{"data":{"id":"us/40-cfr-81.351","jurisdiction":"us","citation":"40 CFR 81.351","heading":"Wyoming.","body":"Wyoming—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\nWyoming—2010 Sulfur Dioxide NAAQS\n[Primary]\nDesignated area 1 Designation\nDate 2 Type\nAlbany County Attainment/Unclassifiable.\nBig Horn County Attainment/Unclassifiable.\nCampbell County Attainment/Unclassifiable.\nCarbon County 4/30/2021 Attainment/Unclassifiable.\nConverse County 4/30/2021 Attainment/Unclassifiable.\nCrook County Attainment/Unclassifiable.\nFremont County (part) Attainment/Unclassifiable.\nAll areas west of the western border of Township 40North-Range 93West, T39N-R93W, and T38N-R93W, and south of U.S. Route 20.\nFreemont County (remainder) 4/30/2021 Attainment/Unclassifiable.\nGoshen County Attainment/Unclassifiable.\nHot Springs County Attainment/Unclassifiable.\nJohnson County Attainment/Unclassifiable.\nLincoln County Attainment/Unclassifiable.\nNatrona County Attainment/Unclassifiable.\nNiobrara County Attainment/Unclassifiable.\nPark County Attainment/Unclassifiable.\nPlatte County Attainment/Unclassifiable.\nSheridan County Attainment/Unclassifiable.\nSublette County Attainment/Unclassifiable.\nSweetwater County (part) Attainment/Unclassifiable.\nAll areas of the county east of U.S. Route 191.\nSweetwater County (remainder) 4/30/2021 Attainment/Unclassifiable.\nTeton County Attainment/Unclassifiable.\nUinta County Attainment/Unclassifiable.\nWashakie County Attainment/Unclassifiable.\nWeston County 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 April 9, 2018, unless otherwise noted.\nWyoming—Carbon Monoxide\nDesignated Area Designation Classification\nDate 1 Type Date 1 Type\nStatewide Unclassifiable/Attainment\nAlbany County\nBig Horn County\nCampbell County\nCarbon County\nConverse County\nCrook County\nFremont County\nGoshen County\nHot Springs County\nJohnson County\nLaramie County\nLincoln County\nNatrona County\nNiobrara County\nPark County\nPlatte County\nSheridan County\nSublette County\nSweetwater County\nTeton County\nUinta County\nWashakie County\nWeston County\n1 This date is November 15, 1990, unless otherwise noted.\nWyoming—Ozone (1-Hour Standard)2\nDesignated area Designation Classification\nDate 1 Type Date 1 Type\nStatewide Unclassifiable/Attainment\nAlbany County\nBig Horn County\nCampbell County\nCarbon County\nConverse County\nCrook County\nFremont County\nGoshen County\nHot Springs County\nJohnson County\nLaramie County\nLincoln County\nNatrona County\nNiobrara County\nPark County\nPlatte County\nSheridan County\nSublette County\nSweetwater County\nTeton County\nUinta County\nWashakie County\nWeston County\n1 This date is October 18, 2000, unless otherwise noted.\n2 The 1-hour ozone standard is revoked effective June 15, 2005 for all areas in Wyoming.\nWyoming—PM-10\nDesignated Area Designation Classification\nDate Type Date Type\nSheridan County:\nCity of Sheridan 5/4/2018 Attainment\nTrona Industrial Area 11/15/1990 Unclassifiable\nCampbell County (part) 11/15/1990 Unclassifiable\nConverse County (part).\nThat area bounded by Township 40 through 52 North, and Ranges 69 through 73 West, inclusive of the Sixth Principal Meridian, Campbell and Converse Counties, excluding the areas defined as the Pacific Power and Light Area, the Hampshire Energy Area, and the Kennecott/Puron PSD Baseline Area—Powder River Basin.\nCampbell County (part), That areabounded by NW1/4 of Section 27, T50N, R71W, Campbell County, Wyoming—Pacific Power and Light Area 11/15/1990 Unclassifiable\nCampbell County (part), That area bounded by Section 6 excluding the SW1⁄4; E1⁄2 Section 7; Section 17 excluding the SW1⁄4; Section 14 excluding the SE1⁄4; Sections 2, 3, 4, 5, 8, 9, 10, 11, 15, 16 of T48N, R70W and Section 26 excluding the NE1⁄4; SW1⁄4 Section 23; Sections 19, 20, 21, 22, 27, 28, 29, 30, 31, 32, 33, 34, 35 of T49N, R70W.—Hampshire Energy Area 11/15/1990 Unclassifiable\nCampbell County (part), That area described by the W1⁄2SW1⁄4 Section 18, W1⁄2NW1⁄4, NW1⁄4SW1⁄4 Section 19, T47N, R70W, S1⁄2 Section 13, N1⁄2, N1⁄2SW1⁄4, N1⁄2SE1⁄4 Section 24, T47N, R71W.—Kennecott/Puron PSD Baseline Area 11/15/1990 Unclassifiable\nRest of State1 11/15/1990 Unclassifiable\n1 Denotes a single area designation for baseline area purposes.\nWyoming—1997 Annual PM2.5 NAAQS\n[Primary and Secondary]\nDesignated area Designation a Classification\nDate 1 Type Date Type\nCasper, WY:\nNatrona County (part) Unclassifiable/Attainment.\nThe portion within the City of Casper.\nCheyenne, WY:\nLaramie County (part) Unclassifiable/Attainment.\nThe portion within the City of Cheyenne.\nEvanston, WY:\nUinta County (part) Unclassifiable/Attainment.\nThe portion within the City of Evanston.\nGillette, WY:\nCampbell County (part) Unclassifiable/Attainment.\nThe portion within the City of Gillette.\nJackson, WY:\nTeton County (part) Unclassifiable/Attainment.\nThe portion within the City of Jackson.\nLander, WY:\nFremont County (part) Unclassifiable/Attainment.\nThe portion within the City of Lander.\nLaramie, WY:\nAlbany County (part) Unclassifiable/Attainment.\nThe portion within the City of Laramie.\nRiverton, WY:\nFremont County (part) Unclassifiable/Attainment.\nThe portion within the City of Riverton.\nRock Springs, WY:\nSweetwater County (part) Unclassifiable/Attainment.\nThe portion within the City of Rock Springs.\nSheridan, WY:\nSheridan County (part) Unclassifiable/Attainment.\nThe portion within the City of Sheridan.\nRest of State:\nAlbany County (remainder) Unclassifiable/Attainment.\nBig Horn County Unclassifiable/Attainment.\nCampbell County Unclassifiable/Attainment.\nCarbon County Unclassifiable/Attainment.\nConverse County Unclassifiable/Attainment.\nCrook County Unclassifiable/Attainment.\nFremont County (remainder) Unclassifiable/Attainment.\nGoshen County Unclassifiable/Attainment.\nHot Springs County Unclassifiable/Attainment.\nJohnson County Unclassifiable/Attainment.\nLaramie County (remainder) Unclassifiable/Attainment.\nLincoln County Unclassifiable/Attainment.\nNatrona County (remainder) Unclassifiable/Attainment.\nNiobrara County Unclassifiable/Attainment.\nPark County Unclassifiable/Attainment.\nPlatte County Unclassifiable/Attainment.\nSheridan County (remainder) Unclassifiable/Attainment.\nSublette County Unclassifiable/Attainment.\nSweetwater County Unclassifiable/Attainment.\nTeton County (remainder) Unclassifiable/Attainment.\nUinta County (remainder) Unclassifiable/Attainment.\nWashakie County Unclassifiable/Attainment.\nWeston 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.\nWyoming—2012 Annual PM2.5 NAAQS\n[Primary]\nDesignated area 1 Designation Classification\nDate 2 Type Date 2 Type\nStatewide:\nAlbany County Unclassifiable/Attainment\nBig Horn County Unclassifiable/Attainment\nCampbell County Unclassifiable/Attainment\nCarbon County Unclassifiable/Attainment\nConverse County Unclassifiable/Attainment\nCrook County Unclassifiable/Attainment\nFremont County Unclassifiable/Attainment\nGoshen County Unclassifiable/Attainment\nHot Springs County Unclassifiable/Attainment\nJohnson County Unclassifiable/Attainment\nLaramie County Unclassifiable/Attainment\nLincoln County Unclassifiable/Attainment\nNatrona County Unclassifiable/Attainment\nNiobrara County Unclassifiable/Attainment\nPark County Unclassifiable/Attainment\nPlatte County Unclassifiable/Attainment\nSheridan County Unclassifiable/Attainment\nSublette County Unclassifiable/Attainment\nSweetwater County Unclassifiable/Attainment\nTeton County Unclassifiable/Attainment\nUinta County Unclassifiable/Attainment\nWashakie County Unclassifiable/Attainment\nWeston 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.\nWyoming—1997 24-Hour PM2.5 NAAQS\n[Primary and Secondary]\nDesignated area Designation a Classification\nDate 1 Type Date Type\nCasper, WY:\nNatrona County (part) Unclassifiable/Attainment\nThe portion within the City of Casper.\nCheyenne, WY:\nLaramie County (part) Unclassifiable/Attainment\nThe portion within the City of Cheyenne.\nEvanston, WY:\nUinta County (part) Unclassifiable/Attainment\nThe portion within the City of Evanston.\nGillette, WY:\nCampbell County (part) Unclassifiable/Attainment\nThe portion within the City of Gillette.\nJackson, WY:\nTeton County (part) Unclassifiable/Attainment\nThe portion within the City of Jackson.\nLander, WY:\nFremont County (part) Unclassifiable/Attainment\nThe portion within the City of Lander.\nLaramie, WY:\nAlbany County (part) Unclassifiable/Attainment\nThe portion within the City of Laramie.\nRiverton, WY:\nFremont County (part) Unclassifiable/Attainment\nThe portion within the City of Riverton.\nRock Springs, WY:\nSweetwater County (part) Unclassifiable/Attainment\nThe portion within the City of Rock Springs.\nSheridan, WY:\nSheridan County (part) Unclassifiable/Attainment\nThe portion within the City of Sheridan.\nRest of State:\nAlbany County (remainder) Unclassifiable/Attainment\nBig Horn County Unclassifiable/Attainment\nCampbell County Unclassifiable/Attainment\nCarbon County Unclassifiable/Attainment\nConverse County Unclassifiable/Attainment\nCrook County Unclassifiable/Attainment\nFremont County (remainder) Unclassifiable/Attainment\nGoshen County Unclassifiable/Attainment\nHot Springs County Unclassifiable/Attainment\nJohnson County Unclassifiable/Attainment\nLaramie County (remainder) Unclassifiable/Attainment\nLincoln County Unclassifiable/Attainment\nNatrona County (remainder) Unclassifiable/Attainment\nNiobrara County Unclassifiable/Attainment\nPark County Unclassifiable/Attainment\nPlatte County Unclassifiable/Attainment\nSheridan County (remainder) Unclassifiable/Attainment\nSublette County Unclassifiable/Attainment\nSweetwater County Unclassifiable/Attainment\nTeton County (remainder) Unclassifiable/Attainment\nUinta County (remainder) Unclassifiable/Attainment\nWashakie County Unclassifiable/Attainment\nWeston 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.\nWyoming—2006 24-Hour PM2.5 NAAQS\n[Primary and Secondary]\nDesignated area Designation a Classification\nDate 1 Type Date Type\nCasper, WY:\nNatrona County (part) Unclassifiable/Attainment\nThe portion within the City of Casper.\nCheyenne, WY:\nLaramie County (part) Unclassifiable/Attainment\nThe portion within the City of Cheyenne.\nEvanston, WY:\nUinta County (part) Unclassifiable/Attainment\nThe portion within the City of Evanston.\nGillette, WY:\nCampbell County (part) Unclassifiable/Attainment\nThe portion within the City of Gillette.\nJackson, WY:\nTeton County (part) Unclassifiable/Attainment\nThe portion within the City of Jackson.\nLander, WY:\nFremont County (part) Unclassifiable/Attainment\nThe portion within the City of Lander.\nLaramie, WY:\nAlbany County (part) Unclassifiable/Attainment\nThe portion within the City of Laramie.\nRiverton, WY:\nFremont County (part) Unclassifiable/Attainment\nThe portion within the City of Riverton.\nRock Springs, WY:\nSweetwater County (part) Unclassifiable/Attainment\nThe portion within the City of Rock Springs.\nSheridan, WY:\nSheridan County (part) Unclassifiable/Attainment\nThe portion within the City of Sheridan.\nRest of State:\nAlbany County (remainder) Unclassifiable/Attainment\nBig Horn County Unclassifiable/Attainment\nCampbell County Unclassifiable/Attainment\nCarbon County Unclassifiable/Attainment\nConverse County Unclassifiable/Attainment\nCrook County Unclassifiable/Attainment\nFremont County (remainder) Unclassifiable/Attainment\nGoshen County Unclassifiable/Attainment\nHot Springs County Unclassifiable/Attainment\nJohnson County Unclassifiable/Attainment\nLaramie County (remainder) Unclassifiable/Attainment\nLincoln County Unclassifiable/Attainment\nNatrona County (remainder) Unclassifiable/Attainment\nNiobrara County Unclassifiable/Attainment\nPark County Unclassifiable/Attainment\nPlatte County Unclassifiable/Attainment\nSheridan County (remainder) Unclassifiable/Attainment\nSublette County Unclassifiable/Attainment\nSweetwater County Unclassifiable/Attainment\nTeton County (remainder) Unclassifiable/Attainment\nUinta County (remainder) Unclassifiable/Attainment.\nWashakie County Unclassifiable/Attainment\nWeston 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.\nWyoming—NO2 (1971 Annual Standard)\nDesignated area Does not meet primary standards Cannot be classified or better than national standards\nEntire State X\nWyoming—NO2 (2010 1-Hour Standard)\nDesignated area Designation a\nDate 1 Type\nAlbany County Unclassifiable/Attainment.\nBig Horn County Unclassifiable/Attainment.\nCampbell County Unclassifiable/Attainment.\nCarbon County Unclassifiable/Attainment.\nConverse County Unclassifiable/Attainment.\nCrook County Unclassifiable/Attainment.\nFremont County Unclassifiable/Attainment.\nGoshen County Unclassifiable/Attainment.\nHot Springs County Unclassifiable/Attainment.\nJohnson County Unclassifiable/Attainment.\nLaramie County Unclassifiable/Attainment.\nLincoln County Unclassifiable/Attainment.\nNatrona County Unclassifiable/Attainment.\nNiobrara County Unclassifiable/Attainment.\nPark County Unclassifiable/Attainment.\nPlatte County Unclassifiable/Attainment.\nSheridan County Unclassifiable/Attainment.\nSublette County Unclassifiable/Attainment.\nSweetwater County Unclassifiable/Attainment.\nTeton County Unclassifiable/Attainment.\nUinta County Unclassifiable/Attainment.\nWashakie County Unclassifiable/Attainment.\nWeston 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.\nWyoming—1997 8-Hour Ozone NAAQS\n[Primary and Secondary]\nDesignated area Designation a Category/classification\nDate 1 Type Date 1 Type\nStatewide Unclassifiable/Attainment\nAlbany County Unclassifiable/Attainment\nBig Horn County Unclassifiable/Attainment\nCampbell County Unclassifiable/Attainment\nCarbon County Unclassifiable/Attainment\nConverse County Unclassifiable/Attainment\nCrook County Unclassifiable/Attainment\nFremont County Unclassifiable/Attainment\nGoshen County Unclassifiable/Attainment\nHot Springs County Unclassifiable/Attainment\nJohnson County Unclassifiable/Attainment\nLaramie County Unclassifiable/Attainment\nLincoln County Unclassifiable/Attainment\nNatrona County Unclassifiable/Attainment\nNiobrara County Unclassifiable/Attainment\nPark County Unclassifiable/Attainment\nPlatte County Unclassifiable/Attainment\nSheridan County Unclassifiable/Attainment\nSublette County Unclassifiable/Attainment\nSweetwater County Unclassifiable/Attainment\nTeton County Unclassifiable/Attainment\nUinta County Unclassifiable/Attainment\nWashakie County Unclassifiable/Attainment\nWeston County Unclassifiable/Attainment\na Includes Indian Country located in each county or area, except as otherwise specified.\n1 This date is June 15, 2004, unless otherwise noted.\nWyoming—2008 8-Hour Ozone NAAQS\n[Primary and Secondary]\nDesignated area Designation Classification\nDate 1 Type Date 1 Type\nUpper Green River Basin Area, WY: 2 Nonattainment Marginal.\nLincoln County (part)\nThe area of the county north and east of the boundary defined by a line starting at the point defined by the intersection of the southwest corner Section 30 Range (R) 115 West Township (T) 27N and the northwest corner of Section 31 R 115 West T27N of Sublette County at Sublette County's border with Lincoln County. From this point the boundary moves to the west 500 feet to Aspen Creek. The boundary follows the centerline of Aspen Creek downstream to the confluence of Aspen Creek and Fontenelle Creek (in R116W T26N, Section 1). From this point the boundary moves generally to the south along the centerline of Fontenelle Creek to the confluence of Fontenelle Creek and Roney Creek (in R115W T24N Section 6). From the confluence, the boundary moves generally to the east along the centerline of Fontenelle Creek and into the Fontenelle Reservoir (in R112W T24N Section 6). The boundary moves east southeast along the centerline of the Fontenelle Reservoir and then toward the south along the centerline of the Green River to where the Green River in R111W T24N Section 31 crosses into Sweetwater County.\nSublette County\nSweetwater County (part)\nThe area of the county west and north of the boundary which begins at the midpoint of the Green River, where the Green River enters Sweetwater County from Lincoln County in R111W T24N Section 31. From this point, the boundary follows the center of the channel of the Green River generally to the south and east to the confluence of the Green River and the Big Sandy River (in R109W T22N Section 28). From this point, the boundary moves generally north and east along the centerline of the Big Sandy River to the confluence of the Big Sandy River with Little Sandy Creek (in R106W T25N Section 33). The boundary continues generally toward the northeast along the centerline of Little Sandy Creek to the confluence of Little Sandy Creek and Pacific Creek (in R106W T25N Section 24). From this point, the boundary moves generally to the east and north along the centerline of Pacific Creek to the confluence of Pacific Creek and Whitehorse Creek (in R103W T26N Section 10). From this point the boundary follows the centerline of Whitehorse Creek generally to the northeast until it reaches the eastern boundary of Section 1 R103W T26N. From the point where Whitehorse Creek crosses the eastern section line of Section 1 R103W T26N, the boundary moves straight north along the section line to the southeast corner of Section 36 R103W T27N in Sublette County where the boundary ends.\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.\nWyoming—2015 8-Hour Ozone NAAQS\n[Primary and Secondary]\nDesignated area 1 Designation Classification\nDate 2 Type Date 2 Type\nAlbany County Attainment/Unclassifiable\nBig Horn County 1/16/2018 Attainment/Unclassifiable\nCampbell County 1/16/2018 Attainment/Unclassifiable\nCarbon County 1/16/2018 Attainment/Unclassifiable\nConverse County 1/16/2018 Attainment/Unclassifiable\nCrook County 1/16/2018 Attainment/Unclassifiable\nFremont County 1/16/2018 Attainment/Unclassifiable\nGoshen County 1/16/2018 Attainment/Unclassifiable\nHot Springs County 1/16/2018 Attainment/Unclassifiable\nJohnson County 1/16/2018 Attainment/Unclassifiable\nLaramie County Attainment/Unclassifiable\nLincoln County 1/16/2018 Attainment/Unclassifiable\nNatrona County 1/16/2018 Attainment/Unclassifiable\nNiobrara County 1/16/2018 Attainment/Unclassifiable\nPark County 1/16/2018 Attainment/Unclassifiable\nPlatte County 1/16/2018 Attainment/Unclassifiable\nSheridan County 1/16/2018 Attainment/Unclassifiable\nSublette County 1/16/2018 Attainment/Unclassifiable\nSweetwater County 1/16/2018 Attainment/Unclassifiable\nTeton County 1/16/2018 Attainment/Unclassifiable\nUinta County 1/16/2018 Attainment/Unclassifiable\nWashakie County 1/16/2018 Attainment/Unclassifiable\nWeston 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.\nWyoming—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":"3fbb610957b83f2b1d2019b5fa6d0f0dc22e037bddecadbdf19d4da4bb6a2987","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-81.350","next":"us/40-cfr-81.352"},"notice":"GroundRules: Original legal text. Not legal advice."}