Study on the dynamic effects of plateau hypoxic and cold environment on the thermal adaptation of short-term sojourners in Xizang.

The plateau hypoxic environment can affect the thermoregulation process of the human body, and due to the different acclimatization ability to the hypoxic environment, the thermal requirements among the people who enter Xizang at different times may be different. Accordingly, this study aims to clarify how plateau hypoxic environments influence the physiological and subjective responses of people entering Xizang at different times. And field experiments were conducted in Xi'an and Lhasa, respectively, to compare the thermal responses and oxygen responses of the subjects under different temperature conditions on the plain, the first day of entering Xizang and the 15th day of entering Xizang. The results showed that under the hypoxic environment, the thermal sensation of the subjects decreased. With the extension of the time entering Xizang, the influence of the hypoxic environment on thermal comfort was gradually weakened, but under the low temperature environment, the effect of hypoxia on thermal response was not significantly reduced. The results of this study can help to reveal how plateau hypoxic environments affect human thermal comfort and provide a theoretical basis for the design of indoor thermal environment parameters suitable for sojourners entering Xizang at different times.

Oxygen comfort evaluation method based on symptom index for short-term internal migrants to Tibet.

In Tibet, the hypobaric-hypoxic environment found at high altitudes leads to dysfunction in short-term internal migrants and has noticeable effects on physiology, psychological health, and comfort level. Therefore, it is essential to accurately determine the degree of hypoxia and improve the hypoxic environment of plateaus. Despite advances in the medical diagnosis and treatment of pathological hypoxic injuries, there are some limitations in the oxygenic evaluation of internal migrants with mild hypoxia. An oxygen comfort evaluation method (OCEM) based on typical anoxic symptomatology and physiological indices is proposed in this study. Experiments with different oxygen concentrations were conducted to measure anoxic symptomatology and physiological indices. Using item and exploratory factor analyses, 19 symptom indices were screened to predict oxygen sensation in humans. Finally, the OCEM was established using an artificial neural network and fuzzy mathematics method and its accuracy was verified through a field survey. The results showed that the artificial neural network model using symptomatologic indices could predict human oxygen sensation, with an area under the receiver operating characteristic curve of 0.630-0.913 and prediction accuracy of 93 %. Oxygen comfort can be predicted from the oxygen sensation and typical physiological indices using the fuzzy mathematics method; the weighted kappa coefficient was 0.825, indicating a strong correlation between the predicted and actual values. The proposed OCEM can help determine the oxygen comfort conditions of high-altitude internal migrants and provide a basis for indoor oxygen environment regulation in high-altitude buildings.

Dry response and acclimated characteristics of people ascending the Tibetan Plateau.

Due to a long period of low humidity, exposure to the dry environment of the Tibetan Plateau can cause skin and respiratory diseases and threaten human health. To examine the characteristics of acclimatization response to humidity comfort in visitors to the Tibetan Plateau based on an examination of the targeted effect and mechanism of the dry environment. A scale corresponding to local dryness symptoms was proposed. Eight participants were selected to conduct a two-week plateau experiment and a one-week plain experiment under six humidity ratios, respectively, to explore the characteristics of dry response and acclimatization of people entering the plateau. The results indicate that duration has a significant effect on human dry response. On the sixth day after entering Tibet, the degree of dryness reached the maximum, and acclimatization to the plateau environment began on the 12th day. The sensitivity of different body parts to the change in a dry environment was different. When the indoor humidity ratio increased from 9.04 g/kg to 21.77 g/kg, the symptoms of dry skin were most significantly relieved by 0.5 units of scale. After de-acclimatization, the degree of dryness in the eyes was most significantly alleviated, reducing by nearly one scale. The analysis of human symptom indicators in a dry environment shows that subjective and physiological indices are influential and essential in measuring human comfort in a dry environment. This study extends our understanding of dry environment responses and cognition of human comfort and lays a solid foundation for humid built environments in the plateau.