Air Quality Designations for Particle Pollution
- On February 7, 2024, the EPA promulgated a revised primary annual PM2.5 NAAQS, strengthening the standard from 12.0 micrograms per cubic meter (µg/m3) to 9.0 µg/m3. Learn More
- On February 21-22, 2024, the EPA will hold two informational webinars to provide an overview of the PM2.5 designations process. Learn More
Title I of the Clean Air Act requires that after we set a new National Ambient Air Quality Standard (NAAQSStandards established by EPA for maximum allowable concentrations of six "criteria" pollutants in outdoor air. The six pollutants are carbon monoxide, lead, ground-level ozone, nitrogen dioxide, particulate matter, and sulfur dioxide. The standards are set at a level that protects public health with an adequate margin of safety.) or we revise an existing standard, we must then designate areas in the United States as being in “attainment” or “nonattainment” with the standard.
This website provides information on the process EPA follows to designate areas as being in attainment or nonattainment with the standards for . EPA uses technical information and recommendations from states and tribes to "designate" areas as attainment or nonattainment.