It’s hard not to forget the 2023 Canadian wildfire season, when more than 16 million hectares of forest were lost, thousands were displaced and smoke suffocated cities across both Canada and the U.S.

And it turns out Canada experienced its worst air pollution levels that year since 1998, according to a new report released today by the University of Chicago’s Air Quality Life Index (AQLI). At the same time, the report found that pollution levels didn’t change much for the rest of the world in 2023.

If those levels continued for a person’s lifetime, the average Canadian would lose roughly two years of their life expectancy, according to the report.

Efforts have been made around the world, including in Canada, to curb harmful emissions of fine particulate matter with a diameter of less than 2.5 micrometres, also known as PM 2.5. But wildfires are reversing those advances — with serious health consequences.

“Air pollution is the greatest external threat to human well-being on the planet, and I don’t believe that that is widely recognized,” said Michael Greenstone, one of the report’s authors. “More years of life expectancy are lost for the average person on the planet due to air pollution than to maternal and child malnutrition, than due to alcohol, than due to tobacco.”