 Xenon has a minimum <unk> concentration ( <unk> ) of 72 % at age 40 , making it 44 % more potent than <unk> as an anesthetic . Thus it can be used in concentrations with oxygen that have a lower risk of hypoxia . Unlike nitrous oxide ( <unk> ) , xenon is not a <unk> gas and so it is also viewed as environmentally friendly . Xenon vented into the atmosphere is being returned to its original source , so no environmental impact is likely . 
