A non-contact gas dispenser (200) comprising a headset apparatus (202), a gas source (210), a conduit (208) for directing the desired gas to a region proximate to the user's nose, and mouth. The gas source preferably is a pressure swing adsorption apparatus (Fig. 9) that allows the user to select at least two predetermined settings of product gas, each setting having a distinct concentration, and flow rate different from the other settings.