Particulate polycyclic aromatic hydrocarbons in Urban Air of Tehran

ABSTRACT

Polycyclic Aromatic Hydrocarbons are ubiquitous in the urban atmosphere and one of the most atmospheric pollutants to be identified as suspected carcinogens .The objective of this study was to compare particulate PAH profiles from several sites across Tehran. Atmospheric concentrations of Polycyclic Aromatic Hydrocarbons in Tehran were evaluated to study particulate PAH profiles in different sites. The particles size distributions were unimodal with a fine mode diameter [PM<0.49 micro m]. Five sites were selected in residential areas and one site in rural area for representing various situations and role of motor vehicles in producing Polycyclic Aromatic Hydrocarbons. Organics on the filter were extracted with acetonitrile and a group of 16 Polycyclic Aromatic Hydrocarbons was selected for evaluation. PAH identification was done by High Performance Liquid Chromatography. Total PAH concentration associated with particles collected on the six-stage cascade impactor stages and after-filter in different sites ranged between 0.132 to 234.3 ng/m[3]. The mean concentrations of Polycyclic Aromatic Hydrocarbons, collected on each stage were 4.17 ng/m[3] for PM[10-7.2] micro m, 5.69 ng/m[3] for PM[7.2-3] micro m, 11.95 ng/m[3] for PM[3-1.5] micro m, 9.18 ng/m[3] for PM[1.5-0.95] micro m, 2.82 ng/m[3] for PM[0.95-0.49] micro m and 47.91 ng/m[3] for PM < 0.49 micro m respectively