Chemical characterization of PM2.5 fractions of urban aerosol collected in Budapest and Istanbul

In the present work, a comprehensive chemical characterization of PM2.5 fractions of urban aerosol collected with high-volume aerosol samplers in Budapest (Hungary) and Istanbul (Turkey) was carried out from June 2010 to May 2011. The analyses included (i) gravimetric determination of PM2.5 mass concentration; (ii) trace element determination (Bi, Cd, Co, Cr, Cu, Fe, Ga, Li, Mn, Mo, Ni, Pb, Pt, Rb, Sb, Sn, Te, Tl, U, V. Zn) after microwave-assisted aqua regia and sonication-assisted water extraction by inductively coupled plasma sector field mass spectrometry; (iii) evaluation of major anions (SO42-, NO3-, Cl-) as well as NH4+ concentrations in the aerosol samples subjected to sonication-assisted water extraction by ion chromatography and spectrophotometry, respectively; iv) assessment of total and water-soluble carbons by a C/N analyzer in the samples. The mean PM2.5 mass concentrations were 23.0 mu g/m(3) and 40.0 mu g/m(3) in Budapest and Istanbul, meanwhile the target value for this parameter set by the European Commission as annual mean value is 25.0 mu g/m(3). The determined trace metal concentrations were 1.2-20 times higher for all elements in Istanbul than in Budapest. Generally, the water extractability of trace elements was similar irrespectively of the sampling sites with exception of Cr, Mn, Ni and V which had higher solubility in the samples collected in Istanbul. Seasonal variations of the NO3-/PM2.5 and SO42-/PM2.5 mass concentration ratios were observed in both cities. Higher concentrations of total (TC) and water-soluble carbon (WSC) were measured in Istanbul than in Budapest, however, the contribution of the TC content to the PM2.5 mass was more significant in the latter city. The WSC/PM2.5 mass concentration ratios showed also seasonal profile in both sampling sites. (C) 2012 Elsevier B.V. All rights reserved.