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Short-term exposure to wildfire smoke linked to 440 deaths in Canada each year, over 33,000 deaths worldwide: study

TORONTO – An international team of researchers has calculated that short-term exposure to smoke from wildfires is attributable to approximately 440 deaths in Canada and more than 33,000 deaths worldwide each year.

The study, which was published earlier this month in The Lancet, looked at the association between wildfire pollution and deaths in 749 cities in 43 countries.

Between 2000 and 2016, researchers measured daily concentrations of PM2.5, which are tiny particles smaller than 2.5 microns and are the main pollutant in smoke from forest fires. These figures were compared to the daily number of deaths from cardiovascular, respiratory and all causes.

The researchers calculated that about 0.33 percent of all deaths in Canada were attributable to forest fires, which occurred within the first three days of exposure. Likewise, smoke from short-term wildfires was attributable to 0.33% of all cardiovascular deaths and 0.32% of respiratory deaths in the country.

In Canada, researchers also found that a 10 micrograms per square meter increase in PM2.5 content was associated with a 2.3% increase in the risk of respiratory mortality.

“We noticed that the effects were mainly higher for respiratory mortality, which was not surprising because we know that forest fires have an impact on the respiratory system,” said Eric Lavigne, professor at the Faculty of University of Ottawa medicine and one of the study’s authors, to in a telephone interview on Sunday.

The highest forest fire mortality rates were seen in Central America and Southeast Asia, where the percentages of forest fire smoke deaths exceeded 1.6%.

The cities of Saskatoon and Regina had some of the highest daily concentrations of PM2.5, the researchers also found.

Lavigne says this could be due to smoke from British Columbia’s wildfires blowing eastward toward Saskatchewan.

“I would say climatological or environmental factors may be at play, but in this study we can’t say why,” Lavigne said.

For months, British Columbia has struggled with runaway heat and drought-fueled forest fires that have destroyed cities and caused widespread evacuations. As of Monday, more than 860,000 hectares have burned in British Columbia and 1,594 forest fires have been recorded this year.

One limitation of the study is that it only looked at deaths from short-term exposure to smoke from wildfires, Lavigne noted.

“There is still some uncertainty with people who are repeatedly exposed each year, whether it increases their risk of dying from these causes from a long-term perspective. This is a limitation that we need to keep in mind when doing this. interpretation of the results, “he said.

Nonetheless, the authors say the data underscores the need for policymakers to tackle smoke from forest fires from a public health perspective.

“Policy makers and public health professionals should raise awareness about pollution from forest fires to guide rapid public responses and take action to reduce exposure,” the authors wrote.


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