No, Wearing A Mask Isn't Dangerous

Myths about masks are running rampant, mixed in with and distracting from the critical advice and facts we all need to know to wear them responsibly. Many of these myths are directly tied to conspiracy theories that fall apart when you take a minute to think about them, but they still circulate because they seem like they could be true. So let’s run through a few myths and a truth.

Myth: Masks make you breathe too much carbon dioxide (or not enough oxygen)

Air contains a mixture of gases. It’s mainly nitrogen (which our body doesn’t use at all), with small amounts of oxygen and carbon dioxide. The cells of our body need oxygen; with each breath we use a little bit of that oxygen and we give back a bit of carbon dioxide.

If you’re trapped in an enclosed space for a long time, yes, it would be possible to see the carbon dioxide levels in that space rise. That’s why you don’t let children put plastic bags over their heads. But there are viral posts suggesting that high carbon dioxide, or hypercapnia, is a common consequence of mask wearing, and that it can make you feel drowsy or confused.

But a mask is not a plastic bag. The tiny amounts of carbon dioxide that you breathe out are not trapped by a cloth mask or a surgical mask. N95 masks, when they are properly fitted and have a tight seal around the face, can sometimes make it hard to breathe for people with certain health conditions—but that’s not because of a buildup of carbon dioxide. It’s from the physical effort of having to breathe harder to get enough air through the mask material. Even cloth or surgical masks can sometimes feel uncomfortable when they get damp or warm from your breath. But that’s not a health risk.

We’ve written about this before, but just for the extra perspective, I asked Saskia Popescu, the infection preventionist who recently answered readers’ mask questions, if hypercapnia is an issue for either the general public or the hospital staff she works with. Not at all, she said. “I have healthcare workers who wear N95's all day,” she said. “They don’t run into those issues. So I’m not quite sure where [the concern about hypercapnia] comes from.”

Myth: You can get sick from breathing your exhaled viruses

This is a weird one. It turned up in Plandemic, which claimed that a mask “activates” the viruses you breathe out. And then I saw another viral post claiming that a mask redirects viruses from your exhaled breath into your nose, where they can enter your brain. Huh?

Not only does that make basically zero sense, it presumes that you are breathing out the COVID-19 virus. If that’s the case, you’re already sick, so how could the mask pose a further danger to you?

But just in case I was missing something, I asked Popescu about this, too. Maybe there was some grain of truth that inspired the myth? Could masks possibly exacerbate viral illnesses in some way?

“That’s not how it works. I mean, I’m sorry, I don’t know how else to say it, but this is not how it works,” she said.

Myth: Masks can’t block viruses

Viruses are very, very small. Not just microscopic, but so small that typical microscopes cannot see them at all.

The weave on a cloth mask is loose enough you can often see right through it. Clearly, it’s not going to stop viruses from getting through individually. I’ve heard people liken the phenomenon to “bees through a chain link fence.” But from there, anti-mask folks conclude that that’s all the information you need to say that a mask cannot stop a virus.

But that’s not an accurate description of what’s going on. Viruses don’t fly around like bees. The virus that causes COVID-19 leaves our bodies as part of respiratory droplets. Think about someone sneezing in a beam of sunlight. You’d see millions of tiny bits of mucus/saliva/god-knows-what glimmering as they spewed forward and floated gently to the ground. Those are respiratory droplets.

Cloth masks do stop respiratory droplets. And when you wear the mask right in front of your mouth and nose, it will stop most of them. (Masks are most effective when worn by the person who is infected, and they’re recommended for everybody because you can have and spread the virus without feeling sick.)

So a better analogy might be the one that likens masks to pants: if someone pees on your leg and neither of you is wearing pants, you’ll get wet. But if the person peeing is wearing pants, most of the pee will just soak their own pants and not get to you.

(Instead of bees through a chain link fence, sometimes people ask how a mask can stop viruses when underwear doesn’t stop a fart. Well, the molecules that carry the odor of a fart are small—smaller than a virus—and they do float through the air without being stuck in droplets. So they are free to go right through the underwear to your nose, where you can claim that whoever smelt it, dealt it.)

Truth: Masks won’t necessarily protect you from other people’s viruses

This one is true, but I’m including it in the list because it’s often discussed alongside these other myths. You don’t wear a mask for your protection. Masks work best to minimise (not completely stop) the spread of the wearer’s germs.

My mask protects you; your mask protects me.

So to wear a mask responsibly, you need to be aware of its limitations. Putting on a mask does not protect you from the virus you might encounter if somebody is breathing out small droplets near you, or if you’re in an enclosed space with lots of people singing or shouting. Wearing one is still probably better than nothing, though.

The closer you are to somebody who is spewing droplets, the larger those droplets are likely to be, which is why masks may give you a little bit of protection if you are taking care of a loved one who is sick. But masks aren’t a substitute for the other good practices, like physical distancing. Keep your distance and wear your mask, and you’ll be doing your best to keep others safe.