4 May
2005
4 May
'05
6:13 a.m.
>>>> "der" == der Mouse <mouse
at rodents.montreal.qc.ca> writes:
> Note that the body works perfectly well with
substantially less
> air than you get at sea level -- that's how you function in an
> airplane.
der> "Less air" for what value of "air"? What the body wants, as
I
der> understand it, is a partial pressure of oxygen at least vaguely
der> equal to that in the air it's used to. On airplanes, this is
der> done by using a gas mixture (proportionately) richer in oxygen
der> than air, at a lower pressure.
Not true, unless you're thinking about fighter planes.
Unpressurized planes (small planes) simply have the ambient air
inside. Pressurized planes (airliners) compress the outside air
roughly to the pressure that prevails around 8000 feet or so. It's
still plain old air, 21 percent oxygen.
Moderately healthy humans function fine up to about 10,000 feet, less
so as you go up from there. This is why aviation rules allow pilots
to fly unpressurized planes without restriction up to 10,000 feet, but
require supplemental oxygen if they stay above 10k for more than 30
minutes (or above 14k for any time).
Needless to say, mountain dwellers are more tolerant than that.
paul