National Ambient Air Quality Standards (NAAQS) and Nonattainment Designations
To view PDF files, you need the Acrobat® Reader®.
National Ambient Air Quality Standards (NAAQS)
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 PM2.5 standard can be downloaded from the EPA website.