On the assessment of dynamic thermal comfort and pedestrian psychophysiological responses during heatwaves : A focused analysis

Duration and frequency of summer heat waves have growing on a global scale, dramatically impacting the thermal comfort and psychophysiological response of pedestrians. This study longitudinally tracked the dynamic thermal comfort of 20 pedestrians throughout the predefined walking circuit (indoor-hallway-shade/sunlight-hallway-indoor) during summer heatwaves in Chongqing, China. Four cases of the trials, including SH: indoor-hallway-shade-hallway-indoor, SU: -sunlight-, SH-SU: -shade to sunlight-, and SU-SH: -sunlight to shade-, were conducted in two typical outdoor spaces and their adjacent building. Participants' psychological questionnaires [thermal sensation vote (TSV), thermal comfort vote (TCV) and perceived sweat vote (PSV)] and physiological responses [mean skin temperature and wettedness (T_skin and MSW) and tympanic temperature (T_t)] were monitored throughout the walking circuit. Results show that T_skin, T_t and MSW in the SH were 1.3 °C, 0.5 °C, and 0.07 lower than in the SU, with TSV, TCV and PSV 1–1.5 scores lower. Moreover, comparative results on a global scale revealed that cities—which are closer to the tropics—have higher neutral temperatures and ranges in UTCI. To assess the time for pedestrians' psychophysiological parameters to return to normal levels after outdoor thermal exposure, a predictive framework for recovery time was developed based on the TSV and MSW, which is informative for assessing the recovery state and thermal comfort during heat waves.