Spatial effects of climate warming on the health risks due to urban heat exposure: a case study of China

The effects of global urbanization and climate warming on public health, including the health risk caused by the urban heat environment, have drawn extensive attention. Therefore, methods to appraise the spatiotemporal response mechanism of climate warming and the high temperature exposure dose (HTED) of urban residents need to be investigated to achieve sustainable cities. Based on an environmental health risk appraisal model and using the six ring roads in Beijing of China, this study simulated the spatial distribution of future high temperatures in three shared socioeconomic pathways (SSPs), SSP1-2.6, SSP3-7.0, and SSP5-8.5, by determining the correlation between the future mean maximum temperatures and sunny-day mean temperatures. Additionally, the HTED of commuting on foot or by bicycle was assessed based on the point of interest data of subway stations, architectural composition, and traffic surveys. Results demonstrate that during 2020-2040, 66.57% and 50.07% of areas for commuting on foot and by bicycle within the sixth ring road exposed to high temperatures (including low, medium, and high-risk areas). The exposure risks of both commuting methods were concentrated, and the exposure dose was the highest between the fifth and sixth ring roads, whereas the first to fourth ring roads were dominated by non-risk, minimum-risk, and low-risk areas. Moreover, compared with SSP1-2.6 and SSP5-8.5, SSP3-7.0 exhibited low HTED in both commuting methods. The proposed method provides a scientific basis to aid in identifying urban areas with high temperature exposure risk and a reference in assisting the planning of resilient and sustainable cities.