Passive Sampling of Aromatic Hydrocarbons Toluene, Xylene and Ethylbenzene Using Activated Carbon Fabric in Ambient Air of Tehran

Background and Objectives: Air pollution is one of the most important environmental problems in large cities. Aromatic hydrocarbons as volatile organic compounds (VOCs) have been listed in Hazardous Air Pollutants (HAPs) by Environmental Protection Agencies (EPA). The aim of this study is Passive sampling and determination of aromatic hydrocarbons (AHs) toluene, xylene and ethylbenzene using activated carbon fabric in ambient air of Tehran Methods: Activated carbon fabric (ACF) was used as adsorbent for adsorption of aromatic hydrocarbons. The chemical specifications of activated carbon fabric such as specific surface area and pores volume were determined by nitrogen adsorption isotherm (BET method), the microscopic images by scanning electron microscopy (SEM) and surface functional groups by X-ray Photoelectron Spectroscopy (XPS). Air sampling was achieved by passive samplers equipped with activated carbon fabric in cylindrical holders at 8 different stations of Tehran. Gas chromatography mass spectrometry (GC-MS) was used for determination of Toluene, Ethylbenzene, and Xylene after extraction in CH2Cl2. Results: The results showed activated carbon fabric is an efficient adsorbent for passive sampling of aromatic hydrocarbons and at different stations the concentrations of Toluene, Ethylbenzene, and Xylenes were determined. The results indicated that Javadiyeh station (Region 17) and Imam Khomeini station (Region 10) were polluted than other stations, whereas at Chitgar station (Region 22), Sattari station (Region 5) and Tehran pars station (Region 8) had lower concentrations of AHs. The good correlation between carbon monoxide and aromatic hydrocarbons concentrations in each sampling station showed they have similar source of emission (cars). The concentration of these pollutants is influenced by topography, wind direction and speed and the number of car passing through different stations. Conclusion: As the concentrations of aromatic hydrocarbons in ambient air are low using AFC in passive sampler is an efficient method for sampling and adsorption of AHs and then their determination. For this purpose it is necessary to exist special functional groups and especially oxygen containing fuctional groups on the surface of carbon fabric.