Climate-Driven Wildfires Threaten Air Quality Progress in North America

Global air pollution levels are increasing, with the United States and Canada experiencing the most significant rises due to unprecedented wildfires intensified by climate change. A recent report from the Air Quality Life Index (AQLI) highlights that these fires are erasing decades of progress made in air quality, particularly in 2023.

The AQLI’s annual report utilizes satellite data to monitor particulate matter levels worldwide, with historical records available since 1998. This data translates concentrations into years of life expectancy lost, reflecting findings from peer-reviewed studies. According to Michael Greenstone, an economics professor at the University of Chicago and co-creator of AQLI, “Particulate matter remains the greatest external threat to human health on the planet, period.” He emphasizes that it surpasses other serious health risks, such as tobacco smoke and HIV-AIDS.

The report reveals that Canada’s wildfire season in 2023 led to a more than 50 percent increase in particulate levels compared to 2022, while the United States experienced a 20 percent rise. Although the data is limited to 2023, the trend is expected to persist as both nations face increasingly severe wildfire seasons driven by higher temperatures and drought conditions linked to human-induced greenhouse gas emissions. Notably, 2025 is already projected to be Canada’s second-worst wildfire season.

Greenstone expressed surprise at the resurgence of air pollution in regions like Canada and the United States, likening it to a zombie that has returned after being thought defeated. Traditionally, the most polluted areas in the United States have been in California, but this pattern is shifting. States downwind of Canadian wildfires, including Wisconsin, Illinois, Indiana, and Ohio, are now experiencing worsening air quality.

The report indicates that over half of Canadians inhaled air with pollution levels exceeding their national standard of 8.8 micrograms per cubic meter, a stark increase from less than five percent in the previous five years. The provinces most severely affected include the Northwest Territories, British Columbia, and Alberta, where particulate pollution levels rival those found in countries like Bolivia and Honduras, reducing lifespans by an average of two years.

Globally, fine particulate levels—measured at 2.5 micrometers and smaller—rose from 23.7 micrograms per cubic meter in 2022 to 24.1 in 2023. This level is nearly five times higher than the World Health Organization guideline of five micrograms. Latin America reported its highest particulate levels since 1998, with Bolivia being the hardest-hit country. In South Asia, already recognized as the world’s most polluted region, pollution increased by 2.8 percent. Even China saw a minor uptick of 2.8 percent after a decade of decline attributed to its “War on Pollution.”

On a more positive note, certain regions showed improvements. Within the European Union, particulate concentrations fell by six percent, and Central and West Africa reported an eight percent drop.

The findings from the AQLI report underline the urgent need for coordinated global efforts to address the escalating challenge of air pollution, particularly as climate change continues to intensify its impacts on public health.