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Important Notes for the:
Whole or Part County Nonattainment Status by Year Since 1992 for All Criteria Pollutants Report

These state/county reports list the annual nonattainment and maintenance status of each county by designated area name by National Ambient Air Quality Standard (NAAQS).

The presence of a year indicates that a county was in one or more nonattainment areas for a NAAQS during that calendar year. If different parts of a county fall within the boundaries of separate areas for a NAAQS, the nonattainment year will be displayed as long as any of the areas remain in nonattainment. Any county not listed has been designated attainment since 1992.

A blank cell for a year indicates either that: 1) none of the NAAQS area(s) the county is in were designated nonattainment in that year, 2) all of the NAAQS areas the county is in had been redesignated to maintenance, or 3) all of the areas the county is in are for a NAAQS revoked prior to that year.

(See the "Nonattainment/Maintenance Area Status for Each County by Year for All Criteria Pollutants" report for a listing of county rows including the area name and additional information.)

For older NAAQS, many areas were nonattainment before 1992 but the 1992 starting year is based on 40 CFR Part 81 designations, effective January 6, 1992.
See: 40 CFR Part 81 (PDF) (165 pp, 9.3 MB, about PDF)

For the newer NAAQS, original area were designated effective as follows: 8-Hour Ozone (2008) areas were designated July 20, 2012; PM-2.5 (2012) areas were designated April 15, 2015; PM-2.5 (2006) areas were designated on December 14, 2009; PM-2.5 (1997) areas were designated on April 5, 2005; SO2 (2010) areas were designated effective on October 4, 2013; Lead (2008) areas were designated on December 31, 2010.

Revoked NAAQS include 1-Hour Ozone (1979) and 8-Hour Ozone (1997). The 8-Hour Ozone (1997) classified area designations were effective on June 15, 2004 and were revoked on April 6, 2015. 1-Hour Ozone (1979) areas were revoked on June 15, 2005. Counties in Revoked NAAQS areas have "NAAQS revoked" appended to the NAAQS description.

The presence of a "W" (whole county) or "P" (part of the county) for a year indicates that the whole county or part of the county was/is in the boundary of one or more nonattainment areas for that year for that NAAQS.

It is important to understand that this data does not indicate which counties were measuring violations year to year. Only air quality data can be used to show which areas/counties are violating.

See the following pages for details about changes in the designation status of the nonattainment areas:

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