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

Any mask that looks remotely like [this one](https://www.fda.gov/files/surgical-mask.jpg) cannot “trap” air because it doesn’t seal. It catches the bigger things that fly out of your mouth like droplets of spit. The rest of the air goes through or around the mask

Any mask that seals around your face traps less air than you still have in your lungs when you breathe normally. You still breathe in much more fresh air than that.