National air quality standards

Ecology and local clean air agencies monitor and track emissions to ensure levels of outdoor air pollutants meet federal and state air quality standards. We focus on EPA's "criteria" pollutants and other chemicals broadly known as air toxics. Our programs and strategies prevent air pollution from reaching levels that are harmful to human health or the environment.

Mt. Rainier on a clean air day with good visibility. 

Criteria air pollutants

The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS) for six common air pollutants. We monitor these pollutants and take action if levels become unhealthy. The pollutants are:

Air toxics

EPA established a list of 187 hazardous air pollutants. We regulate about 400 toxic air pollutants from commercial and industrial sources. We prioritized 21 of those toxic air pollutants because of their health risk. To reduce levels of these priority pollutants, we are working to reduce diesel emissions and wood smoke.

Air toxics monitoring

We track air pollution throughout the state. Since 2000, we have been measuring air toxics at our Seattle Beacon Hill air monitoring station. By comparing long-term trends to current readings, we have determined that most toxic pollutant levels are declining. This shows that driving clean cars helps keep the air healthy.

We also partnered with local clean air agencies to identify and monitor pollutants that are the greatest health risk. Reports from some of the studies include: