The comparative thermal experience of young and old pedestrians in urban green spaces and in densely built areas

Comfortable walking environments promote healthy lifestyle and facilitate active ageing. Thermal comfort during walking is a relatively unexplored research area. It has become a more critical issue due to the increased frequency of very hot weather. This study conducted a real-site experiment to study thermal comfort during walking for both older and younger adults. Participants walked in a “shaded-unshaded-shaded” sequence in a densely built-up area and a green space during very hot weather conditions. Microclimate variables, participants’ physiological responses and thermal sensation votes were recorded in the experiment. The physiologically equivalent temperatures (PET) during walking status in different environmental settings were estimated for the older and younger adult groups. The results indicated that, after a person walked in an unshaded space and reached a “hot” thermal sensation, walking in a shaded built-up area improved thermal sensation but not to a neutral level. Only a shaded green space could help to restore comfort during walking. While younger adults’ thermal sensation changes were mainly explained by PET changes, older adults tended to be more affected by the different settings of built-up area and green space. Among the physiological metrics adopted in the study, skin temperature and heart rate showed significant correlations with the thermal sensation vote. Design implications such as street greening work and minimum provision of tree shading on pedestrian areas were discussed.