Air quality has taken a serious hit across the United States as a two-fold 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.

Wildfire smoke from the Bear Gulch Fire is affecting air quality across western Washington. Prolonged exposure to smoke can harm lungs, especially for vulnerable groups like children and seniors. Experts advise staying indoors, using masks, and checking air quality updates online for safety.

Millions of Americans across the Midwest, Northeast and swathes of the South and Southwest are under air quality alerts Monday. Newsweek's live blog is closed.