8-Hour Ozone (2015) Nonattainment Area Summary with History

Data is current as of April 30, 2025

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	NUMBER OF AREAS				NUMBER OF COUNTIES				2010 POPULATION
Classif.	Original 2018 Baseline	Adjusted Baseline*	Today	Redesig	Original 2018 Baseline	Adjusted Baseline*	Today	Redesig	Original 2018 Baseline	Adjusted Baseline*	Today	Redesig
Extreme	2	2	2	0	12	12	12	0	19,544,668	19,544,668	19,544,668	0
Severe 15	2	3	3	0	0	1	1	0	1,291,989	4,369,276	4,369,276	0
Serious	2	23	23	0	1	124	124	0	821,740	72,123,048	72,123,048	0
Moderate	5	8	6	2	32	40	26	14	25,711,980	16,841,388	10,208,117	6,633,271
Marginal	38	14	11	3	153	30	18	12	74,984,197	14,296,966	8,920,691	5,376,275
Marginal (Rural Transport)	2	3	1	2	2	2	1	1	31	17,035	0	17,035
SUBTOTAL	51	53	46	7	200	209	182	27	122,354,605	127,192,381	115,165,800	12,026,581
GRAND TOTAL	51	53	46	7	200	209	182	27	122,354,605	127,192,381	115,165,800	12,026,581

* Please Note: Changes can occur that adjust the original baseline counts, e.g., classification changes, area boundary changes, new areas designated nonattainment. See the report listing these adjustments to original 2018 nonattainment areas.

County subtotals and grand totals may not equal sum of parts. Part counties are only counted one time across groups.
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