The city in Washington state has been choked in a shroud of haze all week but on Thursday morning, Seattle reached 240 on the Air Quality Index (AQI), putting it top of the “very unhealthy” range, according to IQAir, a global monitoring service.
The nearby city of Portland, Oregon had the second-worst air quality, and Vancouver in British Columbia was fourth.
Wildfires are burning across the Cascade Mountains which stretch from western Canada to California and run west of Seattle. The Bolt Creek Fire has burned nearly 15,000 acres in the mountains — an area more than 17 times the size of New York’s Central Park. The fire, which started last month, remains just 43 per cent contained.
However residents may soon get a reprieve as rainy weather is expected to move in this weekend and sweep away some of the smoke.
Seattle also had the worst air quality in the world at one point on Wednesday, reports the Seattle Times.
In conditions of such poor air quality, the Washington State Department of Health recommends that people stay inside, use air filters or even leave the region to avoid breathing polluted air, if possible.
The city school district recommended that students stay indoors and limit physical activity as a result of the haze this week, the Times added.
A recent study has even found that smoke from wildfires is undoing “decades of policy-driven improvements in overall air quality,” such as the long-term benefits of the 1963 Clean Air Act.
The small, airborne particles released by a wildfire can get deep into human lungs and even into the bloodstream, according to the Environmental Protection Agency. Small particle pollution has been associated with health issues like asthma, heart disease and respiratory illnesses.
As the planet gets hotter, the western US is likely to see more frequent and severe droughts and heatwaves — perfect conditions for wildfires to spark and grow rapidly.
While this year has been a relatively quiet fire season in Washington state, the three most destructive fire years on record have occurred in the last seven years, Axios reported.