Background and purpose: High concentrations of Respirable Particles may cause high incidence of respiratory diseases and mortality in public populations and in particular in public transportation workers. Epidemiological exposure studies showed that Respirable Particles that emitted from traffic sources have more potential effects on more incidence of hospitalization or mortality caused by cardiovascular diseases. In this study personal exposures of bus drivers to Respirable Particles (PM10) and factors that caused high personal exposure were studied in Sari city.Materials and Methods: In this study, a calibrated real time monitor (Micro Dust Pro) with a personal sampling pump with 2 lit/min flow rate were used to measure Sari’s bus drivers personal exposure to PM10 concentrations on 3 main routs. This study was carried out during a one calendar year and all possible effective factors on personal exposure were recorded in a questionnaire.Results: The mean personal exposures to PM10 concentrations among bus drivers were varied in different months. Exposure to PM10 concentrations were higher in autumn and winter and increased to 300µgm-3 in some days. Personal exposures to these Particles were increased in the evening and on high traffic flow routs. Other factors such as rainy weather and temperature, number of passengers, bus' model year, picking up and dropping off the passengers were the most effective factors on driver's personal exposures.Conclusion: Bus drivers' exposure to Respirable Particles PM10 in Sari was varied in different time. It was due to entrance of outdoor particulate air pollutants into the bus during the picking up and getting off the passengers and resuspension of settled fine Particles.

Background and purpose: High concentrations of Respirable Particles may cause high incidence of respiratory diseases and mortality. Epidemiological exposure assessment is based on fixed site measurements in ambient air. However, major studies reported good relationship between indoor fine particulate air concentrations and personal exposure. This study is focused on personal exposure to PM2.5 in different transportation modes and factors that cause high indoor PM2.5 levels.Materials and Methods: In this study, a calibrated real time monitor (MicroDust Pro) was used to measure PM2.5 levels in 3 mode of transportation (bus, car and train) on the same route. Results were also compared with PM10 concentrations measured by fixed site monitors. A small Poly Urethane Foam (PFU) filter was designed for PM2.5 size fraction monitoring and a small personal sampling pump was used to provide a continuous airflow through the gravimetric adaptor and photo detector.Results: The mean PM2.5 concentration measured in the train was lower than the mean fixed site PM10 concentration. However, the mean PM2.5 levels in car and bus were much higher than those mean PM10 concentrations measured by fixed site monitors. Boarding, picking up, dropping off, and movement of passengers inside the bus and train were significantly related to short-term increases in PM2.5 concentrations. However, stopping at the traffic light was the most important factor associated with peak PM2.5 concentrations inside the car.Conclusion: Penetration of Particles that were created by road traffic and resuspension of fine Particles in the vehicles were the most important factors that may increase Respirable Particles in transportation modes.

Background and aims: Exposure to manganese fume in the welding process leads to adverse neurological effects on the health of welders. The aim of the present study was to investigate the relationship between biomarkers of manganese exposure and compare the frequency of these symptoms with unexposed group.  Methods: 35 welders as exposed group, and 40 administrative workers as unexposed controls, were participated in this study. Neurobehavioral symptoms data were gathered using Q16 questionnaire. Manganese concentrations were determined according to the NIOSH 7301 method. The concentration of manganese in blood of the welders was also measured by ICP-OES. Statistical analysis was performed by using MINITAB 17 software at the significant level of 0.05. Results: The mean exposure to air manganese was 0.45 ± 0.08 mg/m3. Manganese concentrations in blood samples of welders (0.16±0.0 2 µg.ml-1) were significantly higher than unexposed workers (0.04±0.002µg.ml-1). Also the frequency of neurobehavioral symptoms of welders was significantly higher compared to unexposed workers (P <0.05). The correlation between neurobehavioral symptoms and blood manganese was significant for welders (P <0.05, r=0.4). As a result, by increasing the concentration of blood manganese levels, the neurobehavioral symptoms were also increased. Conclusion: Due to the high level of exposure to manganese in welding fume for welders and in order to prevent neurobehavioral symptoms preventive measures such as engineering and management control techniques are recommended to reduce exposure.

Introduction: Considering the great importance of the workforce’s wellbeing as well as the employment of a large number of workers in the cement industries in Iran, the current study was carried out in the aim of evaluation of the Respirable dust concentrations in the workers breathing zone in a cement factory in Khorasan Razavi province.Materials and Methods In this study, Respirable particle concentration was evaluated in the breathing zone of 70 workers in a cement factory who were working at different work sites in the cement factory processes. The standard methodology of 0600 recommended by the US NIOSH was followed to determine Respirable dust concentration using a personal sampling pump, aluminum cyclone and PVC filter.Results The average Respirable dust concentration was 3.9 mg/m3 for all workers. That means 77% of workers were exposed to Respirable cement Particles higher. The maximum mean concentration of Respirable Particles in the workers breathing zone was found in the cement grinding site 9.3 mg/m3 and the minimum one was measured in the stone crushing and mining site 1.8 mg/m3.Conclusion The average concentration of Respirable dust in the workers’ breathing zone was higher than OEL in both warm and cold climates. The warm weather and the wind comes from the desert and dry areas contribute to the increase of the concentration of Respirable Particles in the breathing zone of the workers in various parts of the plant who are exposed to the naturally ventilated air.

Introduction: Cement factory workers exposure to airborne Particles containing crystalline silica in Portland cement chemical compound can caused pulmonary diseases, including silicosis and lung cancer. The aim of this study was to assess the risk of occupational exposure to Respirable cement dust and crystalline silica in a cement factory in Khorasan Razavi province. Methods: In this cross-sectional study conducted in 1397, the method presented by the Institute of Occupational Safety and Health of Singapore was used to assess the health risk of Respirable cement and silica Particles. Also, the standard method MDHS101 / 2 recommended by NIOSH was used to determine the concentration of Respirable cement Particles in the air of the workers' respiratory area and the X-ray powder diffraction method (XRD) was used to determine the concentration of inhalable crystalline silica Particles. Stata software version 14 was used for statistical analysis of data. Results: This study showed that most of the workers employed in various worksites of the cement factory were exposed to Respirable cement dust and crystalline silica Particles higher than the OEL recommended by the Iranian TCOH and the TLV recommended by ACGIH. Exposure risk assessment in different parts of cement factory showed a low risk level for Respirable Particles of cement in the furnace and moderate for other sections. Also a high risk level for workers’,exposure to crystalline silica was found in the cement mill and very high level for workers in other sectors. Conclusions: Employees who were working in this plant were exposed to moderate risk of cement Respirable Particles and high risk level of exposure to crystalline silica. Thus, the engineering control methods of exposure to Respirable Particles is suggested.

Introduction: There are many chemicals in Portland cement including crystalline Silica. Workers' exposure to cement airborne Particles containing Free Crystal Silica may cause some serious diseases. This study was carried out to evaluate Free Crystal Silica particle concentration in the workers' breathing zone in a cement factory in the Khorasan Razavi province. Materials and Methods: The concentration of free Crystal Silica of Respirable cement Particles was evaluated on 42 sample of workers in different sections of a cement factory in the Khorasan Razavi province in 2018. Sampling of Respirable Particles was conducted based on standard method of MDHS101/2 recommended by NIOSH, using a personal sampling pump, a cyclone and a filter. Filters were weighed using an accurate microbalance with one microgram precision. Filter was analyzed by XRD method for determination of free crystalline silica. Results: The mean workers' exposure to cement Respirable Particles was 3. 75± 4. 09 mg/m3 and the average concentration of free silica in cement Respirable Particles was 0. 12± 0. 3 mg/m3 in all studied sections. On average, 69 percent of workers were exposed to free silica higher than OEL. Maximum average of exposure to free silica (0. 54 mg/m 3 ) was observed in stone crushing section and the minimum average exposure was observed in Raw mill section (0. 03 mg/m3). Conclusion: Workers exposure to Respirable cement Particles and free crystalline silica in Respirable Particles were higher than national and international exposure limits. There is a relationship between temperature and Respirable particle concentration. Regarding high exposure of workers to free crystalline silica Respirable particle concentration.

Background and aims: One of the major health issues in developed countries is the workplace air pollution. Cement factories are one of the industries where many workers worked in them. Workers in this industry are exposure with many harmful factors, such as ergonomics factor, physical factors, and in particular various chemical agents, during their job. The most important factors that threaten the health of workers in the cement industry are dust and Respirable Particles of cement. Respirable Particles of cement contain some elements such as arsenic, calcium, aluminum, cadmium, lead, cobalt, zinc, iron, and chromium. Recent studies concluded that the concentrations of arsenic, chromium, lead, and cadmium within the Particles are higher than the other metals. Exposure to heavy metals within cement Respirable Particles can lead to some adverse health effects among exposed workers. Expanding of industries and emission of Respirable Particles containing heavy metals in the workplace ambient causes higher exposure for workers within various industries and therefore has become a major problem in these industries, including the cement industry. To arrive the health goal that is protection of the workers, exposure to chemicals and the dangers of exposure to these substances need to be scrutinized. Risk assessment is defined as the process of assessing the risks arising from risks in the workplace by taking control measures and deciding whether or not to accept them. Risk assessment is a basic action for evaluation of danger in the workplace and the first step for risk management. Quantitative health risk assessment for different chemical agents in industries is necessary to decide on control of risk and management measures to reduce risk and determine risk level of these substances. This process combines scientific information about the toxic properties of chemicals as well as the results of chemical measurements in the workplace can provide comprehensive information on the measure of risk and how best to deal with these potential risks. The aim of this study was to assess the risk level of workers occupational exposure to heavy metals (lead, chromium, cadmium) within cement Respirable Particles for exposed workers in a cement factory. Methods: This cross-sectional study was conducted in one of the cement industries during warm and cold air condition during 3 months (March 2016 to May 2016). In this study, the concentration of Respirable Particles within the breathing zone of 70 workers who were working at different production worksites of a cement factory (Packing worksite, Cement mill, Grill and Greater cooler, kiln, blending, Raw material storage and Mine and crushing) was evaluated. The standard method of 0600 recommended by the National Institute of Occupational Safety and Health (NIOSH) was use to evaluate time weighted average (TWA) of workers' exposure to Respirable cement Particles. Worker's exposure was measured using a personal sampling pump (SKC, model 224-44MTX, UK) with a 2. 5 L. min-1 flow rate, air was passing through an aluminum cyclone (SKC, UK) with a 37 mm 2 micrometer pore size poly vinyl chloride (PVC) filter (SKC, UK) bedding on a plastic cassette. The filters were placed in the desiccator for 24 hours before sampling time. To weigh the filters, a microbalance accurate to 6 decimal places (1 μ g sensitivity Sartorius, Model ME5, Germany) was used. Critical orifice was used to keep the flow constant during sampling period. Workers personal sampling carried out continuously during a complete shift time. A blank filter was used for each batch of samples to eliminate sampling errors. To evaluate workers' exposure to heavy metals including lead, chromium and cadmium within the cement Respirable Particles, the standard method of ID121 recommended by the Occupational Safety and Health Administration (OSHA) was applied. Each filter was dissolved separately at 100 ° C in concentrated nitric acid and perchloric acid until its metals were dissolved in the solution phase. Then, the solution obtained with deionized water was diluted to the lowest level of detection (LOD). The US-made FAAS Model VARIAN 240FS atomic absorption device was used for analysis. Firstly the standard curve was obtained using standard solutions with different concentrations of meals. Samples were then transferred to the atomic absorption apparatus to determine the concentration of the metals within solution. By measuring the sample absorption rate and comparing with the calibration curve and using Bier Lambert's law, the amount of metal elements in the unknown sample was obtained. Semi quantitative risk assessment of heavy metals among exposed workers was carried out using a standard method provided by the Institute of the occupational health and Safety in Singapore. Finally, the risk level for each of the heavy metals (lead, chromium and cadmium) in the Respirable cement Particles was obtained. The degree of exposure (ER) for all parts of the plant was obtained. Since the mean concentrations of these metal in the air of all sections of the cement plant were below the exposure limit recommended by the Iranian Occupational Health Technical Committee (OEL) and the (TLV) recommended by the ACGIH, the E/OEL ratio was lower than one. The hazard rating (HR) of the chemicals was determined using a standard table. Then, the exposure rating (ER) was calculated and determined using air monitoring results using E that is the weekly exposure in milligram per cubic meter or parts per million, F is the number of exposures per week, D is the average time of each exposure in hours, M is the exposure rate in parts per million or milligram per cubic meter, W is the average working hours per week (40 h). Finally, the risk rate (RR) was calculated using the chemical hazard risk (HR) and exposure rate (ER) values. Results: This study showed that the mean concentrations of cadmium, lead and chromium elements were measured as 2. 41, 10. 39, and 1. 36 microgram per cubic meter respectively. The highest average exposure to lead metal in the Respirable cement Particles was 15. 09± 4. 45 μ g/m3 and the lowest mean was 8. 48± 3. 11 μ g/m3. The highest mean chromium concentration in cement Respirable Particles was 2. 27± 1. 15 μ g/m3 and the lowest mean was 1. 11± 0. 48 μ g/m3. The highest mean concentration of cadmium in the cement Respirable Particles was 2. 78± 0. 62 μ g/m3 and the lowest mean was 2. 17± 0. 37 μ g/m3. Most workers in the various cement worksites were exposed to heavy metals less than the OEL suggested by the Iranian Occupational Health Technical Committee and the TLV recommended by the ACGIH. Due to the toxicity of lead metal, the grade 3 risk was considered for this metal. According to the E / OEL ratio, the exposure rate (ER) for all parts of the plant was 1, and since the concentration of this metal in all parts of the cement plant was less than the OEL designed by the Iranian Occupational Health Technical Committee and the TLV recommended by the ACGIH. The risk score for all parts of the plant was 1. 73, and finally the risk score for lead in all parts of the plant was low. Due to the toxicity level of chromium metal, the hazard rate (HR) for this metal was considered 5. According to the E / OEL ratio, the exposure rate (ER) for all parts of the plant was obtained 1and since the concentration of this metal in all parts of the cement plant is less than the OEL designed by the Iranian Occupational Health Technical Committee and the TLV recommended by the ACGIH, the risk score was 2. 23 in all parts of the plant. And the risk rating for chromium metal was low in all parts of the plant. Due to the toxicity level of cadmium metal the (HR) was considered 4 for this metal. Risk score was obtained in all parts of factory number 2 and as a result the risk rating for cadmium metal in all parts of factory was low. Since all workers in a section are exposed to cement Respirable Particles and therefore exposed to lead, chromium and cadmium metal elements in these Particles are different. The risk of exposure to workers exposed to the highest concentrations of the studied metals in the three sections of kiln, blending, and Cement mill was calculated separately. The results showed that workers exposed to cadmium and lead metals were in the medium risk exposure kiln and blending worksites, respectively and workers exposed to chrome metal working in the cement mill were also at low risk. Conclusion: According to the present study, concentrations of chromium, cadmium and lead in the Respirable cement Particles were lower than the exposure limit set by the Occupational Health Technical Committee of Iran (OEL) and (TLV) recommended by the ACGIH. Exposure to lead, chromium and cadmium elements in cement Respirable Particles were at a low risk rates for all worksites of the plant However, some workers in the kiln silo and milling materials that exposed to higher particle concentrations containing cadmium and lead had an average risk rate. Therefore, engineering and management control strategies for heavy metal exposure in those sectors are recommended to reduce the risk and prevent injury to these workers.

Background and Objectives: The dust raised in construction activities is one of the most important occupational hazard for health of construction workers. Due to the nature of the raw materials used, dust contains crystalline silica, which is classified as a confirmed human carcinogen. Due to the lack of personal monitoring of construction workers in Iran, this study was designed to evaluate occupational exposure to the general dust and its component crystalline silica.Materials and Methods: In this cross-sectional study, occupational exposure of 85 construction workers was evaluated. Workers were monitored for Respirable general dust and crystalline silica using methods issued by the National Institute of Occupational Safety and Health (No.0600 and No.7602). Risk assessments in the form of excess mortality rate due to silicosis and lung cancer based on the models presented by Rice and Manettej were calculated.Results: The mean exposure of workers to general Respirable dust and Respirable crystalline silica dust were 9.8±0.35 and 0.13±0.019 as mg/m3 respectively. Workers’ exposure in various task groups had statically significant differences in exposures to Respirable dust (P<0.001) and Respirable crystalline silica (P=0.007). Task groups batching and concrete workers had the highest average exposure to general Respirable dust (11.38±0.77 mg/m3). Cement workers had highest mean exposure to Respirable crystalline silica dust (0.184±0.07 mg/m3). Construction workers’ risk for Mortality rate of silicosis and lung cancer were predicted to be in range of 1-40 and 49-21 per thousand respectively.Conclusion: Due to the high exposure and unacceptable risk assessment of Iranian construction workers to Respirable crystalline silica and Respirable general dusts, administrative and technical control measures are justified.