Elderly residents’ uses of fragmented outdoor spaces in public housing estates in Hong Kong——Decoding causality and heat-risk exposure

Well-designed open/semi-open spaces in public housing estates (PHEs) are important urban living rooms for urban residents to enhance well-beings, relieve from cramped homes, and cope with hotter climate. In order to understand the elderly residents' space use in light of space/neighbourhood attributes and microclimates, mobile field tests including physical measurement, passive observation, and questionnaire survey were carried out in 33 fragmented outdoor spaces (FOSs) in Choi Hung Estate (CH_E) and Upper Ngau Tou Kok Estate (UNTK_E) in Hong Kong from June to early October 2022. GIS application was adopted to map the vitality in association with microclimates. The ordered probit model and multilevel regression model were employed to explore the contributions of factors to the elderly's FOSs use. It is shown that the time of the day, microclimate (mPET—modified PET for hot-humid regions & wind speed), FOSs attributes (SVF, nature view, functionality, size), and neighbourhood attributes (accessibility & building density) significantly influence elderly attendance in FOSs. One degree increase in mPET is associated with around 4.7% decrease in the elderly's FOSs use. The elderly is likely exposed to unconscious heat risks under the compensatory effects of space and neighbourhood building attributes on the thermal environment of a FOS, and popular FOSs contribute to an increase in heat tolerance by approximately 5 °C in terms of mPET. A FOS that maintains mPET between 30.8 °C and 33.1 °C in summer, along with other favourable attributes (SVF, accessibility & functionality) may help mitigate the heat risks and increase overall usage rate.