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Old Apr 10, 10, 9:36 pm
  #11  
SamT
 
Join Date: Sep 2009
Posts: 4
Cool Airline air

Almost all commercial airlines have pressurized cabins. Only small local commuter flights occasionally do not.

There are two problems with pressurized cabins. The first problem is the air outside the airplane at 30,000 and up feet, is so thin that you will become unconscious within about 3 minutes if you try to breath the air. For that reason, airlines that fly above 12,000 feet have pressurized cabins. Pressurized cabins require one of several types of methods to pressurize the cabin. Cabin "altitudes" in commercial aircraft vary from around 10,000 feet to now lower standards of around 7,000 feet. This means, the amount of air in the cabin is the same density as a 7,000 or 10,000 foot mountain. Most people tolerate this with no problem.

The other problem is exchanging air. There are two methods for doing this. One is "scrubbing" the existing air by running it through filters, and the other is letting in outside air which is pressurized in a variety of ways. In order to bring in outside air, there must be an opening on the outside of the plane which requires expending additional fuel to keep the plane pressurized and is not aerodynamic - read costs more to operate the plane.

In order to keep costs down, most commercial airplanes do not exchange the inside air with outside air as often as you would like, resulting in breathing in other passengers used air (read germs, viruses, etc.) Also, the close packing of passengers on most flights means you are much more likely to catch whatever others on your flight already have, even if they are widely separated from you on the airplane because the air is redistributed all over the airplane.

There is nothing inherent in the cabin air that will cause plastic or rubber to disintegrate. Airlines do not add extra ingredients to the air - sorry no vitamins in airline air. It only gets a little more use by others than the air you breath on the ground.
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