Findings from the 2025 report on overburdened communities highly impacted by air pollution

Air quality in Washington's communities most highly impacted by air pollution has improved in recent years, potentially because of lower wildfire activity and lighter traffic during the height of the COVID-19 pandemic. This is according to a newly published report from Ecology and the Washington State Department of Health (DOH).

While the findings show there were fewer days with unhealthy air in these areas compared to data in a previous 2023 report, there remains disparities between those communities and the rest of the state. Though the entire state meets federal air quality standards, these differences in air quality continue to result in higher estimated rates of death and hospitalization in overburdened communities, compared to Washington averages.

Understanding the report

The 2025 report on overburdened communities highly impacted by air pollution is the second edition of this analysis, which is required under the Climate Commitment Act. Air pollution and health data were gathered in 16 of Washington's most highly impacted communities through 2024, which a team of scientists at Ecology and DOH compiled and analyzed throughout 2025. The team tracked the presence and health impacts associated with criteria air pollutants, like fine particulate matter (PM_2.5) and ozone (O₃). They also evaluated how greenhouse gas emissions from stationary sources, like factories, and from mobile sources, like cars, changed over time since the 2023 report. The findings of the 2025 report will inform Ecology's work in communities, grant opportunities, air monitoring strategy, and rulemaking related to the Climate Commitment Act.

Report highlights

On the whole, criteria air pollution levels decreased from 2022-2024 and were consistently below federal standards. However, the elevated levels of criteria air pollution in these communities still increase the risk of developing heart and lung diseases. Kirsten Dodroe, the report's lead author, says there are a couple of major factors that impacted air quality and health in all 16 communities.

"Wildfire smoke is a significant contributor to criteria air pollution in many of the communities included in this report," says Dodroe. "However, we observed relatively lower impacts from wildfire smoke in 2023 and 2024 as compared to the first report. This resulted in dramatically fewer days of unhealthy air quality in these 16 communities during the reporting period."

Examining the most recently available mobile source data from 2019 to 2021, Dodroe noted, "with fewer people commuting to work during the height of the pandemic, greenhouse gas emissions from vehicles were down by about 5% in these communities."

When asked if these air quality improvements may be temporary, Dodroe is careful not to speculate.

"This report certainly demonstrates the importance of lowering greenhouse gas emissions to slow the progression of climate change," says Dodroe. "Climate change both exacerbates the intensity of wildfire seasons and extreme heat events, which put community members at risk of developing heart and lung diseases associated with air pollution. We can reduce these risks by starting fewer accidental wildfires, and electrifying transit and home heating."

For a full breakdown of community highlights, visit the publication page for the report and scroll down to your area of interest.

The following is not an exhaustive list of all report findings:

• Between 2022 and 2024, overburdened communities highly impacted by criteria air pollution experienced as many as 8.3 days or as few as 0 days when air quality was considered "unhealthy for sensitive groups" or worse, for an average of 2.9 days of unhealthy air averaged across all 16 areas.
  • This is down from an average of 7.5 days (range 4.3-12) in the previous reporting period (2020-2022).
• Criteria air pollutants that were monitored within overburdened community boundaries were below the limits of the National Ambient Air Quality Standards (NAAQS).
• According to 2024 Center for Disease Control data, the rates for chronic diseases like asthma, cardiovascular disease, COPD, diabetes, and stroke in the 16 overburdened communities outpace statewide rates.
• In Ecology's statistical models, yearly PM_2.5 exposure in the 16 overburdened communities was associated with an estimated 430 deaths by any cause among adults ages 18-84 and 261 deaths among older adults ages 65-99.
  • The highest estimated rates are seen in East Yakima, Lower Yakima Valley, and Spokane and Spokane Valley.

Visit Ecology's website to learn more about our ongoing work in overburdened communities.