1 $\begingroup$ Okay, so I've been trying to figure out the mechanics for a thing I'm writing. It is supposed to be Earth but after an event I'm not yet specifying, combined with humans being humans and destroying their own planet -- the air has been polluted and got to the level of requiring them to wear masks at all times outside due to not being breathable anymore. Now we get to the issue. I want the air to still allow life. The change cannot be too drastic, but not small enough not to hit. I mean to introduce a mechanic, let's call it, that causes humans to tinker with genetics to simply make themselves adjust. Anyways ... that's what I've come up with so far but I am not sure if it works as I intend it to. N2 79%, O2 19%, Ar 0.9%, CO2 0.3% + trace gasses The question is a) does this cause big breathing issues and if yes, is it still livable? b) does this composition pose a risk to health or imminent death? c) suggestions? The change in the world is both gradual and fueled by certain events. I'm just assuming that some species adjust better than others. biologyplanetsclimateclimate-changecataclysms Share Improve this question Follow edited 13 hours ago elemtilas 41.4k77 gold badges7777 silver badges162162 bronze badges asked 15 hours ago colrelcolrel 1933 bronze badges New contributor colrel is a new contributor to this site. Take care in asking for clarification, commenting, and answering. Check out our Code of Conduct. $\endgroup$ 1 $\begingroup$ Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. $\endgroup$ – Community Bot Commented 11 hours ago Add a comment  |