Posted on 10/07/2020 8:22:54 AM PDT by Red Badger
A simple trick can reveal whether your face mask offers sufficient protection: Try blowing out a candle while wearing it. A good mask should prevent you from extinguishing the flame.
The rule isn't foolproof, but it should help weed out masks that aren't very protective.
Ever since the Centres for Disease Control and Prevention (CDC) began recommending cloth masks for the general public in April, researchers have been evaluating the best materials for filtering the coronavirus.
An ideal mask blocks both large respiratory droplets from coughs or sneezes - the primary method by which people pass the virus to others - along with smaller airborne particles called aerosols, which are produced when people talk or exhale.
It should be sealed around the nose and mouth, since any gaps, holes, or vents could allow droplets to leak out and potentially infect another person.
Assuming masks are worn properly, certain materials consistently perform better than others in studies. Based on the latest research, here's a ranking of the best and worst face coverings:
'Hybrid' masks are among the safest homemade options
As a general rule, mask fabrics should be woven as tightly as possible. That's why fabrics with higher thread counts are better at filtering particles.
It's also preferable to have more than one layer. The World Health Organisation (WHO) recommends that fabric masks have three layers: an inner layer that absorbs, a middle layer that filters, and an outer layer made from a nonabsorbent material like polyester.
N95 masks are the most protective because they seal tightly around the nose and mouth so that very few viral particles seep in or out. They also contain tangled fibres to filter airborne pathogens - the name refers to their minimum 95 percent efficiency at filtering aerosols.
A recent Duke study showed that less than 0.1 percent of droplets were transmitted through an N95 mask while the wearer was speaking.
That's why they're generally reserved for healthcare workers.
Disposable surgical masks are also made of non-woven fabric. A 2013 study found that surgical masks were about three times as effective at blocking influenza aerosols than homemade face masks (that was true, at least, when air flow was slower than a cough but faster than a human breathing during light work).
Still, there are homemade options that come close to the level of protection of an N95 or surgical mask.
An April study from the University of Chicago determined that "hybrid" masks - combining two layers of 600-thread-count cotton paired with another material like silk, chiffon, or flannel - filter at least 94 percent of small particles (less than 300 nanometres) and at least 96 percent of larger particles (bigger than 300 nanometres). Two layers of 600-thread-count cotton offer a similar level of protection against larger particles, but they weren't as effective at filtering aerosols.
That study, however, conducted measurements at low air-flow rates, so the masks might offer less protection against a cough or sneeze. Still, multiple layers of high-thread-count cotton are preferable to face coverings made from a dishcloth or cotton T-shirt. Fabrics like silk or cotton have more variable performances
A June study published in the Journal of Hospital Infection found that masks made from vacuum-cleaner bags were among the most effective alternatives to surgical masks, followed by masks made from tea towels, pillowcases, silk, and 100 percent cotton T-shirts, respectively.
Research from the University of Illinois, meanwhile, found that a brand-new dishcloth was slightly more effective than a used 100 percent cotton T-shirt at filtering droplets when a person coughs, sneezes, or talks. That study (which is still awaiting peer review) also found that a used shirt made of 100 percent silk was more effective at filtering high-momentum droplets, likely because silk has electrostatic properties that can help trap smaller viral particles.
The University of Chicago study came to a different conclusion, however: Those researchers found that a single layer of natural silk filtered just 54 percent of small particles and 56 percent of larger particles. By contrast, four layers of natural silk filtered 86 percent of small particles and 88 percent of large particles at low air-flow rates. Bandanas and scarves don't offer great protection
Bandanas and scarves have performed poorly in multiple studies.
The Journal of Hospital Infection study found that a scarf only reduced a person's infection risk by 44 percent after they shared a room with an infected person for 30 seconds. After 20 minutes of exposure, the scarf only reduced infection risk by 24 percent.
Similarly, the Duke researchers found that bandanas reduced the rate of droplet transmission by a factor of two, which makes them less protective than most other materials.
For the most part, though, any mask is better than no mask, with one notable exception: The CDC cautions people not to wear masks with built-in valves or vents.
Masks with one-way valves can expel infectious particles into the atmosphere, helping to fuel transmission. Mask studies should be taken with a grain of salt
Although research is coalescing around the idea that a few types of masks offer the best protection, it's not always easy to simulate how a mask will perform in real life.
That's because only some tests directly mimic the size of novel coronavirus particles, while others evaluate performance based on viruses like influenza. Researchers also still aren't sure about the degree to which the virus gets transmitted via aerosols, since those tiny particles are extremely hard to trap and study without killing the virus.
Some scientists even have different ideas of what constitutes an aerosol - the generally accepted cutoff is less than 5 microns (that's roughly the size of a dust particle) - and many experts think the delineation is arbitrary altogether.
Different studies also test masks under different circumstances: Some mimic the heavy air flow produced when a person coughs, while others mimic the air flow when a person is talking or breathing normally.
And of course, masks perform differently depending on how they're worn. That's why it's better to stick with more protection over less.
This article was originally published by Business Insider.
Me too :(
For 99.99 percent of mask wearers, this chart is completely, totally, entirely invalidated by this overly optimistic assumption.
Oh, and where's the column for "Efficiency at Filtering an Infinitessimally Small Virus"? This is critical to know because, after the "large droplets" and "aerosols" dry out on the surface of the mask, the damn thing, like any non-HEPA dry filter, unloads the residue (including the virus) either deep into the lungs of the mask-wearer during inhaling the next breath or dispersing throughout the local area during exhaling the next breath.
All of this assumes that a mask-wearing zealot leaves the mask in place during and after the goopy sneeze or the phlegm-filled cough, rather than lift it up to sneeze or cough as I've witnessed several times.
If your glasses fog up, your mask isn’t sealing.
I have a N95 mask. It has no vent. That is possibly a FDA logo................
It should be sealed around the nose and mouth, since any gaps, holes, or vents could allow droplets to leak out and potentially infect another person....
I understood the covid enters the body through eyes, nose and mouth.
as you exhale, the droplets are directed towards your glasses, fogging said glasses.
The covid then re-enters the body through your eyes!
Overall, not a good plan
Gee, on the back of my boxes of ear loop face masks I get at the store, it says not for use in healthcare settings.
I don’t see those masks on the chart....
I normally don’t wear them unless required.
I have two in my pocket, both with good messaging. One is Trump 2020. the other reads “Worn by force, not by fear.”
Dr. uses vape clouds to illustrate how masks do not work
Send "Orange Man Bad" federal and state government desperate Democrats home in November!
Supporting PDJT with a new patriot Congress and state government leaders that will promise to fully support his already excellent work for MAGA and stopping SARS-CoV-2 will effectively give fast-working Trump a "third term" in office imo.
I don’t see any problem with voting Republican ticket for 2020 elections.
Insights welcome.
Single-thickness cheesecloth for me, when I absolutely have to wear one.
And then there is this from Duke with different results: https://nypost.com/2020/08/11/duke-university-face-mask-researchers-share-more-on-study/
And the N-95 makes it impossible to breathe. I have a few, was grateful when air in our town was HAZARDOUS thanks to smoke from forest fires in CA and OR.
> So where does Alyssa Milano’s Crochet Mask fall on the chart? <
Masks come in many, many different colors. So I’m more concerned as to why Alyssa chose to wear a WHITE mask. I mean, how much more racist can you get?
Empirical evidence is hard to dispute.
If you can breathe through a mask, a virus can get in.
The only virus-safe mask is a self-contained breathing apparatus with its own air supply.
Everything else is just wishful thinking
A great benefit to wearing cheesecloth or medical gauze as a mask is that all the Covidians who see that mask intentionally will keep their distance. Good for them, good for us, so I call a Win.
Peach
An old sheet (high thread count) can be used to make DOZENS of masks, of the 2-layer cotton type.
I like how lightweight surgical masks are for summer. The white ones seem to be more aesthetically pleasing than the hospital blue shades.
And I don’t have a pretty mask like this one yet where I both trust its effectiveness and aesthetics:
The only good thing about the muzzle is that it makes frightened people “feel safe enough” to leave their house and help spread the Covid Cooties which allows the virus to run its course and for people to build natural immunity.
I understand the sentiment you expressed. OTOH, there is a person at my workplace who is constantly sneezing, coughing, snorting, clearing his throat, etc. Maybe it is just allergies, but I much prefer that he NOT be in my personal space at any time, and that he wear a mask when he is moving about in the office. I don’t want to catch something from him, whether covid-19, a cold, flu, or anything else.
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