Study on the influence of hypobaric hypoxia on human thermal comfort under step change thermal environments

•Effect of hypoxia on the dynamic thermal comfort of Tibetan sojourner was clarified.•The hypoxic environment in the plateau prolong the time required for skin to rewarm.•The hypoxic environment worsen the decrease of thermal sensation at low temperature.•PMV model was not suitable for predicting the thermal sensation of sojourners. Given the meteorological conditions on the Tibetan plateau such as low temperatures and large diurnal range, people moving in and out of buildings are inevitably exposed to the transient, step change thermal environments. Significant temperature changes are closely related to humans' thermoregulatory processes, and the hypoxic environment may affect the thermoregulation process of sojourners in Tibet, which makes it difficult for people to adapt to temperature changes in time and increases the risk of disease. Nevertheless, most experimental studies on temperature step change were carried out in plain. Only a few experimental studies focused on the effect of temperature step change on human thermal comfort under low temperature and hypoxic environment. In order to understand the impact of this condition, the same temperature step change experiment was conducted in Xi'an and Lhasa, respectively. The results showed that the hypoxic environment of the plateau could cause decreasing of sojourners’ thermal sensation and skin temperature in Tibet under low temperature environment, and prolong the time needed for skin to rewarm. The results of this study can help provide a better thermal environment in buildings to ensure the health and thermal comfort of Tibetan sojourners.