Air Toxics

A Closer Look at Air Toxics

Air toxics are a group of over 400 pollutants known or suspected to cause a number of health problems, including cancer and birth defects, as well as damage to lungs, and immune and nervous systems. In our region, the health risk from air toxics comes primarily from fine particles in diesel exhaust.


  • Fact Sheet on Air Toxics (PDF) - An overview of air toxics of greatest concern in our region, as well as actions the Clean Air Agency is taking to reduce air toxics.
  • 2010 Tacoma and Seattle Area Air Toxics Evaluation - Through a study funded by the U.S. Environmental Protection Agency (EPA), the Puget Sound Clean Air Agency and the University of Washington measured the concentrations of toxic air pollutants in Tacoma and Seattle and identified the chief contributors.
  • 2016 Chinatown-International District Air Toxics Study – The Puget Sound Clean Air Agency sampled over 100 air toxics in the community. The study found diesel exhaust is still the primary concern near our major highways. We found 14 other air toxics that were over one-in-a-million potential cancer risk. These toxics and their concentrations were similar to other sites across the country, and are consistent with previous air toxics levels in Seattle and Tacoma.
Air Toxic Graphs