"Hi to all of the people out there who would also rather live on Pandora (provided that there'd be no chats with a Thanator), :-)

The last time I saw the film (number 5 so far), it occurred to me at the end that a number of the humans (I'm thinking especially of Max) don't have avatars, but are in human form and wearing gas masks, so here's my banal and literal-minded question: How can they survive on Pandora? Won't they run out of oxygen sooner or later?"

"Btw, I believe Pandora does have Oxygen, only not in abundance and in the right proportions like they are on Earth. The gas masks, possibly filter out enough 'other gases' so that the right amount of oxygen gets through."

"hey man. how do you know this?"

"The Pandora air is not toxic due to lack of Oxygen.
It has a high level of Hydrogen Sulphide (H2S). [The other gas in abundance there is Xenon. Xenon is a noble gas and is not toxic although much heavier. The heavy air with lighter gravity is what allows the denizens of Pandora to fly with all that massive bodies and allow the Pandoran creatures to be big] This is the gas that gives a rotten smell and is toxic as well if inhaled for long. Small amounts are not toxic (you would have smelled it in your high school chemistry classes, where there is usually piped supply for analytic chemistry expperiments).
Since it can be removed by adsorption by gas masks (today we will be using charcoal adsorbing masks which will be bigger but we can bet that there will be more technologically advanced and simpler masks with clear see through vision by 2150).
So long as there is supply of masks, it would be OK.
Even if you have Avatars, their human bodies need to breathe "