Characterizing the Compound Extreme Temperature and PM_2.5 Pollution Events: A Multi-Country Analysis

Area of Science:

• Environmental Science
• Atmospheric Science
• Public Health

Background:

• Climate change and air pollution present compound environmental risks.
• Spatiotemporal patterns of extreme temperature and air pollution events are not well understood globally.

Purpose of the Study:

• To quantify global trends and spatial distributions of compound extreme temperature and PM2.5 pollution events from 2003-2023.
• To analyze the relationship between temperature extremes and PM2.5 concentrations across different regions.

Main Methods:

• Analysis of 10,067 monitor locations in 43 countries.
• Quantification of temporal trends and spatial distributions of compound events.
• Sensitivity analyses using alternative thresholds and datasets.

Main Results:

• Compound extreme heat and PM2.5 events decreased in most countries (35/43).
• Compound extreme cold and PM2.5 events exhibited diverse trends globally.
• PM2.5 concentrations during cold conditions were higher in China, India, and Europe; during hot conditions in the USA and Australia.
• India, Pakistan, and China showed disproportionately higher exposure to compound events.

Conclusions:

• While heat-related compound events are decreasing, cold-related events remain significant.
• Regional variations in temperature-PM2.5 relationships influence event prevalence.
• Policies should address temperature-dependent emissions to mitigate amplified pollution during extreme temperatures.