Abstract: An apparatus is provided for dispensing volatile substances which includes a housing, and at least one piezoelectric blower. Each blower includes a piezoelectric element having a first end mounted to the housing and a second end free, and a generally planar impeller blade connected to the free end of the piezoelectric element and having its distal end unconstrained by the housing. A frame is attached to, or provided as an integral part of, the housing and is located in proximity to the distal end of the blade. The frame is adapted to detachably mount a replaceable substrate cartridge containing a volatile substance. In use, a voltage is applied to the piezoelectric element for oscillating its free end perpendicular to its plane at or close to resonance and propagating a traveling wave along each blade to generate and shed vortices at the distal end of the blade which contact the substrate cartridge, thereby dispensing the volatile substance to the surrounding atmosphere.