Partial Pressure of O2 is what's important.
If you have more oxygen, you need less pressure to get enough into your bloodstream.
Earth's atmosphere is about 21% oxygen. If you could get the air in the habitat to 50% oxygen, you would need that much less pressure.
(Of course, people traveling back and forth between the habitat and Earth might have some problems with the pressure differences)
Partial Pressure of O2 is what's important.
If you have more oxygen, you need less pressure to get enough into your bloodstream. Earth's atmosphere is about 21% oxygen. If you could get the air in the habitat to 50% oxygen, you would need that much less pressure. (Of course, people traveling back and forth between the habitat and Earth might have some problems with the pressure differences)