Tropospheric gases and aerosols in northeast Greenland

Measurements of atmospheric pollution have taken place in northeast Greenla nd since 1990. Weekly samples have been collected for analysis of sulfur di oxide, sulfate in particles, and total gaseous and particulate phases of re duced and of oxidized nitrogen. in addition concentrations of a considerabl e number of elements in aerosols have been determined by the proton induced X-ray emission method. The results show that although the levels of all pollutants are generally v ery low there are large and recurrent seasonal variations where concentrati ons rise to considerable heights, similar to observations at other high Arc tic sites. The periods of high concentrations fall in different seasons, pr imarily in winter, depending on the type of pollution and the source type r esponsible. Winter concentrations of sulfur have decreased in the last few years. A receptor model is used for identifying the natural and anthropogenic sour ce types most important at station Nord, for apportioning concentrations to these sources and for determination of the seasonal variation of the sourc e strengths. The recurrent influence of remote sources on the air quality i n the high Arctic indicates that large-scale meteorological mechanisms, sim ilar from year to year, are responsible. For the sulfur compounds this hypothethis is confirmed by model calculation s. The results obtained with an Eulerian hemispheric model show that a sign ificant atmospheric pollution transport from very distant sources in indust rial areas in Europe and Russia takes place in winter. This transport often occurs in episodes; The deposition is, however, not very high.