IMPACT OF THE SULFUR-DIOXIDE SOURCES IN THE KOLA-PENINSULA ON AIR-QUALITY IN NORTHERNMOST EUROPE

An account is presented of sulphur pollution in northernmost continent al Europe, based on analysis of recent observations and on dispersion model calculations. To complement the routine daily observations made at background stations, SO2 has also been measured using an hourly reg istering monitor at Janiskoski in the Russian Kola Peninsula. Sulphur dioxide emissions from the Kola Peninsula, totalling 600 Gg (10(3) ton nes) yr-1, have a dominant impact on SO2 concentrations and S depositi on over large areas, producing an environmental load exceeding the thr esholds for potential detrimental effects. The major part of these emi ssions is produced by two non-ferrous smelters. Due to these sources, SO2 concentrations vary considerably within the study area, from the l ow ''remote background' values to pollution episodes with approximatel y 100 mug(SO2) m-3 as an hourly average, depending on wind direction. High concentrations also occur in summer, providing a great potential for dry deposition and suggesting that exposure is a highly episodic p rocess. On an annual basis, dry deposition predominates over wet depos ition. Precipitation acidity is related mainly to sulphate, and neutra lization by alkaline cations is exceptionally low in the north. Accord ing to model calculations, a potentially critical deposition of 0.3 g( S) m-2 yr-1 is exceeded over an area of 150,000 km2, 32,000 km2 of whi ch are in Finland and 19,000 kM2 in Norway. Within this area the contr ibution of smelter emissions to sulphur deposition ranges from 40% to almost 100%.