Seeking comfort in the urban heat: Unraveling the effects of thermal-acoustic environments on psychological restoration in urban greenways

As environmental pressures from high-density urbanization increase, the comfort of outdoor spaces and their restorative benefits for urban residents have become increasingly important. Although thermal and acoustic environments are key factors influencing outdoor comfort, evidence linking thermal and acoustic comfort with restorative benefits is scarce. This study explores the impact of the thermal-acoustic environment on psychological restorative benefits in urban greenways through on-site meteorological measurements and questionnaire surveys. The results indicate that, during the hot season, compared to densely vegetated greenways, sparsely vegetated greenways are perceived as hotter and noisier. Furthermore, the relationship between the thermal-acoustic environment and restorative benefits is more strongly correlated in sparsely vegetated greenways than in densely vegetated ones. In other words, the environmental comfort in different types of greenways can be targeted for improvement. Secondly, the interaction between thermal and acoustic environments influences restorative benefits. At the same sound pressure levels, restorative benefits decrease as the Universal Thermal Climate Index (UTCI) increases. However, on sparsely vegetated greenways, under conditions of 70–75 dB(A), the increase in UTCI does not significantly affect restoration. Finally, to identify the factors hindering psychological restoration, the study compares the veto power of thermal-acoustic comfort voting (TCV, ACV). This veto power varies according to greenway type. In densely vegetated greenways, ACV has greater veto power than TCV, while in sparsely vegetated greenways, the reverse is true. The findings offer valuable insights for urban planners and policymakers, suggesting that creating comfortable thermal-acoustic environments in outdoor spaces can enhance restorative benefits and contribute to the sustainability of high-density urban areas.