Assessing the Integrated Impacts of Outdoor Thermal Environment and Air Quality on Thermal Comfort in Residential Areas: A Case Study of Wuhan

Climate change and rapid urbanization are intensifying global environmental challenges, particularly the nexus of urban heat stress and air pollution, which collectively impact human health and outdoor livability. This study investigates the spatiotemporal distribution of the outdoor thermal environment and PM2.5 concentrations in residential areas of Wuhan, a city with a hot-summer–cold-winter climate, and evaluates their combined effects on outdoor thermal comfort. Field measurements of microclimatic parameters and PM2.5 levels were conducted in two typical residential communities during winter and summer, supplemented by 582 valid questionnaires to assess residents’ subjective thermal responses. Key findings include (1) residents’ satisfaction decreases by approximately 1 unit for every 90-unit increase in AQI, and PM2.5 concentrations can effectively substitute for AQI in characterizing the impact of air quality on satisfaction. (2) The explanatory power of the UTCI-MTSV model (R²: 0.3152–0.7763) is pollutant-dependent; winter thermal comfort adheres to the linear law of UTCI, while dispersed summer votes indicate a non-linear effect of PM2.5 on comfort. (3) Wuhan residents show high thermal tolerance across AQIs. The lower limits of the Thermal Acceptability Range (TAR) are 7.1 °C (AQI-I) and 8.8 °C (AQI-II), both below neutral ranges, while the summer TAR-UTCI is 30.9 °C (above the neutral range). Better air quality improves the reliability of the thermal acceptability–UTCI fit. (4) TCV peaks at approximately 16 °C, increasing then decreasing with UTCI; at identical UTCI levels, better air quality enhances comfort, particularly within the 0–10 °C range. This study provides empirical evidence to inform urban design strategies for mitigating heat stress and pollution in hot-summer–cold-winter regions.