Experimental Study On Thermal Comfort Of Covid-19 Nucleic Acid Sampling Staff In Hot And Humid Environment

Since the end of 2019,the ruthless raging of COVID-19 has caused the unfortunate death of many medical staff at their jobs.As the most basic protection equipment for nucleic acid sampling personnel,medical protective clothing has good barrier performance,which can effectively block the invasion of external virus to human body.However,it is difficult to give consideration to the comfort while the protective clothing has the barrier ability.The hot and humid wearing experience has a negative impact on the normal work of nucleic acid sampling personnel.The working conditions in the outdoor high temperature and humidity environment aggravate the discomfort of personnel,increase the risk of heat stress of the nucleic acid sampling personnel,and reduce the work efficiency.Therefore,combined with the current situation of epidemic prevention and control and the situation of medical staff working in high temperature and harsh environment,it is of great significance to protect the health and work efficiency of medical staff and study the thermal comfort of nucleic acid sampling staff in high temperature environment.In this paper,the outdoor work place of nucleic acid sampling personnel was built,and the healthy students were selected as samples to carry out the field experimental research on thermal comfort of personnel in high heat and humidity environment.A new environmental stress index（ESI*）considering the influence of outdoor radiation is proposed.The environment was divided into four working conditions:21～23℃,23～25℃,25～27℃and27～29℃.The experiment uses subjective and objective field tests and personnel’s physiological tests simultaneously to analyze the changes of personnel’s physiological parameters under different thermal environment intensities,different genders and different body types.Based on the results of investigation and statistics,the subjective thermal evaluation of the subjects was understood,the correlation between the subjective feelings and physiological parameters of the nucleic acid sampling personnel was discussed,and the importance parameters and significance level of the human thermal comfort of the epidemic prevention personnel were determined.The results show that there was a high correlation between ESI*and wet bulb black bulb temperature index（WBGT）,which proves that ESI*can also be used to evaluate the thermal stress of personnel in thermal environment.It was found that the average skin temperature,heart rate,perspiration and metabolism increased with the increase of thermal stress level and exposure time.When the ESI*index is 25～27℃,the human body begins to have uncomfortable heat feeling.When the ESI*index rises to 27～29℃,the T_skis 33.82-36.48℃,the average heart rate is 103.1bpm,and the average perspiration is 135.34g,which all reach a relatively high level.For trunk skin temperature,under the premise of a certain clothing thermal resistance,the difference decreases with the increase of the thermal stress level.The heating effect of the back of hand,back,abdomen and forehead was obvious with the increase of the thermal environment intensity.The sweating voting proportion of head,face,neck,chest and back was relatively large,which was the sweating sensitive part and has a greater impact on the overall sweating feeling.And these five parts of the uncomfortable vote also accounted for a large proportion.which shows that the thermal regulation range of each part is not the same,the sweating situation of each part is significantly different,and the effect of sweat on human discomfort is more obvious.The results of the study on individual differences showed that body mass index（BMI）and body surface area（BSA）had significant effects on metabolism and sweating.There were also significant differences in the amount of perspiration and metabolism in male and female sex samples,but there was no significant difference in average skin temperature and heart rate.It could be seen that the sensitivity of men to heat stress is higher than that of women.Through the analysis of the correlation between subjective voting and physiological parameters,it could be seen that the average skin temperature and sweat output were the main factors affecting the subjective voting of human body,among which the correlation between average skin temperature and TSV and TCV was the most significant,and the correlation between sweating and HSV was the most significant.When the ESI*is between 27～29℃,at the end of the experiment,100%of the subjects expected the outside temperature to be cold,and the expected value was 0.5～1,and 92%of the subjects expected the humidity to be dry.Finally,when TA≈30℃,Rh≈60%,we need to take cooling measures to reduce the thermal stress of human body.When TA（29）35℃,Rh（27）40%,it is necessary to take cooling measures to reduce the thermal stress of human body.In view of the current research,it provides a theoretical basis for the follow-up research on the cooling strategy of wearing protective clothing.