Air quality, energy & greenhouse gas emissions

All WSDOT projects must comply with the Clean Air Act and Amendments of 1990, the Washington State Clean Air Act, local requirements, and follow agency guidance. Use the webpages linked below to determine what type of analysis and documentation your project requires and for instruction on completing required analyses and documentation.

Determine what type of analyses your project will require

WSDOT addresses air quality, energy, and greenhouse gas emissions from projects together because they often use the same tools, however each analysis has slightly different triggers.

Refer to the Analysis decision tree (PDF 564KB) to determine which types of analyses your project requires. If your WSDOT project needs an analysis, inform the Environmental Documentation and Permit Specialist assigned to your project.

  • Air quality conformity - see list of exempt project types in WAC 173-420-110
  • Mobile source air toxics (MSAT) emissions
  • Greenhouse gas (GHG) emissions
  • Energy
     

166,800 electric vehicle

registrations in Washington in 2023, up from 114,600 in 2022.

87 wetland compensation sites

actively monitored on 918 acres in 2023.

25,000 safe animal crossings

in the Snoqualmie Pass East Project area since 2014.