A dry fog diffuser assembly for use in a refrigerated space comprises a base having an adapter for connection to a high-pressure water supply in a range of 600 to 1,000 psi. The nozzle has an orifice in the range of 0.003-0.012 inches to produce a fine water vapor. A riser operatively connects the nozzle to the adapter to space the nozzle from the base. A housing is mounted to the base and encloses the nozzle. The housing defines an open space below the nozzle providing an air inlet to the interior of the housing. A diffuser comprises a stainless-steel elbow having an inlet end and an outlet end. The inlet end is mounted to the housing. An inner surface of the diffuser has a roughness of at least Ra25, where water vapor from the nozzle is diffused in the elbow and the diffuser produces a dry fog exiting at the outlet end.