Method of separating and distributing oxygen

A method of providing oxygen rich gas, the method comprising:

• separating oxygen from ambient air with an oxygen separator in discrete pulses, one pulse at a time, wherein separating oxygen from ambient air comprises:
• 1) evacuating a separation column to a first pressure through a feed end of a column;
• 2) metering a flow of gas from a last in/first out (LIFO) buffer column into a product end of the separation column while continuing to evacuate the separation column to a second pressure;
• 3) stopping evacuation of the separation column while continuing the flow of gas from the LIFO buffer column at a second flow rate until a third pressure is reached in the separation column;
• 4) pressurizing the separation column with ambient air through the feed end to a pressure of about 1 atm;
• and
• 5) feeding air into the feed end of the column while drawing an oxygen rich gas from the product end of the separation column;
• and
• 6) repeating steps 1 through 5;
• wherein the start of the pulse is synchronized with the beginning of an inhalation of a person;
• and
• wherein the oxygen rich gas in each pulse is separated from the ambient air in real time during a nitrogen adsorption step concurrent with each inhalation.