A treatise on mask styles, filter pockets, and disposable masks
(Turns out there will be a Part 3.)
DISCLAIMER: As always, nothing in this article is meant to be official medical or safety advice. Everything presented here is either publicly available information that’s considered accurate at the time of writing, or just my opinion. If you have health-related questions regarding the pandemic (or anything else), you should seek answers from your health care professional, not a sewing lady off the internet.
Last time, we went over a short summary of Canada’s latest recommendations regarding masks and filters, with an aside for some mask myths and potential mask materials.
This time, we’ll go into a bit more detail on how some of those materials handle when used in actual face masks, as well as the pros and cons of solid 3-layer masks versus masks with filter pockets. Oh, and my thoughts regarding single-use face masks (spoilers: they’re not great, though possibly not for the reasons you’d think).
Some of my opinions are based on what little tested information that’s available at this date, and others on reasoning and my experience as a fabric worker. If you want the science part, search and ye shall find, same as I did — though there’s precious little to find. This isn’t the kind of article that’s going to list citations for all the studies I looked at, just a quick summary.
The government’s most-recommended 3-layer mask system
(And the problems thereof)
The official recommendation says to choose masks with at least three layers, preferably with a non-woven polypropylene-type material sandwiched between two tightly-woven fabrics. Speaking as a seamstress, I find this problematic. Not from an effectiveness standpoint, just a purely practical one.
In my experience, every non-woven material like the one they’re talking about tends to deteriorate fairly rapidly, especially with repeated laundering and heat drying (remember, you’ll need to wash your mask after *every* wearing).
I don’t mean that they all curl up and die after one wash cycle — just that they will lose structural integrity much, much faster than, say, the kind of high-quality tight-woven cotton I might use for the outer shell fabric. They become thin in spots and scrunched up in others, and that creates permeable patches, which kind of defeats the purpose.
Even more troubling: you won’t be able to *see* when the non-woven middle of your fabric sandwich has become useless if it’s hidden between two layers of sturdy quilting cotton!
For myself, I’m sticking to three layers of high-quality, tightly-woven (or tight-knit) fabrics if I’m using a hidden permanent third layer. I don’t fancy tossing out my perfectly good cotton masks every few wearings because I’m afraid the middle’s gone all worn and wonky. Anyway, Big Gov says this is still a quite acceptable option.
They also say you could choose to have a mask with a filter pocket, and get that polypropylene third layer as a separate filter. Which brings us to…
The masks with 3-layers vs. 2 layers with filter pockets
This is a complex issue. But when you pare it down to essentials, it mainly comes down to personal preference, since at this point in time, we don’t have actual peer-reviewed science to tell us one is conclusively better than the other.
The complicated part: how well each system works depends on loads of factors, including but not limited to the fabrics used, how well it fits your face, what filters you choose (if any), how well filter/s play with the mask design, and what you find most comfortable and easy to use.
To VERY BROADLY generalize, assuming all other factors are equal (same quality of materials, same fit, etc), there are pros and cons to both.
PROS: These are simpler to use, in the sense that you don’t need to insert and remove filters every time you wash them (which is after every wearing. Right? Right?). You don’t need to worry about filters shifting around, or whether it’s covering all the relevant areas. You don’t have to keep buying and replacing filters, keeping in mind that even reusable filter materials wear out much more quickly than any decent woven mask fabric. Pretty much any design of mask can be made in three layers.
CONS: Some people find these harder to breathe through than two layers plus a filter, though that may depend on the filter material. Edges and seams can get bulky where all three layers meet, especially if the mask pattern isn’t designed to minimize this. The authorities say we should preferentially choose non-woven polypropylene-type material as the third layer, but it will wear out before the regular woven fabric, meaning you have to toss the whole mask.
Masks with a filter pocket
PROS: Some people feel it’s safer to discard the filter piece after each use (though there’s no evidence that this is better than laundering a reusable material). But you can now use a reusable polypropylene non-woven filter as the third layer and discard it when it starts to get worn, since you can actually see it. You have the option of experimenting with different filter materials to see which one you like best.
CONS: Some people don’t want to faff about with filters every time they use their mask. You have to keep buying and replacing filters, which always wear faster than good-quality shell fabrics. Some filter materials are pretty dodgy (not breathable, ineffective, or even dangerous) so you really have to use your judgment. Filters can shift in your mask, especially if the mask design isn’t compatible with it. Which means some mask designs could be a no-no; for example, many pleated masks don’t play nicely with a lot of filters. Less breathable filters can cause serious problems for people with respiratory issues.
What about single-use/disposable masks?
Officially, we’re asked to choose washable, reusable masks instead of single-use ones when possible for the environment. Which is an excellent and valid reason all by itself. I mean, we have enough problems with without making more of a hash of the planet. The plague is no excuse to be ecologically irresponsible.
I have a whole other, seamstress/designer’s, perspective on the matter, which is that disposable masks are rather like “one size fits all” clothing. They work fine if you just happen to be the tiny minority that they actually fit well. For the rest of us — well, we all know that it should really be “one size fits none.”
Next time you see someone in one of those blue single-use masks, have a good look (from six feet away, of course). Quite often you will see spaces on either side of their nose at the top of the mask, and gaps at the sides of the face where the mask doesn’t sit flush against the skin.
If you have noticeable gaps between your face and the mask, it almost doesn’t matter what it’s made of, or how often you change it. Anything that’s out there can just hop on in, and vice versa. And the consequences of an ill-fitting mask could be far more serious than a bit of spillover from a one-size-fits-none stretchy bra.
Also, for what it’s worth, the government guidelines do specify that masks should fit well against the face without gaps.
Why don’t disposable masks fit better?
Most disposable masks are made as cheaply and therefore simply as possible. They tend to be a pleated rectangle-type affair, sometimes with a nose wire which is supposed to make the ruler-straight top edge seal against the curve of our nose bridge.
This most common single-use mask shape is a lot like our Accordion masks, which is the least popular design we have — for a good reason. It’s one of the oldest mask designs, and for the longest time, at the beginning of the pandemic, it felt like the only available one, which is why I offered it originally.
But your face isn’t a flat plane; it’s got peaks and valleys. There’s only so much a rectangle can do to curve around all your in-and-out bits. If you have a fairly narrow, small face without prominent cheekbones, eyes that aren’t deep-set, shortish chin and thinner or flatter mouth, this shape might work fine for you.
However, the rest of us find that it makes for sizeable gaps when worn. Also, the straight top edge can actually impede your vision if you wear the mask as high as you’re supposed to. This is why you often see people wearing single-use masks dangerously low on their noses — just so they can still see downward. Masks designed to scoop down under the eyes and up over the nose get around this problem, but aren’t commonly found in disposable form.
I’ve sewn countless masks for donation or sale since the early days, and NO ONE who has ever tried one of my newer designs (like the Ziggurat Mask, which is still basically a pleated mask, but with actual shaping for the nose, eyes, and chin) ever goes back to the flat rectangular pleated mask style. I realize this is just anecdotal evidence, but I think it illustrates the point.
The OTHER disposable mask problem
We’re told that masks should be cleaned after every wearing. In addition, if your mask gets wet, it ceases to be protective and you need to change it for a clean dry one as soon as you safely can.
With cold weather, your own exhalation condenses rapidly, meaning your mask WILL get damp if you’re outside for any length of time, say waiting for the bus or walking to the shops. Which means you need to change it the moment you’re able to get your hands clean to do it.
It’s not a big deal if you keep several washable masks in rotation and always carry a couple of spares, as you definitely should, especially in the wintertime. But imagine throwing out three or four disposable masks every day. Do you believe that everyone who uses them will change them each and every time they get wet or soiled?
If you do, where can I get some of your faith in humanity?
Even if you’re right, that’s an awful lot of masks in the landfill….
Next time, in Part 3:
This got way too long, so there will have to be a Part 3, in which your Ancient Aunt Kitty will go over many popularly suggested mask filter materials. We’ll talk general safety, availability, pros and cons for everything from paper towels to vacuum bags to surgical sterile wrap, and maybe a few options you didn’t even know about. If your ambition was to become a mask filter nerd, join me, and we shall…erm…rule the sewing room together.
As for the add-a-filter-pocket-tutorial?
It’s in the works. I’m trying out a few different methods to see which one/s will work best for people without my industrial machinery or specialty sewing notions. Or even a sewing machine, because these days, not a lot of you have one. I’m even trying a no-sew option, though I wouldn’t hold my breath for that one.