Crit. loads of acidification and eutrophication were calcd. for Natura 2000 areas in Poland by the internationally approved methodol. under the Convention on long-range transboundary air pollution. The S and N deposition scenarios until 2020 were used to talc. the crit. load exceedances, and to indicate the ecosystems with a risk due to acidification or eutrophication. The threats of acidification were significantly reduced because of the large S emission redn. The ecosystems with a risk due to N deposition is still remaining as the largest challenge for further N emission redn. both in Poland and in Europe.