Abstract: A device (20) mounted on the exterior of, and communicating with the interior of, plenum (19) or output ducts (18), of an existing air conditioning and heating system of an enclosed structure, to combine the elements of air, and the elements of a scent producing, disinfecting, or germacidal chemical, utilizing, and upstream of, the air currents produced by the fan in the system to distribute the elements mixture at the outlets of output ducts (18) into the areas they serve. The amount of mixture flow, determined by the user, is controlled by manual manipulation of ball valve (23). The frequency of the mixture flow, determined by the user, is controlled either by the automatic cycling of the system fan, or, by manual manipulation of the fan switch on the system control.