US EPA

The Integrated Science Assessment for Ozone and Related Photochemical Oxidants is a concise synthesis and evaluation of the most policy-relevant science, and has been prepared as part of the review of the primary (health-based) and secondary (welfare-based) National Ambient Air Quality Standards (NAAQS) for Ozone and Related Photochemical Oxidants under the Clean Air Act. Welfare effects are non-health effects which, according to the Clean Air Act include, but are not limited to, effects on soils, water, crops, vegetation, animals, wildlife and climate. The Ozone ISA, in conjunction with additional technical and policy assessments, provides the policy relevant scientific information necessary to conduct a review of the current primary and secondary air quality standards for Ozone sufficiently protects public health and welfare.

EPA has established NAAQS for six criteria pollutants. Presently the EPA is reviewing the air quality criteria and NAAQS for photochemical oxidants and ozone; ozone is the current indicator for this NAAQS. Periodically, EPA reviews the scientific basis for these standards by preparing an Integrated Science Assessment (ISA). The ISA, in conjunction with additional technical and policy assessments, provides the policy relevant scientific information necessary to conduct a review of the current NAAQS and the appropriateness of possible alternative standards. These reviews play a significant role in EPA’s commitment to ensuring a clean and healthy environment for the public.

This report provides critical evaluation and integration of the evidence on health and environmental effects of ozone to support EPA's Office of Air with the review of the NAAQS for ozone.

U.S. EPA. Integrated Science Assessment (ISA) for Ozone and Related Photochemical Oxidants (Final Report, Apr 2020). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-20/012, 2020.