An aerosol medication delivery apparatus includes a fixed volume holding chamber which is constructed to allow for a uniformly mixed, concentrated bolus of medicated aerosol to be delivered with each breath. The device further includes a universal inlet, so that any standard small volume nebulizer, as well as any standard metered dose inhaler (MDI), may be utilized therewith. Also filtration can be added to address contaminated patient air and aerosol. A one-way valve is positioned in the patient mouthpiece, to help control the loss of aerosol, and thereby reduce waste.