Long-term deposition patterns of airborne wastes in the North-East of Estonia

The deposition loads of fly ash and sulfur have been high in the NE Estonia since the late fifties, when the oil shale energetics, chemical and cement industry achieved the remarkable extent. The combined effects of both poll utants have seriously damaged sensitive ecosystems (forest on podzolic soil s and bog). The main effects are related with alkalization due to accumulat ion of fly ash components and the Sphagnum growth inhibition due to sulfur load. These effects have the time scale of several years or even more. The pollution loads have been changed during recent 40 years due to launchi ng and reconstruction of enterprises (incl. purification systems) and varia tions of production capacity. First representative data on air pollution de position originate from the middle of eighties. Only model estimations coul d be used to quantify the deposition fluxes before that time, as well as fo r assessing the future scenarios. The air pollution dispersion and depositi on model AEROPOL is used for this purpose. The estimations are based on air pollution emissions per production unit and climatic average dispersion co nditions. The model estimations are compared with available measured values . The deposition loads for a possible development in the future are estimat ed.