Outdoor thermal comfort and activities in urban parks: An experiment study in humid subtropical climates

A pleasant outdoor thermal environment could substantially enrich residents' enjoyment for outdoor activities. However, previous studies on outdoor thermal comfort in humid subtropical regions have given limited attention to urban parks. This study aimed to explore the relationship between outdoor thermal comfort and spatial behaviors in urban parks located in humid subtropical regions. Physical measurements, questionnaire surveys, and behavioral observations were conducted to establish the thermal benchmarks in Xiamen, China, including neutral Physiological Equivalent Temperature (PET), neutral PET range, comfortable PET, and thermal acceptability range. The thermal discomfort factors and preferences for thermal environmental parameters were also identified. The results showed that the neutral PET in Xiamen's urban parks was 19.3 °C in spring and 24.7 °C in summer. In spring, the neutral PET range was found to be between 17.3 and 21.2 °C, whereas in summer, it expanded to 20.9 and 28.4 °C. Comfortable PET was 19.4 °C in spring, but no specific value was determined during the summer testing. In summer, the 90% thermal acceptability range of the residents was below 32.8 °C. Residents were observed to adapt to outdoor thermal conditions by adjusting their activities, such as the change in outdoor time, location, activity level, and clothing. To improve outdoor thermal comfort, it is important to consider the period of thermal discomfort and implement cooling shading measures during the summer, such as mist-spraying facilities or removable sunshade devices. This quantitative assessment of outdoor thermal comfort in urban parks could offer valuable insights for designing urban parks in humid subtropical regions.