Combination of field inspection and dispersion modelling to estimate odour emissions from an Italian landfill

In the case of landfills, the determination of odour emissions is particularly complex. Up to now, no universally accepted methodology for sampling and assessing emissions from landfill surfaces has been established. Besides, the dependence of such emissions from some crucial environmental variables, such as wind speed, has not been univocally defined yet. In this study, odour dispersion modelling and plume inspections by human assessors were combined in order to estimate the odour emissions from a landfill in Southern Italy. Two substantially different approaches were compared: the one that considers emissions as a function of the wind speed blowing over the surface, counterposed to the one that considers odour emissions as constant, in agreement with the most recent studies on the matter. The comparison of the field assessments and the model clearly highlights that the first approach significantly overestimates the landfill odour emissions, whereas the use of a constant odour emission rate results in a much better correspondence between model outputs and field assessments, both in terms of shape and extension of the determined odour plume extents.