A removable replaceable cartridge for use with a liquid diffusing device. The cartridge includes a venturi, a conduit extending to the venturi, a mixing area and an outlet path for atomizing and dispersing a liquid within the cartridge. A diffusion device including a removable replaceable cartridge received within a housing. The housing includes a source of compressed gas which is directed into the cartridge. A venturi head with a unitary body for use with a diffusion device.