Comparison of a Gaussian diffusion model with guidelines for calculating the separation distance between livestock farming and residential areas to avoid odour annoyance

Complaints by the neighbourhood due to odour pollution from livestock farmi ng an increasing. Therefore, some countries have already developed guidelin es to address odour from livestock. These guidelines are in use to assess t he necessary separation distance between livestock buildings and residentia l areas such that odour is not felt as an annoyance. In all these guideline s, the separation distance is calculated as a function of the rate of pollu tion. These are mainly power functions with an exponent between 0.3 and 0.5 . The Austrian regulatory dispersion model, a Gauss model, is used to calcu late the frequency distribution of the dilution factor for 12 classes of di stances between 50 and 500 m downwind from the source. These data were fitt ed to an extended Weibull distribution of the dilution factor to determine the exponent of the power function describing the separation distance as a function of the emission. The exponent has a value of about 0.72. This resu lt, achieved with a wind and stability statistics representative for the Au strian flatlands north of the Alps, indicates a stronger dependance of the separation distance from the odour emission than suggested by the guideline s. (C) 1999 Elsevier Science Ltd. All rights reserved.