For small odour sources with a stack height of about the 2.5-fold of the building height a simple empirical assessment of the odour concentration is presented. The relevant near field dispersion is characterised by a disturbed plume due to the building structure. Some dispersion models can only be applied outside this disturbance zone which can be estimated by about 10 to 20 fold of the reference length of the building. First the adaptation of dispersion models is discussed which mimics odour sensation of humans. For an assessment of the maximum expected odour concentration for an integration time of one single breath (about 5 seconds) a correction factor is introduced. Then two box models are presented which can be applied in the near field. In the transient zone, where Gaussian dispersion models can be applied too, the results of the near-field box models show a conservative estimation of the odour concentration. In some administrative procedures there is a need for such empirical models to reduce costs. Nevertheless this approach has to be seen as a first guess and doesn't want to substitute more sophisticated methods.