6374dedfb9839de2d720605de3a5aa728922f01d0f5e","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-81.305","next":"us/40-cfr-81.307"},"notice":"GroundRules: Original legal text. Not legal advice."}