Smoke from the destructive Wildfires in Canada have gripped a immense swath of the Midwest and Northeast this week, prompting cities across the region to issue air quality warnings.
Extreme smoke levels mean that even able-bodied adults should take certain precautions to protect their health. The increasing severity of wildfires across the continent – driven in part by climate change – means that even places where flames are not burning will still feel their effects.
As of Wednesday, more than 100 fires have burned out of control across Canada, and hundreds more are being monitored or battled. Smoke rose south and east, obscuring the sky from Minnesota to Modern York. Particularly dramatic photos came from Toronto, where commuters headed to work under orange skies on Wednesday morning. The region is also struggling with a heat wave, with temperatures well above 30 degrees Fahrenheit in many areas and the heat index even higher.
On Wednesday evening, Modern York’s air quality index peaked at 180, ranking the city’s air as “unhealthy” as defined by the U.S. Environmental Protection Agency. In other places the situation was even worse, such as in Duluth, Minnesota, the AQI was above 500 (anything above 301 is considered “hazardous” and considered threatening to anyone). Smoke conditions are expected to worsen in parts of the northeastern United States, including Modern York, on Thursday.
Wildfire smoke covering the area contains microscopic particles of matter known as PM2.5 – tiny for particles smaller than 2.5 micrometers, or 30 times smaller than the width of a human hair.
Exposure to PM2.5 can cause or worsen a number of health conditions, especially in vulnerable groups. Nicholas Nassikas, a pulmonologist and assistant professor of medicine at Harvard Medical School, says he has advised his patients with pre-existing conditions such as asthma and lung disease to limit their time outdoors in such a smoky room. Children “breathe faster – they just breathe more,” Nassikas says, while older people, who often have underlying health conditions and may live in less ventilated homes or senior centers, are also at risk.
Jennifer Stowell, an assistant professor at the University of Maryland School of Public Health, says even fit adults may want to take precautions on days when the air quality index exceeds 100: “It’s important to at least limit time spent outdoors to reduce overall exposure.” she says. If you must be outside for an extended period of time, Stowell recommends wearing an N95 mask. Stowell, who is currently in Boston, where the AQI hit 110 on Wednesday, says he had no plans to attend outdoor events until the evening.
Dan Westervelt, a professor of climate physics at Columbia University, is similarly cautious. “I’m going to make sure my kids stay home today,” he says. “I will not do any physical activity such as running today or tomorrow.”
Climate change is causing temperatures to rise. This lengthens the fire season and creates warmer and drier conditions that lead to more explosive fires. AND test published last year estimated that wildfire smoke already causes 40,000 deaths per year in the U.S., and if warming continues, the number of annual deaths could more than double to 70,000 by 2050. As days of needy air quality due to wildfire smoke become more common, research on long-term exposure to wildfire smoke continues to develop. A similar blast of smoke from the Canadian wildfires hit the Northeast in 2023.
“Research has repeatedly shown that exposure to high levels of air pollution over a lifetime or for extended periods of time leads to premature mortality,” says Westervelt. “You could shave months off your life if you live in conditions where you are often regularly exposed to high levels of air pollution.”