An oxygen concentrator is a device that pulls in air from its surroundings and filters out the nitrogen, leaving a mixture made up mostly of oxygen. Air is made up of 78% nitrogen, 21% oxygen and 1% carbon dioxide and other trace gases. In order for air to be breathed https://www.philmedicalsupplies.com/how-you-can-improve-your-life-with-a-portable-oxygen-concentrator/