Interaction effects of outdoor thermal comfort and air pollution

Urban haze pollution is a major problem affecting outdoor environmental quality, thereby hindering the construction of ecological civilization and healthy urban development. The urban physical environment also affects the urban outdoor thermal environment. Both the thermal and air environment have important effects on the subjective comfort evaluations of people. In this study, four typical University Campus Green Spaces (UCGSs) in Xi'an, China, were selected to investigate the thermal and air environments in outdoor spaces. The adaptive thermal comfort due to the interaction between the outdoor thermal environment and air pollution was studied based on questionnaires and field measurements, and a strategy was developed for optimizing the thermal comfort of urban campus green space environments. The results showed that the influence of the thermal air quality environment on subjective comfort varied among different spaces. The influence of haze pollution on subjective comfort was greater in high and low-temperature environments, but less obvious in a moderate temperature environment. When the PM2.5 particle concentration was greater than 100 µg/m³, the evaluation of respiratory comfort was low in the high-temperature environment. The perception of air pollution was less sensitive in the thermal environment in covered road sections. Heat pollution and air pollution will affect human health to varying degrees. The outdoor thermal environment and patients with respiratory diseases are affected most by haze pollution.