A comparative analysis of human thermal conditions in outdoor urban spaces in the summer season in Singapore and Changsha, China

This paper presents the comparative analysis between the findings from two field surveys of human thermal conditions in outdoor urban spaces during the summer season. The first survey was carried out from August 2010 to May 2011 in Singapore and the second survey was carried out from June 2010 to August 2010 in Changsha, China. The physiologically equivalent temperature (PET) was utilized as the thermal index to assess the thermal conditions. Differences were found between the two city respondents in terms of thermal sensation, humidity sensation, and wind speed sensation. No big difference was found between the two city respondents regarding the sun sensation. The two city respondents had similar neutral PET of 28.1 A degrees C for Singapore and 27.9 A degrees C for Changsha, respectively. However, Singapore respondents were more sensitive to PET change than Changsha respondents and the acceptable PET range for Changsha respondents was wider than that for Singapore respondents. Besides, the two city respondents had different thermal expectations with the preferred PET of 25.2 A degrees C and 22.1 A degrees C for Singapore and Changsha, respectively. The results also reveal that Changsha respondents were more tolerant than Singapore respondents under hot conditions. Finally, two regression models were proposed for Singapore and Changsha to predict the human thermal sensation in a given outdoor thermal environment.