How does the oxygen machine for home work? The ambient air around us consists of about 78% nitrogen, 21% oxygen and 1% argon. The fixed oxygen concentrator is employed to separate oxygen from nitrogen and argon to deliver up to 95% oxygen, thus increasing the oxygen saturation within the patient's blood. Hoc usually uses a process called pressure swing absorption. The compressor is employed to separate oxygen and nitrogen along side two containers containing zeolite.