[en] A review is given of the actual knowledge of SO₂ atmospheric processes gained from laboratory and field experiments. Implementation is described of the instrumentation, operational procedures and analytical methods in connection with a field study of the conversion and dispersion of SO₂ in an oil-fired power plant plume. Furthermore, the preliminary results are included of five experiments performed until the end of 1976. Measurements were performed from an aircraft and included continuous registration of NOsub(x), SO₂, SF₆, and particle concentrations, as well as temperature and humidity. It was planned to label sulphur from the source in question with sulphur-35. However, this part of the experiment had to be abandoned because of public opinion on the use of radioactive tracers. Sulphur hexafluoride was used as an internal tracer for the plume. A half-life for SO₂ of about 30 min was determined from one of the experiments. In this connection the possibility of using NOsub(x) as a conservative tracer is shown. Possible ways of removal are discussed and the rate of two of the processes is calculated by means of a model describing the chemical conversion in a dispersing plume. (author)