a compact dedusting apparatus is mounted on the machine utilizing particulate material requiring contaminant cleansing to provide an economical and effective decontamination of particulate material immediately before utilization of the material . the dedusting apparatus includes a downwardly sloped infeed chute having an opening at the bottom thereof . a metering device in the form of a rotatable finned hub blocks the opening to constantly meter the flow of particulate material through the dedusting apparatus . the metering device is formed with flexible blades oriented at a slight angle to the slope of the infeed chute to provide a constant flow of material through the opening . a flow of air is directed through a wash deck positioned below the infeed chute to cleanse the particulate material . the air flow is directed along multiple paths including a path defining an air knife associated with the wash deck to facilitate the cleansing of the material .