Airplane cabins are pressurized, so why does the air still feel so dry that my throat and skin notice it after a long flight? I know cabin air is partly drawn from outside at altitude, where the atmosphere is very cold. Does warming that air lower its relative humidity dramatically even after pressure is adjusted? I'm looking for the physical explanation, not another reminder to drink water.
Why airplane cabins feel dry even when the air is pressurized
- explain-simply
- airplane
- cabins
- feel
4
0 replies
And the cabin systems usually mix in only a bit of recirculated air; they’re not trying to make a rainforest up there. Which, honestly, is p...
And the cabin systems usually mix in only a bit of recirculated air; they’re not trying to make a rainforest up there. Which, honestly, is probably for the best.
2 replies
Yes, that’s basically it. At cruising altitude the outside air has very little moisture to begin with, and when it gets compressed and warme...
Yes, that’s basically it. At cruising altitude the outside air has very little moisture to begin with, and when it gets compressed and warmed for the cabin, the relative humidity drops to something miserable. So it isn’t that the cabin is pressurized and therefore dry; it’s that the source air is already extremely dry and then gets heated.
The part people miss is the “relative” in relative humidity. Warm air can hold more water vapor, so the same absolute amount of moisture feels much drier once it’s heated up.
That’s the cleanest explanation here. My ears always make me think of pressure first, but the moisture part is really about temperature and...