For the purpose of evaluation the influence of Košice municipal waste incinerator plant on the quality of air in adjacent villages an analysis of leaves from deciduous trees was applied. Common arboreous species in this region growing open such as lime-tree (Tilia cordata), birch-tree (Betula pendula), poplar-tree (Populus nigra) and walnut-tree (Jugland regia) were sampled in June, August and October for analysis of elements Tl, Ni, Cd, Cr, Pb, S, Hg, Cu, As, Mn and Co. Results from the 23 points on the area of about 50 km2 were analyzed with aim to ascertain range of waste incinerator flue gas influence. In a course of measurements it was observed that there are another important air pollution sources in this region. The highest concentration of As and S in surroundings point out at sedimentation pond of fly ash from coal fired thermal power plant Košice as their sources, Cd, Cu, Cr, Hg, Pb, and Tl high concentrations were measured in the vicinity of communal waste incineration plant. Immision of Cr, Ni and Mn sustain influence of the East Slovak Ironworks. For the time being it looks like that the heaviest pollution burden is laden on nearest villages around municipal incineration plant Valaliky and Kokšov-Bakša.