An emergency oxygen supply system for use on aircraft in the event of a lossin cabin pressure is configured for delivering allotments of oxygen and timingthe delivery such allotments to each passenger so as maximize the efficiencyof the transfer of such oxygen into the passenger~s bloodstream. The deliveryof each allotment is selected so that the entire allotment is available forinhalation into the region of the lung most efficient at oxygen transfer whilethe volume of the allotment is selected to substantially coincide with thevolume of such region of the lung.
