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Contact EPA Pacific Southwest Air Program

Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Air Actions, California

Additional Areas

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June 2018: (Final rulemaking) Redesignation of the Chico, California Area to Attainment for the 2006 24-hour PM2.5 National Ambient Air Quality Standard (NAAQS)

June 26, 2018: The Environmental Protection Agency has taken final action to redesignate the Chico, California area to attainment for the 2006 24-hour PM2.5 NAAQS, effective August 10, 2018. The EPA has also approved Butte County Air Quality Management District's plan to maintain compliance with the 2006 24-hour PM2.5 NAAQS through 2030.


December 2016: (Final rulemaking) Determination of Attainment of the 2008 Ozone National Ambient Air Quality Standards; Eastern San Luis Obispo, California

December 8, 2016: The Environmental Protection Agency (EPA) is taking final action to determine that the San Luis Obispo County (Eastern San Luis Obispo) ozone nonattainment area (NAA) has attained the 2008 ozone National Ambient Air Quality Standards by the applicable attainment date of July 20, 2016. We received no comments on our proposed action for the same determination.

Contact Information

Nancy Levin (levin.nancy@epa.gov)
Air Planning Office, US EPA, Region 9
(415) 972-3848

Anna Mebust (mebust.anna@epa.gov)
Air Quality Analysis Office, US EPA, Region 9
(415) 972-3265

December 2016: Direct Final and Proposed Determination of Attainment of the 2008 Ozone National Ambient Air Quality Standards; Mariposa County

December 2, 2016: The Environmental Protection Agency (EPA) is taking direct final action to determine that the Mariposa County, California ozone nonattainment area has attained the 2008 ozone National Ambient Air Quality Standards, and proposing a rule based on the same determination. This rule will be effective 60 days after date of publication in the Federal Register unless we receive adverse comments by 30 days after date of publication. If we receive adverse comments, we will publish a timely withdrawal in the Federal Register to notify the public that this direct final rule will not take effect, and we will address the comments in a subsequent final action based on the proposal.

Contact Information

Nancy Levin (levin.nancy@epa.gov)
Air Planning Office, US EPA, Region 9
(415) 972-3848

Anna Mebust (mebust.anna@epa.gov)
Air Quality Analysis Office, US EPA, Region 9
(415) 972-3265


September 2016: (Proposed rulemaking) Determination of Attainment of the 2008 Ozone National Ambient Air Quality Standards; Eastern San Luis Obispo, California

September 28, 2016: EPA is proposing to determine that the San Luis Obispo County (Eastern San Luis Obispo) ozone nonattainment area (NAA) has attained the 2008 ozone National Ambient Air Quality Standards by the applicable attainment date of July 20, 2016. This determination is based on complete, quality-assured and certified data for the 3-year period preceding that attainment date. If this determination is finalized, the Eastern San Luis Obispo NAA will not be reclassified to a higher ozone classification.

Contact Information

Nancy Levin (levin.nancy@epa.gov)
(415) 972-3848


August 2013: Final Rule Determining Attainment for the 2006 24-Hour PM2.5 National Ambient Air Quality Standard in the Chico Nonattainment Area

On August 22, 2013, EPA made a final rule determining that the Chico nonnattainment area in Butte County, California has attained and continues to attain the 2006 24-hour PM 2.5 National Ambient Air Quality Standard.


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