Experimental study and theoretical discussion of dynamic outdoor thermal comfort in walking spaces: Effect of short-term thermal history

Abstract

Chinese urbanites walk approximately 1.2 km on average in each commute. Trees and buildings can affect pedestrians' perceptions of the thermal environment in walking spaces. Accordingly, they can affect urbanites' modes of transportation. Most urban walking spaces are planned by functionality, with little consideration of thermal comfort. In this study, we examined pedestrian perceptions of the thermal environment of urban walking spaces in Beijing during spring and summer. Overall, 62 participants were asked to walk in the outdoor walking space for approximately 1.2 km and complete questionnaires every 100–200 m regarding their immediate thermal response to the environment. A backpack-type microclimate equipment was used to monitor the thermal environment around the participants. According to our findings, air temperature and relative humidity are the two main temporal variables from spring to summer, whereas solar intensity and wind speed are the two main spatial variables. The immediate thermal response is influenced by the short-term thermal history of the past 20–35 s. The sequential order of thermal exposure is associated with the overall thermal evaluation of the environment while walking. By experiencing a worse thermal environment before and an improved thermal environment after, the walking space can be evaluated as more thermally comfortable than by experiencing thermal environments in reverse. The findings of this study can provide guidance for improving the thermal environment of urban walking spaces.