Effects of thermophysiological and non-thermal factors on outdoor thermal perceptions: the Tomebamba riverbanks case

Abstract

Outdoor thermal comfort (OTC) is an indicator of urban-environmental sustainability. A better understanding of OTC requires exploring the effects of contextual, non-thermal and human-related factors on thermal sensation votes (TSV) in addition to the long-studied thermophysiological and microclimatic factors. In this research, the Socio-Ecological Model (SEM) structure was used for grouping thermophysiological and non-thermal factors in three environments: corporeal (level of physical activity, level of clothing, gender, age and skin tone), mental (perceived urban agreeability, perceived urban insecurity and perceived urban noise) and social (company, occupation and cultural background). Field surveys were performed in three representative weeks of the annual climate-type in Cuenca, Ecuador during the hottest month (January), a cooler month (July) and an intermediate month (April), surveying 2321 users of two urban sites located at representative areas of the Tomebamba riverbanks. Statistical descriptive analysis and inferential methods were employed for exploring the effect of these SEM factors on the TSV using the Physiological Equivalent Temperature (PET) calculated with RayMan1.2 from on-site measured data. The analytical results evidenced a low influence of all three SEM environments on the TSV. Additionally, differences in male and female OTC requirements were identified, and two local PET-TSV scales were calculated from (1) urban global radiation data and (2) mean radiant temperature, calculated according to ISO 7726 with Ø 150 mm black-globe-thermometer measurements. The main results show Acceptable Temperature Ranges (rTa) in Cuenca from 29 °C to 34 °C PET (1) and from 26 °C to 37 °C PET (2), for 85% acceptability.