Although the percentage of oxygen in the atmosphere is constant, its partial pressure decreases proportionately as atmospheric pressure decreases. Above 10 000 ft, the partial pressure of oxygen gets lower and the lungs cannot effectively transfer oxygen from the ambient air to the blood to be carried to all tissues in the body. Consequently, for instance, when flying above 10 000 ft with a pressurization malfunction, oxygen deficiency in the body will most likely result in hypoxia.