Canadian Wildfires Drive Detroit, Minneapolis, and Toronto to World's Worst Air Quality

Over 800 wildfires burned across Canada by July 14, most uncontrolled, according to Canada's fire agency. Smoke from Ontario fires degraded air quality in Thunder Bay and Toronto. IQAir ranked Detroit, Minneapolis, and Toronto as the world's three worst for air quality. Northwesterly winds are expected to push smoke into northern US states through the weekend.