Air Quality

Our mission is to improve air quality by ensuring that all CDOT projects and operations comply with federal and state air quality laws and regulations, and by promoting strategies that reduce emissions of motor vehicle pollutants. CDOT evaluates air quality impacts of its transportation projects under 40 CFR Part 93 – Determining Conformity of Federal Actions to State or Federal Implementation Plans (Conformity Regulation) to ensure that the project will not cause or contribute to a violation of the National Ambient Air Quality Standards (NAAQS). CDOT evaluates mobile source air toxics and greenhouse gas/climate change emissions for projects that are not Categorically Exempt under the National Environmental Policy Act (NEPA).

Conformity regulations apply only to nonattainment areas and attainment/maintenance areas that have not yet reached their 20-year conformity end dates. Go to Maintenance Area Conformity End Dates and FAQs to see which maintenance areas no longer need to comply with transportation conformity requirements.