Using microclimate sensations and Physiological Equivalent Temperature to assess outdoor thermal comfort ranges: A case study of Singapore’s urban green space

This poster was presented at the 23rd International Congress of Biometeorology (ICB 2023) on May 14-17, 2023, in Tempe, Arizona, USA.

The 2030 Singapore Green Plan aims to expand, intensify and restore green spaces in the urban landscape to transform Singapore into a City in Nature. While urban green spaces offer vital ecosystem services such as regulating elevated temperatures in cities, less information exists on how urban green spaces influence outdoor thermal comfort (OTC) and thus the utility of the space. OTC, which is dependent on people’s perceptions of the complex interactions amongst ambient humidity, wind and both air and radiant temperatures, can be better understood by comparing microclimate/thermal comfort index against qualitative measurements of comfort perceptions. In this study, we analysed a dataset from an ongoing OTC campaign in Bishan-Ang Mo Kio Park, an urban park situated within a Singapore residential neighbourhood. We calibrated OTC thresholds for physiological equivalent temperatures (PET) by analysing PET against thermal perception survey responses. We examined OTC according to neutral and acceptable temperatures (NT and AT), where respondents perceive ‘comfortable’ outdoors in the outdoor green spaces. A preliminary analysis reveals that the estimated NT of 25.8ºC, when respondents experience neither heat or cold stress, is closely aligned to Singapore’s mean temperatures (26.0 – 27.0ºC). AT ranged from 22.6 to 29.4 ºC. NT for this study is lower compared to the NT of 27.2ºC (for acclimatised respondents) that Heng and Chow derived in their 2019 paper.