How masks reduce the spread of COVID-19
July 4, 2020 11:17 PM   Subscribe

How well do masks work? (YouTube: It's Okay To Be Smart). Quite well, of course, if worn properly, and Schlieren photography (Wikipedia) gives a great visualization of just how well they do.
posted by biogeo (36 comments total) 33 users marked this as a favorite
 
I started looking for info about the business of face masks making. Didn’t find anything comprehensive. I wonder who gets into it, both on small and on large scale
posted by growabrain at 11:39 PM on July 4


I so wish that this was required viewing for every person who ever goes out into public. The sheer number of people who wear their masks below their noses is frightening.
posted by newpotato at 1:42 AM on July 5 [12 favorites]


people who wear their masks below their noses is frightening.

Yes. WTF are they thinking?
posted by Kirth Gerson at 4:46 AM on July 5 [3 favorites]


I get so mad when I see people wearing their masks below their noses. It would be better if they didn't wear one at all so we could see them coming from a greater distance and avoid them.
posted by Too-Ticky at 5:10 AM on July 5 [7 favorites]


Interesting article in today's Japan Times about Japan's long history of mask usage.
posted by flapjax at midnite at 5:17 AM on July 5 [3 favorites]


I saw a guy the other day wearing a mask only over his nose....
posted by GenjiandProust at 5:17 AM on July 5


Goodness, yes, Japan has a long history of mask-wearing. It also has a long history of people not covering their noses, or even just sort of walking around with their masks pulled down over their chins, which reminds me of the time in middle school we all made fun of a classmate who thought that you wear a condom around your balls.
posted by DoctorFedora at 6:05 AM on July 5 [3 favorites]


This is the kind of informative content that you might actually get a relative to watch, so thanks for that. I mean I've read various summaries of why masks work for months now, but good luck getting your boomer aunt to read a PDF of a Lancet article.
posted by aspersioncast at 6:51 AM on July 5 [3 favorites]


people who wear their masks below their noses is frightening

There was a conscious decision to call it "Mund-Nase-Schutz" (Mouth-Nose-Protection) here both because it doesn’t necessarily have to be a mask, and to stress the "nose" part. There’s still a scary number of people wandering around with their masks below their nose.

On the other hand, this seems to be fairly typical. Despite all aircraft safety demos telling you to put "the mask over your nose and mouth", it seems people still forget their noses. (See the pics of the 2018 Southwest incident (NYT) for example).
posted by scorbet at 7:49 AM on July 5 [7 favorites]


Let's all make a bunch of tiny nose-sized supplementary masks and hand them out to people who wear their mask below the nose.
posted by kleinsteradikaleminderheit at 7:50 AM on July 5 [14 favorites]


I wonder if the mask below nose thing is led by glasses wearers? Masks are uncommon where I live but compulsory in hospitals. I had to visit one this week and my glasses steamed up almost immediately so everything was a fog. The nurses clued me and others in rapidly that the cheap masks are a better fit if you crossover the hooks in front of the ear and then put your glasses slightly on top of the mask. Makes all the difference but we all needed to be told.
posted by biffa at 8:18 AM on July 5 [7 favorites]


As anecdata, biffa, no one I've seen with their mask below their nose has been wearing glasses. Seriously, no one.
posted by cooker girl at 8:25 AM on July 5 [14 favorites]


I had to visit one this week and my glasses steamed up almost immediately so everything was a fog.

It also helps a great deal if you get a mask with a wire over the top edge so you can pinch it to the shape of your nose. The mask has a much batter fit and you don't get as much of a puff upwards, fogging your glasses.
posted by bonehead at 8:28 AM on July 5 [7 favorites]


The Science of Mask-Wearing Hasn’t Changed. So Why Have Our Expectations? Michael Osterholm is quoted; he was on Fresh Air a couple weeks ago and it's a good interview.

If you've ever snorkeled or used SCUBA gear, it's hard to trust that you can breathe that way.

I started suggesting that people who sew could be making masks early on, reasoning that blocking droplets could only be useful. So much pushback. Do people behave less safely when they wear a seat belt or helmet? Do they behave less safely wearing a mask? Or is it a vivid reminder that the air is dangerous?
posted by theora55 at 8:39 AM on July 5 [1 favorite]


People wearing masks below their noses might be missing the point, but in many cases it's still better than nothing. Unless they're sneezing, it's less likely that droplets are issuing out from their noses as they breathe the way they do when we exhale through our mouths.

Certainly, more people should be better informed about how to wear a mask properly, and *why*. Not telling people why is a big part of how public health messaging gets dismissed or ignored. It just seems arbitrary and pointless. But someone wearing a mask improperly is someone who at least is trying to do something, and therefore reachable by the right message and messenger.
posted by pykrete jungle at 9:43 AM on July 5 [2 favorites]


Or it's someone who is in a place where masks are mandatory, and does not want to get reprimanded and/or fined but also can't be bothered to do it right.
posted by Too-Ticky at 10:15 AM on July 5 [8 favorites]


it's less likely that droplets are issuing out from their noses as they breathe the way they do when we exhale through our mouths.

This is visible in a couple parts of the video; also your nostrils are pointing down rather than out. It's obviously the wrong way to wear the mask and less-than-ideal, but probably still significantly better than nothing.
posted by aspersioncast at 12:05 PM on July 5


We were at the laundromat today. We waited most of the wash cycle in our car outside (in the blazing heat), but we underestimated how long it would take.

During our brief indoor interlude, we observed almost everybody else wearing masks, with the exception of the white men. About a quarter of the white men (my husband included) had a mask on correctly (as is now required in our county for people occupying indoor public spaces). One of the white men had his mask down over his neck, presumably so he could tug it up if someone actually asked him to. The rest had no masks on at all.

I guess it’s up to the rest of us to protect them, but not the other way around.
posted by armeowda at 12:13 PM on July 5 [8 favorites]


does not want to get reprimanded and/or fined but also can't be bothered to do it right

Yeah, I think there are different dynamics depending on where you are. This is the impression I get where I am too - but I’m in Frankfurt where masks have been compulsory in indoor public spaces and public transport for ~2 months now, and the number of new cases is very low, so there’s an assumed lower risk of getting it.

There’s also not the same politicization surrounding masks and I think, more broad acceptance than in the US and some other countries. There are still people who don’t see the point, but still comply just in a slightly half-assed way. (Leaving the nose out, waiting until they are on the train and seated before pulling out the mask, though it’s off before they leave the train again.)

Do they behave less safely wearing a mask?

I have to admit I did catch myself thinking that I can now do some slightly riskier (for me, and others) things just because I now had a mask on. Granted, everyone else around me was supposed to be wearing a mask too, but my own logic was based solely on me wearing one. (By riskier, I mean taking public transport to go somewhere else for a walk, or going shopping for non-essentials in more crowded areas, and things like that.) Several of the people I was talking to also felt that the social distancing was drastically reduced in shops when masks were made compulsory, even when there was space available.
posted by scorbet at 12:33 PM on July 5


Certainly, more people should be better informed about how to wear a mask properly, and *why*. Not telling people why is a big part of how public health messaging gets dismissed or ignored.

Health communication professional here, and while I haven't worked specifically on mask-related messaging I've got a strong foundation from which to speculate the following -

People who are wearing their masks wrong aren't doing it because they don't know how to wear it properly. That is, they're not doing it because they don't have enough facts (think about all the things that people often do despite knowing that it's maybe not that great but hey it's mostly fine). They're doing it for other reasons - maybe to them their comfort outweighs the reward they get from wearing a mask (not really believing that it does anything since they're not sick!), or they don't feel sufficiently at risk, or they don't feel as though masks sufficiently address their feeling of risk. Quite frankly, most people consider themselves the exception, not the rule.

Good health comms doesn't just blast people with facts. Rather, it's based in theoretical models that connect what people are doing to what they are thinking and why. One useful model is about how people need to both feel at risk, and to feel like they're suitably armed to protect themself - so messages need to incorporate a manageable sense of danger and, in a narrative way, a turn, a sense of relief, of arming yourself with the right tools. It's not just the facts - it's which facts, when, and why.

And, good health comms addresses what's important to you (you, the recipient of the message). A little hackneyed but when I tested messages for older-adult vaccinations that referenced people's grandkids with the message "Stay healthy so you can stay in their life," people legit teared up and said "I never thought about it that way, I'm definitely going to get those shots."

I have watched with frustration throughout the coronavirus pandemic as public health professionals and health comms professionals have been sidelined, despite the science we have about the efficacy of our approaches, and watched politicians bumble their response, their messages, and their recommendations. Health comms is a science, too - there is a way to give people information so that they're more likely to change their behavior. We can test theoretical models, when they apply, when they don't apply, how well they work, etc. But regrettably, too many people think that throwing an encyclopedia at people will get them to do what they want them to do, because facts, and them blame the people when their messages fail.
posted by entropone at 1:00 PM on July 5 [48 favorites]


A recent vlog (Viral Transmissions #14)features a couple of MDs tackled the question of whether wearing a mask affected the wearer's blood oxygen level: one doctor wears an oxygen saturation tester while doing the cast and mask, and regularly shows the results to the camera. Then he adds a second mask atop the first. And a third. And a fourth. And a fifth.

He keeps going until his ears are unable to support any additional straps. Spoiler alert: his blood oxygen does not drop.

I add that at least one of the people on the cast is a mefite, but not a very active one.
posted by ricochet biscuit at 1:37 PM on July 5 [14 favorites]


What about covering your ears? Even though you do not expel or absorb much air through your ears, they are directly connected to your mouth and nose. Virus doesn't worry to much about going through the difficult path.
posted by CRESTA at 2:45 PM on July 5


A recent vlog (Viral Transmissions #14)

I would also point out that the other (unmasked) doctor on the videocast, Dr. Greg Rose, points out the reasons for the shift in messaging between February and June on mask wearing: partly it was to keep procedure masks from vanishing in panic buying (as with toilet paper). He also adds that PHO (Public Health Ontario) had at the time of recording had a message saying that there have been no large randomized control trials that support the use of masks. He adds:
However, in these situations I like to think of an absolutely beautiful... one of the best papers in medicine on any subject was a systematic review that was published in the December 2003 edition of the British Medical Journal -- and Rob may already know the one I'm talking about -- it was a systematic review looking for randomized control trails on the use of parachutes to avoid major trauma when jumping from airplanes. And as it turns out, there is not a single RCT demonstrating that parachutes are beneficial when jumping from high altitudes.

Nonetheless, we use them.
posted by ricochet biscuit at 2:45 PM on July 5 [15 favorites]


Some people dig themselves a hole and don't stop. Seems to be a thing amongst those who praise their own expertise (often entirely a fantasy as well) but dismiss the expertise of others when it doesn't fit their world view.
posted by juiceCake at 8:08 PM on July 5 [4 favorites]


What about covering your ears?

Per everything I can find, seems you're unlikely to catch C19 through your ears, mainly due to the difference in skin type. Your eyes would be more likely than your ears, and glasses would help if you're concerned about that, but virus-bearing particles entering the mouth or nose are still the most likely vectors of infection.

However -- remember that what we're talking about here is primarily preventing the spread of virus from infected people, especially people who don't know they're infected or aren't showing any major symptoms, to other people. The kinds of masks available to most people are not very good at preventing infection from coming in but they're quite good at preventing infection from getting out. Wearing masks is less about protecting ourselves directly and more about protecting others, which is why everyone doing it is so important.
posted by Two unicycles and some duct tape at 9:04 PM on July 5 [7 favorites]


I get weekly updates from [famous university medical system] pathologists and that's pretty much what they've been stressing for the last couple months. Masks are the basket they're putting almost all their "some resumption of normal activity" eggs into. Because they keep the wearer from spraying out virus-laden clouds. Which is also the point of the video in the post.
posted by aspersioncast at 10:30 PM on July 5 [3 favorites]


Fortunately, there's not usually a lot of airflow coming out of your ears. And if there is, well, 1) go ahead and cover them up to protect others, then 2) go see a doctor about it, something's gone terribly wrong in there.
posted by biogeo at 11:04 PM on July 5 [10 favorites]


<ernie>I'm sorry, Bert, I can't hear you, I lack eardrums</ernie>
posted by away for regrooving at 12:25 AM on July 6 [1 favorite]


Some people dig themselves a hole and don't stop. Seems to be a thing amongst those who praise their own expertise (often entirely a fantasy as well) but dismiss the expertise of others when it doesn't fit their world view.

For those who didn’t look at juiceCake’s link, it is delicious: a “wealth strategist” goes to a Toronto hospital with a possible broken finger, refuses to wear a mask, and videos the nurses telling her that she must wear a mask; after the video ends, Security escorts her to the door. She posts the video to Twitter to demonstrate her outrage and... does not get the sympathy and support she is looking for.

The loveliest bit is well down the thread, someone posts a screenshot showing that the original poster has sent the video to Rebel Media, a sort of Canadian Fox News cargo cult, where she describes the video as having gone viral.

Well, yes, in the same sense that Napoleon could describe Waterloo as a triumphant battle.

I mean, I know MeFi has a limited tolerance for posts and comments that amount to, “Look at this asshole,” but this is a superb exemplar of the form.
posted by ricochet biscuit at 6:41 AM on July 6 [13 favorites]


Dr. Greg Rose, points out the reasons for the shift in messaging between February and June on mask wearing: partly it was to keep procedure masks from vanishing in panic buying (as with toilet paper)

It's absolutely insane that doctors, purchasing products for major hospital corporations, would be concerned about competing with the retail market ***(even though it mostly seems to be untrue.) for medical products, and something that screams to me a total failure of our medical market and general preparedness. And since I just said it's untrue, it's insane that our top medical professionals would be so disconnected from hospital procurement procedures that they would think it is true - that hospitals compete with individual consumers for medical purchases that they would tailor their advice to that untruth.

***I mostly say it is untrue for two reasons: where I live, the major hospitals have a separate procurement arm to purchase medical equipment collectively. They do not compete or purchase with retail, though they do compete (obviously) with other unaffiliated hospital networks in other cities, and the number of masks they had to purchase was a major ramp up not terribly different from buying toilet paper from that perspective. It even has a separate CEO, board, staff, etc.

Reason #2 is that increased size of bulk orders required many of the smaller practices around me to form mini- consolidated procurement groups to meet the 1million mask minimum order size dictated by covid-19 factories. In any case, small practices were not directly competing with the home retail market either.

*****Of course, the US is a big place, so maybe some hospitals or small practices do occasionally buy their masks at Target or whatever.
posted by The_Vegetables at 8:53 AM on July 6


You or I won't buy a million masks individually, but Walmart or Target or Home Depot absolutely do. So that they can sell them to individuals. Even if they could be persuaded not to, there's always a money grubber or ten who would love some sweet pandemic retail markup.

That isn't necessarily how it should be, but that is how things work.
posted by wierdo at 10:03 AM on July 6 [2 favorites]


It wasn't individual doctors who came up with the idea that individuals shouldn't rush to buy masks in February and early March in order to preserve the supply for health professionals, it was public health officials at CDC and elsewhere, at least in the U.S. I recall reading multiple analyses and interviews with policymakers and public health officials at that time explaining how a rush of demand for individuals purchasing masks and other PPE would lead to stress in the supply chain preventing medical professionals from having access to this vital PPE, and the perceived benefit of the public masking was seen as lower than the cost of medical professionals not having access to PPE. I also recall seeing many, many stories in March/April about doctors and nurses having to reuse masks, or use improvised or homemade masks, due to lack of availability of supplies caused in part by panic buying and hoarding by the general public. Factors like these were part of the calculation in why we went to full quarantine: to give manufacturers and distributers time to make and disperse more equipment, including masks, that would make it safer for people to leave their homes. Thankfully the supply chain has now had a chance to pick up some slack, exactly as predicted, which is why this is now a non-issue and the consensus is (and has been for some time) firmly that everyone should mask.

So I agree that it's a sign of a truly broken system (one designed to maximize short-term profits at the expense of long-term stability) that doctors would have to be concerned about this issue, but it's also very clear that the concern was well-founded. I don't understand the argument that because major hospitals have large procurement arms that they somehow don't have to worry about the availability of masks in the supply chain, and this idea seems to be at odds with what actually happened.
posted by biogeo at 10:39 AM on July 6 [5 favorites]


I already believe in masks, so I was much more interested in Schlieren photography. That's super interesting, I wish I could set it up at home.
posted by numaner at 12:36 PM on July 6 [1 favorite]


I wonder if a more concerted PR campaign around making masks into a cool, bold fashion statement might help encourage broader adoption even better than trying to convince some people with facts at this point.

Let the Brands have at it. Market them as "freedom shields" for macho conservatives. Pay attractive Influencers to model cute masks on Instagram. Hype up "limited edition" Marvel-branded masks that come with free movie streaming with every purchase. It's hard to hold onto the idea that wearing a mask is a political statement if instead you turn it into a matter of conspicuous consumption.
posted by adso at 6:10 PM on July 6 [3 favorites]


Market them as "freedom shields" for macho conservatives.

On a recent episode, John Oliver pointed out that the Republicans could have ended the virus in days by airdropping a billion red facemasks reading Make America Great Again across the country.
posted by ricochet biscuit at 6:55 PM on July 6 [4 favorites]


numaner: I already believe in masks, so I was much more interested in Schlieren photography.

I, too, already believe in masks and I'd seen a Schlieren demonstration before, and so I was very much interested in how exactly even simple cloth masks make a difference. It makes me feel a lot less ridiculous when I'm once again the only person in the entire Aldi who wears a mask.
Off to make some more ragmasks now.
posted by Too-Ticky at 2:24 AM on July 8 [1 favorite]


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