As Canada grapples with one of its worst wildfire seasons on record, smoke from the blazes have prompted air quality alerts across the U.S.

Air quality has taken a serious hit across the United States as a twofold blow of wildfires in the West and in Canada have sent smoke pouring across large sections of the country — a problem that’s set to linger for days.

Smoke from Canadian wildfires has drifted thousands of miles across the U.S., remaining suspended in the atmosphere for days, according to CNY Central. Meteorologist Violet Scibior explains that intense heat pushes smoke up to 5 miles high into the jet stream,