Assessing inequality in population exposure of urban heat across China's major cities

Abstract

Global warming and intensified heatwaves threaten human health and urban sustainability, representing critical global public health challenges. While previous studies have quantified urban heat exposure (UHE), comprehensive investigations into its spatial distribution and social equity at the block level in China remain limited. This study employs data from 43 major Chinese cities, integrating sources such as OpenStreetMap, remote sensing imagery, and housing prices to reveal UHE patterns and inequity. Our findings show that, in most cities, lower housing prices are associated with higher levels of UHE, underscoring the disproportionate thermal burden borne by socioeconomically disadvantaged populations. Furthermore, cities with elevated UHE Gini coefficients are primarily concentrated in central China, reflecting greater intra-urban inequality in UHE across these regions. Interestingly, in approximately 60.46 % of the cities, cumulative UHE is predominantly concentrated among low-income groups. Finally, our analysis demonstrates that the standard deviations of building density and building height, as well as the mean water area within each block, significantly influence UHE equity, highlighting the role of intra-urban structural heterogeneity in shaping thermal disparities. Overall, these findings deepen our understanding of UHE patterns and inequities within Chinese cities, offering essential insights for urban planning and environmental justice.