Sources and Wet Deposition Fluxes of Polycyclic Aromatic Hydrocarbons (PAHs) in an Urban Site 1000 Meters High in Central Anatolia (Turkey)

Abstract

Wet-only precipitation samples were collected using an Andersen wet only sampler (Andersen Samplers, Inc., Atlanta, GA, USA), between December 2000 and June 2002, in Ankara, Turkey. Polycyclic aromatic hydrocarbons (PAHs) were first pre-concentrated using solid phase (SPE) and ultrasonic extraction procedures. They were then analyzed using gas chromatography-mass spectrometry (GC-MS). Phenanthrene (Phe), fluoranthene (Flt), benzo (b+k) fluoranthene (B (b+k) F) and pyrene (Pyr) were the major components of Sigma 14PAH concentrations during both winter and summer seasons. Concentrations of PAHs did not show a statistically significant relation with meteorological parameters, such as mixing height, wind speed, and wind direction. However, they showed a strong linear relation with the ventilation coefficient (VC), signifying the importance of local sources on measured PAH concentrations. Concentrations of PAHs in winter season were higher than their corresponding concentrations in summer season due to seasonal variations in meteorology and emissions. Sources of PAHs in rainwater were apportioned using principal component analysis. Three factors with eigenvalues 1.0 were extracted. The two factors that explained the largest fraction of system variance represented coal and gas combustion whereas the third factor represented motor vehicles. Half of the rain events accounted for approximately 90% of the wet deposition fluxes of PAHs, demonstrating the highly episodic nature of wet PAH deposition.