PERTURBATION OF BACKGROUND AEROSOL AT RURAL SITES IN THE NORDIC COUNTRIES

Concentrations of several trace elements have been measured in air sam ples collected simultaneously al four remote stations from SW Sweden, along the Norwegian coast to north Finland. The samples showed that th e background aerosol had a large spatial variation in elemental compos ition. During cases of long-range transported air pollution (episodes) , concentrations of pollutants were several times higher than the back ground concentrations. Generally, the background concentration profile varied, showing a decrease in concentrations towards northwest. The l evels of some elements were elevated at the northernmost station as a result of influence from the industrialised areas at the Kola Peninsul a. Trends of concentrations from 1985 and onwards were followed at one of the sites. The highest concentration of trace elements in the fine fraction of particles was observed in the mid-1980s, and a considerab le decrease is observed during later years. Elemental signatures were calculated and compared with the same ratios from large source areas. (C) 1997 Elsevier Science Ltd.