Currently in SL when you make any enclosed area it automatically has oxygen in it,but that’s not how physics works.
When you make a station you should need an oxygen generator to be able to breathe without a spacesuit on.
Of course,we don’t want it to be super complicated,so the amount of power oxygen generators require will not depend on the number of people (or animals?) breathing the air.
10 per second
1 per every block
of air it effects.