study on masks - Printable Version
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study on masks - magnus - 08-08-2020
Researchers at Duke University did a study on 14 different masks, ranging from professionally fitted N95s to bandanas to neck gaiters.
Results were mostly as expected with N95s at the top, followed by surgical three ply masks, but a surprising finding found that neck gaiters actually produced more droplets (probably from breaking down large droplets into smaller ones) than no mask.
https://advances.sciencemag.org/content/early/2020/08/07/sciadv.abd3083
![[Image: F3.large.jpg]](https://advances.sciencemag.org/content/advances/early/2020/08/07/sciadv.abd3083/F3.large.jpg)
I wonder where commercially sold masks (from clothing lines) rank (likely a wide range of quality)
lex24 - lex24 - 08-08-2020
Have to admit, I never thought we would have studies etc on masking. :(
Better off unmasked than masked with a neck gaiter? - JustAnotherFan - 08-11-2020
I thought one of the ways to get kids to actually mask up was to get them neck gaiters that make it easy for them to have on them at all times. Turns out that they may actually INCREASE the risk of Covid-19 transmission relative to wearing nothing. SMDH
Quote:The most secure mask, an N95, led to a droplet transmission of below 0.1 percent. But handmade cotton and polypropylene masks, some of which were made from apron material, also proved effective, with droplet transmission ranging from 0.1 percent to 0.4 percent. One mask, which was knitted, released a higher number of droplets, from 0.1 percent to 0.6 percent. But none of the masks compared with the neck fleece, which had 110 percent droplet transmission (10 percent higher than not wearing a mask).
https://www.yahoo.com/lifestyle/neck-gaiters-may-actually-increase-covid-19-transmission-study-finds-183034882.html
RE: Better off unmasked than masked with a neck gaiter? - OutsiderFan - 08-11-2020
(08-11-2020, 04:10 AM)JustAnotherFan Wrote: I thought one of the ways to get kids to actually mask up was to get them neck gaiters that make it easy for them to have on them at all times. Turns out that they may actually INCREASE the risk of Covid-19 transmission relative to wearing nothing. SMDH
Quote:The most secure mask, an N95, led to a droplet transmission of below 0.1 percent. But handmade cotton and polypropylene masks, some of which were made from apron material, also proved effective, with droplet transmission ranging from 0.1 percent to 0.4 percent. One mask, which was knitted, released a higher number of droplets, from 0.1 percent to 0.6 percent. But none of the masks compared with the neck fleece, which had 110 percent droplet transmission (10 percent higher than not wearing a mask).
https://www.yahoo.com/lifestyle/neck-gaiters-may-actually-increase-covid-19-transmission-study-finds-183034882.html
I wear a neck gaiter over my mask sometimes. But doesn't the material from which the gaiter is made make all the difference?
RE: Better off unmasked than masked with a neck gaiter? - dabigv13 - 08-11-2020
It's an interesting study but not that useful. The gaiter was some spandex material, and they describe it as worse than nothing at all because it generated more small droplets. Also, the material is mostly what matters, not the gaiter shape.
But the gaiter probably did block larger respiratory droplets from traveling farther, this was just not what they were looking to study. We think this disease spreads via respiratory droplets primarily, and aerosol to lesser degree, though this is still an area of study.
Saying neck gaiters are worse than nothing at all is what you get when the media tries to interpret scientific studies. If I was going to an indoor store I'd prefer a surgical mask to a thin gaiter, but I'd prefer a gaiter to nothing all, for myself and fellow consumers.
RE: study on masks - M T - 08-12-2020
Be aware that the study was viewing the droplets from the speech of the mask wearer. The mask wasn't being protective of the speaker. I didn't think much of the study overall, but it does point out some of the issues with consumer/home-made masks.
Regarding big or small droplets, I think it is clear that small droplets are more likely to be aerosolized (actually anything expelled under 100 microns is likely to stay afloat for many minutes to days as it will evaporate to a small nuclei before it can fall to the ground; a 50 micron droplet will travel upward in the thermal plume of a person's body heat). The smaller it is, the further it can go into your airways. (See my notes on the recent UCSF grand rounds. for this, and for how far the droplets can travel in a real environment rather than a dead-air environment.)
My opinion is that there is plenty of evidence that spread happens much further than the 6' that everyone has been warned about. Since we seemingly have no way of knowing just when someone gets infected and from whom they were infected, I don't understand why the early guidance is so doggedly clung to.
More than that, I think the body of evidence is that the effects that are most devastating to individuals most often includes infections in the lower airways, and less often infections in the upper airways (or in the eyes). I would think that suggests it is smaller particles getting into those lower respiratory areas that is causing the devastation. (The UCSF grand rounds referenced how TB seems to require smaller particles so it got into the lungs to do its worst damage.)
Hmmm.... I wonder if any one has yet done similar animal studies on the size of particles containing SARS-COV-2 and the infection course.