Study on thermal comfort differences between older shoppers and vendors in open-air markets in cold regions

Open-air markets, as important public commercial spaces in urban areas, serve as primary activity locations for older shoppers and vendors. This study, based on a case study of an open-air market in Zhangjiakou, utilizes meteorological monitoring and questionnaire surveys to determine the thermal comfort baseline using Physiological Equivalent Temperature (PET), compare the thermal perception differences between older shoppers and vendors, and analyze the physical, individual, social, and psychological factors influencing thermal perception. The findings include: 1) Older shoppers exhibit higher thermal sensitivity than vendors. 2) The Neutral PET (NPET) for older shoppers and vendors are 9.3 °C and 8.3 °C, respectively, with the Neutral PET range (NPETR) for older shoppers being −0.4 ∼ 18.9℃ and for vendors, −4.7 ∼ 21.3℃；Thermal acceptable range (TAR) for older shoppers is −2.3 ∼ 15.9℃, and for vendors, −5.9 ∼ 22.7℃. 3) Among the factors influencing thermal perception, wind speed has the greatest impact on both groups, followed by air temperature. The thermal perception of older shoppers is closely related to physical, individual, social, and psychological factors, while that of vendors is primarily influenced by physical, individual, and psychological factors, with no significant effect from social factors. 4) Based on these analyses, design strategies for optimizing open-air markets are proposed to enhance thermal comfort and meet the needs of different groups.