Eylem Demircioglu 1 Aysun Sofuoglu 2 Mustafa Odabasi 1 1 Faculty of Engineering, Department of Environmental Engineering, Dokuz Eylul University, Izmir, Turkey 2 Faculty of Engineering, Department of Chemical Engineering, Izmir Institute of Technology, Gulbahce-Urla, Turkey Research Article Atmospheric Concentrations and Phase Partitioning of Polycyclic Aromatic Hydrocarbons in Izmir, Turkey Ambient air polycyclic aromatic hydrocarbon (PAH) samples were collected at a sub- urban (n ¼ 63) and at an urban site (n ¼ 14) in Izmir, Turkey. Average gas-phase total PAH ( P 14 PAH) concentrations were 23.5 ng m 3 for suburban and 109.7 ng m 3 for urban sites while average particle-phase total PAH concentrations were 12.3 and 34.5 ng m 3 for suburban and urban sites, respectively. Higher ambient PAH concentrations were measured in the gas-phase and P 14 PAH concentrations were dominated by lower molecular weight PAHs. Multiple linear regression analysis indicated that the mete- orological parameters were effective on ambient PAH concentrations. Emission sources of particle-phase PAHs were investigated using a diagnostic plot of fluorene (FLN)/ (fluorine þ pyrene; PY) versus indeno[1,2,3-cd]PY/(indeno[1,2,3- cd]PY þ benzo[g,h,i]perylene) and several diagnostic ratios. These approaches have indicated that traffic emissions (petroleum combustion) were the dominant PAH sources at both sites for summer and winter seasons. Experimental gas–particle partition coefficients (K P ) were compared to the predictions of octanol–air (K OA ) and soot–air (K SA ) partition coefficient models. The correlations between experimental and modeled K P values were significant (r 2 ¼ 0.79 and 0.94 for suburban and urban sites, respectively, p < 0.01). Octanol-based absorptive partitioning model predicted lower partition coefficients especially for relatively volatile PAHs. However, overall there was a relatively good agreement between the measured K P and soot-based model predictions. Keywords: Gas/particle partitioning; Octanol–air-based absorption model; Polycyclic aromatic hydrocarbon; Soot–air-based model Received: July 5, 2010; revised: November 23, 2010; accepted: November 24, 2010 DOI: 10.1002/clen.201000221 1 Introduction Polycyclic aromatic hydrocarbons (PAHs) are a complex class of organic compounds containing two or more fused aromatic rings, and only carbon and hydrogen. PAHs are formed as a result of incomplete combustion and released into the environment through natural and anthropogenic sources. There are hundreds of individual PAHs in the environment, however, only 16 PAH com- pounds have been classified by the U.S. Environmental Protection Agency (USEPA) as priority pollutants [1]. At ambient temperatures, PAHs are solids. The general characteristics common to the class are high melting- and boiling-points, low vapor pressure, and very low water solubility [2]. Atmospheric PAHs are distributed between gas and particle- phases. The partitioning of PAHs between the gas and particle-phases is an important factor affecting their removal processes [2, 3]. PAHs are removed from the atmosphere by transformation, wet and dry deposition, air–water exchange, and air–soil exchange. Atmospheric levels of PAHs have been widely measured around the world [4–15]. Despite their environmental relevance, only a few studies have been conducted in Turkey on the atmospheric PAH levels [14–19]. The objectives of this study were to investigate (1) the ambient air concentrations of 14 PAHs and their temporal variations in Izmir, Turkey, (2) the effect of meteorological parameters on ambient concentrations, (3) the possible sources of PAHs in the study area, and (4) their gas/particle partitioning. 2 Materials and methods 2.1 Sampling program and collection Ambient air samples were collected at two sampling sites (suburban and urban) in Izmir (Fig. 1). The suburban samples were collected on a 4-m high platform located on the Kaynaklar Campus of the Dokuz Eylul University, 10 km southeast of Izmir’s center. This site is relatively far from any settlement zones or industrial facilities. Correspondence: Dr. A. Sofuoglu, Faculty of Engineering, Department of Chemical Engineering, Izmir Institute of Technology, 35430 Gulbahce- Urla, Turkey E-mail: aysunsofuoglu@iyte.edu.tr Abbreviations: ANT, anthracene; BaA, benz[a]anthracene; BaP, benzo[a]pyrene; BbF, benzo[b]fluoranthene; BghiP, benzo[g,h,i]perylene; BkF, benzo[k]fluoranthene; CHR, chrysene; CRB, carbazole; DahA, dibenzo[a,h]anthracene; FL, fluoranthene; FLN, fluorene; IcdP, indeno[1,2,3-cd]pyrene; MLR, multiple linear regression; OM, organic matter; PAH, polycyclic aromatic hydrocarbon; PHE, phenanthrene; PUF, polyurethane foam; PY, pyrene; TSP, total suspended particles. Clean – Soil, Air, Water 2011, 39 (4), 319–327 319 ß 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.clean-journal.com