Socio-Spatial Vulnerability to Heat: A Study of Mortality in Washington Neighborhoods During the 2021 Western North America Heat Wave

Abstract

This study is a spatially and temporally relevant analysis of mortality and heat patterns within Washington neighborhoods during the 2021 Western North America Heat Wave. Utilizing geocoded mortality data from the Washington State Department of Health, historic daily maximum temperature data from the National Oceanic and Atmospheric Administration, and zip code-level demographic information from the U.S. Census Bureau, this research presents a fine-scale, time-series analysis of the effect of temperature on mortality in Washington and exposes how the sociodemographic composition of neighborhoods can promote or undermine population health in the context of extreme heat. The study employs logistic, Poisson, and linear regression analyses and establishes relationships between increased weekly temperature, certain socio-demographic variables, and mortality at the neighborhood level. Findings at the individual level indicate a higher mortality risk for American Indian/Alaska Natives, men, and those over the age of 67 during an extreme heat scenario. At the community level, population-adjusted analysis reveals that neighborhoods with a higher proportion of individuals who are over 65, lack public transportation, who live alone, are without health insurance, and are foreign born experienced greater mortality. Neighborhoods with younger residents, those lacking access to public transit, and lower-income neighborhoods experienced hotter temperatures during the heat wave, a finding that adds credence to environmental justice literatures imagining ecological disaster and hazards as an outcome of class-based inequality. Finally, this study stresses the potential misclassification and underreporting of heat-related deaths during the heat wave, a concern noted in previous research on the subject. The research contributes a place-based understanding of both individual and population health risks in the context of heat disaster and underscores the importance of equity-centered climate adaptation strategies, particularly in regions historically less affected by extreme heat that lack social and material adaptation strategies.