Regional heterogeneity in heat mortality reduction by urban cooling strategies across Chinese cities.

Driven by climate change, extreme heat events pose growing health threats across China. Although infrastructure-based urban cooling strategies have been promoted, the regional disparities in their cooling efficacy and health benefits remain insufficiently quantified. Using the WRF-SLUCM and regional temperature-mortality exposure-response relationships, this study simulated four typical cooling measures (Green Roof, Cool Roof, Street Tree, and Full Adaptation) across 319 Chinese cities during summer 2022 and quantified heat-related mortality reductions. Results show that Full Adaptation reduces heat mortality by 18.8 % (95 % CI: 12.7 %-24.5 %), while Cool Roof, Green Roof, and Street Tree achieve 11.2 % (95 % CI: 7.6 %-14.6 %), 11.0 % (95 % CI: 7.4 %-14.3 %) and 5.5 % (95 % CI: 3.3 %-7.5 %) reductions, respectively. Beyond regional differences in cooling efficacy, variation in dRR/dT is another key determinant of overall effectiveness. This study emphasizes that the deployment of infrastructure‑based strategies at the regional level should balance both efficiency and equity principles. East China, with its large exposed urban population, delivers the greatest total health benefits. Regions with higher temperature sensitivity, such as Southwest and Northwest China, achieve larger per‑capita mortality reductions per unit temperature drop. In regions such as South China, where populations have developed substantial heat acclimatization, the mortality mitigation effect of cooling interventions is comparatively limited. These findings confirm the effectiveness of infrastructure‑based urban cooling strategies in reducing heat‑related mortality risk across China, while also revealing substantial regional heterogeneity, suggesting that priority should be balanced between areas of high temperature sensitivity and those with large population exposure.