Author(s)

T. Ruoho-Airola & K. Salminen

Abstract

The deposition of the base cations is an important element in determining the total deposited acidity in the critical loads approach used in the protocols of the Convention on Long-range Transboundary Air Pollution. In Finland, where the mineral content and the weathering rate of the soils are low, the atmospheric deposition forms a significant source for base cations. The concentration of the base cations, especially calcium, in both wet and dry deposition has declined widely in Finland since 1985. The southern parts of the country also receive less potassium and magnesium in precipitation than a decade ago. Particulate concentration measurements show a downward trend for calcium, magnesium and sodium in the southeast and for calcium and potassium in the far north. The observed reduction of non-sea-salt base cations is supposed partly to be the result of

Keywords