Spatial and Temporal Variability in Ozone Concentration Level at Two Lithuanian Stations

The ozone concentration measurement results at two rural stations in Lithuania are presented. Ozone measurements have been carried out at the coastal site since 1980 and at the forested one since 1994. Both stations are far from the influence of the local pollution. The established ozone concentration trends at the coastal station were upward in cold and not so distinct in warm seasons during this monitoring time. The tendency even of a decreasing level in some summer months was established: in June and August. These trend results were very close to the results obtained at other European stations.Comparing ozone levels and courses at both stations, significant differences were determined. Clear differences between monthly daytime and daily ozone concentration averages are observed during the warm season. They were three times larger at a forest site as compared with the results at a coastal one.