[en] ⁸⁵Kr is a noble gas which is formed in a nuclear reactor as a waste product of the fission process. During the reprocessing of the nuclear fuel, the total amount of ⁸⁵Kr escapes and is released to the atmosphere. It is well known that the health risk due to airborne ⁸⁵Kr exposure is represented only by a negligible increase in skin dose. However, monitoring of the atmospheric ⁸⁵Kr concentration is of interest because it gives information of the degree of military and civil nuclear activity, it can be used as a tracer to test atmospheric air dispersion models and it might influence the electrical properties of the atmosphere. That is why the atmospheric concentration of ⁸⁵Kr has been monitored since 1979 at our laboratory by means of a very sensitive sampling and measuring system. The extensive data set, obtained in this way, has been statistically analysed to examine the degree of atmospheric ⁸⁵Kr concentration growth over the past decades. Due to the ideal geographical situation of Gent relative to two most important European reprocessing plants, i.e. Cap La Hague (France) and Sellafield (U.K.), there is a high probability of detecting elevated ⁸⁵Kr concentrations. Hence, a large number of data points greatly exceeds the 'normal' population and is influenced by discharges from these reprocessing plants. In this paper, a technique is presented to separate these data points from the background values. The concentration growth rates obtained in this way are in very good agreement with values found in the literature and with the UNSCEAR estimations of civil and military ⁸⁵Kr emissions. (author)