The Effect of Changes in European Anthropogenic Emissions on the Concentrations of Sulphur and Nitrogen Components in Air and Precipitation in Lithuania

Sulphur (S) and nitrogen (N) components are of great concern because acidification and eutrophication still remain an important environmental issue in many regions of the world. Continuous monitoring (1981–1999) of S and N components both in air and precipitation in Lithuania (LT) has allowed us to evaluate the regional and temporal variations in relation to the pollutant emission changes. Despite of inter-site variability in concentration of pollutants within the regional scale, data showed a marked decrease in S concentrations both in air and precipitation over the Lithuania as a whole. Non-seasalt sulphate (nssSO₄ ^2?) concentrations in precipitation and air decreased from 2.06 to 0.52 mgS/l and from 3.97 to 1.07 µgS/m³, respectively. The number of acidic (pH<5) precipitation did not exceed 50 % during 1995–1999. The observed trends for S species are consistent with those for sulphur dioxide (SO₂) emission in Europe and Lithuania. Although nitrogen dioxide (NO₂) concentration in air decreased by 17 %, significant changes in nitrate (NO₃ ^?) concentrations neither in precipitation nor in air have been observed. Three-day backward air isobaric trajectories were used for the identification of the source region of air pollutants