| SERIOUS |
| Clark Co, NV |
| Los Angeles South Coast Air Basin, CA |
| San Joaquin Valley Air Basin, CA |
| Wallula, WA |
| Washoe Co, NV |
| |
| MODERATE |
| Aspen, CO |
| Boise-Northern Ada County, ID |
| Bonner Co (Sandpoint), ID |
| Canon City, CO |
| Clairton & 4 Boroughs, PA |
| Coso Junction, CA |
| Cuyahoga Co, OH |
| Denver Metro, CO |
| Eagle River, AK |
| East Chicago, IN |
| Eugene-Springfield, OR |
| Follansbee, WV |
| Granite City, Nameoki Twsp, IL |
| Grants Pass, OR |
| Indian Wells, CA |
| Jefferson Co, OH |
| Juneau, AK |
| Kent, WA |
| King Co, WA |
| Klamath Falls, OR |
| LaGrande, OR |
| Lake Co, OR |
| Lamar, CO |
| Lyons Twsp., IL |
| Mammoth Lake, CA |
| Medford-Ashland, OR |
| Mohave Co, AZ |
| Mun. of Guaynabo, PR |
| New Haven Co, CT |
| Oglesby, IL |
| Olmsted Co, MN |
| Olympia, Tumwater, Lacey, WA |
| Pagosa Springs, CO |
| Payson, AZ |
| Pierce Co, WA |
| Portneuf Valley, ID |
| Presque Isle, ME |
| Ramsey Co, MN |
| Sacramento Co, CA |
| Southeast Chicago, IL |
| Spokane Co, WA |
| Steamboat Springs, CO |
| Telluride, CO |
| Vermillion Co, IN |
| Wayne Co, MI |
| Weirton, WV |
| Yakima Co, WA |
