The air is rare and thin

been looking for days now and haven't found any reference to this. understand it implies a priviledged club or neighborhood. maybe this is a badly bastardized quote but it's all I can remember. grateful for any help.

It is a fact of physics that as you start leaving the earth's atmosphere the amount of oxygen molecules, AKA air, decreases.

At the risk of being accused of pedantry, air is not synonymous with Oxygen molecules.

DFG