8-Hour Ozone (1997) Nonattainment Areas - NAAQS Revoked
Data is current as of November 30, 2025
View Notes
The 1997 8-hour Ozone NAAQS was revoked effective April 6, 2015
(80 FR 12264).
| EXTREME (June 2024) |
| Los Angeles-South Coast Air Basin, CA |
| Riverside County (Coachella Valley), CA |
| San Joaquin Valley, CA |
| |
| SEVERE 17 (June 2021) |
| Morongo Band of Mission Indians, CA |
| |
| SEVERE 15 (June 2019) |
| Houston-Galveston-Brazoria, TX |
| Los Angeles and San Bernardino Counties (Western Mojave Desert), CA |
| Sacramento Metro, CA |
| |
| SERIOUS (June 2013) |
| Baltimore, MD |
| Dallas-Fort Worth, TX |
| Ventura County (part), CA |
| |
| MODERATE (June 2010) |
| Amador and Calaveras Cos. (Central Mountain Cos.), CA |
| Boston-Lawrence-Worcester (E. Mass), MA |
| Buffalo-Niagara Falls, NY |
| Greater Connecticut, CT |
| Imperial County, CA |
| Inland Sheboygan County, WI |
| Jamestown, NY |
| Jefferson County, NY |
| Kern County (Eastern Kern), CA |
| Mariposa and Tuolumne Cos. (Southern Mountain Counties), CA |
| Nevada County (Western part), CA |
| New York-N. New Jersey-Long Island, NY-NJ-CT |
| Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE |
| Pittsburgh-Beaver Valley, PA |
| Poughkeepsie, NY |
| Providence (all of RI), RI |
| Shoreline Sheboygan County, WI |
| Springfield (W. Mass), MA |
| Washington, DC-MD-VA |
| |
| MARGINAL (June 2007) |
| Albany-Schenectady-Troy, NY |
| Chico, CA |
| Denver-Boulder-Greeley-Ft. Collins-Loveland, CO |
| Essex County (Whiteface Mtn.), NY |
| Rochester, NY |
| San Francisco Bay Area, CA |
| Sutter County (part) (Sutter Buttes), CA |
Notes:
Details about the designations and classifications of previous 1-hour ozone nonattainment and maintenance areas can be found here.
On June 8, 2007, the United States Court of Appeals vacated the Subpart 1 portion of the Phase 1 Rule (Court Order) (PDF).
On May 14, 2012, the Former Subpart 1 nonattainment areas were classified under Subpart 2
(77 FR 28424
) (PDF), effective June 13, 2012.
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