Health risk assessment of exposure to various vapors and fumes in a factory of automobile manufacturing.

This study aimed to comprehensively evaluate the health risk of exposure to various vapors and fumes in a factory of automobile manufacturing. This study was performed in 2021 on 115 workers. Vapors and fumes were gathered by the adsorbent tubes of activated charcoal and mixed cellulose esters (MCE) membrane filter, respectively. The flow rate for vapors and fumes were between 0.05 and 0.20 L per min and 1 to 4 L per min, respectively. After preparing, samples were analyzed. To assess the non-cancer and cancer risk of the pollutants, the method proposed environmental protection agency (EPA) was applied. The total concentration of copper (1.031 ppm), manganese (0.114), and 2-butoxyethanol (91.767 ppm) were found to be higher than The threshold limit values (TLVs). The values of non-cancer risk (HQ) due to exposure to vapors of benzene (6.583), toluene (1.396), ethyl benzene (1.212), xylene (31.148), 2-butoxyethanol (89.302), 2-propanol (4.695), 1,2,3-trimethylbenzene (1.923), copper (2.336), manganese (715.82), aluminum (3.772), and chromium (107.066) were higher than the acceptable limit. Moreover, the estimated LCR for benzene (2.15 × 10-4), ethyl benzene (3.97 × 10-4), vinyl chloride (1.25 × 10-4), and chromium (2.11 × 10-2) were higher than the threshold risk level set by EPA. It is emphasized that preventive measures are performed.

Summer and winter variations of BTEX concentrations in an oil refinery complex and health risk assessment based on Monte-Carlo simulations.

The summer and winter concentrations of BTEX pollutants were investigated in various workplaces of an oil Refinery, Iran. In total 252 air samples from the breathing zones of the following employees were collected: supervisors, safetymen, repairmen, site men, and all workers. Carcinogenic and non-carcinogenic risk values were calculated based on the USEPA methodology using Monte Carlo simulations. BTEX concentrations were higher in the summer than in the winter season for all workstations, especially for toluene and ethylbenzene. The mean values of exposure to benzene for repairmen and site men were higher than threshold limit value of 1.60 mg/m3 for both seasons. Non-carcinogenic risk (HQ) values calculated for summer season for benzene, ethylbenzene, and xylene in all workstations, as well as for toluene for repairmen and site men exceeded acceptable level of 1. In winter season the mean HQ values for benzene and xylene in all workstations, for toluene for repairmen and site men, and for ethylbenzene for supervisors, repairmen, and site men were also > 1. For all workstations definite carcinogenic risk was indicated as calculated LCR values for benzene and ethylbenzene exposure were higher than 1 × 10-4 in both summer and winter seasons.

Development and validation of a biological risk assessment tool among hospital personnel under COVID-19 pandemic conditions.

The need for a biological disease risk assessment method to prevent the contagion of these diseases, particularly among healthcare personnel, is crucial. Therefore, this study aimed to develop and validate a biological risk assessment tool for biological agents among hospital personnel under COVID-19 conditions. This cross-sectional study was performed on 301 employees in two hospitals. Firstly, we identified the items affecting the contagion of biological agents. Then, we computed the weight of the items using the Fuzzy Analytical Hierarchy Process (FAHP) method. We used the identified items and the estimated weights in the next step to develop a predictive equation. The outcome of this tool was the risk score of biological disease contagion. After that, we used the developed method to evaluate the biological risk of the participants. The ROC curve was also used to reveal accuracy of developed method. In this study, 29 items were identified and categorized into five dimensions, including environmental items, ventilation items, job items, equipment-related items, and organizational items. The weights of these dimensions were estimated at 0.172, 0.196, 0.255, 0.233, and 0.144, respectively. The final weight of items was used to develop a predictive equation. The area under ROC curves (AUC) was also calculated as 0.762 (95% CI: 0.704, 0.820) (p<0.001). The tools developed using these items had acceptable diagnostic accuracy for predicting the risk of biological diseases in health care. Therefore, one can apply it in identifying persons exposed to dangerous conditions.

Development of modified rapid entire body assessment (MOREBA) method for predicting the risk of musculoskeletal disorders in the workplaces.

BACKGROUND: Rapid Entire Body Assessment (REBA) technique is one of the tools developed for predicting the risk of musculoskeletal disorders based on the effective risk factors. This method has several limitations. The present study was aimed to develop the Modified Rapid Entire Body Assessment (MOREBA) method to more accurately predict the risk of musculoskeletal disorders. MATERIALS: This cross-sectional study was performed on 300 male workers of a steel factory with a variety of job tasks in Iran. Then, the information related to the various physical risk factors was extracted through observation of their duties and conversation with them. Also, the subjects were asked to complete the Persian version of Cornell musculoskeletal discomfort questionnaires (CMDQ). Then, a theoretical model was drawn in AMOS software. Computed coefficients were used to develop the MOREBA equation. In the end, the final scores were categorized by ROC curves, and the validation of the novel method was investigated using linear regression analysis. RESULTS: The parameters evaluated in the MOREBA method included contact stress, rapid and sudden movement, throwing motion, hand-arm vibration, whole-body vibration, temperature, and work-rest cycle in addition to the parameters of the REBA method, including awkward posture, coupling, force, load, static activity, and repetitive activity. The results showed that the strain produced by the physical risk factors with the total effect coefficient of 0.783 could significantly affect the musculoskeletal symptoms. The computed coefficients of the risk factors were applied to develop a novel index. The final score of the MOREBA method was categorized into four levels by optimal cut-off points of 12.37, 16.51, and 24.35. Based on the results, the MOREBA and REBA methods could justify 67 and 55% of the variations of musculoskeletal symptoms, respectively. CONCLUSIONS: The results revealed that modifications conducted in the REBA method were effective, and the MOREBA method can provide a more accurate prediction of the risk of musculoskeletal disorders.

Development of an observational - perceptual heat strain risk assessment (OPHSRA) index and its validation.

BACKGROUND: The thermal strain can be measured using subjective methods without the use of sensitive equipment. The purpose of the present study was the development and validation of an observational - perceptual heat strain risk assessment (OPHSRA) method. METHODS: This cross-sectional study, in 2019, was performed. At first, an observational-perceptual questionnaire was designed using effective items in producing heat strain. Then, the reliability and validity of the questionnaire were examined. Later, 201 male workers were asked to perform the routine tasks for 90 min under various climatic conditions after resting in a cool room. At the end of the activity, the tympanic temperature of the subjects was accurately measured. Also, the designed questionnaire was completed by researchers and participants. Then, the effect coefficients of the items were calculated and used for developing the novel index. At final, the index validity was investigated. RESULTS: The values of the content validity ratio (CVR), content validity index (CVI), and Cronbach's coefficient alpha (α) of the designed questionnaire with 16 questions were equal to 0.793, 0.913, and 0.910, respectively. The results indicated that environmental, job, administrative, and clothing items assessed by the questionnaire with the coefficients of 0.860, 0.658, 0.783, and 0.566 had significant effects on the thermal strain, respectively. These coefficients were exploited to develop the index. The result revealed that the OPHSRA index justified 69% of the variations of the tympanic temperature (R2 = 0.69). CONCLUSION: The novel index developed by the questionnaire had an acceptable validity. Therefore, this index can be used for estimating the risk of thermal strain in a variety of thermal conditions.

Development and validation of an environmental heat strain risk assessment (EHSRA) index using structural equation modeling based on empirical relations.

BACKGROUND: Need to a simple, available, accurate, comprehensive, and valid indicator is felt to assess thermal effects. Therefore, the present study was aimed to develop and validate the environmental heat strain risk assessment (EHSRA) index using structural equation modeling (SEM) based on empirical relations. METHODS: This cross-sectional study was performed on 201 male workers in environments with various climatic conditions. The heart rate and tympanic temperature of the individuals were monitored at times of 30, 60, and 90 min after beginning the work. At these times, values of dry temperature, wet temperature, globe temperature, and air velocity were also measured and metabolism rate and clothing thermal insulation value were estimated. At the end, a theoretical model was depicted in AMOS software and obtained coefficients were applied to develop a novel index. The scores of this indicator were categorized into four risk levels via ROC curves and validate using linear regression analysis. RESULTS: Indirect effect coefficients of the globe temperature, dry temperature, wet temperature, air velocity, metabolism, and clothing thermal insulation variables on the tympanic temperature were computed by 0.77, 0.75, 0.69, 0.24, 0.49, and 0.39, respectively. These coefficients were applied to develop the index. Optimal cut-off points of boundaries between risk levels included 12.02, 15.88, and 17.56. The results showed that the EHSRA index justified 75% of the variations of the tympanic temperature (R2 = 0.75). CONCLUSIONS: The novel index possesses appropriate validity. It was suggested that this indicator is applied and validated in various environments in the next studies.

Development of a personal heat strain risk assessment (PHSRA) index in workplaces and its validation.

BACKGROUND: There is not a comprehensive heat stress index to screen the people susceptible to heat disorders and illnesses in hot workplaces. The present study was aimed to develop a personal heat strain risk assessment (PHSRA) index in workplaces and validate it. METHODS: This cross-sectional study was carried out on 201 Iranian male employees under various thermal conditions. At first, the demographical data of participants were gathered. After that, the heart rate and tympanic temperature of the subjects were carefully measured at times of 30, 60, and 90 min of starting the work. Environmental factors were measured simultaneously. The metabolism rate and insulation value of clothes were also estimated. At the end, a novel index of the heat strain was developed using structural equation modeling in AMOS and validated using linear regression analysis in SPSS. RESULTS: Indirect effect coefficients of personal factors including age, body mass index, maximum aerobic capacity, and body surface area were equal to 0.031, 0.145, - 0.064, and 0.106, respectively. The coefficients of main factors including dry temperature, wet temperature, globe temperature, wind speed, metabolism, and clothing thermal insulation were obtained as 0.739, 0.688, 0.765, 0.245, 0.482, and 0.383, respectively. These coefficients and normalized values of the factors were used to develop a novel index. The total score of the index was categorized into four levels by optimal cut-off points of 12.93, 16.48, and 18.87. Based on the results of regression analysis, this index justifies 77% of the tympanic temperature as a dependent variable (R2 = 0.77). CONCLUSIONS: In general, the results indicated that the novel index developed by the personal and main factors had proper validity in the prediction of thermal strain.

Comparing the Effectiveness of Three Ergonomic Risk Assessment Methods-RULA, LUBA, and NERPA-to Predict the Upper Extremity Musculoskeletal Disorders.

BACKGROUND: Musculoskeletal disorders are a major problem in all jobs. Several methods are available for assessing the exposure to risk factors associated with musculoskeletal disorders. This study is aimed at comparing three different ergonomic risk assessment methods-rapid upper limb assessment (RULA), loading on the upper body assessment (LUBA), and new ergonomic posture assessment (NERPA) method-to predict upper extremity musculoskeletal disorders. MATERIALS AND METHODS: The study was conducted on 210 workers from three different industries including pharmaceutical, automotive, and assembly in the Isfahan province. A Nordic questionnaire was used for determining the levels of musculoskeletal disorders. Then, selected postures were evaluated with RULA, LUBA, and NERPA methods. Finally, data were analyzed with Kolmogorov-Smirnov test to check the normality distribution of data, Spearman's correlation test to investigate the correlation between the assessed levels with musculoskeletal disorders, and Wilcoxon test to identify significant differences between the values with SPSS version 16. RESULTS: Wilcoxon test revealed a significant difference between the values related to NERPA and RULA (P < 0.001), whereas no significant relation between LUBA and RULA was shown by this test (P = 0.914). The correlation coefficients of the musculoskeletal disorders' level with RULA level, NERPA level, and LUBA level were 0.74, 0.73, and 0.69, respectively. CONCLUSION: Low-risk levels in NERPA, medium-risk levels in LUBA, and high-risk levels in RULA are evaluated better. The results showed that RULA was the best method for assessing musculoskeletal disorders among the three methods.