This volume presents results from an integrated research programme "Effects of Air Pollutants and Acidification" funded by the Swedish Enviornmental Protection Agency (SNV) between 1988/89 and 1992/93. The programme has focussed on the fluxes and environmental effects of acidifying substances and tropospheric ozone in terrestrial, natural ecosystems. During the programme period, 71.5 million SEK were allocated to about 60 projects at different Swedish universities and research institutes.