Optimized spatial planning offers a dual solution for managing urban heat and air pollution in humid subtropical climates

As cities expand, urban heat islands and air pollution have merged, especially in humid subtropical cities. Yet a dual solution remains lacking to simultaneously mitigate these two issues due to complex meteorology-chemistry interactions. Based on numerical simulations and a multi-objective optimization algorithm, we develop an optimized spatial planning that considers the intricate interplay between urban heat and pollution. Optimized development prioritizes urban locations upwind of the summer monsoon, and suggests developing medium-density urban (where the built-up fraction ranges from 0.5 to 0.8), as well as increasing urban green space fractions from 0.15 to 0.27. Such an urban layout yields the greatest reductions in urban warming and pollution. Both regression analysis and numerical simulations confirm the effectiveness of the framework. Enhanced ventilation improves air quality, while strong southerly winds mitigate urban heat. This study underscores the necessity of addressing urban heat and air pollution simultaneously.