It is rare that the boreal forest, Chibougamau, or Uashat mak Mani-utenam is first talked about in New York and Philadelphia. The cloud of smog created by the Quebec wildfires is blurring skies over much of the American Northeast, to the point where air quality indices are almost all in the red. But how did these pollutants travel hundreds of miles? And will this phenomenon remain rare?
Smoke from the wildfires that engulfed Montreal on Monday had spread to North Carolina on Thursday. Although the air quality in the metropolis of Quebec was now “good” again, the concentration of particulate matter in New York was well above the limit set by the World Health Organization (WHO). The US capital has also raised its risk level to code purple, an unprecedented move, according to the Washington Metropolitan Council of Governments.
“It’s clear that all the factors have been brought together over several days, it’s actually a combination of several things,” explains Philippe Lucas-Picher, professor in UQAM’s Department of Earth and Atmospheric Sciences. .
“Of course you need big fires as a base,” he said, setting the table. As of Thursday, there were about 140 active fires in Quebec territory, including 80 classified as “out of control” by the Society for the Protection of Forests from Fire (SOPFEU).
The second condition present is a low-pressure system, “a low-pressure system over the east coast of North America that creates an ‘anticyclonic’ atmospheric circulation,” agrees Patrick Hayes, professor of analytical and atmospheric chemistry at the University of Montreal. The air mass is moving counter-clockwise, breathing in over northern Quebec and pushing everything toward the northeastern part of the United States.
This type of system “is not that rare,” specifies Jules Blais, an environmental pollutants expert at the University of Ottawa, but its persistence explains the magnitude of the current phenomenon.
The other key element mentioned by all experts interviewed is the north wind, which has been blowing for several days. “That explains the rather cool temperatures in Montreal at the moment. “There’s a constant north-south current pushing the low down a corridor toward New York,” Lucas-Picher said. Washington is further south than this city, but in the “same corridor.”
It’s also true that “the smoke plume didn’t have a chance to dissipate,” he adds, and therefore continues to form a very thick, compact mass that annoys our neighbors to the south.
There is a steady north-south current pushing the low down a corridor towards New York
A very remarkable episode
The overwhelming majority of America’s major dailies carried the appalling air quality to the front page Thursday morning, from the east coast to San Francisco. The New York Post used one of the phrases that drew the most reaction on social media. “Blame Canada” read the headline on the front page, accented with orange. “After Putin, this is the unhealthiest thing you can get from Canada,” it says in smaller print.
At the time of writing, New York, Baltimore, and Philadelphia were still “red code.”
More seriously, The Washington Post headlined: “A Burning Truth: The Climate Threat to Health Is Inevitable.” Canada’s wildfires “underscore that the threat to human health from climate change extends beyond national borders,” the article continues .
On the West Coast, the tone was more empathetic: “Canada’s wildfires are fueling a public health scandal that Californians know all too well,” wrote the San Francisco Chronicle.
Anything but an anecdote
“Depression doesn’t move, it’s stationary. And the north wind keeps blowing. It’s an open faucet that pushes the particles straight south,” summarizes meteorologist Gilles Brien. He’s concerned about the poor air quality south of the border, but not only that.
The smog alert continues to apply to Abitibi, where the concentration of fine particles less than 2.5 microns (PM2.5 microparticles) in the air is three to four times the alert threshold set by Environment Canada, an organization where Mr. Brien worked for several decades. These particles are of concern because they are small enough to enter human lungs and enter the bloodstream. “It’s unburned waste, carbon products that are much smaller than a hair,” explains the meteorologist.
The limit set by the WHO is 15 micrograms PM2.5 per cubic meter for daily exposure during limited episodes and 5 micrograms for annual exposure, i.e. more chronic.
By early Thursday afternoon, Toronto was on track to increase that concentration many times over, sadly catching up with the orange horizons of smoky skies across the entire United States. The rain forecast for the afternoon and night gave some glimmer of hope there, just like in Ottawa, “where we’re really breathing better than yesterday,” says Professor Blais from his office in that city.
Environment Canada can also predict where smoke plumes from wildfires will travel thanks to a state-of-the-art model, says the professor.
The Americans will therefore breathe the trees pulverized by the fires on the north coast, in Abitibi and in North du Quebec for a few more days, confirms Philippe Lucas-Picher. “It shows that the air circulates and doesn’t stop at national borders,” he says.
Climate prediction models show that wildfires in Quebec will increase in number and intensity over the next few years. “It’s the new normal and a good reminder that everything is connected,” Mr Blais concludes.