The content of Stotal, and Ntotal were ascertained in assimilatory organs of forest trees in 4 National Parks and 16 Landscape protection areas and were compared with 1483 permanent monitoring plots in Slovakia. The content of S fluctuated between 0.72 and 6.77 g.kg-1 in hardwood and between 0.98 do 4.3 g.kg-1 in soft wood. A critical increase was ascertained in one NP and in four LPA. The content of N fluctuated between 9.7 and 48.7 g.kg-1 in soft wood, and between 7.8 and 51.4 g.kg-1 in hardwood. An insufficient level of N was ascertained in one LPA and a critical increase in four LPA. S:N ratio fluctuated between 0.08 and 0.176 in soft wood, and between 0.078 and 0.253 in hardwood. The assimilation surface organs on hitherto explored 4 NP and 16 LPA in the network of 4 × 4 km was covered by all categories of rigid fall-out particles. Fly ashes from coal combustion were present on all NP and LPA. Mycelia and spore, mineral matters, sand, and soil particles were present on all NP and LPA. Particles arising at aluminium production were found out at 3 LPA. Particles arising at cement production and from lime works were present at 2 NP and 6 LPA. Particles corresponding to ferrous metals industry covered all NP and LPA and particles typical for other technologies were present at 3 NP and 12 LPA.