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mucifer

(23,371 posts)
Sun Aug 9, 2020, 08:54 AM Aug 2020

Duke U study: Neck Fleece Masks Are Worse Than No Masks

Neck fleeces, also called gaiter masks and often used by runners, were the least effective. In fact, wearing a fleece mask resulted in a higher number of respiratory droplets because the material seemed to break down larger droplets into smaller particles that are more easily carried away with air.

Folded bandanas and knitted masks also performed poorly and did not offer much protection.

"We were extremely surprised to find that the number of particles measured with the fleece actually exceeded the number of particles measured without wearing any mask," Fischer said. "We want to emphasize that we really encourage people to wear masks, but we want them to wear masks that actually work."


https://www.cnn.com/2020/08/08/us/duke-university-face-mask-test-trnd/index.html
36 replies = new reply since forum marked as read
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Duke U study: Neck Fleece Masks Are Worse Than No Masks (Original Post) mucifer Aug 2020 OP
I knew it was too good to be true underpants Aug 2020 #1
Interesting. A company is running ads for gaiter masks right now, claiming Mike 03 Aug 2020 #2
I've seen TV ads like that and they avoid the viral issue nuxvomica Aug 2020 #4
I don't think even N95 makers make the claim that masks can prevent covid 19. LisaL Aug 2020 #6
Plus face shield or goggles mucifer Aug 2020 #11
Agree. ananda Aug 2020 #12
I've seen them and I immediately... 2naSalit Aug 2020 #8
I've got to tell my duck-hunting buddy about this nuxvomica Aug 2020 #3
N95 worked the best, but surgical masks worked too. LisaL Aug 2020 #5
Folded bandanas don't do much. Cotton should be 3 ply. mucifer Aug 2020 #7
Bandanas don't fit close to the face. LisaL Aug 2020 #9
Decent bandana mask design: sl8 Aug 2020 #14
The folded bandana they tested didn't do well. LisaL Aug 2020 #22
In their picture, it looks like they're using the bandana "cowboy-style". sl8 Aug 2020 #26
Well, so much for the gaiter I just ordered. crickets Aug 2020 #10
I find it interesting that valved N95 still did better than some of the cottons. LisaL Aug 2020 #23
Makes perfect sense. Ms. Toad Aug 2020 #13
Not really. I wear an N95 at work. I had to be fit tested to make sure it's insanely snug mucifer Aug 2020 #16
The difference is that an N95 acts as a barrier to the virus (based on the size of the holes Ms. Toad Aug 2020 #32
There's more to it than that. Buckeye_Democrat Aug 2020 #33
+1 sl8 Aug 2020 #34
Fitted N95 mask did the best. LisaL Aug 2020 #24
Though their "neck fleece" doesn't look like it's made out of fleece muriel_volestrangler Aug 2020 #15
I Was Thinking The Same ProfessorGAC Aug 2020 #17
Looks like some sort of synthetic material. LisaL Aug 2020 #27
Not a very well written article LeftInTX Aug 2020 #18
Here's the actual study: mucifer Aug 2020 #19
I read it, but they still didn't assign sample numbers in their results. LeftInTX Aug 2020 #20
Actual study has a figure with their results. LisaL Aug 2020 #21
Yes, but which is which? LeftInTX Aug 2020 #30
If you open PDF of the study, it explains which is which. LisaL Aug 2020 #31
Also, link to supplement (PDF) : sl8 Aug 2020 #28
I have three stretchy neck masks ismnotwasm Aug 2020 #25
That study sure indicates you shouldn't be using stretchy neck masks. LisaL Aug 2020 #29
They took too long to do these studies. It was hard ecstatic Aug 2020 #35
Per that study, valved N95 mask still worked somewhat. LisaL Aug 2020 #36

underpants

(182,271 posts)
1. I knew it was too good to be true
Sun Aug 9, 2020, 08:59 AM
Aug 2020

I stopped wearing mine after the first time I wore it.
Didn’t make sense that it could work very well.

Mike 03

(16,616 posts)
2. Interesting. A company is running ads for gaiter masks right now, claiming
Sun Aug 9, 2020, 09:09 AM
Aug 2020

that theirs are used by Serena Williams and Dwyane Wade. Some of you might have heard the ads. I don't recall if they specifically make the claim they prevent COVID-19, but I feel that is the strong implication of the ad. Also, this is a company I've never heard ads from prior to the COVID-19 pandemic.

nuxvomica

(12,360 posts)
4. I've seen TV ads like that and they avoid the viral issue
Sun Aug 9, 2020, 09:25 AM
Aug 2020

I saw one yesterday with an ear to whether they mention viral or bacterial protection and they didn't.

LisaL

(44,962 posts)
6. I don't think even N95 makers make the claim that masks can prevent covid 19.
Sun Aug 9, 2020, 09:29 AM
Aug 2020

Even N95s only block 95% of particles (thus N95), so they are not going to be 100 % effective. And that 95% depends on a perfect fit with no leaks.

2naSalit

(86,039 posts)
8. I've seen them and I immediately...
Sun Aug 9, 2020, 09:31 AM
Aug 2020

concluded they were only half implying that you could use them as virus protection. But if you think out what they are highlighting as features, the cooling aspect, is anything but protective. They claim that the fabric is "moisture activated" for cooling purposes. Anything that increases droplets is just the wrong thing. I figured out the neck ring thing is not an option for protection.


nuxvomica

(12,360 posts)
3. I've got to tell my duck-hunting buddy about this
Sun Aug 9, 2020, 09:21 AM
Aug 2020

The guy spends every moment he can duck-hunting or fishing and has plenty of these things, and wears them when he's out among people for COVID protection. He's also very liberal but rarely goes online and might not be aware of this study. He's the type that when I tell him this will probably rush out to get some N95s. Thanks for posting.

LisaL

(44,962 posts)
5. N95 worked the best, but surgical masks worked too.
Sun Aug 9, 2020, 09:26 AM
Aug 2020

Even cotton masked worked, per the study. As far as I can tell the study focused on spread from the wearer. So N95 work best in preventing the spread as well as protecting the wearer (which we know from other studies)). But surgical masks also prevented spread pretty well, and cotton masks surprisingly did well too (not as well as N95s, but still...)

LisaL

(44,962 posts)
9. Bandanas don't fit close to the face.
Sun Aug 9, 2020, 09:32 AM
Aug 2020

I think the key here to fit close to the face with no leaks. And material that is not knitted.

sl8

(13,584 posts)
14. Decent bandana mask design:
Sun Aug 9, 2020, 12:38 PM
Aug 2020

This is the best no-sew bandana mask design that I've tried so far:



Seems to seal very well. I think the fit around/under the chin is actually better than the disposable 3M N95s I use. Overall, you end up with 4 layers of bandana cotton fabric + 1 layer of filter element. Also, the elastic straps go around the back/crown of head, rather than around the ears.

sl8

(13,584 posts)
26. In their picture, it looks like they're using the bandana "cowboy-style".
Sun Aug 9, 2020, 02:03 PM
Aug 2020

The "cowboy-style" bandana has 2 layers, no filter element, no elastic, no formable nose strip, is completely open along the bottom, and forms a poor seal across the top.

About the only similarity between the the one in the Duke study and the one in my post is that they both incorporate a bandana.


crickets

(25,896 posts)
10. Well, so much for the gaiter I just ordered.
Sun Aug 9, 2020, 11:11 AM
Aug 2020

I can save it to wear when bike riding in winter after this is all over I guess. I am glad to hear how well the basic paper masks work, as well the cotton homemade. I have both, but the cotton is so hot I've relied on paper recently and hoped for the best. Good to know!

I do need to send this to a family member who has been relying on bandanas - maybe she'll finally spring for something safer.

Thanks, mucifer!

LisaL

(44,962 posts)
23. I find it interesting that valved N95 still did better than some of the cottons.
Sun Aug 9, 2020, 01:57 PM
Aug 2020

I don't think there were any tests done on valved N95 masks before declaring them useless for protecting others because exhaled air is not filtered. This study suggests at least some of the valved masks might be o'key.

Ms. Toad

(33,915 posts)
13. Makes perfect sense.
Sun Aug 9, 2020, 12:00 PM
Aug 2020

If something is snug against your face and you are breathing directly into it, the force of your breath will expel the droplets through the covering, and when there is resistance, it will break the droplets into the size necessary to fit through the holes in the covering.

mucifer

(23,371 posts)
16. Not really. I wear an N95 at work. I had to be fit tested to make sure it's insanely snug
Sun Aug 9, 2020, 12:58 PM
Aug 2020

I wear the disposable procedure masks you can buy stores when I don't work.

Ms. Toad

(33,915 posts)
32. The difference is that an N95 acts as a barrier to the virus (based on the size of the holes
Sun Aug 9, 2020, 02:49 PM
Aug 2020

in the mask or filtration device).

If you think about sending used cat litter through a sieve - as long as the sieve holes are bigger than the kitty litter components, the sieve will break up the clumps and send them through the holds.

When you get to an N95 sieve, the holes are too small for the basic kitty litter to go through.

That's the basic principle.

Now use a mask that has holes large enough for the virus to pass through. If you are using a mask that porous right next to your mouth when you cough, speak, etc, the sieve (mask) will break up the droplets that are too large into smaller droplets that still fit through - and aerosolize them.

Your N95 mask has holes too small to let even aerosolized droplets through - so it doesn't matter how close it is to the point of expulsion from the body - they ain't gonna get thorugh.

sl8

(13,584 posts)
34. +1
Sun Aug 9, 2020, 04:20 PM
Aug 2020

Thanks for posting the video. I think a lot of people are thinking of the meltblown fiber of the mask as having "holes" which are smaller than the virus, which is not the case.

I heard one analogy which comparedthe filtering action to shooting an arrow. Imagine shooting an arrow at a target 70 yards away. You're a good shot and all arrows hit the target. Now imagine that the space between you and the target is full of trees and branches. The space betwen the trees and branches tends to be far larger than the cross-section of the arrow, yet the chances of an arrow making to the target are greatly diminished. An imperfect analogy, to be sure, but I liked it.



muriel_volestrangler

(101,146 posts)
15. Though their "neck fleece" doesn't look like it's made out of fleece
Sun Aug 9, 2020, 12:40 PM
Aug 2020

It (#11 in the picture on CNN) looks like it's made out of a shiny material.

At first, I was using a neck gaiter made out of fleece - with a drawstring around the top edge (again, not something theirs seems to have). However, I haven't used it for some time, and in case their shiny 'fleece' is somewhat related to real fleece material, I won't use it again.

ProfessorGAC

(64,413 posts)
17. I Was Thinking The Same
Sun Aug 9, 2020, 01:03 PM
Aug 2020

A lot of those gaiters are made of materials other than fleece.
I wonder if a tighter knit of something like athletic wear would be more effective.
Obviously, the broader the weave, the less effective it will be.

LisaL

(44,962 posts)
27. Looks like some sort of synthetic material.
Sun Aug 9, 2020, 02:06 PM
Aug 2020

Which apparently breaks large droplets into small droplets, thus making mask worse than no mask at all in protecting other people.

LeftInTX

(24,541 posts)
18. Not a very well written article
Sun Aug 9, 2020, 01:26 PM
Aug 2020

It is too vague.

14 masks used in the test, but they don't bother to assign the mask number to their results...

LeftInTX

(24,541 posts)
30. Yes, but which is which?
Sun Aug 9, 2020, 02:35 PM
Aug 2020




Which one is poly/cotton, PolyProp, swath, Cotton1,2,3,4,5 etc etc?


The N95 is obviously #14, Surgical is #1, Fleece is #11 Bandana is #12. But what are #2, #3, #4 etc? You can't tell the material just be looking at a picture. Which one is the MaxAT? #6, #9, and #10 look identical to me...which materials are they made of and where are the in results?
They need better descriptions of each of the masks....

ismnotwasm

(41,917 posts)
25. I have three stretchy neck masks
Sun Aug 9, 2020, 02:01 PM
Aug 2020

I fold them for protective layers. They are annoying and have turned into hair bands. I’m just using regular masks

LisaL

(44,962 posts)
29. That study sure indicates you shouldn't be using stretchy neck masks.
Sun Aug 9, 2020, 02:08 PM
Aug 2020

They did worse than no mask at all.

ecstatic

(32,566 posts)
35. They took too long to do these studies. It was hard
Sun Aug 9, 2020, 04:36 PM
Aug 2020

enough getting people to buy and wear masks. We're over 5 months into this disaster, ffs! At the store, I see a lot of people wearing masks with the valves and all I can do is shake my head and hope that everyone survives this clusterf*ck. Everything about this crisis has been mishandled from day 1.

LisaL

(44,962 posts)
36. Per that study, valved N95 mask still worked somewhat.
Sun Aug 9, 2020, 05:37 PM
Aug 2020

It did better than some of the cottons or a fleece.

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