Wildfire Smoke Darkens North American Skies, Record Air Quality
A massive plume of smoke from over 850 active wildfires burning across Canada has drifted southeast, blanketing large swaths of the U.S. Midwest, Northeast, and mid-Atlantic regions and pushing air quality to hazardous levels in multiple major cities. Milwaukee recorded its worst air quality on record with an Air Quality Index (AQI) of 644, while Minneapolis briefly held the title of worst air quality among major cities worldwide, according to ABC News.
The Scope of the Crisis
As of July 16, at least 109 of the 850-plus active wildfires in Canada were classified as “out of control,” with more than 180 burning in Ontario alone. Canada has recorded 3,549 wildfires in 2026, burning 2.3 million hectares—roughly the size of the United Kingdom. At least nine large fires are also burning in northern Minnesota, compounding the smoke drifting south from Canada.
Air quality alerts are now in effect across at least 18 U.S. states, stretching from Minnesota to New Hampshire to Virginia. Detroit reached an AQI of nearly 570 on Thursday, while parts of New York City measured levels over 200, classified as “very unhealthy.” By Friday morning, smoke was expected to push farther south, affecting areas through Ohio and Virginia, including Washington, D.C., and Baltimore.
Record-Breaking Pollution
Milwaukee’s AQI of 644 more than doubled the previous record of 300 set in 1987, according to city officials cited by ABC News. On Thursday afternoon, Minneapolis surpassed Detroit for the worst measured air quality in the world among major cities, according to IQAir. Chicago and Washington, D.C., ranked among the world’s most polluted major cities early Friday, as reported by CBS News.
Health Experts Sound the Alarm
“The alerts have been going from ‘unhealthy for sensitive groups’ to ‘unhealthy (for everyone),’” said Dan Westervelt, associate research professor at Lamont-Doherty Earth Observatory at the Columbia Climate School, in an interview published by the Columbia Climate School. “Particularly when it’s in that latter category, it’s important for everyone to take action, as there can be health impacts such as coughing, scratchy throat, irritated eyes, etc.”
New York City Mayor Zohran Mamdani warned residents that “this is very serious. We are reaching into a level of air quality that is dangerous for every single New Yorker,” ABC News reported.
Dr. Alexander Azan, assistant professor of population health and medicine at NYU Langone Health, told CBS News that repeated exposure carries long-term risks: “If we keep being exposed to this level of air pollution over time, that increases our risks down the road for developing chronic health conditions.” He recommended N95 or KN95-grade masks for those who must go outdoors.
Climate Change Connection
Scientists emphasize that these events are becoming more frequent due to climate change. Westervelt noted that research has shown climate change doubled the likelihood of the 2023 wildfire smoke event that turned New York City skies orange. “We should expect these to become more common in the future,” he said.
Warming temperatures from burning fossil fuels are making fires more frequent and intense, CBS News reported. Severe drought conditions combined with extreme heat have created “a perfect storm” for wildfire fuel, according to Westervelt. A study released earlier in 2026 found that chronic exposure to air pollution from wildfires is linked to tens of thousands of deaths annually in the United States.
Disruption Across the Region
The smoke has caused significant disruption beyond health concerns. The Federal Aviation Administration slowed arriving flights into Philadelphia International Airport due to low visibility. An American Airlines pilot reported ash sticking to the cockpit windshield while approaching Philadelphia, telling air traffic controllers, “I’ve never seen it stick to the windshield like this.”
Pennsylvania declared a Code Purple air quality alert—its most severe level—for Friday, while Washington, D.C., was under a Code Red alert. World Cup organizers said Friday they were monitoring conditions closely ahead of the tournament’s weekend final in New Jersey, which has been affected by dangerously unhealthy air. “There’s been discussion about it, and we have somebody with the National Weather Service that sits in FIFA headquarters there, so we’re monitoring closely,” Andrew Giuliani, White House World Cup task force executive director, told a briefing, as reported by CBS News.
What’s Next
A cold front is expected to bring some relief by Friday evening and Saturday morning, with cooler temperatures and rain. However, as Westervelt cautioned, “as long as the fires are still burning, we could be in for another wave of smoke after that.” The NASA Earth Observatory noted that as of July 14, Canada’s burned area remained below the extreme fire years of 2023 and 2025, but how the rest of the season plays out remains uncertain.
For now, health officials urge residents in affected areas to stay indoors, limit outdoor activities, wear high-quality masks when outside, and run air purifiers. The recurring nature of these events raises urgent questions about whether cities have adequate infrastructure to protect vulnerable populations from what scientists warn will be an increasingly common phenomenon.