Abstract
Direction-dependent separation distances to avoid odour annoyance, calculated with the Gaussian Austrian Odour Dispersion Model AODM and the Lagrange particle diffusion model LASAT for a site in complex terrain, will be analysed and compared. The relevant short-term peak odour concentrations are calculated with a stability-dependent peak-to-mean algorithm. For both models, the same emission and meteorological data, but model-specific atmospheric stability classes have been used. The estimate of atmospheric stability is obtained from three-axis ultrasonic anemometers using the standard deviations of the three wind components and the Obukhov stability parameter. In addition, separation distances are also determined for an odour threshold of 0.25 (factor 4) of the German TA Luft (Technical Guideline for Clean Air) uniquely applied over all stability conditions and distances. The results are demonstrated for the Austrian village Weissbach in the narrow Saalach valley.
Meteorological data at this site are provided by a three-axis ultrasonic anemometer from which also stability information (Obukhov stability parameter, OSP) is directly deduced. Separation distances are determined fortwo odour impact criteria, namely exceedence probabilities of 3 and 8 %, each in combination with the odour threshold of 1 ouE/m3. The form of the separation distances around the fictitious odour source depends strongly on the prevailing meteorological conditions (wind and stability), on the odour impact criteria and on the peak-to-mean factors.
