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How the dangers of Canadian wildfires spread far beyond the flames

Wildfires are strange beasts for many reasons, but one of the oddest things about them is how they can become more dangerous to you as you move farther and farther away from them, one expert says.

For the past week or so, cities in the northeastern United States as well as Ontario and Quebec have been battling smoggy conditions that have had a myriad of effects on life.

Basically, anything out of doors was put on hold in some cities as they dealt with the effects of the hundreds of wildfires burning in northern Ontario and Quebec.

While the side effects from a fire are naturally dangerous when you are in close proximity to the flames, once the smoke starts to travel, the effects can also be worse further down the line.

“Usually a lot of the worst impacts, like the very highest levels of pollution, will be directly downwind of the fire,” said University of Waterloo professor Rebecca Saari.

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“However, in addition, as those particles do travel through the air, they do react with other things in the air. It’s called aging.”

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She said that gases can be emitted from wildfires and then condense and transform into particles.

“That’s why this is such a regional problem and affecting things on the continental scale,” Saari said.

“Local air quality is affected, but it’s also affected regionally because of this chemistry.”

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So if the soiled air were to be pushed through Toronto before heading to New York, it could pick up more emissions as it passes through Canada’s largest city, then have time for that chemistry to brew before the smoke hits the Big Apple and other places south of the border.

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“It’s picking up more emissions from Toronto and it’s giving it time for that chemistry to happen,” she said.

“There’s what’s called the primary emissions. That’s what comes after the wildfire directly. That would be particles and gases, both of which can be harmful,” Saari explained. “And there’s also what’s called secondary formation.”

She used ozone as an example of a secondary formation because it generally forms downwind from a source as it needs time to take shape.

On Friday morning, air quality conditions in both Toronto and New York had improved unexpectedly as the wind direction was not expected to shift until Sunday.

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So while the adverse effects for those living near the fires themselves are obvious, they may not be for those living in the smog zones.

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Saari said that while the economic impact of air pollution is a staggering $120 billion per year, the most important concern should be the effects on human health.

She said Health Canada has estimated that over 15,000 Canadians die prematurely annually due to exposure to air pollution.

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“Wildfires are the largest contributor to population-weighted particulate matter, which is the pollutant that does the most harm to public health,” she said.

Saari pointed out that there will also be short-term and long-term problems created by exposure.

“If you’re exposed to higher levels of pollution over the long term, that leads to increased risks for all sorts of negative health outcomes,” she explained before pointing to an arm’s length long list of health risks such as mental health, heart and lung diseases.

“The short-term effects that we know about primarily relate to acute respiratory symptoms,” she said, and that will likely lead to an increase in visits to doctors.

“Wildfire smoke has also been shown to impair lung function, including in healthy children. So there are health effects that we need to consider and the public should try to protect themselves from.

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It will be tough for anyone to be fully protected from these situations, especially since the harm is due to invisible threats in the air,  but Saari said researchers are currently looking into how housing conditions play a part in protection.

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There is a big variation in terms of infiltration — how much outdoor air gets inside — in a new well-sealed home with functioning H-VAC and a filter,” she explained. “Research suggests infiltration could be quite low, that the amount of outdoor air pollution inside could be quite low.

“However, if you have an older, leaky home, if you keep your doors and windows open, the levels could be no difference, right?”

She noted that that would essentially be the same as being outdoors and said people should keep their windows and doors closed if possible.

“Run a fan with the filter if you have one, run an air purifier if you have one, and just do your best to keep that infiltration low,” the professor explained.

This is an especially bad year for wildfires in Canada, though this could be the way of the future as experts have warned of the effects of climate change.

Saari, who works in the department of civil and environmental engineering at the university, said it is important that people need to realize the effects of climate change.

“We have to address these together or we can expect to see more days like this,” Saari said.

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