The Na'vi and our oxygen

[Woodsprite]

This is my problem with the theory that Na'vi can breathe human air.

They probably can... if there was enough. The air pressure is higher on Pandora. There are certain toxic gases in the air that prevent humans from breathing it directly, so we need exopacs. The Na'vi, so to speak, have their own "built-in" exopac in their bodies. They breathe pretty-much the same stuff we breathe, only their bodies filter out any toxic gases. In theory, that would mean they could breathe air on earth.

But since the air pressure is much lower on earth, that would automatically mean there's less oxygen to breathe. The Na'vi would be able to survive, but probably wouldn't live as long as they normally would on Pandora.

This is one theory scientists have on how the dinosaurs died out: because there wasn't enough oxygen at one point. A brachiosaurus' nostrils are as big as an average horse's. With 50% more oxygen, they'd survive. With our current atmosphere, they cannot survive. That's why "Jurassic Park" would never work. The dinosaurs cannot breathe as efficiently in our atmosphere as they could long ago. This assumes the atmosphere back then had a higher concentration of oxygen, thus allowing dinosaurs to live.

But anyway, I'm pretty-much in agreement with Banefull on this one. The Na'vi would survive on earth, but not nearly as long as they would if they stayed on Pandora.