Journal of Health and Safety at Work

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Introduction: Occupational exposure to crystalline silica increases the risk of lung cancer and restrictive lung disease with extensive fibrosis. Silica dust is a major health hazard in foundry factories. The aim of this study was to determine core making workers’ exposure to respirable crystalline silica dust in a foundry factory.

Material and Method: This cross-sectional study was conducted in core-making unit of a foundry factory in 2015. Occupational exposure of 55 workers to respirable crystalline silica aerosols was evaluated by using the improved NIOSH7602 method in core-making unit. Risk assessments for silicosis and excess lifetime risk of mortality from lung cancer were done according to Manettej and Rice models, respectively. Data was analyzed with Spss19 software.

Result: The mean of respirable crystalline silica dust was 0.246 ± 0.351 (mg/m3). All  workers’ exposure to respirable crystalline silica was higher than recommended occupational exposure limits. Silicosis mortality risk and excess lifetime risk of mortality from lung cancer were estimated in the range of 6-63 and 65 per thousand people, respectively.

Conclusion: The mean of workers’ exposure to respirable crystalline silica was higher than recommended occupational exposure standards in core making unit. The risk assessment of silicosis mortality and excess lifetime risk of mortality from lung cancer were higher than acceptable levels of risk.

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Introduction: Nowadays, millions of people are exposed to the dusts in their workplaces. Occupational exposure to dusts is considered as one of the most common and serious occupational hazards to workers’ health. The purpose of this literature review was to review the literature related to the occupational exposure to dusts in Iran published over the past 14 years.  
Material and Methods: In this review, published articles were obtained from Web of Science, PubMed, Google Scholar, Scopus, ScienceDirect, Islamic World Sciences Citation (ISC), Magiran, SID، Iran Medex, and Civilica search engine. The main keywords for search were Occupational Exposure, Lung, Dust, Total Dust, and Respirable Dust. The relevant articles published in Iran over the past 14 years were searched and extracted after checking their relevancy. All articles were classified based on the titles, years of publication, places of publication, type of industries, geographic distributions, sampling and analysis methods, fields of study, and the amounts of exposure.
Results: Findings showed that in spite of increases in the rate of published literature in recent years and by considering geographical variation and the large number of dust generating firms and industries, a relatively small number of studies was conducted and published in this field. Majority of the studies in this field considered the levels of dust exposure and respiratory effects of dust exposures.  In most studies the levels of occupational exposure to dusts (and crystalline silica dusts) were higher than the recommended limit values.
Conclusion: Although an increasing number of studies can be seen in recent years on occupational exposure to dusts and their effect, by considering the presence of large and small size industries with dust generating pollution  in Iran, the large number of exposed people, adverse-health  effects,  and  the need for control measures, few studies have been published in this field and further works need to be done in this area.

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Introduction: Many studies, especially in recent years, have evaluated and controlled the occupational heat stress in Iran using environmental indices. However, so far, no comprehensive study has been conducted to review and classify these studies. Therefore, this study aimed to review and investigate the occupational studies performed by environmental heat stress indices in Iran.
Material and method:  In the present study, the published articles from 2000 to 2016 were searched using Persian and English keywords including heat stress, heat strain, hot condition, warm condition, occupational health, thermal environment and Iran. Search of articles was performed in databases such as Web of Science, Google Scholar, PubMed, Scopus, Science Direct, SID, Magiran, Civilica, Iran Medex, Barakatkns and Irandoc. In total, 323 articles were found and 134 articles of them, based on the exclusion criteria, were selected and included in this study. 
Results: Based on the results, most numbers of the studies, with 93.3 percent of the total researches related to published article, have been carried out between years of 2010 to 2016. As well as, most of studies with 61.9 percent were related to the indoor industrial environments. Most of studies were also performed in cities of Isfahan with 31.08 percent, Tehran with 16.89 percent, and Assaluyeh with 11.48 percent, respectively. As well as, WBGT index with 76 percent and the UTCI and PHS indices with 0.6 percent had the highest and lowest usage in all environments and industries, respectively. In addition, the results showed that WBGT index had most usage in industries of melting and casting with 15.7 percent, petroleum with 8.3 percent, and outdoor small occupations with 8.3 percent, respectively. Based on the results, the industries of the refinery, steel, glasswork, melting and casting, mines, and ship repairs have the highest mean values of WBGT index, respectively.
Conclusion: The results showed the need to more attention of researchers for conducting studies in outdoor environments, in different cities of Iran, on development and validation of novel heat stress indices, and on implementation and evaluation of control measures in the environments with high heat stress.

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Introduction: As a metropolitan area in Iran, Tehran is exposed to damage from air pollution due to its large population and pollutants from various sources. Accordingly, research on damage induced by air pollution in this city seems necessary. The main purpose of this study was to forecast ozone in the city of Tehran. Considering the hazards of ozone (O3) gas on human health and the environment and its ascending trend over the past decades, it is also essential to study and predict its quantities in the air. Forecasting ozone in the air can be further used to prevent and control pollution by authorities.
Material and Methods: Using an analytical-applied research method, this study was to predict ozone gas in this metropolitan area via daily ozone data of air quality measurement stations, traffic variables, green space, as well as time factors such as one-day time delay. In this regard, an artificial neural network (ANN) model was employed to forecast ozone concentration using the MATLAB software.
Results: The results of the ANN model were compared with a linear regression one. Correlation coefficient and root-mean-square error (RMSE) of the ANN model were subsequently compared with R2=0.734 and RMSE=0.56 as well as R2=0.608 and RMSE=11.69 regression equations.
Conclusion: It was concluded that the error in the ANN model was smaller than that in the regression one. According to the results of the sensitivity analysis of the season parameters, the length of sunshine hours had the most significant effect on the amount of ozone gas in Tehran air.

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Introduction: The skin, can be exposed to harmful factors like ultraviolet radiation (UV). Exposure to this physical hazardous agent could be contributed to pigmentation, erythemas, early aging, skin cancer, and DNA damage. The aim of this study, therefore, was to fabricate the polyacrylonitrile (PAN) nanofibers with the UV protection property by the use of various concentrations of titanium dioxide (TiO2) nanoparticles.
Material and Methods: The PAN nanofibers (10%wt) containing 0, 1, 5, 10 and 15% wt of TiO2 nanoparticles were produced using electrospinning method. The morphological propertis of nanofibers were studied by scanning electron microscopy (SEM) and the functional groups were investigated by Fourier transform infrared spectrophotometer (FTIR). The UV protection property of nanofibers was studied by measuring UV transmittance as well as calculating UV protection factor (UPF).
Results: The results showed that the diameter and morphological characteristics of nanofibers are different at various concentrations of TiO2 and increasing the concentration of TiO2 has resulted to an increase in nanofibers diameter. The analysis of FTIR results showed that TiO2 nanoparticles have been successfully loaded on nanofibers for UV protection purposes. The findings clarified that nanofibers loaded with TiO2 could increase the UV protection property up to 15%.
Conclusion: Totally, our findings show the successful fabrication of UV-protective nano webs using TiO2 nanoparticles. the new combination used in nano matcould protect employees from UV radiation.

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Introduction: The respiratory system, one of the most important organs of the body, can be affected by adverse effects, disorders and consequences in the workplace. Spirometry is one of the most important screening and testing tools in the periodic medical examination of every employee. This study was aimed to evaluate the factors affecting the respiratory function of staff of Tehran University of Medical Sciences (TUMS).
Material and Methods: This descriptive-analytical and cross-sectional study carried out on 300 employees of TUMS according on during the enrollment phase of the Tehran University of Medical Sciences employee’s cohort (TEC) study was in order to survey the parameters affecting pulmonary function. Demographic data were collected through a demographic questionnaire. Spirometry was used to evaluate respiratory function parameters and bioelectric impedance was used to analyze body composition. Data analysis was performed by SPSS software version 25. Two-sample t-test, one-way ANOVA, and Pearson correlation coefficient were used for statistical analysis. Multiple linear regression was used to determine the effect of independent variables on the parameters of pulmonary function.
Results: It was found that 73.6% of the subjects had a normal lung pattern, 7% had an obstructive pattern, 14.7% had a threatening pattern and 4.7% had a mixed pattern. There was a significant negative correlation between FVC and FEV1 parameters and smoking (P-value <0.05). There was also a significant relationship between FFM, age and BMI with FEV1/FVC (P-value <0.05). Similarly, there was a meaningful relationship between type of job and FVC parameter (P-value <0.05). The findings showed that the highest and the lowest averages of all parameters of pulmonary function was in administrative and occupational services, public and technical services and facilities, security and guard, respectively.
Conclusion: In the present study, it was found that occupation type affects lung function due to exposure to contaminants in different groups. Other factors affecting lung function included age, body mass index, fat mass, fat free mass and smoking. Therefore, changing lifestyle such as proper diet, regular exercise and not smoking can be an effective step towards improving the parameters of lung function.

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Introduction: In recent years, the manufacture of air purification media, especially nanofiber filters using polymeric materials and the electrospinning method, has received much attention in air pollution control. The production of high-performance media and low-pressure drops is an important issue in air filtration. This study aimed to investigate the feasibility of fabricating electrospinning polyethylene terephthalate (PET) media to abduct submicron and micron particles from the air stream.
Material and Methods: To determine the optimal device conditions in the manufacture of PET media, different weight percentages of a PET polymer solution in a mixture of trifluoroacetic acid and dichloromethane solvents (70:30) were first prepared in a pilot study, and various parameters of the electrospinning device were examined and analyzed along with performing the electrospinning process. The surface and morphological characteristics of the media were evaluated using SEM. The pressure drop and efficiency of particle trapping were assessed using a mask and media pressure by a pressure drop test device.
Results: The optimal electrospinning conditions of the PET polymer solution were obtained at a concentration of 20%. The average diameter of nanofibers PET was 163 ± 600 nm with a pressure drop of 26.33 ± 5.5 pa, and average efficiencies of 97.42 ± 1.67% and 99.85 ± 0.21 were obtained for submicron and micron particles, respectively, with a quality factor (QF) value of 0.1740.
Conclusion: The produced media can abduct and remove particles from the air stream for submicron and micron particles in ranges of 96-99% and 99-100%, respectively, with an average pressure drop of 26.33±5.5 pa.

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Introduction: Toluene is significant pollutants in the air. Long-term exposure to toluene can lead to adverse effects.  Biofiltration is one of the air pollutant control methods. In this study, Pseudomonas putida was selected as a microorganism capable of hydrocarbon degradation and its ability to biodegrade toluene in a suspension growth reactor was also investigated.
Material and Methods: Experiments were conducted in two days and in five hours. Each method consisted of three sample reactors (A, B, C) and one control reactor (D). In the first method, the amount of bacteria in the sample reactors is 0.5, 1 and 2 McFarland and the amount of toluene injection into the reactors is the same (0.5 microliters) and in the second method, the amount of toluene injection into the sample reactors is 0.5, 1 and 1.5 microliter and 1.5 microliter in the control reactor and the amount of bacteria in them was the same (1 McFarland).Toluene gas samples and carbon dioxide were periodically analyzed.
Results: In the first method of toluene decomposition, there was a significant difference between the three reactors (p-value = 0.002). The results of the second method were also significantly different between the three reactors (p-value<0.001). The decomposition of toluene in two methods also had a significant difference (p-value = 0.232). The amount of CO2 production was significantly different in the second method (p-value=0.003) and the first method (p-value<0.001), but no significant difference was observed in the comparison of the two methods (p-value=0.15).
Conclusion: Increasing bacterial in suspension growth reactor resulted in increased toluene biodegradation in shorter time while increasing toluene in suspension growth reactor may not have an additive effect on the biodegradation process.

 

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Introduction: The COVID-19 pandemic has been a significant global health challenge. Primary care services, such as screening health centers, were crucial in identifying infected individuals. However, these centers were often crowded and posed a high risk to staff and non-COVID-19 patients. This study aims to assess the risk of airborne transmission of SARS-CoV-2 in such settings through simulation.
Material and Methods: In this study, waiting and sampling rooms of a COVID-19 healthcare center were simulated using different scenarios. Then, the Quanta emission rate was estimated using the viral load in the sputum of infected individuals. Finally, the airborne transmission risk of SARS-CoV-2 was determined using the Wells-Riley method for scenarios of wearing and without masks.
Results: The study showed that the Quanta emission rate in an unmodulated speaking activity was higher than other expiratory activities in both units (p <0.001). Also, the total amount of Quanta was slightly higher in the sampling room than in the waiting room, which was not statistically significant. On the other hand, the calculation of transmission risk showed that the probability of airborne virus transmission in the sampling room was higher (about 2 to 8%). In addition, wearing masks reduced the possibility of airborne transmission of the virus significantly (77 to 81%).
Conclusion: This study shows that the level of risk in the sampling and waiting rooms is moderate. Masks also significantly reduce the possibility of airborne transmission of SARS-CoV-2. Taking appropriate health and safety measures such as avoiding crowds, wearing masks, whispering, and monitoring social distancing can reduce the plausibility of airborne transmission of the SARS-CoV-2 virus.
 

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Introduction: VOCs are harmful air pollutants that must be detected, monitored and eliminated. Adsorber tubes are standard tools for this task, specifically activated carbon tubes with high adsorption and selectivity. This research aims to compare the structural and functional characteristics of domestically produced activated carbon tubes with the conventional commercial ones for sampling toluene, a volatile organic compound.
Material and Methods: The characteristics of each adsorbent, such as structure, morphology, porosity, and element composition, were examined by SEM photography, BET testing, and EDAX analysis. The central composite design (CCD) method was employed to investigate the adsorption properties of the adsorbents. The input concentration and readsorption time of the samples were the variables considered in this study. Additionally, a field phase of personal air sampling was performed to evaluate the effectiveness of adsorbent tubes.
Results: SEM and BET analyses indicated that the porous structure of domestic activated carbon was comparable to the model produced by SKC. EDAX analysis detected a minor impurity (1%) in the domestic activated carbon adsorbent. The adsorption performance was significantly influenced by the variations in readsorption time and pollutant input concentration. The accuracy and precision of the performance of the domestic adsorbent tube were obtained as 90.77% and 91.76%. The field phase results demonstrated that the amount of pollutant adsorbed in the SKC-activated charcoal adsorber did not differ significantly during 0 to 30 days. However, the domestic adsorber showed a significant difference in the same period. The overall performance of the two adsorbers did not exhibit a significant difference between 0 and 30 days.
Conclusion: Despite minor structural differences, the adsorption efficiency of toluene by domestic adsorbent tubes in sampling high concentrations is very similar to its commercial type. However, it is not recommended for use in low-concentration environments (10 ppm and less).

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Introduction: The prevalence of COVID-19 has significantly impacted work environments and the workforce. Therefore, identifying the most important preventive and control strategies, as well as assessing their effectiveness, is of paramount importance. Various studies have shown that machine learning algorithms can be used to predict complex and nonlinear issues, including predicting the behavior of various diseases such as COVID-19 and the parameters affecting it, and can be beneficial. The purpose of this study has been to examine the importance of preventive measures and hygiene behaviors in preventing COVID-19 in the oil refining industry using various machine learning models.
Material and Methods: For this purpose, demographic information and health behaviors of individuals were collected. Subsequently, a multi-layer perceptron (MLP), radial basis function (RBF), and support vector machine (SVM) models were compared to enhance the analysis of the effects of preventive measures on COVID-19 infection. Finally, the most influential factors affecting the likelihood of COVID-19 infection were determined using sensitivity analysis.
Results: The results showed that the accuracies achieved in predicting the impact of preventive measures and health behaviors on COVID-19 in occupational settings were 78.1%, 81.2%, and 78.1% by MLP, RBF, and SVM respectively. The RBF model was identified as the most accurate model for predicting the impact of health behaviors on COVID-19 disease Additionally, the level of social distancing with customers, handwashing frequency and disinfection, the availability of cleansing and disinfecting agents for hands and surfaces in the workplace, and gatherings for eating meals and snacks were identified as the most significant health behaviors influencing the prevalence of COVID-19 in the workplace.
Conclusion: Studies of this nature can underscore the importance of attention to preventive measures and health behaviors in unprecedented circumstances. Furthermore, the utilization of artificial intelligence models and tools such as DSS (Decision Support Systems) can serve as powerful tools for optimizing control measures in work environments.
 

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Introduction: Protection of the respiratory system has been a vital, and for this purpose, various solutions have been proposed, including the use of masks. One of the most important parameters to measure the effectiveness of the mask against the penetration of microbial agents. The present study was conducted with the aim of evaluating the bacterial and particle filtration of medical masks.
Material and Methods: To assess bacterial performance, the national standard 6138, compliant with EN14683, and Type I medical masks were utilized. Staphylococcus aureus bacterial suspension was prepared and passed through the mask using a nebulizer and through an impactor with a flow rate of 28.3 l/min. Plates containing soy agar were placed in the impactor. Subsequently, all plates were incubated, and the bacterial filtration efficiency (BFE) of the masks was determined by counting the bacterial colonies that passed through the mask’s media as a percentage of the total bacteria. It is worth noting that the pressure drop and particle filtration efficiency were also determined for all masks
Results: Based on the results of the particle removal performance for the particle size of 3 µ, the masks were categorized into three groups with efficiency above 99%, above 95% and 90%. According to the standard, all masks had an acceptable pressure drop below 40 Pa. The acceptable bacterial filtration rate for type I masks should be above 95%. The results showed that type A and B masks have an acceptable bacterial filtration rate and there is a significant correlation between the types of masks examined in terms of bacterial and particle efficiency.
Conclusion: The results showed that different types of masks under investigation have significant differences in terms of particle capture efficiency and bacterial filtration performance. In addition, there is a significant correlation between bacterial and particle filtration efficiency.
 

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Introduction: This study aimed to analyze the effects of endurance training (Aerobic) on the levels of inflammatory markers (IL-6/TNF-α) and some metabolic parameters in male rats with non-alcoholic fatty liver disease to investigate the feasibility of using exercise training to reduce inflammation.
Material and Methods: A total of 44 Wistar rats were randomly assigned into two groups: (I) standard diet group of 22 rats and (II) high-fat diet group with 22 rats supplemented with free access to fructose water. After 17 weeks, two rats from each group were sacrificed, and liver tissue was collected for hematoxylin-eosin staining. Subsequently, the remaining 20 rats in the (I) group were divided into a training group (T) and a control group (C). The 20 rats in the (II) group supplemented with fructose water were divided into a fatty liver group (FL) and a fatty liver + training group (FL+T), each comprising ten rats. In the next phase, the T-groups underwent an eight-week endurance training intervention. Then, IL-6, TNF-α, glucose, insulin, insulin resistance and sensitivity levels were measured.
Results: The results of the present study showed that as a result of a high-fat diet with liquid fructose in HFD+HF group rats, non-alcoholic fatty liver disease (NAFLD) with complications such as a significant increase in the levels of IL-6 and TNF-α, Hepatic dysfunction, and metabolic parameters were disturbed (p<0.001). However, endurance training improved most of these complications by reversing the disease process (p<0.001).
Conclusion: According to the results of the present study, it can be concluded that the improvement of inflammatory markers, liver dysfunction, and metabolic parameters through endurance training is one of the key mechanisms of exercise in the treatment of NAFLD, the consequences of which may show the importance of endurance training in treatment of NAFLD highlights.