Effects of interactions between thermal and acoustic environments on subjective comfort evaluations in outdoor public spaces

In this study, five outdoor open areas were selected as the study sites to investigate the effects of thermal and acoustic environments, physical activity levels, and pleasantness on evaluations of the thermal and acoustic comfort in outdoor open spaces. Survey questionnaires and on-site measurements were used to quantitatively assess human thermal and acoustic comfort in outdoor spaces. The following findings were obtained in this study. The acoustic environment affected the thermal sensation, where reducing excessive outdoor noise levels could enhance thermal comfort. Increasing the physiological equivalent temperature amplified the acoustic sensation. Individuals reported the most comfortable acoustic perception outdoors at a physiological equivalent temperature of 30.1 degrees C. Reducing both the thermal and acoustic indices improved the overall comfort to some extent. Decreasing physical activity levels by an appropriate amount enhanced the thermal comfort, acoustic comfort, and overall comfort. Finally, maintaining a sense of pleasantness was conducive to increasing the thermal comfort, acoustic comfort, and overall comfort. In states of moderate and pleasurable feelings (pleasantness level = 0, 1, 2, 3), increased acoustic comfort and pleasantness combined significantly enhanced the thermal comfort.