Size-fractionated aerosol composition during an intensive 1997 summer field campaign in northern Finland

A 12-stage small deposit area low pressure impactor (SDI) was used to colle ct size-fractionated aerosol samples during an intensive 1997 summer field campaign in northern Finland. The samples were analyzed for over 20 element s by PIXE, and some "difficult" elements such as As and Se could be quantif ied. The sea-salt and crustal elements had essentially a unimodal coarse si ze distribution with geometric mean aerodynamic diameter (GMAD) of about 4- 5 mu m. In one third of the samples, S showed only one mode in the fine siz e range, with GMAD of 0.4-0.5 mu m. In the other samples, this fine S mode broke up into two modes, with GMADs of 0.3 and 0.6 mu m, respectively. V, Z n, As, Se and Pb were mainly present in a single submicrometer mode, with G MAD of 0.4-0.5 mu m for V and Se, and slightly larger (i.e., 0.6 mu m) for the other three elements. The highest concentrations of S, V, Ni, Cu, Zn, A s, Se and Pb were encountered in the SDI sample which had been collected in the period 14-16 July. During this sampling, the air masses came in from t he west, but had recirculated over northern Scandinavia and passed over the Kola peninsula. (C) 1999 Elsevier Science B.V. All rights reserved.