MEASURED FLUXES OF SULFUR, CHLORINE AND SOME ANTHROPOGENIC METALS TO THE SWEDISH WEST-COAST

Deposition measurements were performed during one month in autumn 1992 in a rural place on the west coast of Sweden, Airborne particle conce ntrations and deposition fluxes were measured simultaneously. Aerosol sampling was made with a dichotomous virtual impactor which size segre gated the particles into fine (< 2.5 mu m) and coarse particles (2.5-1 0 mu m). The flux determination consisted in measuring the total (bulk ) deposition, wet deposition and dry deposition to three surrogate sur faces. A modified Andersen deposition sampler was used to discriminate between the dry and the wet periods. The analytical techniques for el ement analysis were EDXRF, ICP/MS and ion chromatography. By correlati on analysis of the airborne elemental concentrations in fine and coars e particles it was possible to identify sources of the encountered aer osol. The K/Cl Ca/Cl and Br/Cl ratios in coarse particles were very cl ose to those in sea water, suggesting a predominantly marine source of coarse particle Cl, K, Ca, and Br. The highest correlations were obta ined for coarse particle Br vs Cl (0.99) and for coarse particle K vs Ca (0.98). The Br/Pb ratio in fine particles, approaching the ''ethyl ratio'' in fresh car exhaust, indicated that traffic was the dominant source of the fine particle Br and Pb. The positive correlations betwe en most of the metals in fine particles indicated long distance transp ort from industrial source regions in Europe. The measured dry and wet deposition fluxes are reported for S, Cl, V, Mn, Fe, Ni, Cu, Zn and P b, and estimates of annual total deposition at the measurement site ar e given and compared with reference data. The general feature is that fluxes are smaller in the northeast part of the North Sea compared to the southern part. Average dry deposition velocities obtained in the p resent study are compared with reference data and also with the elemen tal coarse/fine particle ratios. These ratios give a rough estimate of what deposition rate to expect. The fine particle elements having coa rse/fine ratios less than one (V, Ni, Zn, Pb and S) have lower dry dep osition velocities than coarse particle elements (Mn, Fe, Cu, Cl).