Ambient concentrations and gas/particle partitioning of polycyclic aromatic hydrocarbons in an urban site in Turkey

Atmospheric samples were collected between July 2004 and May 2005 in Bursa, Turkey, when there was no rain, and analyzed for gas and particle concentrations of polycyclic aromatic hydrocarbons (PAHs). This study targeted 15 PAH compounds. Vapor-phase PAH compositions were dominated by the more volatile PAHs, relative to the particle phase. On average, 76% of the total (gas + particulate) PAH concentration was in the vapor phase. Average total PAH concentration was 298 +/- 418 ng/m(3). The large seasonal concentration fluctuation was attributed to residential heating, vaporization, industrial activities, and meteorological conditions. The measured average seasonal concentrations were 55 +/- 40, 187 +/- 202, 645 +/- 588 and 148 +/- 132 ng/m(3) for summer, fall, winter, and spring, respectively. The partitioning of PAHs between gas and particle phases was investigated employing the Junge-Pankow model. Plots of log gas/particle partition coefficient (K-p) versus log liquid vapor pressures (P-L(o)) had reasonable correlations for individual samples. Experimentally determined K-p values were compared with the result obtained using absorption ( octanol - air partition coefficient [K-OA]) into aerosol organic matter and adsorption (K-SA + K-OA) onto soot carbon models. Experimentally determined K-p values were generally in the same range with the ones obtained from the models.