Research On The Heat Stress And Warning Mechanism Of The Sanitation Workers In High Temperature Weather

With the warming of global temperature,the thermal risk of high-temperature environments has gradually attracted public attention.As outdoor workers,sanitation workers are exposed to high temperatures and heat for a long time,which can easily cause related heat diseases and even death.Therefore,how to effectively prevent the impact of high temperature environment on the humans has become the focus of thermal stress research.The relationship between the physiological parameters,subjective parameters and ergonomic parameters of sanitation workers in high temperature weather is studied,and the environmental parameters and heat stress indexes are corrected.The weight changes of the physiological parameters of sanitation workers are analyzed and quantified.And the comprehensive physiological index that is easy to measure physiological parameters has been established.Research can provide a scientific guarantee and early warning mechanism for the physical health and work safety of outdoor sanitation workers,and provide scientific methods for the comprehensive assessment of human physiological mechanisms.Based on the dynamic weight,a comprehensive physiological index of the human body is established.Research can provide a scientific guarantee and early warning mechanism for the physical health and work safety of outdoor sanitation workers.The weight changes of the physiological parameters of sanitation workers are analyzed and quantified.And the comprehensive physiological index that is easy to measure physiological parameters has been established.Research can provide a scientific guarantee and early warning mechanism for the physical health and work safety of outdoor sanitation workers,and provide scientific methods for the comprehensive assessment of human physiological mechanisms.In this study,field experiments are used to study the heat stress of sanitation workers in high temperature weather,and 20 sanitation workers were selected as subjects for a 12-day field measurement.Outdoor environmental parameters and subjects’physiological,subjective and ergonomic parameters are measured at 6:00,9:00,14:00and 16:00.Physiological parameters include:blood pressure,heart rate,tympanic temperature and mean skin temperature,subjective parameters include:thermal sensation vote and thermal comfort vote,ergonomic parameters include:grip strength and work willingness.Firstly,the physiological parameters,ergonomic parameters,subjective questionnaires and environmental parameters of sanitation workers are analyzed based on experimental data.Logistic regression is used to evaluate the safety risk of physiological parameters,and the proportion of ergonomic and subjective questionnaires is analyzed.The results show that the mean skin temperature and tympanic temperature of sanitation workers are greatly affected by the environment,while the systolic blood pressure,diastolic blood pressure and heart rate are not great;only the mean skin temperature and the environmental parameters have statistical significance(P<0.05);in addition,the grip strength is mostly 26.2-37.3kg(50.97%),and the work willingness can account for46.46%,and the average and below is 45.45%,the thermal sensation is slightly hot and above accounting for 75.14%,the thermal comfort is acceptable or above accounting for81.67%.Secondly,mathematical planning method is used to combine environmental parameters,physiological parameters and subjective evaluation,and put forward the limits of environmental parameters and common heat stress indexes applicable to sanitation workers.With regard to solar radiation intensity,dry bulb temperature,and relative humidity,sanitation workers are more sensitive to changes in subjective perception than changes in mean skin temperature,but their sensitivity to wind speed is comparable.The safety limits of solar radiation intensity,dry bulb temperature,relative humidity and wind speed in outdoor environment are:182.42 W/m~2,28.42℃,71.35%and 0.15 m/s,and the danger limits are:876.86 W/m~2,34.98℃,36.59%and 1.27 m/s.The revised outdoor heat stress indexes ESI(Environmental Stress Index),DI(Discomfort Index),HI(Heat Index),and RSI(Relative Strain Index)have safety thresholds of 27.08℃,26.23℃,31.71℃and 0.13,respectively,the hazard thresholds are29.60℃,27.84℃,36.21℃and 0.24 respectively.Therefore,sanitation workers can calculate index values based on weather parameters,the degree of environmental hazard can be predicted,and daily work can be carried out reasonably to enhance the prevention of heat diseases.Finally,CPI(Comprehensive Physiological Index)is established based on the entropy weight TOPSIS(Technique for Preference by Similarity to Ideal Solution)model.First,real-time weights of physiological parameters are obtained by entropy method.Second,the TOPSIS method is used to calculate the distance from all physiological parameters to the ideal solution,CPI is established and verified.Last,the CPI and DI are fitted,and the CPI is warned by temperature and humidity.The results show that the mean skin temperature,systolic blood pressure and diastolic blood pressure have a relatively large weight,accounting for 60.1-70.9%.The new index CPI covers the five physiological parameters of the human,and the correlation analysis with grip strength,thermal sensation vote and PSI(Physiological Strain Index)has been carried out to verify the validity.CPI is divided by DI,[0,0.43]is the dangerous zone,(0.43,0.74]is the tolerance zone,(0.74,1]is the safe zone.CPI index parameters are simple and easy to measure,and have little impact on the daily work of sanitation workers.This index can provide real-time monitoring of the physiological state of sanitation workers,minimize heat stress injuries,and protect the lives of workers.