Detroit’s air quality among the world’s worst Wednesday due to Canadian wildfire smoke

Detroit had some of the worst air quality among major cities across the world Wednesday morning, according to IQAir’s air quality index, thanks to the wildfire smoke drifting south from Canada, though conditions have since slightly improved.

Only Delhi, India, had worse air quality than Detroit among major cities as of 10 a.m. Wednesday morning, with an air quality index of 191 compared to Detroit’s 164. New York City followed close behind with 161. These numbers fluctuate throughout the day, though Detroit consistently ranked in the Top 5 on Wednesday morning.

By Wednesday afternoon, Detroit had dropped out of the Top 20.

AirNow.gov, meanwhile, measureed Detroit’s air quality index at 120 as of Wednesday afternoon, which qualifies as unhealthy for sensitive groups. In the morning, it was up to 173, considered unhealthy for the general public.

Air quality is determined by the number of pollutants in the sky; the main culprit in Detroit is the PM2.5 pollutant, a fine particulate matter that causes the sky to look hazy and reduces visibility.

Canada wildfire smoke updatesFlight delays at NYC airports; air quality map

Unusually hot and dry weather this time of year have led to more hazardous conditions, including wildfires in eastern Canada and northern Michigan that have led to smoke and haze in the state’s skies, the National Weather Service said Monday. Southeast Michigan is experiencing the worst of it, including Detroit, Ann Arbor (124) and Pontiac (155).

In late May, wildfires from Alberta drifted over Michigan’s skies, though the smoke was too high to cause air pollution for residents.