K-puszta, 70 km SE of Budapest, regional background air pollution monitoring station was established in a clearing in a mixed forest on the Hungarian Great Plain, in the middle of the Carpathian Basin, as far from the pollution sources as possible in the highly industrialized, densely populated Central Europe. Because of the growing vegetation the station was moved to a bigger clearing, also at the same elevation, approximately 500 m from the original one, in September, 1993.