A dispensing device for at least one air treatment agent is described herein, the dispensing device comprises: a housing having one or more walls to define an interior adapted to receive at least one removable container of air treatment agent at least partially therein； and within said housing the device comprises: an airborne agent detector means operable to detect airborne agents in the air, wherein said means are provided with at least one aperture to the exterior of the device to permit, in use, air from outside of the device to enter said airborne agent detector means； receiving means for receiving said at least one container of air treatment agent； emanation means adapted, in use, to emanate the air treatment agent from the device through one or more exit orifices in the housing； control means in communication with the emanation means and in communication with said airborne agent detector means； characterised in that said airborne agent detector means is substantially completely isolated from any fluid present in the interior of the housing such that any fluid present in the interior of the housing is substantially completely prevented from passing through said one or more housing walls to be detectable by the airborne agent detector means.
