The air we breathe.
 

I found an interesting article online.

http://www.flyana.com/air.html

Has anyone ever had an instance where the Pilot had to adj the air during the flight?

Not convinced about asking for an emergency oxygen bottle just because she wants to feel better :rolleyes: surely the point is they are there for emergencies, and not overly pernickity passengers.

I'm also amused that she would be willing to go around accusing people of having TB... dearie me!

Ya know..... I probably shouldn't say this simply because I don't have the time or inclination to completely back it up with the references.... but it's painfully obvious that the person who wrote that article has no clue of how aircraft pressurization systems work.

Pilots get ten times more oxygen than the passengers?!?

:D

Sounds like a recipe for hyperventilation to me. Oxygen comprises about 21% of the air around us - ten times that amount would be a lotta oxygen indeed. :D

Pilots do have O2 masks at the ready, and for very real safety-related reasons.

I think brassai hit it on the head: the "expert" author Diana Fairechild reveals in this piece her complete ignorance on the subject of aircraft pressurization.

That's what I was thinking. I'll be the first to admit that I don't know how aircraft pressurization systems work, but I do know that in my car when I switch to outside air from recirculated air the noise gets softer. The recirulated air is actually louder.

Here are two links which give a brief summary of the workings of aircraft pressurization:

http://www.boeing.com/commercial/cabinair/

http://www.boeing.com/commercial/cabinair/facts.html

Of course, Ms Fairechild would no doubt point out that Boeing has plenty of incentive to mislead and lie about cabin air, but that doesn't change the facts about how they work.

That's because you're now hearing the suction of the air being recirculated back into the system. If you notice, you probably hear the new louder sound coming from underneath the dash where the return air goes back. When it's coming from the outside, the intake (and the associated noise) is away from the cockpit of the car. The noise at the outlets (cold or warm air) stays the same.