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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 that EPA set National Ambient Air Quality Standards (NAAQS) for six common air pollutants. We are required to monitor the six pollutants and alert you when levels become unhealthy. The pollutants are:

Air toxics

EPA established a list of 187 hazardous air pollutants. Washington state rules define even more than that. In total, we regulate the emissions of about 400 toxic air pollutants from commercial and industrial sources. Twenty of those have been identified as priorities because they present a risk to public health. We are working to reduce diesel emissions and wood smoke to reduce levels of these priority pollutants. 

Air toxics monitoring

We have been monitoring air toxics from our Beacon Hill station in Seattle since 2000. Air samples are collected from this site every six days. By analyzing long term trends with current readings, we have determined that toxic pollutant levels are declining. This is an indicator that driving clean cars and our State Implementation Plans (SIPs) are working to protect air quality.

We also partnered with local clean air agencies to monitor air toxics and identify pollutants, and where they come from, that are the greatest health risks to the public. Below are reports from some of the studies: