Conductivity measurements of distilled water and some electrolytic solution due to the SO2 and CO2 absorption have been performed in the laboratory and on the site. CO2, has been found to cause a decrease in the conductivity of alkaline solutions and an increase in that of CaCO3, and MgCO3, aqueous suspensions. The importance of the direct SO2 absorption was proved to be limited to the zones of extremely high concentrations of this gas in the ambient air.

Time series analysis ofmonthly and daily SO2 data were considered for the detection of trends in SO2 due to possible effect of the emission abatement strategy in the Black Triangle region. Using a time series model, the main components were extracted from the original SO2 time series. Based on SO2 monitoring data from Czerniawa in Izery Mountains in Poland over the period 1993 -1998, our findings showed evidence of declining trends in SO2• A mean annual change of 14.1% was recorded in a 6-year record. It has also appeared that the exponential smoothing which considers a seasonal component and trends provided a reasonable fit to monthly mean SO2 values.