Introduction: Benzo(a)pyren is an indicator of carcinogenic PAHs and enters the body through the respiratory system, gastrointestinal tract, and skin. This compound causes lung, kidney, and skin, cancers. In this study, the concentrations of PM10 and 16 PAHs compounds were measured in the particle phase in an urban and a suburban area of Shiraz and the carcinogenic risk of respiratory exposure to PAHs were assessed.
Materials and methods: A total of 60 samples were collected from Paramont and Sadra during spring 2015 using SKC sampling pump (for 24 h at a flow rate of 10 L/min). Dichloromethane/methanol mixture was used as a solvent. 16 PAHs were identificated using gas chromatography with mass spectrometry.
Results: The mean (±SD) concentrations of PM10 were 62.73±23.83 and 60.88±31.03 μg/m3 in the urban (Paramont) and suburban (Sadra) stations, respectively, which exceeded the PM10 emission limit value of the Europe Commission (50 μg/m3). Also, the mean concentrations (±SD) of the total PM10-bound PAHs were 19.28±7.48 ng/m3 and 17.80±9.17 ng/m3 in Paramont and Sadra stations, respectively. Besides, the BaPeq was 1.307 in Paramont and 0.814 in Sadra station. Incremental Lifetime Cancer Risk (ILCR) values for children below 10 years of age demonstrated the risk of cancer for this age group in both areas.
Conclusions: this study presented the value of PM10 and PAHs concentration in two sampling sites. The PM10 values were higher than Europe Commission and the PAHs concentrations could increase the potential risk of cancer among the children below 10 years old in both sampling areas.

Introduction: Recently contact with bioaerosols has been presented as an important problem which endangers human being’s health. In this study bioaerosol concentration was measured in wastewater treatment (WWTP) units in west of Tehran.
Materials and methods: Passive sampling was carried out around three process and operational units, in 100 m from last unit of wastewater treatment plant and in administrative building. In total 440 samples were collected. The transport culture medium used for bacterial samples was the tryptic soy agar, and for fungal samples, it was dextrose agar. Sampling was carried out according to the sampling calendar of Environmental Protection Agency (EPA) in 2013 for 1 h every 6 days and in the plates of 9 cm.
Results:The results showed that aerobic digester with an average of 3303 CFU/Plate had the greatest effect on emission of bacterial bioaerosols. In addition grit chamber with an average of 586.3 CFU/Plate had a highest impact on fungal emission. Among the bacteria, Bacillus spp. Staphylococcus spp. and Micrococcus spp. were dominant. The highest emission of bacterial aerosol is in July and the lowest is in March. Furthermore, fungi such as Cladosporium spp. Penicillium spp. and Alternaria spp. were the dominant types in the wastewater treatment plant. The highest emission of fungal aerosols is in March and the lowest emission is in July.
Conclusions: According to the results, operational and processing units of WWTP influence pollution load and dispersion of bioaerosols. Therefore, appropriate environmental health management in WWTP could be one of the important factors reducing dispersion of bioaerosols.

Introduction: Formaldehyde is a toxic, carcinogen, mutagen and teratogen compound that is widely released into the atmosphere worldwide. The toxicity effect of formaldehyde on microorganisms is a serious obstacle on the path of using biological treatment methods. The main objective of this study is to evaluate the effect of air velocity on the efficiency of a Biotrickling Filter Reactor (BTFR) for removal of formaldehyde from an air stream.
Materials and methods: A BTFR and Bioscience Laboratory Respirometer were employed for continuous and batch experiments, respectively. Three gas flow rates including 90, 291 and 1512 L/h were used to find out the effect of velocity on the formaldehyde removal efficiency of the BTFR. Monod model was modified to be capable of predicting the BTFR cases having very high formaldehyde removal efficiency.
Results: The results showed that for the gas flow rates of 90, 291 and 1512 L/h in BTFR, formaldehyde removal efficiency of 95, 97 and 99% were achieved, respectively. These results showed that higher air flow velocity lead to higher removal of formaldehyde from air in a BTFR. A very slow formaldehyde removal was observed during batch experiment where the gas velocity is set equal zero.
Conclusions: This study demonstrated that the mass transfer in gas phase is an important step in formaldehyde treatment in a BTFR. Very slow formaldehyde removal in the batch system which can be ascribed to the very low mass transfer rate in gas phase confirms the fact that this rate is a controlling step in overall removal rate in BTFR.

Introduction: Polycyclic aromatic hydrocarbons are among the main pollutants in the urban and industrial atmosphere. An investigation on variation of PAHs in the urban and suburban atmosphere of Tabriz, Iran was conducted in this study.
Materials and methods: TSP and PM10 (particulate matter with aerodynamic diameter <10μm) samples were collected at two sites between September 2013 to July 2014. PAHs were analyzed with GC–MS.
Results: The concentrations of the total PAHs in TSP and PM10 were 47.87±17.28 and 36.69±6.71 ng/m3 in the urban site and 91.88±35.65 and 77.2±22.24 ng/m3 in the suburban sampling site, respectively. 4-5 ring PAHs (Chr, BaA, BghiA, Flu, Nap, and Phen) were the abundant PAHs compounds, which accounted for 75-80% of total PAHs in urban and 85-88% of total PAHs in suburban sampling sites. The ratio of carcinogenic PAHs (BaA, Chr, BbF, BkF, BaP, DahA and Ind) to ΣPAHs respectively ranged from 0.51-0.58 and 0.81-0.85 in urban and suburban sampling sites.
Conclusions: Potential sources of PAHs were identified by using the molecular diagnostic ratios between PAHs. The obtained diagnostic ratios of Anth / (Anth + Phen) and total LMW/ total HMW suggest that pyrogenic sources such as gasoline and diesel vehicles are the major sources of PAHs in the study area.

Introduction: Under the influence of existing microorganisms in soil, the landfilled municipal solid waste, would produce and release high quantities of carbon dioxide, methane and non-methane organic compounds into the atmosphere in anaerobic conditions. The aim of this study was to estimate the amount volume of produced gasses in the landfill located at city of Jahrom.
Materials and methods: To conduct this research, the primary data including waste composition, waste density, waste production capitation, the weight of the annual produced waste were collected using experimentations and calculations. These data were then used in LandGEM for the purpose of landfill gases volume estimation. The Screen view was then used for modeling of pollutants dispersion into atmosphere in 15 km radius around the landfill.
Results: Studies suggest that the waste generation in city of Jahrom is 313.35 g/person.d. The climax of carbon dioxide and methane production in this landfill in 2028 was equal to 10570000 m3/year. Estimation shows that by recycling the obtained methane in this landfill, it is possible to generate 8375 MW of energy by 2016. It is also indicated that the concentration of produced pollutants in the landfill is calculable in 15 km radius.
Conclusions: The obtained results from this study could be used to determine the role of Iran in global emission of greenhouse gasses and be considered for the Iranian energy production planning’s.

Introduction: Indoor air quality in hospitals plays an important role in prevention of infectious disease and inhibits the transmission of infections to staff and patients. The aim of this study is to evaluate the indoor air quality and its relation with environmental air in one of the public hospitals in Qazvin. This cross-sectional study was carried out in a densely occupied educational hospital affiliated with Qazvin University of Medical Sciences.
Materials and methods: In this study, several factors those affect the air quality (including carbon dioxide, temperature, relative humidity, and particulate matters sized PM10, PM2.5, and PM0.3) were measured using direct measurement data logger tools in different wards of hospital in various weather conditions. All data obtained was analyzed by SPSS 20.
Results: The collected data was analyzed using SPSS with a confidence interval of 95% and α=0.05. The mean 24 h concentrations of PM10, PM2.5 and PM0.3 were 83.09, 21.47 and 1.6 μg/m3 at indoor parts of the hospital, respectively. The highest concentrations were observed in men cardiac, women internal, and women cardiac wards. The mean 8 h concentration of carbon dioxide, temperature, and relative humidity were significantly associated with American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) standards.
Conclusions: The highest Indoor to outdoor air quality ratio for particulate matters was PM10=3.75 in men cardiac ward, PM2.5=2.6 in women internal ward and PM0.3=1.31 at women cardiac ward. According to the World Health Organization (WHO) and the Environmental Protection Agency (EPA) standards, the air quality is divided in several categories based on the concentration of particulate matters, and in this study the level of air quality was moderate. Air quality can be improved to optimal levels and pollutants can be reduced through corrective measures such as suitable and efficient ventilation system and further measurements.

Introduction: Maintenance of adequate hospital indoor air quality (HIAQ) in operating rooms (ORs) is critical to the Surgical Site Infection (SSI) in hospitalized patients. This study assessed the concentration of bacterial bioaerosols in various ORs in a hospital.
Materials and methods: The concentration of bacterial bioaerosols was measured in the 8 ORs and 2 nurse stations. Active sampling method was used to monitor bacterial bioaerosols.
Results: The mean concentrations of the total bacteria were 211-386 and 208-443 CFU/ m3 in the first and second floor, respectively. Gram-positive bacteria (e.g., Micrococcus spp., Staphylococcus spp. and streptococcus spp.) were frequently observed in the assessed ORs and nurse stations.
Conclusions: Bacterial bioaerosol monitoring is a useful tool for evaluation of the bio-contamination of ORs in order to improve indoor air quality of them.

Number of scientific studies linking possible effects of air pollution on health are increasing. However, the disparity in the effect estimated from different studies and recognizing important determinants of these diversity are essential . We have explained the types and sources of air pollution, and the common terms in epidemiological studies of air pollution. Then we reviewed the study design and critically evaluated methodological approach to estimate association between air pollution and health with deep insight into dispersion model. The quality of exposure measurement is critical determinant in an environmental epidemiology study. However, the available exposure data and feasible methods for its collection are often the determinant of the design to be used. Beside vast development in this field, epidemiological approaches to find out the risks of exposure to air pollutants is still challenging.