Thermal sensation in outdoor urban spaces: a study in a Tropical Savannah climate, Brazil

摘要

The present study carried out assessments regarding thermal sensations under different weather conditions in three urban areas in Cuiaba, Brazil, a Tropical Savannah climate (Aw) region. Thermal acceptability by means of thermal sensation votes (TSV) was addressed based on the estimation of the Universal Thermal Climate Index (UTCI) values. Important issues related to clothing thermal insulation (Icl), the effect of gender on thermal sensation, and implications of artificial conditioning (AC) systems are also evaluated. Micrometeorological variables were determined and 685 questionnaires were applied to evaluate individual pedestrian thermal preferences. The Icl observed in the Tropical climate was lower than that intrinsically inputted by the UTCI for Temperate climates. The local thermal comfort zone ranged between 21.5 and 28.5 degrees C, with both thresholds higher than those observed in studies conducted in Subtropical, Mediterranean, and Continental Temperate climates while the local hot thermal sensation categories were displaced at least 3 degrees C above than those for the aforementioned climates. The effect of gender on thermal sensation indicated that females are more sensitive to cold stress conditions than males, requiring higher Icl for temperatures below 28 degrees C. The physiological adaptation by continuous exposure to AC systems reduced the neutral temperature between AC and non-artificial conditioning system users (NAC) by 0.8 degrees C, with more intense differences in hot TSV ranges. This study reveals differences between stated TSV classes derived for other climates and those resulting from TSV declared by Savannah local residents, indicating that local thermal sensation scale for UTCI in an important key for environment planning.