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

When someone brings this up, ask them how mouth-to mouth resuscitation works, if we breathe out CO2.

Of course there is “some” CO2, but there is still plenty if oxygen still there when we breathe out.

If I wear a cloth mask for one hour, how am I still alive?