Outdoor Thermal Comfort And Citizen Activities In Subtropical Urban Areas

Under the global warming, urban heat island effect really aggravated the heat stress in cities and influenced the outdoor thermal comfort of city residents and outdoor activities. Thus, the study in urban outdoor thermal comfort and the human activity in outdoor spaces has an important significance for the human’s urban life. This paper studies the main factors that affect the outdoor thermal comfort and the space use in Shanghai area by field meteorological survey and questionnaire survey. The results of the study show that the environmental factors (especially the air temperature) do affect visitors’ evaluation of the outdoor thermal environment. In the both cold season and hot season, there was a significant positive correlation between the subjective thermal sensation and air temperature. The neutral PET range of Shanghai city is 15-29℃ in winter and 20-28℃ in summer. Different building environment can cause obvious difference between the PET values in the selected two sample sites. The PET value in the open lawn area was significantly higher than that of the square area where shaded by the trees and buildings surrounded. In the aspects of human factors, visitors in different age groups show different degree of tolerance to the outdoor thermal environment, older groups significantly are more tolerant, more of them feel comfortable to the current environment than younger groups. In winter, both short term memory and long term memory of space users can influence their subjective perception of the environment. In the summer, people’s preference to natural environment and urban environment can affect users’ feeling to the outdoor space in some extent. Those who more loved outdoor natural environment obviously are more tolerant to the hot summer outdoor environment. On the other hand, in the Shanghai area, the number of outdoor space users is mainly related to the outdoor air temperature. The study results show, in mild season, the outdoor space use and meteorological factors did not significantly correlated; in winter, as temperatures rise, the user number of park square increased; in summer, as temperatures rise, the user number of park square decreased. This result is consistent with the results of other subtropical cities, but in contrast to the summer results in the European region, this difference may be due to the different cultural backgrounds of the two regions.