by Timothy Edward, Local Journalism Initiative reporter

A new study on wildfires in Canada has found that the poor air quality produced during wildfire seasons is projected to reduce life expectancy in parts of Canada. The University of Chicago’s annual Air Quality Life Index, addressing how air quality affects life expectancy, found that particulate pollution “remains the greatest external threat to human life expectancy.”

University of Chicago professor and AQLI co-creator Michael Greenstone elaborated in an interview with AFP.

“I just don’t think this can be repeated enough: Particulate matter remains the greatest external threat to human health on Earth, period. It’s worse than tobacco smoke. It’s worse than child and maternal malnutrition. It’s worse than road accidents. It’s worse than HIV-AIDS, worse than anything in terms of losses.”

The study looked at Canada’s worst wildfire season on record: In 2023, wildfires burned 45.70 million acres of land, and 50% of Canadians breathed air that contained particulates in amounts exceeding the national air quality standard. PM2.5 (fine particulate matter) rose by over 50% during that season.

2025 has been Canada’s second worst wildfire season on record.