Wildfire smoke is invading more than 20 states — doctors reveal who should worry most

Canadian wildfire smoke is drifting across parts of the U.S., prompting doctors to warn that even healthy people may face risks from prolonged exposure to polluted air.

More than 180 wildfires are burning in Ontario alone, while nearly 850 are active across Canada, sending smoke into the Midwest and Northeast, according to NASA.

More than 20 states have been affected, prompting widespread air quality alerts from the Upper Midwest to the East Coast.

DOCTORS WARN YOUR 'STOMACH...