Smoke from forest fires in Canada has engulfed the East Coast, shrouding cities in hazy smog and placing some 100 million people under air quality warnings. More than 400 fires fires in British Columbia, Alberta, Quebec and Ontario, and half are uncontrolled. New York City became home to the worst air quality in the world. Philadelphia also has one code red alertadvising people to stay indoors, and the plumes could continue to flood the region a few more days come, with the smoke stretching through Washington, DC and into Atlanta, Georgia.
In the United States, supercharged wildfires once seemed like a unique West Coast problem, such as the 2018 Camp Fire that destroyed the California city of Paradise. A range of factors contributed to that massive blaze, including the region’s legacy of firefighting, which allowed dead bushes to pile up. Climate change means higher temperatures will dry out and dry out, causing it to burn catastrophically. That is also the problem in Canada right now. The number of fires for this time of year has risen only slightly above average, but “the size of the fires and the intensity of the fires have increased significantly,” said Mike Flannigan, a professor of wildfires at Thompson Rivers University in British Columbia. Columbia. .
In other words: East Coast, welcome to the Pyrocene, or the Age of Fire, as fire historian Stephen Pyne calls it. Climate change and human interference with the landscape have combined to make wildfires bigger and more intense, big enough to send toxic clouds of smoke not just from Canada to the East Coast, but across entire continents. “Climate change is performance-enhancing: it exacerbates what is a natural rhythm,” says Pyne. “There is no reason to believe that those trends will suddenly stop.”
“It’s a global problem now,” said Mary Prunicki, director of air pollution and health research at Stanford University’s Sean N. Parker Center for Allergy Research. The immediate health effects of exposure to wildfire smoke can be devastating for vulnerable people, but less is known about the long-term effects of brief exposure. “This is relatively new, to have this kind of mass exposure in a group that has never been exposed before,” she says.
Wildfire smoke is a complex amalgamation of materials, including burnt plant material and – when buildings go up in flames – man-made material such as plastic. What makes smoke visible are the toxic particles called PM 2.5 and 10, meaning particles smaller than 2.5 and 10 microns. But it also contains many invisible nasty things, such as benzene, formaldehyde, carbon gases and even fungal pathogens. As the smoke travels through the atmosphere, it can actually form new chemical hazards over time, such as ozone, which exacerbates asthma. “The biggest health impacts are certainly from particulate matter,” said Rebecca Hornbrook, an atmospheric chemist at the National Center for Atmospheric Research who has flown planes through wildfire smoke to study its components. “But there are a lot of things that get left out that are on the EPA’s list of hazardous chemicals.”
Smoke from wildfires can cause immediate health effects such as heart attacks, strokes and bronchitis, especially in more vulnerable people with respiratory problems, and can pose a threat to pregnant women. “These single exposure events can be really devastating for people with pre-existing conditions,” said Shahir Masri, an air pollution scientist at the University of California, Irvine.
Exposure to this type of pollution can also weaken the immune system. A 2021 study found that Covid-19 cases and deaths in California, Oregon and Washington were exacerbated last year by an increase in fine particulate air pollution from wildfire smoke. “Whether it’s Covid or another virus, now is a time to not only avoid exposure to outdoor particulate matter, but to really try not to get sick,” said Francesca Dominici, professor of biostatistics, population and data science at Harvard University. TH Chan School of Public Health who participated in the study. “Your ability to fight the virus is less effective.”
This year’s fire season in Canada is “unprecedented” and could be record-breaking, Flannigan says. Hundreds of fires are burning in Canada — some for days or weeks — usually started by human activity or lightning, then fueled by dry vegetation and made worse by hot, dry, windy weather. Rising warm air on land has lifted that smoke to between 5,000 feet and 20,000 feet, where the haze is quickly transported south and east in high winds.