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Under the Clean Air Act, the EPA is required to review and, if appropriate, revise the air quality criteria for the primary (health-based) and secondary (welfare-based) national ambient air quality standards (NAAQS) every 5 years. On March 23, 2008, the EPA published a final rule to revise the primary and secondary NAAQS for ozone to provide increased protection of public health and welfare. With regard to the primary standard for ozone, the EPA revised the level of the 8-hour ozone standard to 0.075 ppm. With regard to the secondary ozone standard, the EPA made it identical in all respects to the primary ozone standard, as revised. The D.C. Circuit upheld the primary standard, but remanded the secondary standard back to the EPA. The EPA initiated the current review in October 2008 with a workshop to discuss key policy-relevant issues around which EPA would structure the review. This review included the preparation of an Integrated Science Assessment, Risk/Exposure Assessment, and a Policy Assessment Document by the EPA, with opportunities for review by EPA's Clean Air Scientific Advisory Committee and the public.

Overall Description of Deadline: Must be proposed by December 1

Statement of Need:

Under the Clean Air Act Amendments of 1977, EPA is required to review and if appropriate revise the air quality criteria for the primary (health-based) and secondary (welfare-based) national ambient air quality standards (NAAQS) every 5 years.

Summary of the Legal Basis:

Review of the NAAQS is authorized by Clean Air Act Sections 108 and 109.

Alternatives:

The main alternative for the Administrator's decision on the review of the primary and secondary national ambient air quality standards for ozone is whether to retain or revise the existing standards.

Anticipated Costs and Benefits:

The Clean Air Act makes clear that the economic and technical feasibility of attaining standards are not to be considered in setting or revising the NAAQS, although such factors may be considered in the development of State plans to implement the standards. Accordingly, when the Agency proposes revisions to the standards, the Agency prepares cost and benefit information in order to provide States information that may be useful in considering different implementation strategies for meeting proposed or final standards. In those instances, cost and benefit information is generally included in the regulatory analysis accompanying the final rule.

Risks:

Health and welfare risks associated with exposure to O3 in the ambient air have been assessed. The final health and welfare Risk and Exposure Assessments for Ozone were released in August 2014, and are available at: http://www.epa.gov/ttn/naaqs/standards/ozone/data/20140829healthrea.pdf