8-Hour Ozone (2015) Maintenance Area (Redesignated from Nonattainment) Summary

Data is current as of March 31, 2025

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Classification	Number of Areas	Number of Counties	2010 Population
Extreme	0	0	0
Severe 15	0	0	0
Serious	0	0	0
Moderate	2	14	6,633,271
Marginal	3	12	5,376,275
Marginal (Rural Transport)	2	1	17,035
SUBTOTAL	7	27	12,026,581
GRAND TOTAL	7	27	12,026,581

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.