National Ambient Air Quality Standards (NAAQS) and Nonattainment Designations

To view PDF files, you need the Acrobat® Reader®.

National Ambient Air Quality Standards (NAAQS)

2008 8-hour Ozone Standards

2006 PM2.5 and PM10 Standards

Nonattainment Designations under the 1997 8-Hour Ozone and PM2.5 Standards

Transportation Conformity Rule Amendments to Address the 1997 Standards

An Introduction to Particulate Matter for Transportation Officicals (or PDF - 296 KB)

Particulate Matter (PM2.5) Nonattainment Area Maps

8-hour Ozone Nonattainment Area Maps

Associated EPA Guidance:

• Transportation Conformity and the Revised 24-hour PM2.5 Standard. A PDF copy of this guidance can be downloaded from the EPA Website
• Conformity Information to Inform PM-2.5 Designations
• Designations for the Fine Particle National Ambient Air Quality Standards. A PDF copy of this guidance for designating nonattainment areas under the PM_2.5 standard can be downloaded from the EPA website.