Decline in Aerosols Could Lead to More Heatwaves in Populated Areas
July 16, 2025

Heatwaves are becoming more frequent around the world. And while rising temperatures caused by greenhouse gas emissions are part of the problem, the declining levels of aerosols — the small particles that make up smog and air pollution — may be driving the rise even more, particularly in populated areas.

This finding comes from a study published in Environmental Research Letters and led by researchers at The University of Texas at Austin. While recent research has linked declining aerosols to rising regional temperatures, this study is the first to examine aerosols’ impact on people’s exposure to heatwaves.

“We knew that aerosol emissions were suppressing global warming at the regional level, but the impact of that same suppression on heatwaves near urban centers was much greater than we expected,” said study co-author Cameron Cummins. “So, as cities seek to curb their aerosol emissions to improve public health, they will also likely experience more heatwaves.”

Using global climate models, the researchers found that aerosols are up to 2.5 times more influential than greenhouse gases at driving changes in heatwave occurrence in populated areas – with higher levels of aerosols suppressing heatwave exposure by reflecting the sun’s rays.

…