DETROIT: Thick smoke from hundreds of wildfires burning across Canada engulfed a vast stretch of the United States from the Midwest to the Northeast on Thursday, prompting urgent health warnings and forcing officials to urge residents to remain indoors as hazardous air quality readings shattered records.
Detroit registered the worst air quality of any major city worldwide Thursday, according to monitoring firm IQAir, with a pollutant index reading of 600, double the level the U.S. Environmental Protection Agency classifies as “hazardous.”
Federal data showed dangerous concentrations of fine particulate matter across Minnesota, Michigan, northern Illinois, northern Ohio and into Ontario, with hazardous readings in Minneapolis, Milwaukee and Toronto. At least 10 states reported locations with “unhealthy” air quality, stretching from Minnesota southward to Maryland.
In Chicago, the smoke obscured the skyline and left a burning scent in the air, according to reports.
“It’s wild because when you look outside you think it’s fog, and it’s completely covered the city, and it’s smoke, because when we walk outside it burns,” said Stephanie Villanova, 33, who was walking downtown with her 68-year-old father. Both wore face masks.
The Minnesota Star Tribune reported the cancellation of outdoor shows, fairs and other events Thursday due to poor air quality, including a concert by the rock band Creed at Mystic Lake Amphitheater outside Minneapolis. The Minneapolis Park and Recreation Board also closed municipal swimming pools, nature camps, golf courses and all outdoor events and programs.
In Minnesota’s northeastern Iron Range region along Lake Superior, including Duluth and Hibbing, fine-particulate concentrations reached as high as 900 micrograms per cubic meter — triple the threshold considered hazardous, according to the state Pollution Control Agency.
“It’s basically a river of smoke pouring into the Midwest right now,” said Emily Fischer, an atmospheric chemist and professor at Colorado State University. “This is a direct connection to climate change. This is the climate change that people breathe.”
Forecasters said conditions were expected to worsen through the day. In New York, where the sky took on an orange haze and the air carried an acrid smell, local officials urged residents to limit outdoor time and warned the elderly, pregnant women and those with heart or lung conditions to stay inside.
The dangerous conditions in the New York metropolitan area came just days before the FIFA World Cup soccer final was set to be played in nearby New Jersey on Sunday before more than 80,000 fans.
“Today is expected to be the worst day of this event,” New York City Mayor Zohran Mamdani said at a Thursday briefing. “At ‘unhealthy’ levels, everyone, not just people with asthma or heart conditions, not just older adults, everyone may feel health effects. So today, every New Yorker should take precautions.”
New York City, it’s hot and air quality today will likely reach unhealthy levels. Take precautions to stay cool and out of harm’s way ⬇️ https://t.co/MSXlLCfhgX
— Mayor Zohran Kwame Mamdani (@NYCMayor) July 16, 2026
The mayor said the city was distributing free KN95 face masks at hundreds of libraries, police precincts and firehouses.
As of Thursday morning, officials counted 858 active fires across Canada, with 111 considered out of control. Most were concentrated in the central provinces of Manitoba, Saskatchewan and Ontario.
According to government data, roughly 5.9 million acres (2.4 million hectares) have burned so far this wildfire season. Climate experts say rising global temperatures are increasing the frequency and intensity of wildfires worldwide.
Wildfire smoke, which can linger in the air for weeks and travel thousands of miles, is more toxic than ordinary air pollution. Studies have linked it to higher rates of heart attacks, strokes, cancer, pregnancy complications and weakened immune defenses.
