• § 81.11 - Scope.

• § 81.12 - National Capital Interstate Air Quality Control Region (District of Columbia, Maryland, and Virginia).

• § 81.13 - New Jersey-New York-Connecticut Interstate Air Quality Control Region.

• § 81.14 - Metropolitan Chicago Interstate Air Quality Control Region.

• § 81.15 - Metropolitan Philadelphia Interstate Air Quality Control Region (Pennsylvania-New Jersey-Delaware).

• § 81.16 - Metropolitan Denver Intrastate Air Quality Control Region.

• § 81.17 - Metropolitan Los Angeles Air Quality Control Region.

• § 81.18 - Metropolitan St. Louis Interstate Air Quality Control Region.

• § 81.19 - Metropolitan Boston Intrastate Air Quality Control Region.

• § 81.20 - Metropolitan Cincinnati Interstate Air Quality Control Region.

• § 81.112 - Charleston Intrastate Air Quality Control Region.

• § 81.113 - Savannah (Georgia)-Beaufort (South Carolina) Interstate Air Quality Control Region.

• § 81.114 - Augusta (Georgia)-Aiken (South Carolina) Interstate Air Quality Control Region.

• § 81.115 - Northwest Nevada Intrastate Air Quality Control Region.

• § 81.116 - Northern Missouri Intrastate Air Quality Control Region.

• § 81.117 - Southeast Missouri Intrastate Air Quality Control Region.

• § 81.118 - Southwest Missouri Intrastate Air Quality Control Region.

• § 81.119 - Western Tennessee Intrastate Air Quality Control Region.

• § 81.120 - Middle Tennessee Intrastate Air Quality Control Region.

• § 81.121 - Four Corners Interstate Air Quality Control Region.

• § 81.122 - Mississippi Delta Intrastate Air Quality Control Region.

• § 81.21 - San Francisco Bay Area Intrastate Air Quality Control Region.

• § 81.123 - Southeastern Oklahoma Intrastate Air Quality Control Region.

• § 81.124 - North Central Oklahoma Intrastate Air Quality Control Region.

• § 81.125 - Southwestern Oklahoma Intrastate Air Quality Control Region.

• § 81.126 - Northwestern Oklahoma Intrastate Air Quality Control Region.

• § 81.127 - Central New York Intrastate Air Quality Control Region.

• § 81.128 - Genesee-Finger Lakes Intrastate Air Quality Control Region.

• § 81.129 - Hudson Valley Intrastate Air Quality Control Region.

• § 81.130 - Southern Tier East Intrastate Air Quality Control Region.

• § 81.131 - Southern Tier West Intrastate Air Quality Control Region.

• § 81.132 - Abilene-Wichita Falls Intrastate Air Quality Control Region.

• § 81.22 - Greater Metropolitan Cleveland Intrastate Air Quality Control Region.

• § 81.133 - Amarillo-Lubbock Intrastate Air Quality Control Region.

• § 81.134 - Austin-Waco Intrastate Air Quality Control Region.

• § 81.135 - Brownsville-Laredo Intrastate Air Quality Control Region.

• § 81.136 - Corpus Christi-Victoria Intrastate Air Quality Control Region.

• § 81.137 - Midland-Odessa-San Angelo Intrastate Air Quality Control Region.

• § 81.138 - Central Arkansas Intrastate Air Quality Control Region.

• § 81.139 - Northeast Arkansas Intrastate Air Quality Control Region.

• § 81.140 - Northwest Arkansas Intrastate Air Quality Control Region.

• § 81.141 - Berkshire Intrastate Air Quality Control Region.

• § 81.142 - Central Massachusetts Intrastate Air Quality Control Region.

• § 81.23 - Southwest Pennsylvania Intrastate Air Quality Control Region.

• § 81.143 - Central Virginia Intrastate Air Quality Control Region.

• § 81.144 - Northeastern Virginia Intrastate Air Quality Control Region.

• § 81.145 - State Capital Intrastate Air Quality Control Region.

• § 81.146 - Valley of Virginia Intrastate Air Quality Control Region.

• § 81.147 - Eastern Mountain Intrastate Air Quality Control Region.

• § 81.148 - Eastern Piedmont Intrastate Air Quality Control Region.

• § 81.149 - Northern Coastal Plain Intrastate Air Quality Control Region.

• § 81.150 - Northern Piedmont Intrastate Air Quality Control Region.

• § 81.151 - Sandhills Intrastate Air Quality Control Region.

• § 81.24 - Niagara Frontier Intrastate Air Quality Control Region.

• § 81.152 - Southern Coastal Plain Intrastate Air Quality Control Region.

• § 81.153 - Western Mountain Intrastate Air Quality Control Region.

• § 81.154 - Eastern Shore Intrastate Air Quality Control Region.

• § 81.155 - Central Maryland Intrastate Air Quality Control Region.

• § 81.156 - Southern Maryland Intrastate Air Quality Control Region.

• § 81.157 - North Central Wisconsin Intrastate Air Quality Control Region.

• § 81.158 - Southern Wisconsin Intrastate Air Quality Control Region.

• § 81.159 - Great Basin Valley Intrastate Air Quality Control Region.

• § 81.160 - North Central Coast Intrastate Air Quality Control Region.

• § 81.161 - North Coast Intrastate Air Quality Control Region.

• § 81.162 - Northeast Plateau Intrastate Air Quality Control Region.

• § 81.25 - Metropolitan Kansas City Interstate Air Quality Control Region.

• § 81.163 - Sacramento Valley Intrastate Air Quality Control Region.

• § 81.164 - San Diego Intrastate Air Quality Control Region.

• § 81.165 - San Joaquin Valley Intrastate Air Quality Control Region.

• § 81.166 - South Central Coast Intrastate Air Quality Control Region.

• § 81.167 - Southeast Desert Intrastate Air Quality Control Region.

• § 81.168 - Great Falls Intrastate Air Quality Control Region.

• § 81.169 - Helena Intrastate Air Quality Control Region.

• § 81.170 - Miles City Intrastate Air Quality Control Region.

• § 81.171 - Missoula Intrastate Air Quality Control Region.

• § 81.26 - Hartford-New Haven-Springfield Interstate Air Quality Control Region.

• § 81.172 - Comanche Intrastate Air Quality Control Region.

• § 81.173 - Grand Mesa Intrastate Air Quality Control Region.

• § 81.174 - Pawnee Intrastate Air Quality Control Region.

• § 81.175 - San Isabel Intrastate Air Quality Control Region.

• § 81.176 - San Luis Intrastate Air Quality Control Region.

• § 81.177 - Yampa Intrastate Air Quality Control Region.

• § 81.178 - Southern Delaware Intrastate Air Quality Control Region.

• § 81.179 - Aroostook Intrastate Air Quality Control Region.

• § 81.181 - Down East Intrastate Air Quality Control Region.

• § 81.182 - Northwest Maine Intrastate Air Quality Control Region.

• § 81.27 - Minneapolis-St. Paul Intrastate Air Quality Control Region.

• § 81.183 - Eastern Connecticut Intrastate Air Quality Control Region.

• § 81.184 - Northwestern Connecticut Intrastate Air Quality Control Region.

• § 81.185 - Northern Washington Intrastate Air Quality Control Region.

• § 81.187 - Olympic-Northwest Washington Intrastate Air Quality Control Region.

• § 81.189 - South Central Washington Intrastate Air Quality Control Region.

• § 81.190 - Eastern Idaho Intrastate Air Quality Control Region.

• § 81.191 - Appalachian Intrastate Air Quality Control Region.

• § 81.192 - Bluegrass Intrastate Air Quality Control Region.

• § 81.193 - North Central Kentucky Intrastate Air Quality Control Region.

• § 81.194 - South Central Kentucky Intrastate Air Quality Control Region.

• § 81.195 - Central Michigan Intrastate Air Quality Control Region.

• § 81.28 - Metropolitan Baltimore Intrastate Air Quality Control Region.

• § 81.196 - South Central Michigan Intrastate Air Quality Control Region.

• § 81.197 - Upper Michigan Intrastate Air Quality Control Region.

• § 81.199 - East Alabama Intrastate Air Quality Control Region.

• § 81.200 - Metropolitan Columbus Intrastate Air Quality Control Region.

• § 81.201 - Mansfield-Marion Intrastate Air Quality Control Region.

• § 81.202 - Northwest Ohio Intrastate Air Quality Control Region.

• § 81.203 - Sandusky Intrastate Air Quality Control Region.

• § 81.204 - Wilmington-Chillicothe-Logan Intrastate Air Quality Control Region.

• § 81.205 - Zanesville-Cambridge Intrastate Air Quality Control Region.

• § 81.29 - Metropolitan Indianapolis Intrastate Air Quality Control Region.

• § 81.213 - Casper Intrastate Air Quality Control Region.

• § 81.214 - Black Hills-Rapid City Intrastate Air Quality Control Region.

• § 81.215 - East Central Indiana Intrastate Air Quality Control Region.

• § 81.216 - Northeast Indiana Intrastate Air Quality Control Region.

• § 81.217 - Southern Indiana Intrastate Air Quality Control Region.

• § 81.218 - Wabash Valley Intrastate Air Quality Control Region.

• § 81.219 - Central Oregon Intrastate Air Quality Control Region.

• § 81.220 - Eastern Oregon Intrastate Air Quality Control Region.

• § 81.221 - Southwest Oregon Intrastate Air Quality Control Region.

• § 81.226 - Lincoln-Beatrice-Fairbury Intrastate Air Quality Control Region.

• § 81.30 - Southeastern Wisconsin Intrastate Air Quality Control Region.

• § 81.230 - Allegheny Intrastate Air Quality Control Region.

• § 81.231 - Central West Virginia Intrastate Air Quality Control Region.

• § 81.232 - Eastern Panhandle Intrastate Air Quality Control Region.

• § 81.233 - Kanawha Valley Intrastate Air Quality Control Region.

• § 81.234 - North Central West Virginia Intrastate Air Quality Control Region.

• § 81.235 - Southern West Virginia Intrastate Air Quality Control Region.

• § 81.236 - Central Georgia Intrastate Air Quality Control Region.

• § 81.237 - Northeast Georgia Intrastate Air Quality Control Region.

• § 81.238 - Southwest Georgia Intrastate Air Quality Control Region.

• § 81.239 - Upper Rio Grande Valley Intrastate Air Quality Control Region.

• § 81.31 - Metropolitan Providence Interstate Air Quality Control Region.

• § 81.240 - Northeastern Plains Intrastate Air Quality Control Region.

• § 81.241 - Southwestern Mountains-Augustine Plains Intrastate Air Quality Control Region.

• § 81.242 - Pecos-Permian Basin Intrastate Air Quality Control Region.

• § 81.243 - Central Minnesota Intrastate Air Quality Control Region.

• § 81.244 - Northwest Minnesota Intrastate Air Quality Control Region.

• § 81.245 - Southwest Minnesota Intrastate Air Quality Control Region.

• § 81.246 - Northern Alaska Intrastate Air Quality Control Region.

• § 81.247 - South Central Alaska Intrastate Air Quality Control Region.

• § 81.248 - Southeastern Alaska Intrastate Air Quality Control Region.

• § 81.249 - Northwest Oregon Intrastate Air Quality Control Region.

• § 81.250 - North Central Kansas Intrastate Air Quality Control Region.

• § 81.32 - Puget Sound Intrastate Air Quality Control Region.

• § 81.251 - Northeast Kansas Intrastate Air Quality Control Region.

• § 81.252 - Northwest Kansas Intrastate Air Quality Control Region.

• § 81.253 - South Central Kansas Intrastate Air Quality Control Region.

• § 81.254 - Southeast Kansas Intrastate Air Quality Control Region.

• § 81.255 - Southwest Kansas Intrastate Air Quality Control Region.

• § 81.256 - Northeast Iowa Intrastate Air Quality Control Region.

• § 81.257 - North Central Iowa Intrastate Air Quality Control Region.

• § 81.258 - Northwest Iowa Intrastate Air Quality Control Region.

• § 81.259 - Southwest Iowa Intrastate Air Quality Control Region.

• § 81.33 - Steubenville-Weirton-Wheeling Interstate Air Quality Control Region.

• § 81.260 - South Central Iowa Intrastate Air Quality Control Region.

• § 81.261 - Southeast Iowa Intrastate Air Quality Control Region.

• § 81.262 - North Central Illinois Intrastate Air Quality Control Region.

• § 81.263 - East Central Illinois Intrastate Air Quality Control Region.

• § 81.264 - West Central Illinois Intrastate Air Quality Control Region.

• § 81.265 - Southeast Illinois Intrastate Air Quality Control Region.

• § 81.266 - Alabama and Tombigbee Rivers Intrastate Air Quality Control Region.

• § 81.267 - Southeast Alabama Intrastate Air Quality Control Region.

• § 81.268 - Mohave-Yuma Intrastate Air Quality Control Region.

• § 81.269 - Pima Intrastate Air Quality Control Region.

• § 81.34 - Metropolitan Dayton Intrastate Air Quality Control Region.

• § 81.270 - Northern Arizona Intrastate Air Quality Control Region.

• § 81.271 - Central Arizona Intrastate Air Quality Control Region.

• § 81.272 - Southeast Arizona Intrastate Air Quality Control Region.

• § 81.273 - Lake County Intrastate Air Quality Control Region.

• § 81.274 - Mountain Counties Intrastate Air Quality Control Region.

• § 81.275 - Lake Tahoe Intrastate Air Quality Control Region.

• § 81.276 - Nevada Intrastate Air Quality Control Region.

• § 81.35 - Louisville Interstate Air Quality Control Region.

• § 81.36 - Maricopa Intrastate Air Quality Control Region.

• § 81.37 - Metropolitan Detroit-Port Huron Intrastate Air Quality Control Region.

• § 81.38 - Metropolitan Houston-Galveston Intrastate Air Quality Control Region.

• § 81.39 - Metropolitan Dallas-Fort Worth Intrastate Air Quality Control Region.

• § 81.40 - Metropolitan San Antonio Intrastate Air Quality Control Region.

• § 81.41 - Metropolitan Birmingham Intrastate Air Quality Control Region.

• § 81.42 - Chattanooga Interstate Air Quality Control Region.

• § 81.43 - Metropolitan Toledo Interstate Air Quality Control Region.

• § 81.44 - Metropolitan Memphis Interstate Air Quality Control Region.

• § 81.45 - Metropolitan Atlanta Intrastate Air Quality Control Region.

• § 81.46 - U.S. Virgin Islands Air Quality Control Region.

• § 81.47 - Central Oklahoma Intrastate Air Quality Control Region.

• § 81.48 - Champlain Valley Interstate Air Quality Control Region.

• § 81.49 - Southeast Florida Intrastate Air Quality Control Region.

• § 81.50 - Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region.

• § 81.51 - Portland Interstate Air Quality Control Region.

• § 81.52 - Wasatch Front Intrastate Air Quality Control Region.

• § 81.53 - Southern Louisiana-Southeast Texas Interstate Air Quality Control Region.

• § 81.54 - Cook Inlet Intrastate Air Quality Control Region.

• § 81.55 - Northeast Pennsylvania-Upper Delaware Valley Interstate Air Quality Control Region.

• § 81.57 - Eastern Tennessee-Southwestern Virginia Interstate Air Quality Control Region.

• § 81.58 - Columbus (Georgia)-Phenix City (Alabama) Interstate Air Quality Control Region.

• § 81.59 - Cumberland-Keyser Interstate Air Quality Control Region.

• § 81.60 - Duluth (Minnesota)-Superior (Wisconsin) Interstate Air Quality Control Region.

• § 81.61 - Evansville (Indiana)-Owensboro-Henderson (Kentucky) Interstate Air Quality Control Region.

• § 81.62 - Northeast Mississippi Intrastate Air Quality Control Region.

• § 81.63 - Metropolitan Fort Smith Interstate Air Quality Control Region.

• § 81.64 - Huntington (West Virginia)-Ashland (Kentucky)-Portsmouth-Ironton (Ohio) Interstate Air Quality Control Region.

• § 81.65 - Joplin (Missouri)-Northeast Oklahoma Interstate Air Quality Control Region.

• § 81.66 - Southeast Minnesota-La Crosse (Wisconsin) Interstate Air Quality Control Region.

• § 81.67 - Lake Michigan Intrastate Air Quality Control Region.

• § 81.68 - Mobile (Alabama)-Pensacola-Panama City (Florida)-Southern Mississippi Interstate Air Quality Control Region.

• § 81.69 - Paducah (Kentucky)-Cairo (Illinois) Interstate Air Quality Control Region.

• § 81.70 - Parkersburg (West Virginia)-Marietta (Ohio) Interstate Air Quality Control Region.

• § 81.71 - Rockford (Illinois)-Janesville-Beloit (Wisconsin) Interstate Air Quality Control Region.

• § 81.72 - Tennessee River Valley (Alabama)-Cumberland Mountains (Tennessee) Interstate Air Quality Control Region.

• § 81.73 - South Bend-Elkhart (Indiana)-Benton Harbor (Michigan) Interstate Air Quality Control Region.

• § 81.74 - Northwest Pennsylvania-Youngstown Interstate Air Quality Control Region.

• § 81.75 - Metropolitan Charlotte Interstate Air Quality Control Region.

• § 81.76 - State of Hawaii Air Quality Control Region.

• § 81.77 - Puerto Rico Air Quality Control Region.

• § 81.78 - Metropolitan Portland Intrastate Air Quality Control Region.

• § 81.79 - Northeastern Oklahoma Intrastate Air Quality Control Region.

• § 81.80 - Las Vegas Intrastate Air Quality Control Region.

• § 81.81 - Merrimack Valley-Southern New Hampshire Interstate Air Quality Control Region.

• § 81.82 - El Paso-Las Cruces-Alamogordo Interstate Air Quality Control Region.

• § 81.83 - Albuquerque-Mid Rio Grande Intrastate Air Quality Control Region.

• § 81.84 - Metropolitan Fargo-Moorhead Interstate Air Quality Control Region.

• § 81.85 - Metropolitan Sioux Falls Interstate Air Quality Control Region.

• § 81.86 - Metropolitan Sioux City Interstate Air Quality Control Region.

• § 81.87 - Metropolitan Boise Intrastate Air Quality Control Region.

• § 81.88 - Billings Intrastate Air Quality Control Region.

• § 81.89 - Metropolitan Cheyenne Intrastate Air Quality Control Region.

• § 81.90 - Androscoggin Valley Interstate Air Quality Control Region.

• § 81.91 - Jacksonville (Florida)-Brunswick (Georgia) Interstate Air Quality Control Region.

• § 81.92 - Monroe (Louisiana)—El Dorado (Arkansas) Interstate Air Quality Control Region.

• § 81.93 - Hampton Roads Intrastate Air Quality Control Region.

• § 81.94 - Shreveport-Texarkana-Tyler Interstate Air Quality Control Region.

• § 81.95 - Central Florida Intrastate Air Quality Control Region.

• § 81.96 - West Central Florida Intrastate Air Quality Control Region.

• § 81.97 - Southwest Florida Intrastate Air Quality Control Region.

• § 81.98 - Burlington-Keokuk Interstate Air Quality Control Region.

• § 81.99 - New Mexico Southern Border Intrastate Air Quality Control Region.

• § 81.100 - Eastern Washington-Northern Idaho Interstate Air Quality Control Region.

• § 81.101 - Metropolitan Dubuque Interstate Air Quality Control Region.

• § 81.102 - Metropolitan Quad Cities Interstate Air Quality Control Region.

• § 81.104 - Central Pennsylvania Intrastate Air Quality Control Region.

• § 81.105 - South Central Pennsylvania Intrastate Air Quality Control Region.

• § 81.106 - Greenville-Spartanburg Intrastate Air Quality Control Region.

• § 81.107 - Greenwood Intrastate Air Quality Control Region.

• § 81.108 - Columbia Intrastate Air Quality Control Region.

• § 81.109 - Florence Intrastate Air Quality Control Region.

• § 81.110 - Camden-Sumter Intrastate Air Quality Control Region.

• § 81.111 - Georgetown Intrastate Air Quality Control Region.