Vegetation and Thermal Comfort in Open Spaces: The Case of Sistan Province

Given the role of open spaces in quality of living environment and the importance of climatic comfort for effective usage of such spaces, this research examines the impact of vegetation in producing thermal comfort in the hot arid Sistan Province, southeast Iran. For this purpose, 29 points were selected in Zabol University in two different locations—adjacent to buildings and vegetation; or solely surrounded by vegetation. The climatic parameters were then measured 3-hour intervals for these points during the warmest summer days of August 2016 at three microclimate, local and city levels. The parameters measured were air temperature, relative humidity, wind velocity, etc. These measurements were then used to calculate the Wet Bulb Globe Temperature (WBGT) as the main comfort criteria in open spaces.
The results indicate that vegetation can bring all climatic parameters to comfort levels in their immediate proximity. These parameters are not affected in their vicinity, however. Therefore, mean climatic comfort was higher at microclimatic level as compared with local or city levels. Furthermore, the parameters most affected by vegetation were found to be wind velocity and average radiant temperature.