Abstract
Since odour pollution is typically a short-range problem, it is important to simulate as precisely as possible the fate of the pollutant close to the release points. This means that specific effects such as stack orientation, presence of rain cap, and building downwash must be considered. The aim of this paper is to describe the implementation of a building downwash algorithm into the Lagrangian particle model LAPMOD. A literature review guiding to the choice of a specific algorithm is initially briefly described. Then the implementation of the building downwash algorithm into the model is described. The results of the sensitivity analysis carried out with and without the building, with the source at different distances, show that the model behaves as expected, predicting high concentrations close to the building. A comparison with the results of CALPUFF, implementing the PRIME algorithm for building downwash, for a simple situation shows that this model predicts much higher concentrations with respect to LAPMOD. Also, CALPUFF predicts constant concentrations over the building and at short downwind distances from it.
