Wildfire smoke continues to blanket Seattle and the Northwest, afflicting residents with some of the worst air since the wildfires two years ago.

A monitor in King County registered Saturday a reading of 153 PM 2.5, a measure of tiny airborne particles that are 2.5 micrometers in diameter. (Think: 30 times smaller than a hair from your head.) That preliminary data appears to be the worst pollution in almost two years, when Gov. Jay Inslee said air quality in the state was at “historically polluted levels.”

Saturday was by far King County’s worst day of 2022, which to this point has had cleaner air than the five-year average. Before 2020, the county registered its highest pollution levels in August 2018, when six days topped 150 PM 2.5.

Air quality has marginally improved Sunday throughout the Seattle region, with readings of 90 PM 2.5. 

Wildfire evacuations, Stevens Pass closure remain amid Bolt Creek fire

Port Townsend and Port Angeles had poorer air quality Sunday afternoon, with readings considered unhealthy for sensitive groups, while Marysville, Mount Vernon and Bellingham were bearing the worst, with unhealthy air quality.  

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State officials suggest people limit time outdoors, avoid strenuous activity, close windows and doors, and use a HEPA filter if possible. 

There is some good news on its way, however: “The weather conditions that brought the very dangerous fire pattern to Western Washington have started to ease quite a bit,” said Matthew Dehr, the Washington State Department of Natural Resources’ wildland fire meteorologist.  

Dehr expects conditions by midweek to improve the air quality significantly. 

“By Tuesday we should see nice clear sunshine here on the west side of the state,” he said. 

That’s thanks to cooler, autumnal temperatures and onshore flow conditions, said Samantha Borth, a forecaster with the National Weather Service in Seattle. 

“We’re looking at temperatures in the upper 70s to low 80s for much of the region,” with even cooler temperatures on the coast, Borth said. Some light precipitation also may fall in the Seattle area throughout the coming week. 

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In an effort to provide relief from the smoke, the King County Regional Homelessness Authority has activated a severe weather shelter at Compass Housing Alliance’s day center, which will provide 50 beds for people to stay overnight at 77 S. Washington St. in Seattle.

Wildfire closes Stevens Pass, sends residents and hikers fleeing, and drops ash across Western WA

Across the Cascades, air quality is also at unhealthy levels in the Tri-Cities, Spokane and Pullman area because of wildfires in Idaho, Montana, and Oregon. 

“They have not had as strong of winds as we’ve had here,” Dehr said. “So what’s happening there is the smoke’s really just kind of settling there due to the lack of winds to transport it away.”

A storm system is expected statewide early next week to disperse that smoke. Meanwhile, a red flag warning remains in effect for most of Western Washington, meaning fire risk is high. King County’s Stage 2 burn ban also remains in place, prohibiting all outdoor recreational fires.