That blue bar is extremely pessimistic. Humans can survive pretty well with 15% oxygen, and do so in several places in the Andes mountains, China and India. I wouldn’t recommend doing it without lengthy acclimatizing, especially not considering my last paragraph, but it’s completely survivable by itself.
Humans also don’t really have a problem with 25% oxygen, although that will definitely bring down the life expectancy.
On the other hand, note how those pointers talk about giant insects, megafauna and other scary things. Those are a much bigger problem than the air you’re breathing.
Dumb question, but in a very oxygen rich environment, can you just breathe through a paper bag or something? Mostly just breathe your own exhaled CO2 with a bit of O2 leaking in?
Mosquitos are kind of modern, being only 45 million years old, way after the megafauna bugs died.
but think 40cm long, meter wide “dragonflies”, half-meter long “scorpions”, 60cm “spiders” with knifelike front legs and 250cm long millipedes (technically not an insect, but eh)
But if you’re looking for giant mosquitoes, you’re in luck: the very much not-extinct elephant mosquito can grow over 1.5cm long.
Oxygen is really rough on the DNA due to making the cells “rust” which hampers cell division and/or increases risks of mutations or cancers
So those memes that were “warning” that oxygen was dangerous because it created rust in metal rods is actually true ??