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8-Hour Ozone (2015) Nonattainment Area Summary

Data is current as of March 31, 2025


Classification Number of Areas Number of Counties 2010 Population
Extreme 2 12 19,544,668
Severe 15 3 1 4,369,276
Serious 23 124 72,123,048
Moderate 6 26 10,208,117
Marginal 11 18 8,920,691
Marginal (Rural Transport) 1 1 0
SUBTOTAL 46 182 115,165,800
 
GRAND TOTAL 46 182 115,165,800

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