Investigating differences of outdoor thermal comfort for the elderly among genders across seasons: A case study in Chongqing, China

With global warming and aging, more attention should be paid to outdoor thermal comfort of the elderly in developing countries. Metabolism of the elderly, which affects thermal perception, is always slower than young population, especially in hot humid climate. Therefore, meteorological measurements coupled with thermal questionnaire surveys were collected to investigate outdoor thermal comfort of the elderly during summer and winter in open spaces in Chongqing. Physiological equivalent temperature (PET) was calculated and results showed that: (1) Neutral PET was 22.6 °C with a ranges of 18.1–27.1 °C for the elderly. (2) Thermal sensation of the elderly was greatly affected by air temperature, relative humidity and solar radiation, but less by wind velocity. (3) Thermal perception existed significant differences between seasons with higher neutral PET and narrower acceptable PET range in summer. (4) Thermal perception of female was more susceptible to solar radiation with better acceptance in high temperature. It is worth noting that the elderly, even when feeling comfortable, can experience risk of thermal stress. The findings can provide reference for open space design of the elderly in Chongqing, which is conducive to reducing the risk of heat and cold stress during outdoor activities.