Journal of Health and Safety at Work

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Introduction: In real Conditions, pollution emission are mostly released as mixed components rather than a single pure emission of the chemicals. In this study, a miniature stirred tank bioreactor was optimized for treatment of waste gas containing BTX (benzene, toluene and xylene).

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Material and Method: The sludge of an oil refinery was sampled based on the assumption that it contains BTX-degrading microorganisms and used as microbial consortium. Also, silicone oil was added to improve removal efficiency. The operational parameters of the bioreactor were optimized during the study.

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Result: The removal efficiency and elimination capacity of benzene, toluene and xylene vapors simultaneously in the presence of 10% silicone oil as an organic phase showed increasing trend up to the concentrations of 1730 mg/m3, 1710 mg/m3 and 1380 mg/m3, respectively. In these concentrations the removal efficiency and elimination capacity of benzene were 100% and 59 g/m3/h, toluene 100% and 58 g/m3/h and xylene 91% and 42 g/m3/h, respectively. The total removal efficiency and elimination capacity for BTX were 91 to 100% and 159 g/m3/h, respectively.

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Conclusion: It was shown that presence of 10% silicone oil increased 44.5% in total removal efficiency of BTX. The microbiological experiments on the bioreactor media showed that three spices of Pseudomonas putida, Chryseobacterium and Ralstonia pickettii can be found, when BTX ware treated. This work revealed that two phase partition bioreactors (TPPBs) can be successful method for the treatment of streams contaminated with BTX.

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Introduction: Air health is an important environmental issue which has been endangered in recent years due to application of advanced technologies used for improving the financial welfare and relative prosperity of humans. Making use of pollution control systems and refinement methods are some general ways to control environmental pollution. Since several different techniques of control, each with its advantages and disadvantages are employed in order to mitigate the spread of air pollution, the aim of current study was to design a fuzzy multi-attribute decision making model to select the most appropriate air pollution control equipment in Mashhad Shargh Cement Company.
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Material and Method: After identifying the desired industry and also the production process, all factors affecting decision-making process including environmental factors, technical factors and economic factors were considered by utilizing Fuzzy Analytic Hierarchy Process method. Importance weight of these criteria was calculated and subsequently the priority of model choices were also determined using this approach.
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Result: Among main criteria of the model, economic criteria was identified as the most important factor influencing the selection of the type of air pollution control equipment, with the wight of 0.555. Environmental and technical factors with weighting of 0,286 and 0,159 also gained the next priorities, respectively. Final weights of Electro filter, Baghouse and Hybrid filter technologies were calculated 0.256, 0.415 and 0.329 in cement mill unit and 0.291, 0.374 and 0.334 in material grinding and furnace unit, respectively.
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Conclusion: Finally, the proposed model that is based on the Fuzzy Analytic Hierarchy Process indicates that the Baghouse Technique is the most appropriate technique for the purpose of dust filtration in major sources of air pollution spread in Shargh Cement Company.

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Introduction: One of the harmful pollutants in the indoor environments is particulate matters. Particles smaller than 2.5 micrometer in diameter that are suspend in the industrial environments air are the most deleterious dusts which can cause lung disease and cancer. In present study PM2.5 concentration in the fast-food shops air and its cancer risk for shop workers were assessed.  
Material and Methods: In this descriptive-analytical study, all of Sari city 132 fast foods were included. Air sampling was conducted by calibrated real-time GRIMM-monitor device. Data were analyzed by using of SPSS16 and Prism6 software with T-test, Pearson correlation and descriptive statistics. Finally PM2.5 cancer risk in workers was calculated by EPA method equation.
Results: The PM2.5 concentration in shops indoor air (308.5µg/m3) significantly was higher than its concentration in outdoor air (121.98µg/m3) (p<0.05). Highest correlation was observed between indoor PM2.5 concentration with smoking (0.366) and local ventilation (-0.384) (p<0.01). The concentration PM2.5 in the indoor and the outdoor of shops was 273.55 and 86.98µg/m3 higher than acceptable level respectively. Cancer risk was 5.6 per 100 thousands and 1.97 per 10 thousands in the rest and cooking time respectively.
Conclusion: The most affective source in the elevation of PM2.5 level in shops indoor air is the cook-emitted particles. PM2.5 concentration in shops indoor and outdoor air was much higher than EPA admissible level and cancer risk for workers was unacceptable that it has required to basic solutions for air pollution control at source.

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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: Nowadays, air pollution is now considered to be the largest environmental health threat. This study was conducted with the aim of determining occupational exposure to chemical pollutants, including sulfur dioxide (SO2) and hydrogen sulfide (H2S) and assessing the health risk of exposure to these compounds using a combination of AERMOD and SQRA methods.
Material and Methods: The present study is considered as a descriptive-analytical and cross-sectional research, which was conducted in 2002 in one of the gas air refineries of South Pars in the Persian Gulf region, in such a way that the amount of emissions coming out of refinery chimneys was measured by the Testo 350- XL. AERMOD model was used to simulate the dispersion of H2S and SO2 chemical pollutants. Respiratory exposure and health risk assessment of refinery personnel and nearby residents were performed using the recommended method by the Singapore Occupational Health Services Pte Ltd.
Results: Hydrogen sulfide and sulfur dioxide were introduced as the most dangerous chemicals. According to the results, the highest risk value for sulfur dioxide among the exposure groups was related to the sulfur recovery unit (SRU), the west side of the Train Gas unit and the gate pass building of the refinery, and the highest risk values for sulfur dioxide among the exposure groups were related to the HSE building, security door, fire stations building, tanks, steam generating unit, west side of Train Gas unit, dining hall and gate pass building of the refinery. Hydrogen sulfide obtained a low to medium risk level, and sulfur dioxide a low to high risk level in terms of frequency.
Conclusion: This model can be considered as a suitable and quick solution in the superior management of the concentration of pollutants and also a promising solution in order to increase the ability of decision makers to assess the health risk of industries’ personnel. Also, ensuring quality   monitoring results and reducing sampling costs are discussed.

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Introduction: Despite the legal prohibition of asbestos fiber usage in the country, numerous studies have documented its presence in the air of various cities, including Tehran. This urban air pollution stems from the extensive use of asbestos in construction materials such as pipes, insulators in cooling and heating systems, and friction devices like brake pads and clutch plates, among other consumer products. Prolonged exposure to these fibers can have severe health consequences for residents, leading to respiratory issues, pulmonary fibrosis, and cancers such as mesothelioma. Consequently, we conducted a descriptive cross-sectional study to examine both the extent and nature of asbestos fiber distribution in Tehran’s air.
Material and Methods: This study measured the concentration of asbestos fibers in Tehran’s air over a 12-month period. Monthly samplings were conducted at eleven Tehran Air Quality Control Company-operated stations. The sample collection, preparation, and analysis adhered to the NIOSH 7400 method. Microscopic examination results were then translated into asbestos fiber concentrations using the appropriate formulas.
Results: Analysis of samples taken across four seasons revealed that spring recorded the highest average asbestos fiber concentration at 0.00134 f/ml, while the lowest concentration was observed in summer at 0.117 f/ml.
Conclusion: Given the widespread ban on asbestos use in many countries, including Iran, its presence in urban air is unexpected. Regrettably, flawed policy decisions made during the import ban announcement and the extended timeframe set for the ban’s initiation allowed companies to import and stockpile asbestos indiscriminately for future use.