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8-Hour Ozone (1997) Maintenance Area (Redesignated from Nonattainment) Summary - NAAQS Revoked

Data is current as of September 30, 2021
The 1997 8-hour Ozone NAAQS was revoked effective April 6, 2015 (80 FR 12264).



Classification Number of Areas Number of Counties 2010 Population
Extreme 0 0 0
Severe 17 1 1 2,844
Severe 15 0 0 0
Serious 0 0 0
Moderate 12 78 29,882,382
Marginal 11 43 14,651,861
SUBTOTAL 24 122 44,537,087
 
Former Subpart 1 56 136 22,506,809
SUBTOTAL 56 136 22,506,809
 
Moderate EAC 0 0 0
Marginal EAC 0 0 0
Subpart 1 EAC 0 0 0
SUBTOTAL 0 0 0
 
GRAND TOTAL 80 258 67,043,896

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.