On this page:

• Rule Summary
• Rule History
• Additional Resources

Rule Summary

EPA revised the primary and secondary national ambient air quality standards (NAAQS) for ozone (O3) to provide protection of public health and welfare in 2008. The revision is based on EPA’s review of the air quality criteria for ozone (O3) and related photochemical oxidants and for O3.

With regard to the primary standard for O3, EPA revised the level of the 8-hour standard to a level of 0.075 parts per million (ppm), to provide increased protection for children and other ‘‘at risk’’ populations against an array of O3- related adverse health effects. With regard to the secondary standard for O3, EPA revised the standard to make it identical to the revised primary standard.

Rule History

01/19/2010 - Proposed Rule

03/27/2008 - Final Rule

07/11/2007 - Proposed Rule

Additional Resources

Fact Sheet- 2008 Final Revisions to the National Ambient Air Quality Standards for Ozone

Scientific and Technical Documents Supporting the 2008 Review of the Ozone Standards

Information on the Interstate Transport "Good Neighbor" Provision for the 2008 Ozone National Ambient Air Quality Standards (NAAQS) under Clean Air Act (CAA) Section 110(a)(2)(D)(i)(I)

Policy for Establishing Separate Air Quality Designations for Areas of Indian Country Memorandum

Related Rules

1997 National Ambient Air Quality Standards (NAAQS) for Ozone

Implementation of the 2008 National Ambient Air Quality Standards (NAAQS) for Ozone: State Implementation Plan (SIP) Requirements

2015 National Ambient Air Quality Standards (NAAQS) for Ozone