According to one aspect, there is provided a device (4) for providing supplemental oxygen to a subject (8), the device (4) comprising a subject interface (10) through which the subject (8) can inhale； a container (12) that has a first outlet (18) connected to the subject interface (10) to allow gas with an elevated oxygen level stored in the container (12) to be inhaled by the subject (8), a first inlet (24), and a material (15) for removing a specific gas from air passing through the container (12) to increase the oxygen content of the air passing through the container (12)； and an air blower (14) that is connected to the first inlet (24) of the container (12) and that is configured to supply air into the container (12) as the subject (8) uses the device (4).
