This is how masks protect us from the coronavirus 3:43
(CNN) ––
It's official: wearing a mask not only protects others from respiratory droplets (which can spread the coronavirus), but it also protects you.
This is established by a new guide from the Centers for Disease Control and Prevention of the United States (CDC, for its acronym in English).
"Evidence has accumulated that masks work in terms of reducing risk for everyone," said Harvard environmental health researcher Joseph Gardner Allen, who also directs the Healthy Buildings program at Harvard TH Chan School of Public Health.
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But what type of mask offers you and others the best protection against any new coronavirus circulating in the air?
You want to have a mask with at least two layers.
Preferably a three-layer mask, ”Allen said.
Precisely, this expert has focused his career on "sick buildings" and how they affect the performance and productivity of workers.
In that sense, it is best to avoid bandanas and leggings masks, unless they are all the only things available.
A recent study found that both types of masks are the least effective in terms of protection.
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"Besides the level of filtration, we have to pay attention to the fit," Allen continued.
“You want the mask to go over the bridge of the nose, under the chin and be flush with the face, resting along the skin.
You want your breath to pass through the filter media and not leak out the sides, "he said.
No N95 masks or exhalation valves to protect you from the coronavirus
This is important: Don't buy N95 masks for personal use, the CDC warns.
Although these masks are the most effective –– they filter 95% of all particles––, they are considered critical supplies and should continue to be reserved for healthcare workers and other emergency personnel.
Additionally, N95 masks must be adjusted to adhere to the unique contours of each doctor or nurse's face.
You and your loved ones don't have access to that kind of expert accommodation.
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masks might help
And be especially wary of N95-like masks sold at major retailers, Dr. Marybeth Sexton, an assistant professor of medicine in the division of infectious diseases at Emory University in Atlanta, recently told CNN.
"Some of those N95 community-use masks have exhalation valves," he said.
"They make them more comfortable to wear, but they don't protect the people around you, they put the air flow directly into the environment," he said.
“Actually, it can make the situation worse by concentrating your breath on that valve.
Which allows it to pass with some force and the drops can go a little further.
Therefore, we strongly recommend that people do not wear a mask that has an exhalation valve.
Wear a thick fabric mask
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Cloth masks with a high thread count appear to be a great option against coronavirus, according to the new CDC guidance.
Look for a tight fabric that is 100% cotton, according to studies.
And use the light test to check the material - if you can easily see the outline of individual fibers when you hold the mask to the light, it probably won't be effective.
Try to find masks with as many layers as possible, but without sacrificing breathability.
Precisely, if you cannot breathe with the mask, you will not keep it on your face.
Two- and three-layer masks seem to work for most people in the face of the coronavirus threat.
According to the CDC, 'Multiple layers of fabric with higher thread count have shown superior performance compared to individual layers of fabric with fewer thread count, in some cases filtering almost 50% of fine particles smaller than 1 micron ».
READ: What is the best material to make your own mask?
Quilted cotton beats handkerchief, new study finds
That's good news.
Studies have detected the coronavirus in aerosols between 1 and 4 microns.
In addition, research has found that multi-layer fabric masks can block 50% to 80% of droplets and fine particles.
As well as "limiting the future spread of those that are not caught," the CDC said.
And they added that "cloth masks in some studies performed on a par with surgical masks as barriers to source control."
Upgrades
The CDC indicates that polypropylene, one of the most common plastics produced in the world, can "improve the effectiveness of filtration."
The reason?
Creates a triboelectric effect, or in simple terms, static adhesion.
See the affordable, reusable mask created by MIT 1:02
That static electricity traps both your outgoing breath and any drops that come your way from others.
As cotton is a more comfortable fabric for the skin, polypropylene is often used as a filter that can be placed inside a two or three layer mask.
Washing finishes the electric charge, but don't worry.
A vigorous rubbing between the fingers should restore that "sticky" charge.
One option with a lot of breathability, according to the CDC, is silk.
This material "can help repel damp droplets and reduce moisture in the fabric, thereby maintaining breathability and comfort," the agency said.
A study published in September evaluated the ability of cotton, polyester and silk to repel moisture when used in masks or as mask inserts.
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"We found that silk face liners repelled droplets in aerosol tests, as did single-use disposable surgical masks," the authors wrote.
They also added that silk masks "may be more breathable than other moisture-wicking fabrics, and are reusable by cleaning."
That makes an important point.
To avoid catching germs that could irritate your face or reduce the effectiveness of the mask, reusable masks should be washed daily with soap and hot water.
Do not use the mask again until it is completely dry.
Precisely because it is more difficult to breathe through wet fabric.
“If you use a filter in your mask, make sure to change it regularly because it can get clogged.
You can tell if you get the feeling that it's a little harder to breathe, ”Sexton said of Emory.
Etiquette in the use of masks for coronavirus
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Even the most protective mask will fail if you misuse it.
Full face protection is necessary at all times.
And that means you shouldn't let it slide down your nose, please.
Noses are important.
The droplets from the nose are usually smaller than those from the mouth.
Which also means that they can stay in the air for longer.
Studies with high-speed cameras show that sneezing can spread respiratory droplets 7 to 8 meters.
That is, well above the height of a giraffe (6 meters).
If you have trouble breathing with a stuffy nose, find a mask that fits you better.
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It is also important to wear the mask wherever you go, even in the car if you are with people outside your environment.
"If you are going to ride an Uber taxi, you absolutely must wear a mask and the driver must have a mask," Allen said.
And you want to roll the windows down, even in bad weather.
Opening the windows a bit will really help.
Always carry hand sanitizer
Regardless of the type of mask you use, you will have to put it on and take it off to eat, or adjust it in some way while it is on your face.
That makes hand sanitizer a mask's best friend, experts say.
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"Masks slip on all the time, especially when talking," said Dr. Henry Wu, associate professor of infectious diseases at Emory University School of Medicine in Atlanta.
"Therefore, you may need to adjust it frequently," Wu explained.
"That's all the more reason to have a hand sanitizer with you to keep your hands clean to tighten that mask or lift it up again."
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