F. Halek - Academia.edu (original) (raw)

Papers by F. Halek

Research paper thumbnail of GIS ASSESSMENT OF THE PM<sub>10</sub>, PM<sub>2.5</sub> AND PM<sub>1.0</sub> CONCENTRATIONS IN URBAN AREA OF TEHRAN IN WARM AND COLD SEASONS

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences

In recent years, atmospheric models, such as GIS, are used for environmental analysis and the rel... more In recent years, atmospheric models, such as GIS, are used for environmental analysis and the related management for supporting the environmental decision makers in different countries. In this study, concentrations of PM<sub>10</sub>, PM<sub>2.5</sub> and PM<sub>1.0</sub> are found in urban areas of Tehran in warm and cold seasons and the data applied in the related modelling, using Arc-GIS. For this purpose, samples were collected from 42 sites in an 18 km<sub>2</sub> region located in the west and central parts of Tehran. The mean concentrations of PM<sub>1.0</sub>, PM<sub>2.5</sub> and PM<sub>10</sub> are found to be 13.14…

Research paper thumbnail of Seasonal variation in ambient PM mass and number concentrations (case study: Tehran, Iran)

Environmental Monitoring and Assessment, 2010

Tehran, the capital city of Iran, is an important industrial and commercial center. This city is ... more Tehran, the capital city of Iran, is an important industrial and commercial center. This city is one of the worst cities in the world in terms of air pollution, which is mostly due to mobile sources rather than stationary sources. Particulate matter (PM), which is a complex mixture of extremely small particles and liquid droplets, is considered as an important source of air pollution in Tehran. In this study, our objective was to study PM(10), PM(2.5), and PM(1.0) mass and number concentrations and find the correlations of these two parameters in the west-central parts of Tehran during two consecutive warm and cold seasons. The particles collected from five stations were analyzed for their mass and number simultaneously by a laser-based Grimm dust monitor. In general, it was found that the accumulation of the PM in this region is more in the cold season. PM(10) mass concentration increases almost twofold and PM(2.5) and PM(1.0) almost three times in this season. The mean number concentration of the particles (0.3-20 microm) was found to be almost 4.8 times in the cold season. It was also noticed that the average dimensions of the particles decrease in that season.

Research paper thumbnail of Concentrations and Source Assessment of Some Atmospheric Trace Elements in Northwestern Region of Tehran, Iran

Bulletin of Environmental Contamination and Toxicology, 2010

Outdoor concentrations of some elements such as iron, aluminum, magnesium, titanium, copper, zinc... more Outdoor concentrations of some elements such as iron, aluminum, magnesium, titanium, copper, zinc, lead, manganese, sulfur, chromium and arsenic in PM 10 and PM 2.5 , was evaluated at four points in northwestern part of Tehran in winter 2007. The total concentration of the elements in PM 10 and PM 2.5 at the north Karegar avenue found to be as high as 82.05 and 60.64 lg/m 3 , respectively, while at the Arjantin square it was measured to be 34.30 and 28.03 lg/m 3. The emission sources of the trace elements were attributed to the adjoining local industries in the west parts of Tehran.

Research paper thumbnail of Evaluation of Indoor-Outdoor Particle Size Distribution in Tehran's Elementary Schools

A simultaneous study on indoor and outdoor particulate matter concentrations was done in five ele... more A simultaneous study on indoor and outdoor particulate matter concentrations was done in five elementary schools in central parts of Tehran, Iran. Three sizes of particles including PM10, PM2.5 and PM1.0 were measured in 13 classrooms within this schools during winter (January, February and March) 2009. A laser- based portable aerosol spectrometer Model Grimm-1.108, was used for the continuous measurement

Research paper thumbnail of Ceramic ultramarine blue pigment from Iranian raw materials

Research paper thumbnail of Mica colors: Focus on pigments & dispersions

Research paper thumbnail of Ceramic blue pigment from Iranian materials

Pigment & Resin Technology, 1993

Research paper thumbnail of Continuous biodiesel production in a helicoidal reactor using ultrasound-assisted transesterification reaction of waste cooking oil

Clean Technologies and Environmental Policy, 2014

Designing of a continuous biodiesel production system from waste cooking oil with ultrasonic homo... more Designing of a continuous biodiesel production system from waste cooking oil with ultrasonic homoge- nizer assistant through transesterification reaction was studied. Through some pre-tests based on cavitation phe- nomenon to accelerate the transesterification reaction, two types of reactors (batch and continuous) were used. GC– MS results showed the total content of 94.2 % of methyl esters derived from different fatty acids formed in a batch reactor using a magnetic stirrer and an electrical heater. These results were then compared to those of two ultra- sonic homogenizers with low and high capacities of 400 and 1,500 W, which tested successfully under mild con- ditions. The results indicated the advantages of using ultrasonic homogenizer. The continuous system consisted of a 1,500 W ultrasonic homogenizer and glass helicoidal reactor with a tube length of 20 m. This set-up was kept submerged in a hot water bath. As a result, the reaction time decreased to 150 s, the methanol/oil molar ratio was 8.6 and the weight % of NaOH/oil was 0.5 %. After sep- aration of undesired contents, the physical and chemical characteristics of the final product were measured accord- ing to ASTM standard methods. Study of performance of the system also showed a significant improvement in yield of the reaction (90 %) compared to prior studies.

Research paper thumbnail of Dependency of polycyclic aromatic hydrocarbon concentrations on particle size distribution in Tehran atmosphere

Toxicological & Environmental Chemistry, 2010

In this work, the airborne particulate matter with an aerodynamic diameter less than 10 mm (PM 10... more In this work, the airborne particulate matter with an aerodynamic diameter less than 10 mm (PM 10) was fractionated in a six-stage high-volume cascade impactor to identify particulate size distribution in Tehran atmosphere. The study was conducted at 15 sites located in the north, south, east, west, and central parts of Tehran in 2005. Air samples were analyzed for 16 polycyclic aromatic hydrocarbons (PAHs) by HPLC. The daily PM 10 concentrations at the peak of traffic in roadside areas were found to be 106-560 mg m À3. The cumulated concentration sum of PAHs, based on 16 species, was found to have an average concentration of 380 ng m À3. Furthermore, it was found that more than 60% of PAHs belonged to the small particulate size range, having sizes of less than 0.49 mm, some containing benzo(ghi)perylene and indeno(123cd)pyrene (high molecular weight) with average concentrations of 8 and 6 ng m À3 and fluorene, phenanthrene, and fluoranthene (low molecular weight) with average concentrations of 14, 13, and 19 ng m À3 , respectively. In addition, the results revealed that the lighter three-and fourring PAH compounds were the most abundant pollutants in the air collected at all the sampling sites.

Research paper thumbnail of Photocatalytic decoloration of Acid Red 27 in presence of SnO 2 nanoparticles

Water Science & Technology, 2010

In this paper, the photocatalytic decoloration of Acid Red 27 (AR27) has been investigated using ... more In this paper, the photocatalytic decoloration of Acid Red 27 (AR27) has been investigated using ultraviolet (UV) irradiation in presence of SnO2 nanoparticles. SnO2 nanoparticles were synthesized via hydrothermal process. The SnO2 nanoparticles' average crystallite sizes derived from X-ray analyses which were synthesized for 2, 12 and 24 hrs were about 3.73, 5.31 and 7.6 nm, respectively. Brunauer-Emmett-Teller (BET) analyses showed high surface area of about 183, 120 and 90(m2/g), respectively for aforementioned synthesized samples. Our investigations indicated that reaction rate constant and photocatalytic efficiency of AR27 decoloration have a direct relation with SnO2 nanoparticles' specific surface areas and band gap energies. Decoloration kinetics was investigated by using Langmuir–Hinshelwood model. The values of the adsorption equilibrium constant, K[AR27], and the kinetic rate constant of surface reaction, kc, were found to be 0.0924 (l/mg) and 0.2535 (mg/l min), r...

Research paper thumbnail of Biodiesel as an Alternative Fuel for Diesel Engines

World Academy of Science, …, 2009

... [9] PK Srivastava, and M. Verma, “Methyl ester of karanja oil as an alternative renewable sou... more ... [9] PK Srivastava, and M. Verma, “Methyl ester of karanja oil as an alternative renewable source energy ... [18] V. Hofman, Biodiesel Fuel, NDSU Extension ... [20] AS Ramadhas, S. Jayaraj and C. Muraleedharan, “Biodiesel production from high FFA rubber seed oil.” Fuel, vol. 84, pp. ...

Research paper thumbnail of Simultaneous size distribution study of indoor and outdoor particulates in tehran

Journal of Aerosol Science, 1990

Research paper thumbnail of Measurement of carbon monoxide in Tehran's atmosphere

Journal of Aerosol Science, 1995

Carbon monoxide is a problem in big cities esp. in winter time. Motor vehicles produce about

Research paper thumbnail of Indoor air pollution, monitoring of environmental tobaccosmoke nicotine and determination of nicotine in Iranian cigarettes

Journal of Aerosol Science, 1991

Research paper thumbnail of Role of motor-vehicles and trend of air borne particulate in the Great Tehran area, Iran

International Journal of Environmental Health Research, 2004

Tehran, the capital city of Iran, is one of the largest cities in the world. It extends over an a... more Tehran, the capital city of Iran, is one of the largest cities in the world. It extends over an area of approximately 2,300 square kilometers and has a population of more than 10 million people. The city is suffering from atmospheric pollution arising from the rapid urbanization during the last 3 to 4 decades. The city will develop towards the west to Karaj, and large volumes of traffic will be going east-west by the year 2015. With more than 2 million vehicles in Tehran, most of which are more than 20 years old, traffic is the major source of air pollution in Tehran. The city of Tehran has a significant air pollution problem and suspended particulate matter (SPM) appears to rank high on the list pollutants. The monthly average of PM-10 in Tehran is high in autumn and low in spring. Maximum average value observed in September is over 370 microg/m(3); the minimum in March (102 microg/m(3)) and early April (65 microg/m(3)). The diurnal variation PM-10 concentration have been studied.

Research paper thumbnail of The Contribution of Gasoline to Indoor Air Pollution in Tehran, Iran

Indoor and Built Environment, 2004

Page 1. Key words BTEX • Benzene • Toluene • Ethyl-Benzene • Xylene VOCs • Air quality • Indoor p... more Page 1. Key words BTEX • Benzene • Toluene • Ethyl-Benzene • Xylene VOCs • Air quality • Indoor pollution • Gasoline emission Abstract Volatile organic compounds (VOCs) are released con-tinuously into the indoor environment ...

Research paper thumbnail of Polycyclic aromatic hydrocarbons study and toxic equivalency factor (TEFs) in Tehran, IRAN

Environmental Monitoring and Assessment, 2008

Polycyclic aromatic hydrocarbons (PAHs) are toxic pollutants released by various urban combustion... more Polycyclic aromatic hydrocarbons (PAHs) are toxic pollutants released by various urban combustion sources. Benzo[a]pyrene (BaP) is a representative member of the class of PAHs. Health risk assessment associated with inhalatory PAHs uptake is often estimated on the basis of the BaP concentrations in air. Atmospheric particulate PAHs concentrations were measured at five locations in Tehran, Iran. Sixteen PAHs were extracted from the airborne particles and analyzed by HPLC. Total PAHs concentrations (16 compounds) at five station Arjanteen, Enghelab, Azadi, Bahman, Haft Houz were respectively, 70.2, 96.5, 130, 79.1, 44.1 ng/m 3. The information obtain from the present study indicated that mean of human carcinogens are: benzo[a]antheracene (0.17-4.76 ng/m 3), chrysene (1.74-3.62 ng/m 3), benzo[b]fluoranthene (0-5.25 ng/m 3), benzo[k]fluoranthene (0.32-1.72 ng/m 3), benzo[a]pyrene (1.41-3.82 ng/m 3), dibenzo[a,h]anthracene (0.33-2.13 ng/m 3), and indeno[1,2,3-cd]pyrene (0.25-11.08 ng/m 3). The development and the establishment of a toxicity equivalency factor (TEF) are used in the assessment of mixtures containing PAHs. The contribution of the carcinogenic potency of BaP alone is in the range of 49.6-76.3% of the total carcinogenic activity. The annual number of lung cancer cases (persons per million) among Tehran residents (population=10 millions) attributable to these carcinogenic PAHs compounds in 2005 was estimated at 58 persons per million. In Tehran urban areas vehicular emission are the primary contributor to PAHs concentrations, with additional local contributors like industrials emissions.

Research paper thumbnail of Production of biodiesel as a renewable energy source from castor oil

Clean Technologies and Environmental Policy, 2013

The constantly increasing demand for energy can result in a huge crisis at the end of fossil fuel... more The constantly increasing demand for energy can result in a huge crisis at the end of fossil fuels era. To prevent such an awkward situation, studies on finding alternatives have been seriously undertaken since the first oil crisis in the 1970s. Biodiesel, with a history of more than a century, has always been a potential candidate. In this research, the process of producing biodiesel from castor oil, which is a highly adaptable plant to Iran's climates was studied. Methanol and castor oil as reactants with 10:1 molar ratio and sulfuric acid as catalyst with mass percent of 3 were allowed to react through trans-esterification reaction under mild conditions. The results from gas chromatography-mass spectrometry (GC-MS) showed the purity of more than 94 % esters for any conducted experiments which count as a success for an oil with more complicated structure than other raw vegetable oils. GPC analysis illustrated that the castor oil has a molecular weight of 1,068, which is almost three times that of colza oil. Some significant chemical and physical properties of the product, such as kinematic viscosity, flash point, pour point, etc. were calculated to approve conformity to ASTM D6751 standards. Eventually, the polluted emissions were measured by an Orsat gas analyzer. The outcomes completely corroborate the assumption which claims that adding biodiesel to conventional diesel fuels has a strong influence on lowering CO 2 , CO, HC, and smoke.

Research paper thumbnail of Distribution of Polycyclic Aromatic Hydrocarbons in Gas phase in urban atmosphere

International Journal of …, 2008

Research paper thumbnail of Concentrations and Source Assessment of Some Atmospheric Trace Elements in Northwestern Region of Tehran, Iran

Bulletin of Environmental Contamination and Toxicology, 2010

Outdoor concentrations of some elements such as iron, aluminum, magnesium, titanium, copper, zinc... more Outdoor concentrations of some elements such as iron, aluminum, magnesium, titanium, copper, zinc, lead, manganese, sulfur, chromium and arsenic in PM 10 and PM 2.5 , was evaluated at four points in northwestern part of Tehran in winter 2007. The total concentration of the elements in PM 10 and PM 2.5 at the north Karegar avenue found to be as high as 82.05 and 60.64 lg/m 3 , respectively, while at the Arjantin square it was measured to be 34.30 and 28.03 lg/m 3. The emission sources of the trace elements were attributed to the adjoining local industries in the west parts of Tehran.

Research paper thumbnail of GIS ASSESSMENT OF THE PM<sub>10</sub>, PM<sub>2.5</sub> AND PM<sub>1.0</sub> CONCENTRATIONS IN URBAN AREA OF TEHRAN IN WARM AND COLD SEASONS

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences

In recent years, atmospheric models, such as GIS, are used for environmental analysis and the rel... more In recent years, atmospheric models, such as GIS, are used for environmental analysis and the related management for supporting the environmental decision makers in different countries. In this study, concentrations of PM<sub>10</sub>, PM<sub>2.5</sub> and PM<sub>1.0</sub> are found in urban areas of Tehran in warm and cold seasons and the data applied in the related modelling, using Arc-GIS. For this purpose, samples were collected from 42 sites in an 18 km<sub>2</sub> region located in the west and central parts of Tehran. The mean concentrations of PM<sub>1.0</sub>, PM<sub>2.5</sub> and PM<sub>10</sub> are found to be 13.14…

Research paper thumbnail of Seasonal variation in ambient PM mass and number concentrations (case study: Tehran, Iran)

Environmental Monitoring and Assessment, 2010

Tehran, the capital city of Iran, is an important industrial and commercial center. This city is ... more Tehran, the capital city of Iran, is an important industrial and commercial center. This city is one of the worst cities in the world in terms of air pollution, which is mostly due to mobile sources rather than stationary sources. Particulate matter (PM), which is a complex mixture of extremely small particles and liquid droplets, is considered as an important source of air pollution in Tehran. In this study, our objective was to study PM(10), PM(2.5), and PM(1.0) mass and number concentrations and find the correlations of these two parameters in the west-central parts of Tehran during two consecutive warm and cold seasons. The particles collected from five stations were analyzed for their mass and number simultaneously by a laser-based Grimm dust monitor. In general, it was found that the accumulation of the PM in this region is more in the cold season. PM(10) mass concentration increases almost twofold and PM(2.5) and PM(1.0) almost three times in this season. The mean number concentration of the particles (0.3-20 microm) was found to be almost 4.8 times in the cold season. It was also noticed that the average dimensions of the particles decrease in that season.

Research paper thumbnail of Concentrations and Source Assessment of Some Atmospheric Trace Elements in Northwestern Region of Tehran, Iran

Bulletin of Environmental Contamination and Toxicology, 2010

Outdoor concentrations of some elements such as iron, aluminum, magnesium, titanium, copper, zinc... more Outdoor concentrations of some elements such as iron, aluminum, magnesium, titanium, copper, zinc, lead, manganese, sulfur, chromium and arsenic in PM 10 and PM 2.5 , was evaluated at four points in northwestern part of Tehran in winter 2007. The total concentration of the elements in PM 10 and PM 2.5 at the north Karegar avenue found to be as high as 82.05 and 60.64 lg/m 3 , respectively, while at the Arjantin square it was measured to be 34.30 and 28.03 lg/m 3. The emission sources of the trace elements were attributed to the adjoining local industries in the west parts of Tehran.

Research paper thumbnail of Evaluation of Indoor-Outdoor Particle Size Distribution in Tehran's Elementary Schools

A simultaneous study on indoor and outdoor particulate matter concentrations was done in five ele... more A simultaneous study on indoor and outdoor particulate matter concentrations was done in five elementary schools in central parts of Tehran, Iran. Three sizes of particles including PM10, PM2.5 and PM1.0 were measured in 13 classrooms within this schools during winter (January, February and March) 2009. A laser- based portable aerosol spectrometer Model Grimm-1.108, was used for the continuous measurement

Research paper thumbnail of Ceramic ultramarine blue pigment from Iranian raw materials

Research paper thumbnail of Mica colors: Focus on pigments & dispersions

Research paper thumbnail of Ceramic blue pigment from Iranian materials

Pigment & Resin Technology, 1993

Research paper thumbnail of Continuous biodiesel production in a helicoidal reactor using ultrasound-assisted transesterification reaction of waste cooking oil

Clean Technologies and Environmental Policy, 2014

Designing of a continuous biodiesel production system from waste cooking oil with ultrasonic homo... more Designing of a continuous biodiesel production system from waste cooking oil with ultrasonic homoge- nizer assistant through transesterification reaction was studied. Through some pre-tests based on cavitation phe- nomenon to accelerate the transesterification reaction, two types of reactors (batch and continuous) were used. GC– MS results showed the total content of 94.2 % of methyl esters derived from different fatty acids formed in a batch reactor using a magnetic stirrer and an electrical heater. These results were then compared to those of two ultra- sonic homogenizers with low and high capacities of 400 and 1,500 W, which tested successfully under mild con- ditions. The results indicated the advantages of using ultrasonic homogenizer. The continuous system consisted of a 1,500 W ultrasonic homogenizer and glass helicoidal reactor with a tube length of 20 m. This set-up was kept submerged in a hot water bath. As a result, the reaction time decreased to 150 s, the methanol/oil molar ratio was 8.6 and the weight % of NaOH/oil was 0.5 %. After sep- aration of undesired contents, the physical and chemical characteristics of the final product were measured accord- ing to ASTM standard methods. Study of performance of the system also showed a significant improvement in yield of the reaction (90 %) compared to prior studies.

Research paper thumbnail of Dependency of polycyclic aromatic hydrocarbon concentrations on particle size distribution in Tehran atmosphere

Toxicological & Environmental Chemistry, 2010

In this work, the airborne particulate matter with an aerodynamic diameter less than 10 mm (PM 10... more In this work, the airborne particulate matter with an aerodynamic diameter less than 10 mm (PM 10) was fractionated in a six-stage high-volume cascade impactor to identify particulate size distribution in Tehran atmosphere. The study was conducted at 15 sites located in the north, south, east, west, and central parts of Tehran in 2005. Air samples were analyzed for 16 polycyclic aromatic hydrocarbons (PAHs) by HPLC. The daily PM 10 concentrations at the peak of traffic in roadside areas were found to be 106-560 mg m À3. The cumulated concentration sum of PAHs, based on 16 species, was found to have an average concentration of 380 ng m À3. Furthermore, it was found that more than 60% of PAHs belonged to the small particulate size range, having sizes of less than 0.49 mm, some containing benzo(ghi)perylene and indeno(123cd)pyrene (high molecular weight) with average concentrations of 8 and 6 ng m À3 and fluorene, phenanthrene, and fluoranthene (low molecular weight) with average concentrations of 14, 13, and 19 ng m À3 , respectively. In addition, the results revealed that the lighter three-and fourring PAH compounds were the most abundant pollutants in the air collected at all the sampling sites.

Research paper thumbnail of Photocatalytic decoloration of Acid Red 27 in presence of SnO 2 nanoparticles

Water Science & Technology, 2010

In this paper, the photocatalytic decoloration of Acid Red 27 (AR27) has been investigated using ... more In this paper, the photocatalytic decoloration of Acid Red 27 (AR27) has been investigated using ultraviolet (UV) irradiation in presence of SnO2 nanoparticles. SnO2 nanoparticles were synthesized via hydrothermal process. The SnO2 nanoparticles' average crystallite sizes derived from X-ray analyses which were synthesized for 2, 12 and 24 hrs were about 3.73, 5.31 and 7.6 nm, respectively. Brunauer-Emmett-Teller (BET) analyses showed high surface area of about 183, 120 and 90(m2/g), respectively for aforementioned synthesized samples. Our investigations indicated that reaction rate constant and photocatalytic efficiency of AR27 decoloration have a direct relation with SnO2 nanoparticles' specific surface areas and band gap energies. Decoloration kinetics was investigated by using Langmuir–Hinshelwood model. The values of the adsorption equilibrium constant, K[AR27], and the kinetic rate constant of surface reaction, kc, were found to be 0.0924 (l/mg) and 0.2535 (mg/l min), r...

Research paper thumbnail of Biodiesel as an Alternative Fuel for Diesel Engines

World Academy of Science, …, 2009

... [9] PK Srivastava, and M. Verma, “Methyl ester of karanja oil as an alternative renewable sou... more ... [9] PK Srivastava, and M. Verma, “Methyl ester of karanja oil as an alternative renewable source energy ... [18] V. Hofman, Biodiesel Fuel, NDSU Extension ... [20] AS Ramadhas, S. Jayaraj and C. Muraleedharan, “Biodiesel production from high FFA rubber seed oil.” Fuel, vol. 84, pp. ...

Research paper thumbnail of Simultaneous size distribution study of indoor and outdoor particulates in tehran

Journal of Aerosol Science, 1990

Research paper thumbnail of Measurement of carbon monoxide in Tehran's atmosphere

Journal of Aerosol Science, 1995

Carbon monoxide is a problem in big cities esp. in winter time. Motor vehicles produce about

Research paper thumbnail of Indoor air pollution, monitoring of environmental tobaccosmoke nicotine and determination of nicotine in Iranian cigarettes

Journal of Aerosol Science, 1991

Research paper thumbnail of Role of motor-vehicles and trend of air borne particulate in the Great Tehran area, Iran

International Journal of Environmental Health Research, 2004

Tehran, the capital city of Iran, is one of the largest cities in the world. It extends over an a... more Tehran, the capital city of Iran, is one of the largest cities in the world. It extends over an area of approximately 2,300 square kilometers and has a population of more than 10 million people. The city is suffering from atmospheric pollution arising from the rapid urbanization during the last 3 to 4 decades. The city will develop towards the west to Karaj, and large volumes of traffic will be going east-west by the year 2015. With more than 2 million vehicles in Tehran, most of which are more than 20 years old, traffic is the major source of air pollution in Tehran. The city of Tehran has a significant air pollution problem and suspended particulate matter (SPM) appears to rank high on the list pollutants. The monthly average of PM-10 in Tehran is high in autumn and low in spring. Maximum average value observed in September is over 370 microg/m(3); the minimum in March (102 microg/m(3)) and early April (65 microg/m(3)). The diurnal variation PM-10 concentration have been studied.

Research paper thumbnail of The Contribution of Gasoline to Indoor Air Pollution in Tehran, Iran

Indoor and Built Environment, 2004

Page 1. Key words BTEX • Benzene • Toluene • Ethyl-Benzene • Xylene VOCs • Air quality • Indoor p... more Page 1. Key words BTEX • Benzene • Toluene • Ethyl-Benzene • Xylene VOCs • Air quality • Indoor pollution • Gasoline emission Abstract Volatile organic compounds (VOCs) are released con-tinuously into the indoor environment ...

Research paper thumbnail of Polycyclic aromatic hydrocarbons study and toxic equivalency factor (TEFs) in Tehran, IRAN

Environmental Monitoring and Assessment, 2008

Polycyclic aromatic hydrocarbons (PAHs) are toxic pollutants released by various urban combustion... more Polycyclic aromatic hydrocarbons (PAHs) are toxic pollutants released by various urban combustion sources. Benzo[a]pyrene (BaP) is a representative member of the class of PAHs. Health risk assessment associated with inhalatory PAHs uptake is often estimated on the basis of the BaP concentrations in air. Atmospheric particulate PAHs concentrations were measured at five locations in Tehran, Iran. Sixteen PAHs were extracted from the airborne particles and analyzed by HPLC. Total PAHs concentrations (16 compounds) at five station Arjanteen, Enghelab, Azadi, Bahman, Haft Houz were respectively, 70.2, 96.5, 130, 79.1, 44.1 ng/m 3. The information obtain from the present study indicated that mean of human carcinogens are: benzo[a]antheracene (0.17-4.76 ng/m 3), chrysene (1.74-3.62 ng/m 3), benzo[b]fluoranthene (0-5.25 ng/m 3), benzo[k]fluoranthene (0.32-1.72 ng/m 3), benzo[a]pyrene (1.41-3.82 ng/m 3), dibenzo[a,h]anthracene (0.33-2.13 ng/m 3), and indeno[1,2,3-cd]pyrene (0.25-11.08 ng/m 3). The development and the establishment of a toxicity equivalency factor (TEF) are used in the assessment of mixtures containing PAHs. The contribution of the carcinogenic potency of BaP alone is in the range of 49.6-76.3% of the total carcinogenic activity. The annual number of lung cancer cases (persons per million) among Tehran residents (population=10 millions) attributable to these carcinogenic PAHs compounds in 2005 was estimated at 58 persons per million. In Tehran urban areas vehicular emission are the primary contributor to PAHs concentrations, with additional local contributors like industrials emissions.

Research paper thumbnail of Production of biodiesel as a renewable energy source from castor oil

Clean Technologies and Environmental Policy, 2013

The constantly increasing demand for energy can result in a huge crisis at the end of fossil fuel... more The constantly increasing demand for energy can result in a huge crisis at the end of fossil fuels era. To prevent such an awkward situation, studies on finding alternatives have been seriously undertaken since the first oil crisis in the 1970s. Biodiesel, with a history of more than a century, has always been a potential candidate. In this research, the process of producing biodiesel from castor oil, which is a highly adaptable plant to Iran's climates was studied. Methanol and castor oil as reactants with 10:1 molar ratio and sulfuric acid as catalyst with mass percent of 3 were allowed to react through trans-esterification reaction under mild conditions. The results from gas chromatography-mass spectrometry (GC-MS) showed the purity of more than 94 % esters for any conducted experiments which count as a success for an oil with more complicated structure than other raw vegetable oils. GPC analysis illustrated that the castor oil has a molecular weight of 1,068, which is almost three times that of colza oil. Some significant chemical and physical properties of the product, such as kinematic viscosity, flash point, pour point, etc. were calculated to approve conformity to ASTM D6751 standards. Eventually, the polluted emissions were measured by an Orsat gas analyzer. The outcomes completely corroborate the assumption which claims that adding biodiesel to conventional diesel fuels has a strong influence on lowering CO 2 , CO, HC, and smoke.

Research paper thumbnail of Distribution of Polycyclic Aromatic Hydrocarbons in Gas phase in urban atmosphere

International Journal of …, 2008

Research paper thumbnail of Concentrations and Source Assessment of Some Atmospheric Trace Elements in Northwestern Region of Tehran, Iran

Bulletin of Environmental Contamination and Toxicology, 2010

Outdoor concentrations of some elements such as iron, aluminum, magnesium, titanium, copper, zinc... more Outdoor concentrations of some elements such as iron, aluminum, magnesium, titanium, copper, zinc, lead, manganese, sulfur, chromium and arsenic in PM 10 and PM 2.5 , was evaluated at four points in northwestern part of Tehran in winter 2007. The total concentration of the elements in PM 10 and PM 2.5 at the north Karegar avenue found to be as high as 82.05 and 60.64 lg/m 3 , respectively, while at the Arjantin square it was measured to be 34.30 and 28.03 lg/m 3. The emission sources of the trace elements were attributed to the adjoining local industries in the west parts of Tehran.