[en] Instrumental neutron activation analysis has been utilized for the analysis of 19 different fly ashes, 1 sample of coal and 3 samples of industrial emissions. Both short and long irradiations in a nuclear reactor have been used. The irradiated samples have been measured by means of a computer based Ge(Li) gamma-ray spectrometer. The concentrations of 27 elements have been determined in the samples. The elements Fe, Al, Na, K, Ca, and Ti occur in fly ashes and emissions in the highest concentrations (0.1-20%). A further group of elements (V, Mn, La, Sc, Sm, Ce, Cs, and Cr) occurs in these materials in lower concentrations and the concentration fluctuations in the dependence on the origin of the sample and time of sampling are rather small. The highest differences in concentration can be found in the third group of elements: As, Sb, Co, Zn, Th, Eu, and Se. These elements are promising for an identification of sources of emissions and consequently imissions. (T.G.)