perception. This factor dominates over the peak-to-mean ratiosderived from Robins (1979) or ultrasonic anemometer measurementsat larger distances, as seen in Figs. 3 and 4. The application ofthis constant factor neglects the effect of atmospheric turbulencewhich is going to reduce local concentration differences in a plumeby turbulent mixing downwind an emission source. This isassumed most effective in unstable conditions, its importancdecreasing with increasing atmospheric stability. Separation distancescalculated with this factor are judged unrealistically large,especially in the main wind directions and at sites where low windspeeds and/or stable dispersion categories are prevalent.Schauberger et al. (2012) demonstrate that the peak-to-mean factordepends on several parameters, like stability of the atmosphere,intermittency, travel time, or distance from the source. Theassumption of a constant peak-to-mean factor can therefore only beused as a very rough estimate and is generally not recommended atsites where stable conditions and/or low wind speeds are frequent.The current investigation as well as the relationship betweenseparation distances and annoyance discussed in Section 4 deliversa good empirical evidence to assess odour exposure by use ofdispersion models. Even the influence of the selected peak-to meanapproach can be assessed by field measurements (Ranzato et al.,
2012; Schauberger et al., 2012). In the present investigation, no