Researchers from the Institute of Atmospheric Physics within the Chinese Academy of Sciences examined how Canada’s 2023 wildfire season influenced air quality across the globe. The findings appeared in the journal Advances in Atmospheric Sciences (AAS).
The fires that swept Canadian forests over the spring and summer broke records, drawing international attention not only for their scale but also for how deeply they altered the composition of the Earth’s atmosphere. The study highlights how such extreme events can ripple far beyond their origin, changing air quality on multiple continents.
To conduct the analysis, the team embedded a custom module into the broader Earth system model developed by the Chinese Academy of Sciences, enabling a detailed simulation of atmospheric processes driven by fire emissions.
The results show a clear link between Canadian wildfire activity and deteriorated air quality in much of the Northern Hemisphere, driven by the long-range transport of pollutants carried by wind patterns. The study notes that during peak pollution episodes, fine particulate matter from the fires spreads across oceans and over large swaths of Europe and Central and East Asia, increasing exposure in these regions.
Model simulations indicate that during the worst periods, PM2.5 particles, including ash and soot with diameters of about 2.5 micrometers, reached concentrations associated with elevated health risks in many northern latitudes. In some areas, PM2.5 levels surpassed the 1 microgram per cubic meter threshold in numerous parts of the Northern Hemisphere, while wind-driven dusts in parts of northwestern China reached around 2 micrograms per cubic meter. These values point to widespread enhancements in aerosol loading linked to the Canadian fires.
Within Canada itself, the study found PM2.5 concentrations rising far above typical ambient levels, signaling a pronounced local impact alongside the transcontinental transport that carried pollutants far from their sources. The magnitude of these effects underscores the importance of recognizing how regional fire activity can influence air quality well beyond national borders and across hemispheres.
These findings contribute to a growing body of work that connects wildfire emissions with global air quality dynamics, illustrating the interconnected nature of the atmosphere as a single, shared environment. The research emphasizes the role of atmospheric transport pathways in shaping regional exposure to air pollutants and highlights the need for integrated monitoring and modeling efforts to better anticipate air quality crises linked to large wildfire events.
Overall, the Canadian wildfires of 2023 serve as a stark reminder that the consequences of regional fires extend into distant regions, affecting air quality, climate processes, and public health in multiple jurisdictions. Continued collaboration among international modeling teams and ongoing refinement of Earth system models are essential to improving early warning capabilities and informing policy decisions aimed at reducing exposure during severe fire seasons.