Last week Seattle was credited with having the worst air quality in the world. According to the air quality monitoring site IQAir, Seattle’s concentration of PM 2.5 — tiny particles less than 2.5 microns in width — on Thursday afternoon was 38 times higher than the annual guideline recommended by the World Health Organization. Smoke drifting in from forest fires in the Cascade Mountains have collected in Seattle, giving the city the worst air quality in the world on Oct. 20.
Those taking notice from West Seattle’s Seacrest Park has observed the skyline which continues to be obscured by a thick haze of smoke. Researchers state that PM2.5 is extremely bad for human health — it can exacerbate respiratory and cardiovascular problems, and frequent high exposures have been shown to affect cognition and children’s test scores.
Seattle’s air quality index, or AQI, reached over 240 last week — a level defined as “very unhealthy” for all groups. The main culprit is wildfire smoke. It was wildfire smoke that made the city’s air worse than Delhi’s or Beijing’s. According to the air quality monitoring site IQAir, Seattle’s concentration of PM 2.5 — tiny particles less than 2.5 microns in width — on Thursday afternoon was 38 times higher than the annual guideline recommended by the World Health Organization.
Weeks of unusually dry and hot weather is also a major factor in why the air quality is worse. On Sunday, Seattle broke a record for the hottest day this late in the fall, at 88 degrees. One expert said that a persistent ridge of high pressure has kept storms from settling over Seattle.
Researchers are trying to understand whether wildfire smoke is worsening — and how it is affecting human health on the West Coast and beyond. Based on previous research that may be the case. Between 2006 and 2010, the researchers found, fewer than 500,000 people every year were exposed to a single day of extreme levels of PM2.5. But between 2016 and 2020, that number climbed to more than 8 million.
