Vertical profiles of air pollutants in a severely damaged spruce forest depending on the amount of precipitation

Vertical profiles of air pollutants were studied in a spruce forest to find out correlations with the damage, observed mainly in the upper zones of the canopy. Gaseous HNO3, NH3, total suspended particles, throughfall, plant surface water, wash-off solutions and deposits on surrogate surfaces with different orientations were analyzed. After a dry episode in most cases the profiles of the concentrations of the measured components of plant surface water as well as the dposition rates were similar to the profile of the wind speed. After low rainfall it was about the same, but after medium rainfall the maximum values were shifted from top to bottom. Specific differences depending on secondary processes are discussed. Leaching of acids in the canopy is evident.