Journal of Health and Safety at Work

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Introduction: Exposure to Bioaerosols is related to a grand range of sanitation’s effects including intense poisoning effects, allergy and cancer. This study has done to determine the type and concentration Bioaerosols in the air of one of the industrial live stocks slaughterhouse in Shiraz.

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Material and Method: A total of 112 air samples from different parts of industrial live stocks slaughterhouse are collected in this cross-sectional study. According to the NIOSH method, Bioaerosols sampling was done in blood agar medium and dextro agar and by Anderson one-stage sampler with flow rate of 28.3 Lit/min, sampling duration of 10 minutes and concentration measured in CFU/m3.

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Result: According to the result, the most pollution is in blood cook place (3281.44 CFU/m3) and the least pollution exists in meat delivery place (99.1 CFU/m3 ). Also the result of the study showed that Bioaerosols concentration in industrial live stocks slaughterhouse is 28 times more than its concentration in reference site. Which is 5 km from slaughterhouse and 5 species of fungi were observe which aspergillus niger and penicillium were dominat.

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Conclusion: Bioaerosols concentration in live stocks industrial slaughterhouse is higher than the threshold limit and suggested range. Therefore, it is essential to take measures, such as improving the process and technical-engineering interventions including the use of suitable ventilation systems and also management personal monitoring measures.

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Introduction: Noise is one of the most common health hazards at the workplaces that can cause not only somatic problems, but also adversely affect mental health. The aim of this study was to investigate and evaluate occupational noise exposure and noise annoyance in one of the petrochemical companies.

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Material and Method: The study population included 47 people working in Administrative and Manufacturing parts of the petrochemical company. First, dosimetry of production workers and noise frequency analysis of Administrative employees were performed. Then, self-report questionnaire for the assessment of noise annoyance at workplace was completed by the subjects. The questionnaire consisted of three parts: scoring of the noise intensity in the workplace, scoring of the noise annoyance in the workplace and determining the feelings and emotions (e.g. fatigue, sleepiness, and concentration problems) that experienced by subjects during the working day.

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Result: The results of noise dosimetry measurements showed that mean eight hour equivalent continuous A-weighted sound pressure level was 86.13 dBA. According to the frequency analysis of office rooms, mean noise level and Preferred Noise-Criteria (PNC) was 69.4 dBA and 62 dB, respectively. The findings of our analysis revealed that 17.9% of administrative staff and 63.2% of manufacturing workers assigned “very high” score to the noise intensity in the workplace. The annoyance score was obtained “very annoyed” by 10% of employees of office section and 42% of manufacturing workers. For noise-related complaints and sensations defined by subjects, 49% of administrative staff and 60% of manufacturing workers marked the “sometimes” and “more” item of the questionary.

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Conclusion: Based on the obtained results of investigating the noise level (objective exposure) as well as the noise annoyance (subjective exposure) at the studied company, it is necessary to adopt the management –technical noise reduction measures at manufacturing sectors as the personal noise exposure and environmental noise exposure and also noise personal exposure of administrative staff can be decreased.

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Introduction: Bioaeroslos released from wastewater treatment plants may contain pathogens existing in the sewage which could endanger the health of workers. The aim of this study was to evaluate the status of bioaerosol emissions form in a sanitary wastewater treatment plant.

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Material and Method: This cross-sectional study was carried out in different units of a sanitary wastewater treatment plant. For this purpose, air samples were collected on blood agar and dextro agar in an Andersen single-stage sampler with flow of 28.3 lit/min for 10 minutes. Collected samples were shipped to the lab immediately and incubated for 48 hours. Then, incubated samples were counted for colonies concentration.

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Result: Based on the result of this study, the mean density of bacterial and fungal bioaerosols in all wastewater treatment plants were 412.86±23.30 and 53.72±23.99 CFU/m³, respectively. Microbial contamination of the air within a kilometer away from the site (control areas) was 17 times less than its average density.

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Conclusion: Wastewater treatment processes can contaminate the air surrounding the plant, particularly with bacteria bioaerosols. Therefore, it is necessary to control the emissions and protect the health of workers against risks arising from exposure to bioaerosols.

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Introduction: One of the factors influencing on indoor air quality of the buildings is performance of HVAC (heating, ventilation, and air conditioning) systems. These systems supply clean and odorless air, with temperature, humidity, and air velocity within comfort ranges for the residents. The aim of this study was to evaluate performance HVAC system in an administrative building in Tehran.

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Material and Method: A questionnaire, developed in their research was used to assess the building occupants’ perception about the performance of HVAC system. To evaluate the performance of HVAC systems, air velocities were measured in the diffusers using a thermal anemometer. Moreover, CO2 concentration, air temperature and relative humidity were measured in the whole floors of the building. Air distribution inside the building was evaluated using smoke test.

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Results: Most of the studied people complained about the direction of airflow, thermal conditions and cigarette odor. The highest level of carbon dioxide was measured at 930 ppm inside the restaurant. The maximum and minimum air temperatures and relative humidity were measured 28.3-13.8° C and 28.4-23% respectively. Smoke test showed that the air distribution/direction wasn’t suitable in one third of air diffusers.

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Conclusion: Improper air distribution / direction was the main problem with the studied HVAC system which could be corrected by adjusting and balancing of the system.

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Introduction: The Power plants are as the major industries that have a large number of workers, providing they health is important. Exposure to occupational noise is the pervasive physical agent in industries like power plants and may impact health and for safety status for people. Determination of the sources of noise in workplaces is important step in noise control plans. This study aimed to assess noise pollution and determine the main sources of noise in a power plant for.

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Material and Method: This descriptive cross-sectional study was conducted on the ground floor of the turbine unit of a thermal power plant. Measurements was done based on the ISO-9612 and ISO-11200 standard using by the calibrated sound level meter model TES-1389 on “A” frequency weighting and “Slow” mode for time response. Surfer V.10 software was used for interpolation and noise maps producing. Based on grid method measuring for indicating of noise propagation, we set buffer of danger areas to determine main sources of noise. Also, we used the minimized grid method for measuring and study of noise denotation in vertical surface in each main sources.

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Result: The results showed that the measured indoor sound pressure level in all areas where at the risk category of the units. The highest average sound pressure level was belonged to the unit 2, with 93.1 dB(A). We find the feed water pumps were the main sources in all of the studied units. Among the four main components of the main sources, the highest noise levels associated with the main pump and the gearbox section with about 100 9B(L) and dominant frequency of 2000 Hz.

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Conclusion: Considering that feed water pumps had major sources in indoor power plant noise pollution, engineering noise control such as providing enclosures is necessary to reduce noise pollution to safe levels in the studied plant it is necessary.

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Introduction: Kitchen workers are in danger of slip accident because of slippery surfaces created by contaminants like grease, water and food material. The aim of this study was to investigate the prevalence and slip risk assessment in cooking sites of Shiraz.

Material and Method: This cross-sectional study was conducted on 322 cases from commercial kitchens in traditional and fast food restaurants, located in Shiraz, Iran, who was willing to cooperate in the project. (The total number of restaurants was 1303 cases. And simple random sampling method was used). The risk of slips was assessed using Slip Assessment Tool (SAT), developed by Health and Safety Executive (HSE). Prevalence of slip accidents was investigated using a questionnaire among kitchens staffs. Roughness coefficient was measured using Roughness Meter TQC-SP1560. Data analysis was performed using SPSS-22 software.  

Result: The level of slip risk was at moderate level in 47% of studied kitchens and others had low level of slip risk. Slip risk level in kitchens of traditional restaurants was significantly higher than fast foods. The average value of the measured surface roughness was obtained 4191/39 µm. The highest and lowest, respectively 4458/2 and 3977/3 µm were reported. The prevalence of slip accidents was reported to be 50.3%. Most of slip accidents was occurred in the kitchens, and when the floor was wet with water or contaminated with food products.

Conclusion: The results of this study showed that due to differences in the type, method and time of food services and also workload of personnel, slip risk in kitchens of traditional restaurants was higher than fast foods. Approximately, in 50% of studied kitchens, the level of slip risk was assessed as moderate. Some basic interventions in spillage control and cleaning procedures, floor surface characteristics and using slip-resistant shoes are required to reduce the risk of slip in kitchens.

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Introduction: Skin disease caused by exposure to the chemicals is one of the major health-related problems in the workplaces. This study has done to prioritize the strategies for skin exposure with chemical in a painting company.
Material and Method: In this analytical cross-sectional study 7 criteria and 8 selection control methods were initially chosen by surveying the existing records and through the assessments of expert panel and checking the result of previous studies. Subsequently, control strategies were prioritized according to the criteria using Fuzzy Analytical Hierarchy process & Topsis.
Result: Results of the paired comparison showed that the safety of the control strategy (w=0.298) and it’s up to date (w=0.0138) were the most and least important criteria for skin control strategies. Among skin control strategies for chemical exposure, the highest and lowest importance were for training (w=0.817) and work-rest schedule (w=0.233), respectively.
Conclusion: In this study, training was determined as the best control strategies for skin chemical exposure in the studied painting company according to the investigated criteria. This decision-making process could be applied for promotion of the skin health among workers.

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Introduction: Hydrogen sulfide is one of the most important impurities in natural gas. Due to the fact that this gas is hazardous, toxic, corrosive and volatile, therefore, the removal of hydrogen sulfide has been studied using several methods. One of the most known procedures is the adsorption process. In the present study, activated carbon and activated carbon-based composite scaffolds (MOF-5) were used as a cartridge mask to remove hydrogen sulfide from respiratory air.
Methods and Materials: First, activated carbon (AC) was converted to powder form by ball mill, and AC / MOF-5 composite with 10%, 25%, and 40% MOF-5 to AC was synthesized from the MOF-5 metal-organic scaffold. Then, the rates of adsorption and breakthrough time using a designed setup were tested in two ranges of temperatures, humidities and concentrations. XRD, SEM and BET were used to determine the properties of composite absorbents.  The Aeroqual S500 Direct-reading sensor with 0.01 ppm accuracy was used to measure the exact amount of hydrogen sulfide gas.
Results: The AC/MOF-5 composite showed higher adsorption and breakthrough time compare to the other adsorbents. The Specific surface area (BET), average pore diameter, and total pore volume of the adsorbent were 814 m² /g, 1.6795 nm, and 0.342 cm³ /g, respectively. The isotherm diagram showed that, according to IUPAC, most of the pore size of this adsorbent was classified in the micro-porous group. The maximum adsorption (mg/gS) and breakthrough time (min) were related to AC/MOF-5_{(40 Wt. %)} adsorbent with 60.41 mg/gS (SD = 1.08) and 56.26 min (SD =2.38) at a temperature of 15 ° C, a concentration of 9.88 ppm (SD = 0.70), a moisture content of 51.06% (SD = 0.15) and a pressure drop of 51.34 mm water. By adding more than 25% MOF-5 metal-metal scaffold to activated carbon, the amount of adsorption, breakthrough time and pressure drop were increased.
Conclusion: AC / MOF-5 composite adsorbent due to its porous structure, high specific surface area, and most importantly, having Zn-O-C groups increased the adsorption rate as well as the pollutant Breakthrough time. However, it showed a relatively higher pressure drop than commercial activated carbon (AC).