Excess oxygen is actually harmful to humans, but all the climate warnings are about losing oxygen, not nitrogen edit: but when we look for habitable planets, our focus is ‘oxygen rich atmosphere’, not ‘nitrogen rich’, and in medical settings, we’re always concerned about low oxygen, not nitrogen.
Deep sea divers also use a nitrogen mix (nitrox) to stay alive and help prevent the bends, so nitrogen seems pretty important.
It seems weird that our main focus is oxygen when our main air intake is nitrogen. What am I missing?
edit: my climate example was poor and I think misleading. Added a better example instead.
That makes sense, thanks, since our threshold for co2 is less than 0.5%.
I may have worded my question poorly; I’m more asking why low oxygen is a problem vs low nitrogen. In retrospect, my climate focus may be distracting. It was what made me wonder about this in the first place, but the medical and scuba points are much more relevant. That has little to do with co2 (I think?) and more to do with the relative compounds in our air.
I’m still confused why we hear about oxygen but never nitrogen. Another example: when we look for habitable planets, the focus is ‘oxygen rich atmosphere’, but not ‘nitrogen rich’.
Maybe nitrogen could be replaced with other gases, but we need oxygen in our lungs and bloodstream to survive. So maybe it’s more important for our survival?
Here’s an interesting post about the different formulations and pressures required to have breathable oxygen mixtures.
https://space.stackexchange.com/questions/28280/could-we-breathe-an-atmosphere-that-is-not-nitrogen-based#28283
Based on OP’s question, we don’t care about nitrogen, because it’s not strictly necessary for our survival.
That explains it very well, thank you!
So from what I understand, we need a rather precise amount of oxygen plus a large amount of an inert gas – pretty much any inert gas, barring a few that have narcotic effects. So nitrogen isn’t special, except that it’s inert and doesn’t get us high.
But I’m also curious whether the reactive gas in low quantities (oxygen) can also be replaced. I’m not a chemist, and this is fascinating. I’ll keep reading.
Thanks again!
I’m not a biologist, doctor, or chemist, but my guess is “no.” We have evolved to use oxygen to create energy within our cells, not some other gas.
I would hazard an additional guess that it’s not a simple matter to just swap out the oxygen molecules for something else. Carbon monoxide binds better and more readily to our cells, yet that mixture would asphyxiate you.
https://www.nhlbi.nih.gov/health/lungs/breathing-benefits
We don’t need a precise amount of oxygen - we can survive in a fairly wide range. Think about living in the mountains vs by the ocean.
Nitrogen gets us absolutely high. Balls to the wall high. It’s why gas narcosis used to be called nitrogen narcosis. Also known as the “rapture of the deep”.
Also, oxygen gets you high. Also, oxygen kills you, but that’s another matter.
It’s pretty amazing we’re alive at all, when you put it that way.