Heavy, pungent smoke from hundreds of wildfires burning across Canada has blanketed a large swath of the United States from the Great Lakes to parts of the East Coast, triggering hazardous air quality alerts and prompting officials to urge millions of residents to stay indoors. The thick smoke, which has darkened skies and reduced visibility for commuters, is coming from fires burning primarily in Canada but also in northern Minnesota.
As of Thursday morning, officials tallied 858 fires burning across Canada, including 111 considered out of control. Most of the fires were in the central provinces of Manitoba, Saskatchewan and Ontario. More than 800 wildfires are burning across Canada, with air quality alerts now extending south into multiple US states. The large cluster of fires affecting northwestern areas of Ontario are responsible for sending thick plumes of smoke and poor air quality across Thunder Bay and Toronto, with lower concentrations of smoke high in the atmosphere drifting over the Great Lakes and above New York.
Hazardous Air Quality Across the Midwest and East Coast
The air quality in large parts of the northern states of Michigan and Minnesota is deemed 'hazardous' by the US Air Quality Index program, with people recommended to stay indoors. Alerts span the Upper Midwest, the Great Lakes region and into the northeast. Entire states including New York, New Jersey, Connecticut, Delaware, Massachusetts, Michigan, New Hampshire, Ohio, Pennsylvania, Rhode Island and Wisconsin were under air quality alerts.
Detroit registered the worst air quality of any city in the world on Thursday, according to monitoring company IQAir, with a pollutant index of 600 — twice the level considered 'hazardous' by the US Environmental Protection Agency. Federal data showed dangerous levels of smoke across Minnesota, Michigan, northern Illinois, northern Ohio and into Ontario, with hazardous readings in major cities Minneapolis, Milwaukee and Toronto. Milwaukee recorded the worst air quality in its history — a record-breaking Air Quality Index measured at over 600.
In the Chicago area, air quality ranged from very unhealthy to hazardous. The city closed all of its public beaches and outdoor pools. Chicago along with Toledo, Ohio, and areas in Minnesota relatively close to the fires were well into the 700s on the air quality index during the afternoon, with much of the rest of the upper Midwest also experiencing AQI levels in the worst category of 'hazardous'.
New York and East Coast Affected
Further east, smoke from the Canadian wildfires enveloped New York City, prompting Mayor Zohran Mamdani to urge residents to 'take precautions to stay cool and out of harm's way' while dealing with both the smoke and high temperatures. 'Today is expected to be the worst day of this event,' Mamdani said at a gathering on Thursday. '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,' he said.
In the New York City area, a thick haze tinged the morning sky orange and yellow and partly obscured Manhattan's skyline. Authorities encouraged New Yorkers to spend as little time outside as possible, handing out free KN95 face masks at hundreds of libraries, police precincts and firehouses. In western regions of New York state, the air quality on Thursday is considered 'very unhealthy', while in the New York City metro area the air quality is 'unhealthy'.
Health Warnings and Disruptions
Wildfire smoke contains dangerous, tiny pollutants called PM2.5 that can travel deep into the lungs or enter the bloodstream when inhaled. The minuscule particles can lead to breathing problems like bronchitis and cause inflammation that aggravates diabetes, heart disease and other health conditions. People with lung or heart disease, children and older adults are especially at risk for smoke-related illness.
The smoke has caused widespread disruptions. In Detroit, businesses and attractions closed due to poor air quality. Some workers inside Ford Motor's Michigan Assembly plant in Wayne were hospitalized amid the smoky haze and intense heat. A planned concert by rocker John Mellencamp at Pine Knob Music Theatre in Clarkston, Mich., was canceled. The start time for the MLB game between the New York Mets and the Phillies on Thursday in Philadelphia was moved up an hour due to air quality concerns, and an MLS game in Chicago was postponed.
Gwen Moseley, 65, was among the first patrons at Rosedale Library in Queens to take advantage of the free masks, saying she was on the road much of the day working as a therapist for children with autism. 'Who wants to be breathing this? It's not healthy,' Moseley said. 'When I'm out walking, I can feel the scratchiness in my throat'. Bill Ostrowski, 76, wore a mask as he walked through downtown Chicago, where wildfire smoke shrouded skyscrapers. 'It stinks. It's not a good sign when you wake up in the morning and you can smell the air,' he said.
Climate Change Connection and Outlook
'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'. Laura Chasmer, a professor of geography and the environment at the University of Western Ontario, noted that wildfires have become more frequent since 2015. 'This is associated with some of the extreme climate warming that we've been seeing, and the atmospheric drying of the surface,' she said.
Northwesterly winds will continue to blow the smoke into northern US states for the rest of this week and into the weekend, leading to concerns smoke will drift into New Jersey where Sunday's World Cup final is due to take place. A change in the wind direction by Monday means that the smoke will tend to be steered across Quebec with an improvement in air quality further south in the US. Michigan's statewide air quality alert was extended through Friday before cooler weather was expected to move the smoky pall out of the Great Lakes region.
