Ozone National Ambient Air Quality Standards (NAAQS)
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Rule Summary
On December 23, 2020, EPA completed its review of the full body of currently available scientific evidence and exposure/risk information and decided to retain the existing ozone NAAQS. EPA’s decision is based on its judgment that the current NAAQS protect the public health, with an adequate margin of safety, including the health of at-risk populations, and protect the public welfare from adverse effects. The existing primary and secondary standards, established in 2015, are 0.070 parts per million (ppm), as the fourth-highest daily maximum 8-hour concentration, averaged across three consecutive years.
Rule History
- 12/23/2020 - Review of the Ozone NAAQS - Final Decision
- 7/13/2020 - Review of the Ozone NAAQS - Proposed Decision
Additional Resources
- Fact Sheet on the Decision
- Scientific and Technical Documents Supporting Current and Past Reviews of Ozone National Ambient Air Quality Standards (NAAQS)
- Basic Information and Fact Sheets Regarding 2015 Revision to 2008 Ozone National Ambient Air Quality Standards (NAAQS)