A new empirical model to calculate separation distances between livestock buildings and residential areas applied to the Austrian guideline to avoid odour nuisance

In Austria a new guideline is under development to calculate the separation distance between livestock and residential areas to avoid odour annoyance. On the basis of dispersion model calculations for 6 sites by the Austrian odour dispersion model (AODM) a regression model is developed, using a power function S = a Eb. The power function is defined by four input parameters. The basis of the power function is the odour emission rate E (ouE s−1) in the range between 400 ouE s−1 ≤ E ≤ 24 000 ouE s−1. The factor a and the exponent b of the power function are defined by two meteorological parameters, the relative frequency of the wind direction F, the mean wind velocity W of the wind direction for 10° sectors as well as the odour exceedance probability P of the odour impact criterion. One of the requirements for this empirical model is the aspiration to substitute the complex calculation with a dispersion model by the new empirical model. The empirical model can be used in a paper and pencil mode, which enables an evaluation of a planned livestock building in a simple way. For a more detailed assessment, a dispersion model can be applied with the entire meteorological information (e.g., stability of the atmosphere, wind field models), the geometry of the emission source, a time depending odour emission rate, and the orography of the site.