The trace metal, sulphur and polycyclic aromatic hydrocarbon concentration-depth profiles in dated lake-sediment cores are used to establish the history of contamination of the atmosphere above the study lakes. The results from three chemical groups give the same qualitative description of contamination. The atmosphere became contaminated in the areas of high present day acid deposition early last century in Scotland and late last century in southern Scandinavia. Contamination increased this century and the sulphur, polycyclic aromatic hydrocarbon and sometimes the trace metal fluxes to the sediment drop over the past 10-30 years. There was little or no contamination at the low recent acid-deposition sites in both study regions.
