Quantification of the effect of thermal indices and sky view factor on park attendance

Outdoor shading affects the thermal environment and human thermal comfort, thereby influencing the usage of space. The objective of this study is to establish a relationship between the thermal environment and number of people visiting an outdoor space, and to explore the utilization of outdoor space during different seasons with various shading levels. This study includes onsite investigations of the microclimate parameters of the thermal environment and attendance at a park in central Taiwan. The results in cool seasons showed a positive correlation among the air temperature, mean radiant temperature (Tmrt), and physiologically equivalent temperature (PET) of shaded areas and the number of visitors. In hot seasons, the Tmrt and PET, which also reflect solar radiation conditions, are negatively correlated with the number of visitors. In other words, the higher Tmrt/PET values indicate that fewer people visit the park during the summer. Meanwhile, a significant correlation exists between park utilization and solar radiation conditions. This study proposes the use of area-averaged sky view factor (SVFa), instead of the traditional single-point sky view factor from fisheye photographs (SVFsp), as the indicator for measuring the shading level at various areas in parks. Analytical results indicate that the lower the SVFa, the higher the park utilization. This study highlights the importance of shade design in parks located in tropical or subtropical climates. The results can serve as a reference for park design in the future.