A system for purifying or filtering air or gas to capture increased oxygen content is described. The system uses a controller that reads data from one or more sensors to optimise the timing of expulsion or intake of air or gas to be processed. The system includes one or more separation beds (310, 312) for adsorption of nitrogen or other gas, valves controlling intake of external gas (332, 336), one or more sensors (352) and a controller (350) that uses information from the sensor/s to determine when the separation bed is full, when to equalise the pressure between multiple separation beds etc.
