EPA's Process for Updating the National Ambient Air Quality Standards

Reviewing the National Ambient Air Quality Standards is a lengthy undertaking. First, EPA’s Office of Research and Development develops a “criteria document” a compilation and evaluation of the latest scientific knowledge useful in assessing the health and welfare effects of the air pollutant. In developing this document, EPA must consider the advice of the Clean Air Scientific Advisory Committee (CASAC).

Based on the criteria document, EPA also develops a “staff paper” that helps translate the science into terms that can be used for making policy decisions. The staff paper, prepared by staff in EPA’s Office of Air Quality Planning & Standards, includes recommendations to the EPA Administrator about any revisions to the standards needed to ensure that they protect public health with an adequate margin of safety, and that they protect the environment and the public welfare.

Before either the criteria document or staff paper can be used as the basis for any policy decisions, they undergo rigorous review by the scientific community, industry, public interest groups, the general public and CASAC. Based on the scientific assessments in the criteria document and on the information and recommendations in the staff paper, the EPA Administrator determines whether it is appropriate to propose revisions to the standards.

Information on EPA's revised process for reviewing the NAAQS