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8-Hour Ozone (1997) Nonattainment Area Summary - NAAQS Revoked
8-Hour Ozone (1997) Nonattainment Area Summary - NAAQS Revoked
Data is current as of November 30, 2025The 1997 8-hour Ozone NAAQS was revoked effective April 6, 2015 (80 FR 12264).
| Classification | Number of Areas | Number of Counties | 2010 Population | Attainment Date | ||||
|---|---|---|---|---|---|---|---|---|
| Extreme | 3 | 12 | 19,983,195 | 06/2024 | ||||
| Severe 17 | 1 | 0 | 913 | 06/2021 | ||||
| Severe 15 | 3 | 14 | 9,004,260 | 06/2019 | ||||
| Serious | 3 | 16 | 9,707,337 | 06/2013 | ||||
| Moderate | 19 | 102 | 47,517,220 | 06/2010 | ||||
| Marginal | 7 | 32 | 12,606,192 | 06/2007 | ||||
| SUBTOTAL | 36 | 176 | 98,819,117 | |||||
| Former Subpart 1 | 0 | 0 | 0 | |||||
| SUBTOTAL | 0 | 0 | 0 | |||||
| Moderate EAC | 0 | 0 | 0 | |||||
| Marginal EAC | 0 | 0 | 0 | |||||
| Subpart 1 EAC | 0 | 0 | 0 | |||||
| SUBTOTAL | 0 | 0 | 0 | |||||
| GRAND TOTAL | 36 | 176 | 98,819,117 | |||||
County subtotals and grand totals may not equal sum of parts. Part counties are only counted one time across groupings. Multi-state nonattainment areas are not considered maintenance areas until all states in the area have been redesignated.
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.