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Areas with a Maintenance Plan Requirement Under Section 110(a)(1) of the CAA

Data is current as of June 15, 2005

Classification	Number of Areas	Number of Counties	2010 Population (1000s)
Serious	6	6	1,127
Moderate	9	24	9,108
Marginal	19	31	7,950
Other	1	5	1,552

SUBTOTAL	35	65	19,707

Section 185A	5	9	2,181
Incomplete Data	19	22	1,793

SUBTOTAL	24	31	3,974


GRAND TOTAL	59	96	23,681

County and area subtotals and grand totals may not equal sum of parts. Hillsborough Co, NH is in both the Boston (Serious) and Manchester (Marginal) area and therefore is counted only once in the totals.

The former 1-Hour Ozone designations and classifications as of June 15, 2004, are being retained in subpart C of Part 81 for purposes of the anti backsliding provisions of 40 CFR 51.905. 40 CFR 51.905(c) references subpart C of part 81 for the areas affected by the anti-backsliding regulation.

The Nashville, TN and Greensboro-Winston Salem-High Point, NC 1-Hour Ozone maintenance areas were Early Action Compact (EAC) areas. The 1-Hour standard was revoked for the EAC areas on April 15, 2009, one year after the effective date (April 15, 2008) of their designation as attainment for the 8-Hour Ozone standard. At that time, the Nashville, TN and Greensboro-Winston Salem-High Point, NC areas were required to submit a 10-year maintenance plan under section 110(a)(1) of the CAA and the Phase 1 Rule.