A wildfire burns near Port Alberni on Vancouver Island in August. A new Nature study highlights the far-reaching impact of pollution and associated deaths caused by Canadian fires.COLBY REX O'NEILL/AFP/Getty Images
Smoke from Canada’s record-breaking 2023 wildfire season may have led to more than an estimated 82,000 premature deaths globally, according to a new study.
The study, published in the scientific journal Nature on Wednesday, highlights the far-reaching impact of pollution and associated deaths caused by the Canadian fires, primarily in North America and Europe. Researchers concluded that more than 354 million people worldwide were exposed to Canada’s wildfire toxins.
Michael Brauer, a professor at the University of British Columbia’s School of Population and Public Health and the only Canadian researcher involved in the study, said it highlights a worsening global phenomenon and the need to do more to protect public health.
“This is one manifestation of climate change that we are living with and are going to have to live with,” he said. “The take-away is, how do we co-exist with smoke? How prepared are we to do that?”
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He said Canada is already investing in efforts to mitigate wildfire risks as it experiences more intense and frequent wildfires, putting it on the front lines of the climate crisis. But more can be done in Canada and other jurisdictions in the line of smoke, such as implementing clean air shelters, enhanced masking and air purification systems.
In 2023, Canada faced its most destructive fire season in recorded history. More than 17 million hectares of land were scorched, according to the Canadian Interagency Forest Fire Centre, and smoke from the raging blazes clogged skies across Canada and the U.S. – and even transported to Europe and Asia.
Smoke itself has become a political issue between Canada and the U.S. This summer, Republican lawmakers demanded that Canada better contain its wildfires, saying the acrid smoke has soured summer plans for hordes of Americans.
The U.S. representatives have called for actions such as additional forest thinning and prescribed burns, but have not acknowledged in their letters or statements the role of climate change in amplifying fire activity.
Canada has defended its wildfire response but the issue continues to add pressure to relations between the neighbouring countries, which are already under significant strain due to the tariff war.
Hazy conditions caused by wildfire smoke obscure the skyline in Vancouver on Sept. 3.Jennifer Gauthier/Reuters
Prof. Brauer said it is unfortunate that some people may try to spin the newly published study for political gain, when the research underlines forest fires as a global issue.
Authors of the study used satellite observations, machine learning and a chemical transport model, which is used for air pollution forecasting, to study exposure and health impacts related to the 2023 wildfires. The study is focused on the particulate matter in wildfire smoke, referred to as PM2.5, which can penetrate deep into the lungs and even into the bloodstream.
Their findings are subject to some limitations. Prof. Bauer noted that the premature deaths are based on statistical relationships and are not an actual death count.
The study concludes that 5,400 immediate and 64,300 chronic deaths, which happen over time, in North America and Europe were attributable to PM2.5 exposure during the 2023 Canadian wildfires. Although exposure to pollution was more severe in Canada, the population density of the U.S. and Europe worsened the overall impact.
Authors of the study also looked at how many “Canada smoke days” people were exposed to based on PM2.5 guideline levels set by the World Health Organization. They determined that 354 million people in North America and Europe were exposed to at least one smoke day.
The vast majority of the Canadian population experienced, on average, roughly 27 smoke days in 2023.
“Given recent trends in the frequency and severity of boreal and temperate wildfires and further projected increases in extreme fires under climate change, the global health impacts of the wildfires we assess can be expected to continue and grow in the future,” concluded the study.
It noted that the “vast extent and remoteness of many fire-prone forests presents a daunting and long-term task” but that accurate air-quality forecasting and pollution alert systems may be quick and cost-effective options for reducing exposure to smoke.