Nature comes from inside air, we often say the air in headroom is rarer, but content of tall aerial oxygen, the aerobic content with the ground is same, they are 21% .
No matter be altitude,so 1 meter still is altitude 10 thousand meters, aerobic scale does not have occurrence change, since say aerobic scale does not have change, why can the person still breathe difficulty in the place with high height above sea level?
Although the scale that the answer is oxygen did not change, but aerobic content becomes little however, generally speaking atmosphere is as altitude lift and reduce, the height of altitude is so taller, atmospheric pressure is lower also.
Gas depress brought about air rare, air is rare also mean oxygen rare, for example the person falls in normal circumstance, minutely need sucks 5 litres air, but once arrived altitude 3000 meters place, absorb 7.5 litres air with respect to need.
So because need to suck 2.5 litres air more, ability satisfies physiology requirement of the person, the person accelerates breathing frequency necessarily, so the person reached downy area, with respect to the feeling with meeting occurrence hurried breath.
Like that later generations aboard when, the air with will rare conference compresses the engine of the plane, next among them the air of one part, can be heated to be released go among engine room, furnish next people breathes.
But the air that compresses considering course engine, average temperature is relative tall, if be released directly,arrive among engine room, be afraid the person on the plane wants to bake ripe.
There is an air regulating system on the plane so, these systems are OK the air that will heat is cool, release engine room again next in the center, why don't this lack aerobic account on the plane namely. . . . . . .
