I know that a greenhouse is not air tight so I imagine it breathes somewhat and exchanges gas with the outside. However, I also assume that it’s going to use up the co2 in it for plant growth. How does it not run out? I think you could vent it, but then wouldn’t that cool it off and thus defeat the purpose of a greenhouse? All my web searches either give climate change facts or co2 supplementation by farmers.
I can’t tell if you’re joking or not. Unless a home is small, effectively airtight, filled with people, and the doors and windows are never opened, oxygen concentrations aren’t going to fall enough to be impactful.
CO2 levels can get too high on new construction, but that’s a 600-1000 ppm increase.
Elevation will have a much larger effect on your body’s O2 availability compared to what humans can deplete.
https://youtu.be/1Nh_vxpycEA
Yes but CO2 concentrations might grow high enough to impact you.