U.S. EPA FACT SHEET
EPA Determinations that Seven Areas in California have Attained
the 1997 Ozone National Ambient Air Quality Standard
August 30, 2012
Summary
•	EPA is determining that seven ozone nonattainment areas in California have attained and
continue to attain the 1997 8-hour ozone National Ambient Air Quality Standard (1997 ozone
NAAQS).
•	The seven ozone nonattainment areas are: Amador and Calaveras Counties, Butte County, Kern
County (Eastern Kern), Mariposa and Tuolumne Counties, Nevada County (Western Part),
Sutter County (Sutter Buttes), and Ventura County.
•	Today's action signifies a milestone of continued air quality improvement in California
accomplished through the joint efforts of the air districts, Air Resources Board, and EPA to
protect public health.
•	EPA is also determining, as required in section 181(a)(2) of the Clean Air Act, that the Amador
and Calaveras Counties, Butte County, Kern County (Eastern Kern), Mariposa and Tuolumne
Counties, Nevada County (Western Part), and Sutter County (Sutter Buttes) nonattainment
areas met their attainment deadlines for 1997 ozone NAAQS.
•	This action suspends certain air planning requirements for these areas as long as they continue
to meet the 1997 ozone NAAQS.
Background
•	EPA's determination is based upon complete, quality-assured, and certified ambient air quality
monitoring data.
•	Today's action does not suspend all of the submittal requirements (e.g., new source review),
and the official attainment status for each of the areas remains nonattainment until California
submits and EPA approves a redesignation request, maintenance plan, and supporting
documentation.
•	Today's action only concerns the 1997 ozone NAAQS. The Amador County, Tuolumne
County, and Sutter County (Sutter Buttes) areas are already attaining the more stringent 2008
ozone NAAQS. Additional progress is needed for the Butte County, Calaveras County, Kern
County (Eastern Kern), Mariposa County, Nevada County (Western Part), and Ventura County
nonattainment areas to also attain the more stringent 2008 ozone NAAQS.
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Next Steps
• EPA is approving this action as a direct final rule without prior proposal because we view this
as a noncontroversial action. If we receive adverse comments, we will withdraw the rule and
address public comments in a subsequent action.
For More Information:
http://www.epa.gov/region9/air/actions/ca.html
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