FiO2 not changing with elevation edit

Intuitively it sounds wrong that the FiO2 would not change with elevation. It is the partial pressure that changes O2 uptake, but all gases in the atmosphere have different densities, so would one not expect a higher proportion of the lighter ones the higher one goes? Continuous wind would reduce any layering, but it's hard to believe that there would be no effect. If there truly isn't any density layering, it would be nice to add a line about that to the article. Tenbergen (talk) 02:35, 8 May 2008 (UTC)Reply