What is ozone?
Ground level ozone impacts public health. Ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of heat and sunlight. The Valley experiences its highest ozone levels in the summer. EPA has established ozone standards based on 1-hour averaging periods, and for 8-hour averaging periods. More information is available on EPA’s website.
Adopted Ozone Plans
- 2020 RACT Demonstration
The District adopted the 2020 RACT Demonstration for the 2015 8-Hour Ozone Standard on June 18, 2020.
- 2016 Plan for the 2008 8-Hour Ozone Standard
The District adopted the 2016 Plan for the 2008 8-Hour Ozone Standard in June 2016. This plan satisfies Clean Air Act requirements and ensures expeditious attainment of the 75 parts per billion 8-hour ozone standard.
- Summary of Rule 4694 Analyses under the 2016 Ozone Plan
Summary of District modeling analyses conducted in accordance to commitments in the 2016 Ozone Plan to understand the potential ozone improvements that may be brought about by requiring further VOC controls for wine fermentation.
- 2014 RACT SIP
The District adopted the RACT Demonstration for Ozone SIP in June 2014.
- 2013 Plan for the Revoked 1-Hour Ozone Standard
The District adopted the 2013 Plan for the Revoked 1-Hour Ozone Standard in September 2013.
Flares Further Study
District Rule 4311 (approved by EPA on November 3, 2011) reduces emissions from flaring activities in the San Joaquin Valley through a combination of emission limitations, monitoring, reporting, and other requirements. This study includes an assessment of the implementation of Rule 4311 and an evaluation of potential opportunities for additional requirements.
- 2009 RACT SIP
The District adopted the RACT Demonstration for Ozone SIP in April 2009.
2007 Ozone Plan
The District adopted the 2007 Ozone Plan in April 2007. This plan addresses EPA’s 8-hour ozone standard of 84 parts per billion (ppb), which was established by EPA in 1997.
- 2004 Extreme Ozone Attainment Demonstration Plan
The District adopted this plan in October 2004 to address EPA’s 1-hour ozone standard. However, since EPA revoked this standard in 2005, EPA did not act on this plan until 2010, when a court decision required EPA action. EPA’s 2010 action approved the plan, but subsequent litigation led to a court finding that EPA had not properly considered new information available since the District adopted the plan in 2004. EPA thus withdrew its plan approval in November 2012, and the District and ARB withdrew this plan from consideration. While the 2004 plan is not a federally-approved plan, it is included here for reference.
Upcoming Ozone Plans
2022 Plan for the 2015 8-Hour Ozone Standard
The U.S. Environmental Protection Agency (EPA) set the latest national ambient air quality standard (NAAQS) for 8-hour ozone at 70 parts per billion (ppb) effective December 28, 2015. EPA designated the San Joaquin Valley as Extreme nonattainment for this standard in August, 2018, with an attainment deadline of 2037. The District is mandated under federal Clean Air Act requirements to develop a new attainment plan for the revised ozone standard by 2022. Despite the significant air quality progress that has been made in the Valley, addressing the 2015 8-hour ozone standard will pose a challenge for the San Joaquin Valley given the naturally high background ozone levels and ozone transport into the Valley. Significant further emissions reductions will be needed to come into attainment of the stringent new standard. This will require concerted ongoing effort by the District, working closely with Valley residents, businesses, and other stakeholders, to continue implementing effective and efficient air quality.
The attainment plan for the 2015 federal ozone standard will build upon comprehensive strategies already in place from adopted District plans and California Air Resources Board (CARB) statewide strategies. The NOx reduction commitments from the recent 2018 PM2.5 Plan and 2016 Ozone Plan, and other ongoing measures will assist the Valley in meeting the 70 ppb federal ozone standard. Strategies for attainment of the 2015 8-hour ozone standard will be developed through a public process, building on decades of effective control strategies. District staff will present regular updates regarding the development of the plan at public meetings and workshops, including upcoming meetings of the District Governing Board, Citizens Advisory Committee (CAC), and the Environmental Justice Advisory Group (EJAG).
For information on public workshops for the development of this plan click here.
For email notifications on District plan development activities sign up here.
Attainment of the 1-hour Ozone National Ambient Air Quality Standard
For the first time in recorded history, in 2013, the Valley had zero violations of the 1-hour ozone standard established by EPA under the federal Clean Air Act. The Valley now meets the 1-hour ozone standard based on air monitoring data. As such, the District submitted an attainment request to EPA in May 2014.
1-Hour Ozone Attainment Request
- On May 6, 2014, the District submitted a formal request that the EPA determine that the Valley has attained the federal 1-hour ozone standard, allowing nonattainment penalties to be lifted under federal Clean Air Act section 179B.
- On July 13, 2015, the District submitted a second formal request that the EPA determine that the Valley has attained the federal 1-hour ozone standard, allowing nonattainment penalties to be lifted under federal Clean Air Act section 179B.
On July 18, 2016, EPA published in the Federal Register a final action determining that the San Joaquin Valley has attained the 1-hour ozone national ambient air quality standard. This determination is based on the most recent three-year period (2012-2014) of sufficient, quality-assured, and certified data.