Science Bits: Why Does My Mask Get So Wet?

Last week, I had the pleasure of joining Malia Segal of @shoreplaytherapy for a live chat about STEM opportunities at home. Click here to watch!

You’ve all felt it: the gross, moist, stickiness inside your mask at the end of the day. Why does it happen? What is it? (Spoiler: it’s not anything gross, like sweat or mucus!)

It all comes back to Biology 101: cellular respiration. In order for your body to function, your cells need energy. Cells get energy in the form of ATP by breaking down sugars, such as glucose. All of this happens in the mitochondria (the powerhouses of the cells!). This process is called cellular respiration.

For cellular respiration to occur, your cells need sugar, such as glucose, and oxygen. In return, your mitochondria spit out ATP so your body can do all of the things it needs to do. The byproducts of cellular respiration are carbon dioxide and water, which your body gets rid of as waste.

The waste leaves the cells, travels the body through the bloodstream, and ends up, primarily, in the lungs. (Water goes elsewhere to form other waste products like sweat and urine, but those don’t end up in the lungs. Eww.) When we exhale, we get rid of a lot of this carbon dioxide and water.

Water? We’re breathing out water? Yes. In small amounts, as water vapor. You can test it for yourself: if you are unmasked, cup your hands in front of your mouth and breathe out a couple of times. Notice your hands getting a little moist?

When the warm water vapor leaves your mouth, it condenses (changes from gas to liquid) on whatever surface is closest: your hands, a window you want to fog up, or your mask.

Keep in mind that carbon dioxide is small enough to escape through the tiny holes in the fabric of your mask, so you won’t suffocate by wearing a mask. Luckily, the water is not able to escape, because the water vapor from our lungs is what carries all sorts of goodies like coronavirus.

There’s no way to avoid a soggy mask; it’s a sign your body is functioning properly! Instead, carry around a couple of extra masks and toss them in the washing machine every few days.

Now you know!