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

Slow down – lives are on the line. 

In 2023, speeding continued to be a top reason for work zone crashes.

Even one life lost is too many.

Fatal work zone crashes doubled in 2023 - Washington had 10 fatal work zone crashes on state roads.

It's in EVERYONE’S best interest.

95% of people hurt in work zones are drivers, their passengers or passing pedestrians, not just our road crews.