Long-range PM_2.5 pollution and health impacts from the 2023 Canadian wildfires

Area of Science:

• Environmental Science
• Public Health
• Atmospheric Chemistry

Background:

• Extreme wildfires in Canada during 2023 significantly impacted air quality across numerous regions.
• Particulate matter (PM2.5) exposure from wildfire smoke poses a substantial threat to human health.

Purpose of the Study:

• To quantify the global and regional PM2.5 exposure attributable to the 2023 Canadian wildfires.
• To assess the associated human health impacts, including acute and chronic mortality.

Main Methods:

• Utilized satellite observations to monitor smoke plumes.
• Employed machine learning algorithms for exposure assessment.
• Applied a chemical transport model to simulate PM2.5 dispersion and impact.

Main Results:

• Global annual PM2.5 exposure increased by 0.17 μg/m³, with North America experiencing the largest rise (1.08 μg/m³).
• Canadian wildfire smoke contributed significantly to PM2.5 levels in the USA, exceeding domestic wildfire contributions.
• An estimated 354 million people in North America and Europe were exposed, with 5,400 acute and 64,300 chronic deaths linked to this exposure.

Conclusions:

• The 2023 Canadian wildfires demonstrated the extensive reach of PM2.5 pollution and its severe health consequences.
• Wildfire-driven air pollution represents a significant public health burden with transboundary implications.
• Urgent strategies are needed to mitigate the health impacts of large-scale wildfire events.