> I’m amazed at the number of people I see wearing N95s or KN95s with a clear gap at the top. Why bother?
Uncharitably: People think it's a magical talisman; wear this mask and be protected. There's no grasp of the mechanism, so "wearing" the mask can be arbitrary.
Charitably: If people grasp how masks work, it's easy to forget, or not think of it, or not check that it's (still) on correctly.
(Bluntly, I think the former option more likely, but I try to think of charitable options)
I have a KN95. I can't get it to fit on the top. Always fogs my glasses. But when I breathe in, I can clearly see by the fabric's motion that air is substantially being pulled through the material rather than around it (edit: or that might just be pressure differential).
In any case, we are talking about mitigation of risk, minimization of exposure. If my mask is only filtering 80% of the air at 95%, that still a lot fewer viral particles I'm exposing myself to than otherwise. I don't think that its a matter of whether 1 viral particle gets through, but how many that determines likelihood of an infection or serious illness.
And its effectiveness is backed up by studies of unfitted 95s.
Consider how the fit can be pretty and still result in fogging up your glasses. In general but especially on cold days, you avoid fogging your glasses because the air you exhale is moving usually quickly enough that it is past your glasses by the time any of it starts diffusing and moving upward.
An N95 slows it down enough that some of the warm, moist air will make its way up to your glasses. It'll be especially noticeable if you're outdoors int he winter. Plus, the shape of some N95s and KN95s looks like it would cause some of your exhaled air to diffuse out through the mask in a more upward direction that it would if you were maskless.
> I can clearly see by the fabric's motion that air is substantially being pulled through the material rather than around it.
I suspect that the fabric’s motion doesn’t mean what you think. You’re just seeing motion from the pressure change. A non permeable plastic film will also move as the pressure changes. This doesn’t mean any air is going through it.
> If my mask is only filtering 80% of the air
If your mask is leaking around the edges, it is extremely unlikely that your mask is filtering anything close to 80% of the air.
My most important point though is that if your goal is to reduce your risk, then wearing an 95 type mask, even an unfitted one, achieves that goal. Its not all or nothing.
> I have a KN95. I can't get it to fit on the top. Always fogs my glasses. But when I breathe in, I can clearly see by the fabric's motion that air is substantially being pulled through the material rather than around it.
IIRC, KN95s were designed for flatter, asian noses. I think I read somewhere that one of the motivating factors for the design was that it's harder for asians to get a good fit with some types of N95, because they were designed for caucasian noses.
I have a big nose, so KN95s never work for me, unless I retrofit a really long and beefy metal strip for the nose.
Depends on degree; I was thinking of people who aren't even covering their noses when I wrote my comment. Good point, though; I hadn't thought of "physically doesn't fit".
Lately, I've been using FFP3 masks with N95-style double headbands. All the FFP3 masks I've seen have a foam nose bridge that makes it much easier to get a good seal than any of the KN95s I've seen.
I have a collection of various 94+% masks that I amassed towards the beginning of the pandemic. About 6 or 7 types. Only 1 of them doesn’t fog my glasses in the winter (and it’s a freakin Honeywell respirator) That means all of the others are leaking, even when I wear them “properly”
Water vapor is a lot smaller than viral particles and is likely to pass through even a N95 mask, which is good, as you'd drown pretty quickly if it didn't.
I wouldn't read too much into fogging.
(That said, I do wish there were better options for people with giant noses like mine.)
I mean, they’re fogging because the top of the mask leaks, and the breath takes the path of least resistance and goes around rather than out of the mask.
Likely, but not necessarily. My silicone half-face (with disabled check valves) slightly fogs my glasses because enough water vapor is leaving the filter close to my glasses. I'm sure it's not leaking, because I can feel the silicone pull away from my face when it does.
For me, fogging my glasses means I have a leak and the air is being forced out gaps around my nose. Maybe under extreme weather conditions a perfect fit would still fog, but that's not what the op is talking about.
I think it's more about the direction of the water vapor than the fact that the masks can pass vapor. If there was no leakage one might expect vapor to leave through the mask uniformly or in the same pattern as it did without masking (e.g. mostly forward.)
I mean, sometimes people don't really care and they have to just adhere to the rules. (Some of those people have already had covid and the vaccines and are at such low risk of spreading it or catching it, the reduction in risk posed by the mask is negligible.) People in the trades, or with similar hobbies tend to have them lying around. Plenty of times I've just grabbed a used up N95 dust mask I had lying in the truck because I had to run to the hardware store really quick and I forgot my more comfortable mask.
More often, it's probably just a lack of training / reading the instructions on how to press-fit the nose bridge.
Then there's people like me with weird faces that fail fit tests no matter how careful with basically everything except the duck masks.
This is sometimes an “optical illusion”. Good masks have a metal sheet there that you can bend to fit your nose. However, when you bend it, the outer cloth of the sheet pocket will not follow the curves as tightly, if at all. It appears as if the wearer had not attempted to bend the metal sheet at all.
I’m not sure what this means. The use of an N95 or equivalent provides value only when rightly fitting. It sounds like you’re describing a mask that gaps no matter how it’s fitted.
A lot of the people I see like this seem to have bent the nose piece so tight that it’s actually lifting the top edge off their faces (because the nose cannot fit in the tiny space created). I’m not sure if they think the absurdly tight nose piece is sealing better or if they are intentionally doing this to make it more “breathable”.
Ah, I see what you mean. I’m pretty sure that I’m not seeing an illusion most of the time, because I’m not looking at the cloth. I’m looking at the very visible skin beneath the gap. But it makes sense that the outer layer of cloth could be misleading.
> The too-tight nose piece is probably because that’s how the masks are packaged.
You’re probably right. I normally see this on the center-folded masks. This would mean that people are just throwing on the mask without fitting rather than doing an astonishing bad job at attempting to fit, or intentionally fitting to create a space. That’s certainly more understandable.
It could certainly happen. I hope not. We’re gonna see a lot of wasted n95s if so. Few people know how to fit them and a whole lot of people have beards.
There is simply no system for random joe to find masks that fit them.
Suppose you buy a mask and it doesn't fit, what do you do, but random ones untill uou find one that works? They have no categorisation, even if you find one, often you cant but it again as shops change their stock randomly.
I’m not talking about “poor fit”. I’m talking about a significant visible gap. As in I could probably put my pinkie between the mask and their face. I see this a lot and while I understand fitting masks can be hard, this it’s hard to explain like that.
Those are mostly the people just wearing a mask because they have to. Personally my thinking is "the mask mandate is here for a reason, and if I have to wear a mask anyway, I might as well wear it so it actually protects me", but even I have "misadjusted" an FFP2 mask for better ventilation when sitting in a 90% empty train on a hot day...
By my own very much baseless estimation of people wearing FFP2 in Germany: about 10% have their noses out, 60% have the mask completely unfitted, and 30% have at least tried to fit it.
Are they? If most air is coming around the edges I’d expect that whether the mask is woven cloth, surgical, n95, or solid plastic just doesn’t matter much.
I'd have thought it's pretty straightforwardly a case that effectiveness is capped at the percentage that comes through the material; so as long as some is, a better material will do a bit better. For sake of argument if you're getting 80% effectiveness from a perfect fit, that's 40% if 50% air comes around the sides, and better than an alternative that's 20% effective however well it fits. (All made-up round numbers.)
I’m not sure if it is or not. It’s something I’d actually like to understand.
I would imagine that if there’s a significant gap, most air would actually bypass the mask entirely. And “significant” here is still fairly small. I’m thinking you only need a cross section as large as your nostrils for most air to flow around the mask. And as you make the mask less breathable/more resistive, more air will bypass the mask.
Is it possible that "worse" masks actually perform better in this case, because more air actually passes through the material instead of through gaps? Not advising to use flimsy masks of course, just wondering.
