Criteria Air Pollutants

Our job is to ensure the people of King, Kitsap, Pierce and Snohomish counties have clean, healthy air to breathe. We do this in part by ensuring our region meets federal air quality standards for six common air pollutants known as "criteria air pollutants." Criteria air pollutants include: particle pollution, ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, and lead.

Our efforts to reduce carbon monoxide, sulfur dioxide, nitrogen dioxide and lead in our air continue, although levels of these pollutants are now well below federal air quality standards.

Criteria Pollutants of Concern

Two criteria air pollutants, however, remain of concern to our region: particle pollution and ozone (smog). Exposure to particle pollution (including diesel exhaust and wood smoke) and ozone can cause heart attacks, strokes, asthma attacks and even premature death. These impacts affect our quality of life and our economy.

Recent studies consistently show that these pollutants cause harm, even at levels that meet national standards. We aim to reduce pollution to levels well below the existing standards to better protect public health.

  1. Particulate Matter
  2. Ozone

Particulate Matter

Dust, dirt, soot, smoke – in air quality lingo are considered “particulate matter,” or “particle pollution.” Particle pollution is one of the six criteria air pollutants monitored and regulated by the Clean Air Agency. Easily inhaled into our lungs, particle pollution poses a host of serious health effects and represents the most important criteria air pollutant challenge facing our region.

What is Particle Pollution?Airborne Particle Pollution Diagram

Particle pollution refers to tiny solid or aerosol particles in the air. They measure a fraction the diameter of a human hair and easily enter our bloodstream and cause health problems such as breathing troubles, heart and lung disease, stroke and premature death. Children, older adults and people with respiratory illnesses are especially at risk.

How Are Particle Pollution Levels in the Puget Sound Region?

Though we’ve made progress in reducing particle pollution over the years, we still have work to do. Wood smoke from wood stoves and outdoor burning continue to be a major source of particle pollution, especially in colder winter months.

What Can Be Done to Reduce Particle Pollution?Sources of Wintertime Particle Pollution Graph

Opt for alternatives to wood-burning for home heating like natural gas and propane; reduce driving and choose cleaner cars and fuels; and refrain from lighting outdoor fires – these are all steps we can take to reduce particle pollution. Public and private fleets that rely on diesel fuel can look into our Diesel Solutions program for additional ways to reduce particle pollution from fleet operations.