Air Pollution Surges in U.S. and Canada Due to Unprecedented Fires

CHICAGO, Ill. — Air pollution has worsened significantly in the United States and Canada due to unprecedented wildfires, according to a study released Thursday by the University of Chicago.

The annual Air Quality Life Index (AQLI) report uses satellite data to assess fine particulate levels worldwide and converts them into lost years of life. Michael Greenstone, an economics professor at the University of Chicago, emphasized the severity of the threat, stating, “Fine particles remain the greatest external threat to human health on the planet.”

Greenstone pointed out that air pollution from these particles is “worse than tobacco smoke, worse than maternal and child malnutrition, and worse than road accidents and HIV.”

The study revealed that the catastrophic wildfire season in Canada during 2023 led to a more than 50% increase in particulate levels compared to the previous year, while the United States experienced a 20% rise in the same period. Although data currently covers only the years 1998 to 2023, experts expect this trend to continue as both countries face increasingly intense wildfire seasons, accelerated by climate change.

Already, 2025 is ranking as the second worst wildfire season in Canada. Greenstone remarked, “What is surprising is that in some areas of the world, undoubtedly in Canada and the United States, but seemingly also in parts of Europe, air pollution is like that zombie we thought we had eliminated but is now back.”

In the United States, pollution traditionally concentrated in California has spread to states like Wisconsin, Illinois, Indiana, and Ohio due to winds carrying smoke from Canada. In Canada, over half of the population breathed air that exceeded the national pollution standard of 8.8 micrograms per cubic meter in 2023, a significant increase from less than 5% over the past five years.

The hardest-hit areas were the Northwest Territories, British Columbia, and Alberta, where pollution levels rivaled those of Bolivia and Honduras, shortening life expectancy by two years.

Latin America also recorded its highest pollution levels since 1998, with Bolivia being the most affected country. Globally, fine particulate levels rose from 23.7 micrograms per cubic meter in 2022 to 24.1 in 2023, nearly five times the World Health Organization‘s recommendation of five.

In South Asia, the world’s most polluted region, pollution increased by 2.8%. Even China saw a slight rise of 2.8% after a decade of decline in its pollution control efforts.

However, there was a slight ray of hope: within the European Union, particulate concentrations decreased by 6%, and in Central and West Africa, they dropped by 8%.