Air Quality Achievements
EPA Finds Valley in Attainment of 1997 Annual PM2.5 Standard
In January 2026, EPA determined that the Valley attained the 1997 annual PM2.5 standard of 15 µg/m3 by the attainment date of December 31, 2024, based on air monitoring data from the 2022-2024 period. Reaching this clean air milestone would not have been possible without the significant commitment and investment by Valley residents, businesses, and public agencies to reduce emissions over past several decades.
EPA Finds Valley in Attainment of 1997 24-hour PM2.5 Standard
In January 2022, EPA determined that the Valley attained the 1997 24-hour PM2.5 standard of 65 µg/m3 by the attainment date of December 31, 2020, based on air monitoring data from the 2018-2020 period. This finding also relied upon technical analysis that the Valley’s air monitoring data was impacted by wildfire smoke in 2020, which EPA also approved in July 2021. Reaching this clean air milestone would not have been possible without the significant commitment and investment by Valley residents, businesses, and public agencies to reduce emissions over past several decades.
EPA Finds Valley in Attainment of Federal 1-hour Ozone Standard
In 2015, the District submitted an updated formal request to the California Air Resources Board (CARB) and EPA for a determination that the Valley has attained the federal 1-hour ozone standard, based on air quality data from the 2012-2014 period. In July of 2016, EPA recognized this historic accomplishment by finding the Valley in attainment of the 1-hour ozone standard and reaffirming the effectiveness of the investment and commitment by Valley businesses and residents to reduce emissions and improve public health. Subsequently, on September 25, 2025, EPA approved the 2023 Maintenance Plan and Redesignation Request for the Revoked 1-Hour Ozone Standard as meeting all CAA requirements. EPA also finalized the Valley's attainment redesignation request and terminated all anti-backsliding obligations for the revoked 1-hour ozone standard.
EPA Redesignates San Joaquin Valley to Attainment for Federal PM10 Standard and Approves PM10 Maintenance Plan
In 2008, the U.S. Environmental Protection Agency (EPA) redesignated the Valley to attainment of the federal PM10 standard and approved the 2007 PM10 Maintenance Plan. This historic achievement represents years of hard work by individuals, industry, Valley communities and the District.
