The structure of cooling tower plumes depends on meteorological conditions, especially on wind, temperature gradients, and turbulence. This influence of meteorological atmospheric conditions on the plumes may be quantitatively described by so-called diffusion parameters. These parameters may be determined with the aid of tracer measurements by determining tracer diffusion and, from the distribution of the tracers, calculating the diffusion parameters. At the Neurath power plant, there were three of these tracers. First, the vertical concentration distribution of the atmospheric background aerosol may yield information on the vertical stratification. Secondly, pollutants from anthropogenic sources, e.g., from the stacks of Neurath fossil-fuel power plant itself, may be used for investigation. In the present study, particle concentrations and SO/sub 2/ content of the air due to the waste gases from the power plant stacks were used for measurement.