Trends in Airborne Sulphur and Nitrogen Compounds in Norway during 1985–1996 in Relation to Air Mass Origin

Major reductions in emissions of sulphur dioxide and nitrogen dioxide in Europe have significantly reduced the ambient concentrations of both sulphur dioxide, particulate sulphate and nitrogen dioxide, as well as of sulphate in precipitation at Norwegian monitoring sites. In this study, trends in ambient air concentrations were studied in relation to air mass origin by sector analysis. Associated trends in ambient concentrations were derived by non-parametric statistical methods and evaluated on the basis of emission figures within the various sectors. The observed trends correspond well with reported trends in emissions.