Detroit was ranked as having the world’s worst air quality on Thursday after smoke from wildfires near the Minnesota-Ontario border in Northern Ontario blanketed Michigan and spread across other parts of the United States.
According to IQAir, Detroit’s Air Quality Index (AQI) reached 426, well above the hazardous threshold of 301. By 11:30 a.m. on July 16, the city’s AQI had climbed to 724. AirNow also classified the Metro Detroit area as having hazardous air quality.
Four North American cities dominate global air pollution rankings
As of 11 AM on July 16, IQAir ranked the world’s five cities with the worst air quality as:
- Detroit, USA
- Toronto, Canada
- Minneapolis, USA
- Chicago, USA
- Kinshasa, Democratic Republic of the Congo
Toronto recorded an AQI of 360, while Minneapolis registered 349.
Under the US AQI scale, readings of 0-50 are considered “Good,” 51-100 “Moderate,” 101-150 “Unhealthy for Sensitive Groups,” 151-200 “Unhealthy,” 201-300 “Very Unhealthy,” and any reading above 301 is classified as “Hazardous.”
More than 800 wildfires are currently burning across Canada. According to the Canadian Wildland Fire Information System, there are 858 active fires, including 30 new fires reported on Thursday, with the vast majority burning out of control.
Air quality alerts now extend across multiple US states. The US Air Quality Index program classifies air quality in large parts of northern Michigan and Minnesota as “hazardous,” with residents advised to stay indoors. The US National Weather Service (NOAA) said alerts span the Upper Midwest, the Great Lakes region and into the Northeast.
The large cluster of fires in northwestern Ontario has sent thick smoke across Thunder Bay and Toronto, while lighter concentrations of smoke have drifted over the Great Lakes and above New York, creating hazy skies and redder sunrises and sunsets.
In western New York, air quality on Thursday was considered “very unhealthy,” while the New York City metropolitan area recorded “unhealthy” conditions. On Wednesday, New York activated its air quality emergency protocols alongside its heat emergency plans, opening hundreds of cooling centers and making KN95 masks available citywide.
Forecasters said northwesterly winds will continue pushing smoke into northern US states through the weekend, raising concerns that smoke could drift into New Jersey ahead of Sunday’s World Cup final. A change in wind direction by Monday is expected to steer the smoke toward Quebec, improving air quality farther south in the United States.