Canadian wildfire smoke brings dangerously high pollution to US cities

Lead

Heavy smoke from hundreds of wildfires in Canada has blanketed a swathe of the US from the Great Lakes to parts of the East Coast, prompting health warnings and forcing cities to take precautions. 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.

The smoke, which comes primarily from fires in Canada but also from northern Minnesota, has triggered air quality alerts in more than 20 states, with millions of Americans expected to face unhealthy conditions. As reported by The Guardian, the alerts covered parts of North Carolina, Minnesota, Vermont, Connecticut, New York, Massachusetts, Rhode Island, New Jersey, New Hampshire, Pennsylvania, Illinois, Indiana, Ohio, Delaware, West Virginia, Colorado, Virginia, Maryland, Washington DC, Michigan and Wisconsin.

Coverage comparison

The extent of the smoke's impact was documented across multiple outlets. ABC Australia reported federal data showing dangerous levels of smoke across Minnesota, Michigan, northern Illinois, northern Ohio and into Ontario, with hazardous readings in major cities including Minneapolis, Milwaukee and Toronto. The same report noted that ten states registered at least some locations with an "unhealthy" reading, stretching from Minnesota to as far south as Maryland.

France 24 described the Manhattan skyline as obscured by thick haze and reported that Chicago had closed its beaches as out-of-control Canadian wildfires raged. The outlet also noted that US states near the Canadian border — including Minnesota, Wisconsin, Michigan and Illinois — were particularly affected, while the Northeast, including New York, experienced deteriorating air quality. The Guardian added that the National Aeronautics and Space Administration (Nasa) said winds carried smoke from the Ontario fires "primarily south-east over much of the southern part of the province, as well as parts of Quebec and the US midwest and north-east, tinting the sky shades of gray and yellow and the sun orange in many areas."

TASS, citing its own correspondent, reported dense smoke descending on New York, with visibility dropping to a few hundred meters. The agency also cited IQAir's estimate of air quality in New York at 208, a level consistent with "very unhealthy." TASS further reported that, according to Canadian authorities, over 800 wildfires were raging in the country, with about 100 of them not yet under control.

Key claims

• Detroit registered the worst air quality of any city in the world on Thursday, with a pollutant index of 600, as reported by ABC Australia and corroborated by France 24, which noted that IQAir listed Chicago and Detroit as the top polluted cities globally.
• Federal data showed dangerous levels of smoke across Minnesota, Michigan, northern Illinois, northern Ohio and into Ontario, with hazardous readings in Minneapolis, Milwaukee and Toronto, as reported by ABC Australia.
• Air quality alerts were issued for parts of over 20 states, including North Carolina, Minnesota, Vermont, Connecticut, New York, Massachusetts, Rhode Island, New Jersey, New Hampshire, Pennsylvania, Illinois, Indiana, Ohio, Delaware, West Virginia, Colorado, Virginia, Maryland, Washington DC, Michigan and Wisconsin, as reported by The Guardian.
• The Manhattan skyline was obscured by thick haze, and Chicago closed its beaches on Thursday, as reported by France 24.
• New York City Mayor Zohran Mamdani urged residents to spend as little time outside as possible, warning of the "serious threat" of heavy heat and unsafe air. He noted that at "unhealthy" levels, everyone may feel health effects, not just those with pre-existing conditions, as reported by ABC Australia and France 24.
• The city's Department of Emergency Management said the smoke event could become the most significant in New York City since 2023, when the air quality index reached a dangerous 465, as reported by France 24.
• The Michigan Department of Environment expected dangerous conditions to continue through Friday, as reported by ABC Australia.

Perspectives

New York City officials

Mayor Zohran Mamdani urged residents to stay inside, limit outdoor activity, and take precautions, emphasizing that everyone — not just vulnerable groups — may feel health effects. The city made free KN95 masks available at hundreds of locations, including libraries, police stations and firehouses, and opened hundreds of cooling centers.

New York Governor

Governor Kathy Hochul warned that the smoke, combined with hot weather, would affect air quality in the city and its surroundings, advising residents to monitor their health, as reported by TASS.