Forest fires reversed decades of air issues specific to Canada and the United States, according to new data published on Thursday.
Researchers from the University of Chicago have published their annual index on air quality life (AQLI), which follows air pollution and its impact on life expectancy. This year’s report analyzed the data collected in 2023.
That year, when Canada was facing its worst forest season in history, burning more than 40 million acres in land, flames have caused air pollution levels at unructed levels in the United States and since 1998 in Canada, AQLI years have started to record air quality data. Canada and the United States had made great progress to reduce air pollution in the past, but forest fires have reversed this progress. The two countries have known the highest air pollution in the world in 2023 – despite the two strict air quality rules at the time. High fires of pollution in the pockets of the United States, and have also changed the geographic distribution of pollution in the United States, the most polluted counties in the United States are generally concentrated in California, but that year, forest fires caused counties in several other states, including Wisconsin, Illinois and Indiana, and south of the southern.
Around the world, 2023 has seen concentrations of PM2.5 – particles of small size 2.5 micrometers or less diameter which are released in air by fires and other sources of pollution – increased by 1.5% compared to the levels of 2022, according to AQLI data – with regard to almost five times the World Health Organization (WHO). Long -term PM2.5 exposure can increase the risk of health impact, including heart disease, lung cancer and stroke.
The results are a striking warning of what could be a new reality to fight against air quality. This year’s fire season has been the second worst registered, with a total of 18.5 million acres burned since the beginning of 2025. Climate change has increased the frequency and intensity of forest fires, the most important increases occurring in the western study of the United States and boreal forests in North and Russia, according to a study by NASA.
This occurs at the same time as the Trump administration is working to roll up it the air standards specific to the United States. In March, the Environmental Protection Agency announced that it planned to cancel historical pollution standards, including national ambient air quality standards, which regulates harmful pollutants such as particles.
The administration also proposed to revoke the “endangering conclusion” of 2009 which determined that greenhouse gases constituted a threat to public health and provided a legal backbone for regulations under the Clean Air Act. Researchers say that climate change and air pollution are deeply linked and that the reduction in carbon dioxide emissions, which increases temperatures and aggravates forest fires, is an essential element in reducing air pollution.
“Climate change and air pollution are driven by the same source – the combustion of fossil fuels of vehicles, power plants and industry,” wrote researchers in the report. “In this regard, reductions in the consumption of fossil fuels have the potential to reduce atmospheric pollution concentrations and the risks of disturbing climate change.”
