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
It’s not dangerous for adults if it happens, which is unlikely in the first place. If you keep rebreathing enough CO2, you will eventually feel suffocation and remove the mask to get air, no problem. If you breathe into a bag for a bit you will see when you start feeling like you need to breathe, and then you’ll stop doing that.
It can be a problem for small children because they may not know better, or for unconscious adults, which is the reason mask guidelines exclude them.
The mask only prevents droplets from going out, air is completely able to go in and out at all times.
CO2 does not cause damage to any tissues, the only danger is it getting in the way of the O2 you need in your lungs and ultimately your brain. If you legitimately start passing out, go ahead and pull your mask down for a minute, but like everyone else is saying, those molecules won’t get stuck in any sensible mask.
The misconception exists because you exhale about 5% CO2, and that also happens to be the concentration at which CO2 starts showing toxic effects (around 5% and higher).
And this would indeed be very deadly, if you were to breathe into a plastic bag that is tied around your head.
However, that is not what you are doing. You are breathing out into a mask, which is not airtight. Even medical masks, which are layers of melted polymers and fabric, are not air tight. If they were, yes, you would die. But they aren’t. So you never breathe in that 5% CO2 concentration you breathe out.
Make no mistake – breathing with a mask could become strenuous and eventually dangerous if you require a higher air circulation, such as when performing exerting physical activity like exercising, either for a prolonged duration of time or to a high degree of exertion, as they do restrict your air circulation to a degree (at least if the mask is any good. A simpler mask like a basic dust mask will not have as strong an effect as a medical mask, and will not be as helpful against viruses either).
But when not under physical strain or any other reason that would require a higher air circulation than usual, there’s essentially no risk.
Fun fact – in small concentrations, CO2 actually serves an important role in blood vessel constriction regulation.
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?
The CO2 goes through the mask, the warm air inside is just that, heat and humidity. You are not breathing the same air, it’s just warmer.
CO2 is a gas – the molecule is really tiny compared to the “pores” in the fabric masks we wear.
The only way you would breathe back in the CO2 that you exhaled is if your mask was made of Saran wrap.
Just compare the volume between mouth and mask to your lung volume. To trap enough air to have any impact on your oxygen levels, the mask would have to look like a baloon nearly as big as your chest, when you exhale.
Disclaimer: not a doctor.
As far as I can tell, SARS COV2 is not airborne: it is instead transmitted through contact (either direct or via surfaces) or airborne droplets carrying the virus. Masks are designed to prevent the spread through that second vector.
Some people think that masks need to be fine enough to stop viruses from traveling through them, but they don’t: all they need is to stop (as many as possible) droplets carrying the virus that get ejected through breathing/talking/sneezing. These are relatively massive, and even a cloth mask will be *relatively* good at it.
CO2, O2 and the virus itself are actually much smaller than the holes in the mask and can pass through relatively unimpeded (again, the virus needs a droplet to spread, so not an issue), and that’s ignoring that the mask isn’t airtight. CO2 buildup under the mask is simply not a real problem (a few experiments were carried out where blood O2 saturation was measured with masks on while performing strenuous activity => there was no significant effect), and anyone claiming serious respiratory discomfort as a result of mask use (outside of a few diagnosed conditions) is likely experiencing psychosomatic symptoms, assuming they’re not talking out of their ass as a way to avoid acting as responsible citizens (a common trend among anti-maskers unfortunately).
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.
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