How is it not dangerous to breathe in the CO2 that we breathe out into our masks?

Question

I’ve heard a lot of anti-maskers use the argument that since we breathe out CO2, it will become trapped in the mask and is dangerous to breathe back in.

Obviously, this isn’t the case, because doctors wear their masks for hours and hours on end while doing surgeries. However, I am wondering, how does it work?

In: Biology

Answer 1

Co2 is a very small molecule, just like other gases it has little difficulty traveling though a cloth barrier. If the mask was completely airtight, it would be very difficult to breathe at all.