1. exhale into a bag
2. close the bag (with minimum outside air contact),
3. inhale air,
4. exhale air,
5. open the bag (with minimum outside air contact),
6. inhale in the bag
and repeat steps 1-6 can you create around 100% CO2 in the bag?
(steps 2-4 prevent passout)
Don't give an answer like: you don't exhale 100% CO2.
I mean building up the CO2 every time you exhale in the bag. I forgot about the nitrogen concentration, so I change 100% CO2 to 20% CO2. Now, how would 20% kill me, if I take breaths outside of the bag in between? That would keep my oxygen level normal while the CO2 level in the bag would increase. My own CO2 level would stay normal too, because I breathe it out in the normal air too.