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 itself isn’t dangerous. Our special proteins in our red blood cells preferentially bind oxygen in the air we breathe. If the proportion of oxygen in each breathe is decreased substantially, then it might pose a problem but we breathe in Carbon Dioxide all the time. But oxygen comes with it.