Multiple effects of visual-acoustic-thermal perceptions on the overall comfort of elderly adults in residential outdoor environments

We selected typical residential outdoor spaces and five common sounds (birdsong, dance music, traditional opera, conversation and traffic sound) with three A-weighted equivalent continuous sound pressure level (LAeq) (60, 70 and 80 dBA) as visual-acoustic-thermal conditions. 458 elderly adults completed a subjective questionnaire while environmental parameters (meteorological parameters, illumination intensity (LUX), visible green index (VGI) and LAeq) were simultaneously measured to determine effects of visual-acoustic-thermal perceptions on overall comfort. We found that: 1) When physiological equivalent temperature (PET) was above 43.80 °C, the elderly felt thermally uncomfortable. Older adults perceived traffic sound as acoustic uncomfortable when LAeq was higher than 66.1 dBA. A higher VGI decreased the sensitivity of respondents to LUX. 2) Thermal sensation vote (TSV) and thermal comfort vote (TCV) were susceptible to the acoustic and visual environments. The influence of the visual environment and PET on acoustic sensation vote (ASV) and acoustic comfort vote (ACV) were not significant. We found a significant correlation between PET and sunlight sensation vote (SSV). 3) Acoustic and thermal comfort had a one-vote veto tendency relative to overall comfort, but no absolute veto power. Thermal comfort was the most important factor affecting overall comfort in summer while acoustic comfort was the most important in spring. 4) A binary logistic regression to predict overall comfort of elderly adults had 84.7 % accuracy, indicating a good performance.