National Ambient Air Quality Standards

Updated: September 3, 2024

Federal standards that set allowable concentrations in ambient air for indicator pollutants. Pollutants regulated under the NAAQS include ozone, particulate matter, lead, carbon monoxide, sulfur oxides, and nitrogen oxides.

EPA Proposes Action on Marginal Nonattainment Areas for 2008 Ozone Standard
EPA publishes the Proposed Rule for Determinations for the 2008 Ozone NAAQS
EPA Sets New Ozone Standard at 70 ppb
EPA’s Final Action on Marginal Areas under 2008 Ozone NAAQS published in the Federal Register
EPA publishes the Implementation Rule for the 2015 Ozone NAAQS