Regional Variation in Humidity and Heat-Related Mortality

This research report investigates the impact of humidity on heat-related mortality across various cities worldwide. The study utilizes extensive epidemiological and climatological datasets to analyze the association between multiple heat stress indicators (HSIs) and daily human mortality in 739 cities from 43 countries. It identifies significant differences in the long-term trends and timing of heat events as detected by HSIs. The findings indicate that air temperature (Tair) is a strong predictor of heat-related mortality in cities with a strong negative correlation between Tair and relative humidity. However, in cities with weak correlations, HSIs that incorporate humidity provide improved predictive capabilities. The report emphasizes the need for enhanced heat-health alert systems that account for humidity, particularly in regions where the integration of humidity significantly affects mortality predictions. This study aims to bridge the gap in understanding how to effectively incorporate humid heat into public health strategies in the context of climate change.