Hundreds of wildfires still burning in Canada are expected to undermine air quality across the Upper Midwest and Northeast into Tuesday.

With hundreds of wildfires burning across Canada, smoke has drifted into the northern United States, lowering air quality across roughly a dozen states.

Smoke from nearly 200 uncontrolled wildfires in Canada is triggering widespread air quality alerts across the Upper Midwest and Northeast. Fires in Saskatchewan, Manitoba, and Ontario have scorched more than 16.