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.

Effect of wearing a face mask on microclimate around the eyes and the tear film

“…Leakage of exhaled air from the top of the mask has been observed in previous experiments and CFD simulations. 35,36 In addition, as measured by Zhang et al, 57 the temperature and humidity of the air inside the surgical face mask were high because of disturbed heat dissipation and accumulation of exhaled air.…”

“…In addition, the effect of the increase in body temperature due to wearing a mask on ocular surface conditions may need to be considered in environments with high temperatures or using masks with low air permeability. 57,68 Furthermore, glasses or face shields worn with the mask are expected to affect the microclimate around the eyes because they change the direction of the airflow. In future studies, it would be useful to clarify the effects of the ambient environment, mask type and other accessories on the microclimate around the eyes when wearing a mask.…”

Evaluation of the physiological changes in prehospital health‐care providers influenced by environmental factors in the summer of 2020 during the COVID‐19 pandemic

“… 5 Wearing a surgical mask did not affect tympanic or oral temperatures, whereas wearing an N95 mask significantly increased tympanic and oral temperatures. 6 Similarly, skin temperature was not affected by wearing a surgical mask 10 ; the mean skin temperature of the nose showed a steady change, and that of the forehead showed a small change over time. 10 This could explain why forehead temperature abruptly increased as air temperature increased, whereas tympanic temperature rose constantly.…”

“…6 Similarly, skin temperature was not affected by wearing a surgical mask 10 ; the mean skin temperature of the nose showed a steady change, and that of the forehead showed a small change over time. 10 This could explain why forehead temperature abruptly increased as air temperature increased, whereas tympanic temperature rose constantly. Forehead temperature rose rapidly when WBGT reached 28°C, and no difference between tympanic and forehead temperature was found at 33°C.…”

Effect of wearing medical protective masks on treadmill running performance in the postpandemic era: a randomised trial

“…Therefore, the influence of running-induced fatigue on VGRF at touchdown should be further demonstrated by considering the runner's speed. Moreover, past studies have concluded that the good facial fit and filtration properties of medical surgical masks can impede human breathing and heat dissipation to some extent [ 11 ]. The extra respiratory muscle work may make the body more prone to fatigue, leading to higher impact and even a higher risk of lower extremity injuries during running.…”