Trends and attributions of the long-term thermal comfort across the urban–rural gradient in major Chinese cities

Improving the understanding of ambient thermal comfort (TC) is a crucial prerequisite for addressing heat-related issues. Thus, this study is conducted to explore the dynamic signatures and potential drivers of TC (indicated by summertime physiological equivalent temperature, PET) in 101 Chinese cities along their urban-rural gradients (urban core area, UCA; urban expansion area, UEA; and rural area, RA) and urbanization processes (2000–2020). The major results showed that, (1) >60 % case cities generally experienced uncomfortable TC (>29 °C), with relatively high PET in their UCA > UEA > RA. (2) Since 2000, PET in all the spatial gradients deteriorated significantly, ranged from 0.26 to 0.28 °C/decade. This trend is more prominent in RA than UCA and UEA, especially in the latter stages of the study period (2011–2020). (3) Vegetation coverage, population density, and impervious surface coverage served as the major contributors of PET in the case cities, but they varied across different gradients and times. These findings highlight the detailed spatiotemporal characteristics of TC and admonish the associated intensified heat-exposure risks to local residents in Chinese cities. Further research with more details is required to provide a comprehensive reference for heat risk issues in both urban and rural areas.