Gauging the impact of heatwaves on the thermal perception of pedestrians with thermal walks in a humid subtropical climate

Abstract

Studies point to an increase in the frequency of heatwaves, revealing that they are longer lasting and more intense, with noticeable impacts from climate change observed in the south of Brazil. This study evaluates the impact of a heatwave event in Curitiba, Brazil, and investigates whether the excessive heat caused during this period influenced the thermal perception reported by participants in a fieldwork carried out during dynamic microclimatic surveys on a university campus. To this end, volunteers took part in thermal walks accompanied by a researcher carrying a portable equipment for monitoring environmental variables, covering points of interest previously defined in a walking circuit with different morphological and land cover configurations. Concurrently, the volunteers' thermal perception was assessed at five stops using standard perceptual and affective questionnaires. The sample during six campaigns comprised 50 participants, which cast a total of 300 subjective thermal perception responses along the walking circuit. As a means to compare participants' subjective responses during the heatwave, we used a database of surveys with pedestrians conducted in a previous study that also covered the summer season, though without the influence of a heatwave. A lower thermal sensitivity of respondents was observed, expressed through the variation between the thermal sensation vote and the Dynamic Thermal Sensation (DTS) during the heatwave days. During the thermal walk, subjects experienced thermal respite in a vegetated area on campus, potentially with positive alliesthesia.