Abstract: A portable breathing device is disclosed comprising an upper conduit section having an opening in one end to communicate with at least the user's oral passages and a breathing aperture in the other end and a lower flexible and inflatable respiratory gas container section for receiving and containing ambient respiratory gases. The respiratory gas container section has an upper opening communicating with the breathing aperture of the upper section and a lower opening relatively larger than the upper opening for communicating with ambient respiratory gases to thereby permit the user to entrap a volume of ambient respiratory gases within the respiratory gas container section. A seal device is provided for releasably sealing the lower opening of the respiratory gas container section to ensure containment of the entrapped volume of ambient respiratory gases. In the preferred embodiment the upper conduit section is provided with a facial mask adapted to enclose the oral and nasal passages of the user.