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Investigation of polycyclic aromatic hydrocarbon (PAH) deposition in Ankara

Gaga, Eftade O
In this work, wet deposition samples were collected at Middle East Technical University campus, Ankara, between December 2000 and May 2002. Snow samples were collected from 50 grids in January, 2001 in Ankara to investigate dry deposition of PAHs. The collected samples were preconcentrated by Solid Phase Extraction and ultrasonic extraction tecniques. Extraction methodologies were improved prior to analysis of samples. Extracted samples were analyzed by Gas Chromotography-Mass Spectrometry for 14 Polycyclic Aromatic Hydrocarbons. Selected Ion Monitoring mode was used throughout the analysis. Phenanthrene, fluoranthene, pyrene and benzo (b+k) fluoranthene were found to be dominant PAHs in wet deposition samples. Seasonal variation of PAHs were observed having higher concentrations in winter period. Meterological parameters were also examined together with PAH concentrations. Contribution of PAHs coming from North East and South West direction were found to be dominant. Wet deposition fluxes were calculated and compared with other urban sites. Wet deposition fluxes are lower than industrial sites and comparable with urban sites in Europe. PAH ratios and factor analysis results demostrated combustion and traffic emissions are major sources of pollutants in the city. Dry deposition of PAHs were invesigated using snow as a natural collecting surface. Dry deposition fluxes calculated using snow surface are compareble with other similar sites. Dry deposition pollution maps of PAHs were drawn by MapInfo software and it was observed that the major pollution regions are the localities where low income families live and low quality coal used for heating purpose. Ratio calculations showed that the central parts of the city is mostly affected from traffic emissions while coal emissions are dominating at the other parts of the city. Factor analysis applied to data set and 6 factors