SEATTLE — Wildfire smoke is pushing the Seattle-Tacoma region into unfamiliar territory, with the area now ranking among the nation’s worst metropolitan areas for short-term particle pollution, according to a new report.
The American Lung Association’s (ALA) newly released State of the Air 2026 ranks Seattle-Tacoma as the eighth-worst metro area in the United States for daily fine particulate pollution, known as PM2.5, a shift for a region long associated with relatively clean air. The ALA attributes the worsening short-term pollution largely to increasingly severe wildfire smoke events across the Pacific Northwest and western Canada.
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PM2.5 consists of microscopic airborne particles that can penetrate deep into the lungs and bloodstream. Exposure has been linked to asthma attacks, heart disease, respiratory illness, stroke and premature death, according to the ALA.
Despite Seattle-Tacoma’s poor showing for short-term spikes in particle pollution, the report offers a more nuanced view of the region’s overall air quality. Seattle-Tacoma did not appear in the report’s “Worst 25” rankings for ozone pollution or annual year-round particulate pollution, suggesting air quality remains relatively good outside wildfire smoke seasons.
The ALA said worsening wildfire activity is increasingly reshaping air quality across the West.
“Smoke from wildfires continues to be reflected in the severity of the grades for particle pollution,” the report stated.
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The findings also highlight how climate change is altering environmental risks in the Pacific Northwest. Seattle’s marine climate and coastal airflow have historically helped limit smog formation compared with cities such as Los Angeles or Phoenix. But, more intense wildfire seasons have increasingly shifted the region’s air pollution profile away from chronic smog and toward episodic smoke events.
The report notes smoke exposure has become more frequent, longer-lasting and more severe in recent years as fires grow larger across Washington, Oregon, British Columbia and California. During major smoke episodes, air quality in Seattle has occasionally reached “Very Unhealthy” or “Hazardous” levels under federal air quality standards.
The ALA warns that vulnerable groups face the greatest risk during smoke events, including children, older adults, pregnant individuals, and people with asthma, COPD or cardiovascular disease. In the Seattle-Tacoma metro area, the report estimates there are more than 1 million children under 18, 831,000 adults over 65, 448,000 adults with asthma, and 184,000 people living with COPD.
Even as the region’s particle pollution ranking worsened, several Washington counties — including Pierce, Skagit and Thurston — were recognized among the cleanest in the nation for ozone pollution.
The report also points to emerging concerns about growing electricity demand and data center expansion, which could add pollution pressures in regions such as the Pacific Northwest as artificial intelligence and cloud infrastructure rapidly expand.
Overall, the report underscores a growing reality for the Seattle region: While traditional urban smog remains comparatively low, wildfire smoke and climate-driven air pollution are becoming defining environmental challenges for the Pacific Northwest.
