Effect of heat mitigation strategies on the thermal environment of hardened pavement and pedestrian thermal comfort in a hot and humid area: A case study of Guangzhou, China.

Abstract

The synergistic effect of heat waves and urban heat islands (UHI) adversely affect the urban environment, building energy consumption, and human health. The absorption and storage of short-wave radiation by hardened pavement is the primary reason for high-temperature heat waves and the UHI effect. Three mitigation strategies were assessed to alleviate the influence of high-temperature hardened pavement on the thermal environment and thermal comfort of pedestrians, water-spray vehicles (spray) and pavement watering (watering) to take advantage of evaporative cooling, and a fan based on convective heat transfer. In addition, the fan-spray and fan-watering combinations were evaluated to increase the evaporative cooling rate. Field measurements showed that the five heat mitigation strategies improved the thermal environment and reduced environmental thermal stress. The thermal sensation, comfort sensation, and mean skin temperature (MST) were analyzed in thermal perception experiments. The result indicated that the mitigation strategies changed the subjects' thermal perception. Moreover, regression analysis between the universal thermal climate index (UTCI) and the thermal response showed that the neutral temperature and the range of comfort threshold of UTCI and MST increased after implementing the mitigation strategies.