Vol 3 No 2 (2018): Spring 2018

Original Research

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    Introduction: Traffic and mobile sources are possibly responsible to the most of the ambient volatile organic compounds (VOCs) in urban areas. This study aimed to measure and determine the traffic - related concentrations of benzene, toluene, ethylbenzene, xylenes, formaldehyde, and acetaldehyde at the main streets of Tehran, Iran.
    Materials and methods: The samples were taken from highly populated streets or main roads with heavy traffic in Central, Northern, Eastern, Southern, and Western areas of Tehran. In total, 33 points for BTEX and 23 points for formaldehyde and acetaldehyde were selected for sampling. The sampling and analysis were performed according to NIOSH methods 1501 and 2016.
    Results: The averages (± SD) of benzene, toluene, ethylbenzene, xylenes, formaldehyde and acetaldehyde concentrations in Tehran were 15.04 (± 9.18), 23.42 (± 8.73), 4.97 (± 2.55), 11.81 (± 4.46), 107.11 (± 30.58) and 57.10 (± 18.28) ppbv, respectively. Benzene concentrations were 3.30 to 26.00 times higher than air quality standard of European Union (5 μg / m3). High concentrations of BTEX and formaldehyde / acetaldehyde were found in central and eastern areas, respectively. High correlation coefficients were found between BTEX species (r = 0.77-0.95) and also formaldehyde and acetaldehyde (r = 0.98). The highest coefficient of variation (CoV) as a measure of spatial variability was observed for benzene (54.5 %).
    Conclusion: The high outdoor concentrations observed in this study needs to be decreased immediately, especially in case of benzene.

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    Introduction: High level of noise can be harmful for human mental and physical health. Therefore, it is important to study the noise pollution in cities. The aim of this study is to investigate the situation of noise pollution in Ilam, Iran.
    Materials and Methods: 18 locations of Ilam city were selected to measure the noise level. The noise was measured in four different times including 9 AM, 12 PM, 6 PM and 9 PM in all week days. Then, the collected data was analyzed by standard statistical tests. Finally, the map of noise pollution for Ilam was prepared by ArcView GIS.
    Results: The results showed that the highest noise level was measured in the areas of Saadi market, Imam Khomeini street and nearby Mostafa Khomeini hospital. The highest noise pollution in Ilam was measured on Saturday and Tuesday (about 61 dB). The noise pollution was slightly reduced to 60 dB on Wednesday and Thursday. The noise pollution was sharply reduced to 55.8 dB on Friday
    Conclusion: The noise pollution in the most areas of Ilam, was more than the maximum permissible level. Therefore, this city needs to develop a plan for noise management.

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    Introduction: Predicting the concentration and emission rates of air pollutants before constructing industrial towns via modeling can be an appropriate method for determining the industrial towns’ construction sites. For this purpose, it is necessary to compile proper information about fuel consumption rate by industrial units in various groups.
    Materials and methods: In order to obtain the average fuel consumption in different groups, some questionnaires were prepared, then, filled in 5 industrial towns. Subsequently, using the AP - 42 emission factors, the production rate of various pollutants produced by these industrial groups was estimated. Later, the collected data were used to investigate the effect of constructing phase-II of Baharan Industrial Town, Hamadan, on the area’s weather in an area of 15*15 km2 using AERMOD.
    Results: Based on the results derived from the questionnaires, the highest natural gas consumption rate was related to the food and textile zones with the estimated average consumption rates of 0.023532 (m3 / ha.s) and 0.021785 (m3 / ha.s), respectively. However, the lowest rate was related to the non - metallic minerals zone with the estimated average consumption rate of 0.00097 (m3/ ha.s).
    Conclusions: Zoning the modeling results indicated that constructing phase-II of Baharan Industrial Town, Hamadan, would not increase the average concentration of air pollutants in the area to above the standard level.

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    Introduction: Nowadays, air pollution has become one of the problems of human society. In order to control air pollution, it is essential to know the sources of pollutants and rate of pollutants emission. Although various studies have been done to determine the airborne emission in Isfahan metropolitan, no studies have yet been conducted on the emission of volatile organic compounds (VOCs) from gasoline storage tanks in this city. Therefore, the aim of this study was to determine the rate of VOCs emission from gasoline storage tanks in Isfahan metropolitan and to model dispersion of VOCs in the atmosphere of this city.
    Materials and methods: The TANKS model was used to determine the emission rate of VOCs. Input data for the TANKS model was provided through the Isfahan Oil Refining & Distribution Company. The AERMOD model was also used to model VOCs distribution. The basic information required by the AERMOD model was also collected through relevant organizations such as the Islamic Republic of Iran Meteorological Organization and Iran National Cartographic Center.
    Results: The research showed that there are 21 large gasoline storage tanks in Isfahan metropolitan. The gasoline storage tanks emit 494839 tons of VOCs into the atmosphere annually. The amount of VOCs emitted from the 21 gasoline storage tanks was estimated as much as 154618081 g / year. The results showed that 99.9 % of VOCs emitted through the pipe connections in the gasoline storage tanks into the atmosphere.
    Conclusions: The results showed that gasoline storage tanks of Isfahan metropolitan are responsible for about 0.001 % of the VOCs emission in this metropolitan.

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    Introduction: The aim of this study was to evaluate the effect of national events and holidays on PM2.5 concentrations in Tehran megacity.
    Materials and methods: Air quality data were collected from Tehran Air Quality Control Company (TAQCC) over a period of four years, 2012 – 2015, then data from 10 air quality monitoring stations were processed using R- 3.3.3. The Iranian New year, Ashura and Eid al - Fitr were the national events that considered to study. To compare the daily mean PM2.5 concentrations in Norooz holidays and other days of spring, the Mann - Whitney test and difference in PM2.5 concentrations in each season were investigated with Kruskal-Wallis test.
    Results: In Norooz holidays, the daily mean PM2.5 concentrations in comparison with other spring days were decreased significantly (Pvalue < 0.001). The same decreasing occurred for 10 fi rst days of Muharram too (Pvalue < 0.01) but the daily PM2.5 concentrations during Ramadan days were signifi cantly higher than that of summer days (Pvalue < 0.001). Based on Kruskal-Wallis test the difference in PM2.5 concentrations between seasons was signifi cant and only between summer-autumn (Pvalue > 0.05) and winter-summer (Pvalue > 0.05) was not.
    Conclusions: The effect of holidays on PM2.5 concentration was not observed in summer, however it was an effect in autumn. In addition the concentration of PM2.5 was not influenced by holidays in winter regarding the thermal inversion and stability of air.

Review Article(s)

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    Everyday millions tons of different gases are emitted into the atmosphere from municipal solid waste landfills (MSWL). Several of these gases are toxic, carcinogen or mutagen. Therefore, it is important to have information about health effects of MSWL gases. Some of MSWL gases have negative effects on human reproductive system. The aim of this article was to collect short information about negative effects of some gases emitted from MSWL on human reproductive system.
    This study was carried out in two steps. First, recognizing the gases emitted from MSWL using an extensive literature review and second, finding their intensity of negative effects on human reproductive system.
    The major part of gases emitted from MSWL is methane and carbon dioxide. Both of these gases are not known as a toxic compound for human reproductive system. Many compounds that have been categorized as non - methane organic compounds such as 1, 1, 1- trichloroethane, 1, 1, 2, 2-tetrachloroethane, 1, 1- dichloroethylene, 1, 2- dichloroethane1, 2- dichloropropane, acrylonitrile, benzene and acetone are toxic for human reproductive system.
    The most important method to prevent the negative effects of gases emitted from municipal solid waste landfills is combusting of them to recover their energy.