Separation distance to avoid odour nuisance due to livestock calculated bythe Austrian odour dispersion model (AODM)

Odour emission of livestock buildings is major burden for ambient residenti al areas. Using a dispersion model to calculate ambient odour concentration s, the separation distance between livestock buildings and residential area s was defined by a pre-selected odour threshold and an exceeding probabilit y. The dynamic Austrian odour dispersion model (AODM) was used to calculate the separation distance for several combinations of these two values, whic h represent the protection level of various land use categories. The AODM c onsists of three modules: (1) odour release on the basis of a simulation mo del for the indoor climate of livestock buildings; (2) a regulatory dispers ion model (Gauss) to calculate hourly or half-hourly ambient odour concentr ations; and (3) a fluctuation module, calculating the instantaneous odour c oncentration, depending on wind velocity and stability of the atmosphere. T he calculated separation distances for a pig fattening unit of 1000 heads w ere compared with empirical guide lines used in some countries (Austria, Ge rmany, Switzerland, The Netherlands, USA). For most guide lines, the separa tion distances were smaller compared to the model calculation, except for t he German guide line applied for non-agricultural areas, Odour sensation oc curred predominantly around sunset, with neutral or slightly stable atmosph eric stability. The presented AODM is a useful tool for regulatory purpose. (C) 2001 Elsevier Science B.V. AR rights reserved.