Air Quality
Exposure to impaired air quality
Particle pollution, also called particulate matter (PM), is a mixture of tiny solids or liquid droplets that includes smoke, soot, dirt, and dust floating in the air. PM2.5 (particles less than 2.5 micrometers) is identified as a pollution problem in many Washington communities and is associated with a number of adverse health impacts. This indicator tracks the percent of the Puget Sound population exposed to air quality that does not meet the state healthy air goal for PM2.5 (20 µg/m3).
Exposure to impaired air quality
Percent of the Puget Sound population exposed to air quality that does not meet Ecology’s healthy air goal for fine particulate matter (PM2.5) of 20 µg/m3.

Key Vital Sign Indicator Results

  • In 2020, greater than 99% of the Puget Sound population was exposed to impaired air quality. An extensive and severe wildfire smoke episode in late summer caused unhealthy air quality across the state, with many areas reaching the very unhealthy and hazardous ranges of PM2.5 for several days. All but one monitoring site in the Puget Sound watershed (Neah Bay) recorded 98th percentile PM2.5 concentrations above Washington's healthy air goal of 20 μg/m3. During this smoke event, many monitoring sites set records for their highest concentrations ever recorded. Outside of the wildfire season, PM2.5 concentrations were relatively low.

  • After two consecutive years of prolonged wildfire smoke impacts in 2017 and 2018, calendar year 2019 was marked by a mild wildfire season with very few smoke-impacted days. The exceedances of Washington's healthy air goal of 20 μg/m3 were primarily observed during brief episodes of cold and stagnant weather in the winter months. These episodes occurred with moderate frequency relative to other years. Residential wood combustion is a dominant source of PM2.5 during cold, stagnant weather.

  • In 2017 and 2018, smoke from local and regional wildland fires caused impaired air quality across western Washington for several weeks. The wildfire smoke incidents were so extensive and prolonged that they caused PM2.5 concentrations to rise above Washington's healthy air goal of 20 μg/m3 for an extended period at most monitoring sites in the Puget Sound region. Consequently, the majority of Puget Sound residents were exposed to air quality that did not meet the state's healthy air goal for PM2.5 in both years.

Contributing Partners

Recovery Target

No targets are currently set for this indicator.

Vital Sign Indicator Reporter
Methods and More Results
Last Updated
4/30/2021