In order to design optimal water spraying devices to minimize fugitive dust emissions generated at bulk solids handling the physical mechanisms responsible for their arising and their precipitation have to be understood. The dust suppression mechanism at bulk solids handling during water spraying can be divided into a moistening step of bulk solids, which prevents dust generation (primary dust suppression effect) - and secondly into a step by which the still generated dust particles will be captured by the water droplets (secondary dust suppression effect). This primary
and secondary dust suppression effects were compared.