Seattle air pollution ranks among worst in U.S., report finds
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Seattle's air quality is among the worst in the nation for short-term particle pollution, according to a new report.
Why it matters: The findings come as the White House is reconsidering EPA rules and regulations meant to curb pollution and promote cleaner air.
Driving the news: Nearly half of Americans are now exposed to potentially dangerous levels of ozone or particle pollution, per the American Lung Association's 2025 State of the Air report.
- That's almost 25 million more compared with last year's report, and the highest number in the past decade of the report's history.
Zoom in: The Seattle-Tacoma area ranked No. 9 nationally for worst short-term particle pollution, per the report.
- It ranked No. 54 worst for ozone pollution and No. 107 worst for year-round particle pollution out of more than 200 metropolitan areas.
- King County, home to Seattle, received a grade of "F" for both ozone and daily particle pollution but "passed" for annual particle pollution since the average stayed below federal limits.
Threat level: Year-over-year EPA data shows that Seattle's air quality is getting worse over time, with fine particle pollution rising more than 17% in the last decade.
- The average percentage of fine particle pollution in the Seattle metro area, which includes Bellevue and Tacoma, increased from 6.28 micrograms per cubic meter in 2014-16 to 7.4 micrograms in 2021-23, per the EPA.
- Seattle's air pollution is about 10% higher than in similarly sized U.S. cities, largely due to industrial activity and busy transportation corridors, with fossil fuels as the main source, IQAir CEO Glory Dolphin Hammes told KIRO Newsradio.
Yes, but: Climate-related factors— including extreme heat, wildfires and drought — are also degrading air quality nationwide, the Lung Association says.
How it works: The ALA report used local air quality data from 2021 to 2023 to grade and rank locations based on ozone pollution, daily particle pollution and annual particle pollution.
- Ozone is a gas that, at ground level, is a harmful irritant. Particle pollution involves tiny airborne particles from wildfires, fossil fuel burning and more.
The intrigue: The "geographic distribution of air pollution" shifted eastward toward the end of the covered period, the report notes, due in part to smoke from wildfires in Canada.
What they're saying: Pollution rules need to be strengthened, not rolled back, as climate-driven wildfires and heat waves worsen, said ALA clean air policy director Katherine Pruitt.