Wildfire smoke brings hazardous air to Midwest and Northeast

Smoke from wildfires in Canada and northern Minnesota spread across the Great Lakes and into the Northeast this week, triggering air quality alerts in multiple states and exposing millions of people to unhealthy or hazardous pollution.

Detroit, Minneapolis and Chicago ranked among the five most polluted major cities in the world on Thursday, CBS News reported, as smoke pushed southeast on winds from fires burning in Canada and Minnesota. NPR reported that heavy smoke reached New England and extended as far south as Maryland, affecting cities including Philadelphia, New York City and Baltimore.

The scale of the fires is large. CBS News reported that more than 100 wildfires were burning in Canada, while NPR, citing the Canadian Wildland Fire Information System, reported that more than 800 wildfires were actively burning across the country. Multiple wildfires were also burning in northern Minnesota.

Officials in Minnesota issued an air quality alert through Friday for areas including the Twin Cities, with very heavy smoke expected in the northeastern part of the state. Air quality in northeast Minnesota reached hazardous levels, making conditions unsafe for everyone. Michigan and Wisconsin officials also warned residents that poor air could last for days. All of Michigan was under an air quality alert Thursday, with the possibility of an extension.

New York state issued an air quality advisory for Thursday, and officials said N95-style masks would be distributed to commuters in New York City. Pennsylvania declared a Code Red air quality alert, saying wildfire smoke had created unhealthy pollution levels for everyone. Massachusetts also placed the entire state under an air quality alert.

In the Boston area, CBS News Boston reported that skies shifted from milky white to a brown-yellow haze as smoke moved in. “It almost felt like you were at a campsite with an active fire going,” West Roxbury resident James Venezia told the station. The yellowish haze also spread across Vermont, New Hampshire and Maine.

Forecasters and health experts warned that smoke and extreme heat were combining to create dangerous conditions. “Those two things coinciding with each other is not good from a health perspective,” said Tyler Hasenstein, a meteorologist with the National Weather Service in Chanhassen, Minnesota.

NPR reported that record-breaking temperatures produced a heat dome across western Ontario and Minnesota, with some places topping 100 degrees. The heat and dry conditions helped fires continue on an “unprecedented run,” said Derek Mallia, a professor of atmospheric sciences at the University of Utah. “You have a firehose of smoke coming right now,” Mallia said.

Fine particulate matter in wildfire smoke can be inhaled deep into the lungs and may enter the bloodstream. Health experts said it can cause coughing, shortness of breath, dizziness and fatigue, and can worsen heart and lung disease. Dr. David Eisenman, a professor of medicine at UCLA, said studies link wildfire smoke pollution to increases in heart attacks, heart failure, stroke and respiratory illness. He warned that smoke pollution can still be dangerous even when skies do not appear dark. “Even if the sky is not brown, it still might be toxic for you,” he said.

Experts urged people to check air quality reports, reduce or avoid outdoor activity, close windows, use air purifiers or air conditioning, and wear N95 or KN95 masks if they must go outside. “Whether you’re somebody who’s working outdoors [or] you have an errand that you just can’t not do today or tomorrow, the best way to keep yourself safe is buying an N95 or KN95-grade mask,” Dr. Alexander Azan of NYU Langone Health told CBS News.

In Ontario, videos showed intense flames and smoke-filled skies, NPR reported, and thousands of people have been forced to evacuate. CBS News reported that a freight train near Armstrong, Ontario, was surrounded by burning trees earlier this week. “This could potentially overtake us here, this has gotten a little scary,” one crew member said in video of the incident. Canadian National Railway later suspended rail operations there and said everyone on board got through safely.