[en] Experiments are carried out at the Kernforschungszentrum Karlsruhe in order to determine the atmospheric diffusion of pollutants. The influence on atmospheric diffusion by conditions specific to the site will be investigated. For evaluation of the measurements the diffusion is assumed to be a steady-state process. A two-dimensional Gaussian distribution is used as the theoretical approximation of the concentrations. The dependence of the dispersion parameters sigmasub(y) and sigmasub(z) on the downwind distance is described by a power function. A least squares fit is applied to calculate the horizontal and vertical dispersion parameters and the normalized diffusion factor with the respective errors from the measured wind velocity, emission rate and concentration distribution. The dispersion parameters determined are assigned to stability classes by the measured standard deviation of the vertical wind direction. The reported dispersion parameters are derived from 18 experiments with mostly two sampling periods of 30 min duration each. In 17 experiments two different tracers were released simultaneously at 160 m and 195 m height, in one experiment three different tracers were released. The results of the individual experiments have been combined and smoothed to a set of dispersion parameters for the stability classes A to F. In Part 1 of this report the diffusion experiments are described and the measured data are presented in detail. The results of earlier experiments performed at the Kernforschungszentrum Karlsruhe for emission heights of 60 m and 100 m have been published already. (orig.)