The distorted power of medical surgical masks for changing the human thermal psychology of indoor personnel in summer

Abstract

The medical surgical mask (MSM) has been the essential protective equipment in people's daily work. The experimental purpose is to explore the effects of wearing MSM on human thermal sensation, thermal comfort, and breathing comfort in office buildings in summer. A total of 30 healthy college students were recruited for the testing. The experiment was carried out in a climate chamber, which can simulate the office buildings in summer. The experiment collects the subjects’ skin temperature, microclimate in the mask, and subjective votes, including thermal sensory votes (TSV), thermal comfort votes (TCV), and respiratory comfort votes (BCV). Experimental results show that wearing MSM has no significant effect on the skin temperature of the human body. The microclimate temperature inside the MSM reaches over 34℃, and the relative humidity reaches over 70%. The high-temperature and high-humidity microclimate put human beings in an uneven thermal environment, which leads to poor human tolerance to the thermal environment and becomes the main reason for destroying human thermal comfort. Wearing MSM has a significant impact on the subjective thermal sensation, thermal comfort, and breathing comfort of the human body, and the impact becomes more significant as the environmental temperature increases. Once the mask is taken off, the human body will enter an extremely comfortable environment, resulting in an excessively high vote value. The difference in voting values before and after removing the mask becomes larger with the environmental temperature. By fitting the voting results and perform data processing, it can be found that wearing MSM will reduce the neutral temperature by 1.5°C, and the environmental temperature with the optimal thermal comfort by 1.4°C, and as the temperature increases, the respiratory discomfort will become more and more intense. Regardless of whether wearing a MSM, the subjects preferred a slight warmer environment. In conclusion, with the increase of ambient temperature, wearing MSM can cause the human worse tolerance to the thermal environment, and this disturbance will become more and more intense.