Substantial increase in the joint occurrence and human exposure of heatwave and high‐PM hazards over South Asia in the mid‐21st Century

Extreme heat occurrence worldwide has increased in the past decades. At the same time, many cities are facing severe air pollution problems featuring high‐PM episodes (high concentration of particulate matter due to various sources) that last from days to weeks. The main purpose of this study is to bring forth a greater awareness of the potential larger increase in the coincidence of two stressors.

This study presents an integrated assessment of human exposure to the joint occurrence of the heatwave and high‐PM extremes, and possible future changes have been missing. In addition to the expected elevation in the heatwave and high‐PM‐related extremes, the authors also show that the rare jointed events would have quite large increases in the future with a 175% increase in frequency. The fraction of land exposed to prolonged high-PM hazard (HHH) would increase by more than tenfold in 2050. The alarming rate of increases in just a few decades poses great challenges to adaptation.