Small-scale spatial patterns of bulk atmospheric deposition

In total 14 bulk atmospheric deposition collectors were distributed over the city of Lund (about 20 km~) in the south of Sweden during September 1980 to June 1981. The observations were made to investigate small-scale spatial variability of atmospheric deposition. Monthly bulk deposition samples were analyzed for CI, Ptot, Zn, Cu, and Pb.Correlation analysis shows that the spatial scale for the variation pat-tern is of the order > 10 km for precipitation and CI, and about 2 kmfor Ptot and metals. This indicates that remote sources with a general large-scale deposition pattern are dominating for CI deposition and that local sources dominate for P,o,, Zn, Cu, and Pb. The total atmospheric deposition in the investigated urban area is assumed to be superposed by three components: (i) regional background, (li) urban background, and (iii) urban point deposition. The urban background deposition may be considerable in relation to regional background deposition. The urban point sources may represent deposition rates of twice or more of the total deposition.