TL;DR: Not all cloth masks are created equal, and it’s important (very) that the edges of surgical and cloth masks fit against your face well.
I recently (January 2021) realized a lot of my conscientious mask-wearing friends and loved ones aren’t aware of one or more of the above or the science behind them. So, a post!
Please note “surgical masks” here refers to masks made with melt-blown material (it will say something like that on the package); the term is very occasionally also used to refer to pleated paper masks, which are much less protective.
Safety
On the other hand, a two-layer, not especially tightly-woven cotton mask (for example, a lot of the inexpensive cloth masks being sold, or a handmade mask from an average-thread-count bedsheet) or a t-shirt material mask–especially without filter layers–are better than nothing but not as protective as particularly-tightly-woven cloth masks with filter layers or good-quality surgical masks.
Breathability
Surgical masks are more breathable; I can feel it when I’m wearing a three-layer cloth mask, but in a surgical mask I can power-walk, run, whatever without breathing hard. An older relative who started scrupulously wearing cloth masks at the beginning of the pandemic, and starts breathing hard when walking quickly in them, hadn’t tried surgical masks because they didn’t know about their breathability, which is why I realized it isn’t common knowledge and wrote this!
If you aren’t certain of the quality of your surgical masks (most work well, but some are not as protective), their breathability makes them a good option for double-masking without decreasing the breathability of a mask worn over them. Just make sure both masks fit:
Double-masking
Double-masking is an increasingly common way to gain additional protection. While it can be a useful option, I see a lot of people wearing a surgical plus cloth mask with both masks gappy at the edges. If unfiltered air is coming in the edges, that’s a large risk regardless of number of masks.
Fit
I notice a lot of people (not just the open-nose crowd; I have conscientious friends who don’t know about this!) wearing cloth or surgical masks with big gaps at the cheeks, or with the nosepiece not creased three times (bridge of nose, side of nose, side of nose). Masks need to protect others/you from aerosols floating in the air/in your breath, not just direct spray, which is why vaguely laying a mask across your face and putting on the ear loops isn’t enough.
Particularly in order to protect yourself (which of course also means protecting people you subsequently come in contact with), the edges of your mask should fit to your face well. Ties tend to help with fit more than ear loops do, and you can also increase the seal using pantyhose (see below).
A surgical or cloth mask fits well if…
- It isn’t gapping at any of the edges
- The top edge/nosepiece makes a (very, very flat) W against your face. Use (clean) fingers to really crease the nosepiece not only around the bridge of your nose (I like to almost-fold it in half before putting it on) but also firmly in against each side of your nose.
(Less of a widespread problem, but: you don’t want a mask that’s smashed up against your face so tightly that your lips or tongue press against it, either. The idea is for the *edges* of the mask to seal well against your face.)
[id: an MS Paint sketch of a mask saying “Please don’t lay me vaguely across your face. That won’t protect you from aerosols,” and, in Papyrus font, “Graphic design is my passion.” end id.]
Pantyhose
[id: Two photos of researcher with and without a piece of pantyhose wrapped around her face over a cloth mask, under the headline “Adding A Nylon Stocking Layer Could Boost Protection From Cloth Masks, Study Finds.” end id.]
Other updated “don’ts”
This January 2021 Yahoo Life article has a rundown on other don’ts (don’t let it get wet, nor put it in your pocket, nor touch it with your tongue, nor re-wear disposable masks, nor spray masks with disinfectant…)
Glasses tape
Tape (preferably gentle medical tape) can be used to stop glasses from fogging by taping the top edge of a mask against the skin. (Lengthwise, most of its surface area should be on your mask, not on your skin; less than a few millimeters/a sixth of an inch or so on skin holds it in place.)
Mask braces
Mask braces–a rubbery loop over a mask around its edge–can help get that all-important edge fit. Researching which braces and brace designs have been scientifically proven is beyond the scope of this post, but they’re out there!
Non-N95 high-filtration options
- When fit well (they don’t seal as tightly as N95 masks do) a genuine KN95 offers very high levels of protection, but counterfeiting is an especially widespread problem with these. If you’re able to get KN95 masks you’re reasonably confident are genuine, and follow best practices in getting a good fit, they’re some of the best protection outside of an N95.
- When fit well (they too don’t seal as tightly as N95 masks) a well-fitted KF94 offers some of the best protection outside of an N95. I didn’t come across similar warnings about KF94 counterfeiting, suggesting it’s not common (though there are probably some counterfeits out there, as there are with all personal protective equipment right now).
- An elastomeric respirator offers a very high level of protection to the wearer–N95-level or above when using the correct types of filters–though most have exhale valves that must be carefully sealed with tape, melt-blown material or other options for the mask to provide protection to people around the wearer. They’re reusable with disposable filters; some medical workers prefer them to N95 masks.
[id: Screenshot of three photos of elastomeric respirators from different brands. end id.] (Not intended as an endorsement of specific brands, etc.)
- This Google doc by an MIT researcher lists specific companies selling high-filtration masks that they or a colleague have lab-tested (KF94, KN95, close equivalents, and extra-high-quality surgical). (I’m side-eyeing some of the doc since it cites a statistic that “cloth masks” [no further specification] block only a small percentage of particles, but the author has solid credentials, and the list of specific mask companies they’ve actually lab-tested seems like a good and reliable resource.)
