The controversy over the use of N95 masks 2:58
(CNN) -
Think of face masks as the newest fashion accessory that can save your life and the lives of your loved ones.
But instead of the pattern, logo or slogan it displays, choose your mask based on its effectiveness against the deadly coronavirus in the environment you find yourself in.
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The different types of masks and their effectiveness against covid-19
Guidelines on how to help you make that decision should be released in mid-spring, according to Jonathan Szalajda, deputy director of the National Laboratory for Personal Protection Technology, part of the National Institute for Occupational Safety and Health at the Centers for Occupational Safety and Control. Disease Prevention USA (CDC).
Working closely with government agencies, industry stakeholders, and ASTM International, an international technical standards organization, the standards will apply to filter efficiency, size and fit, cleanliness, and the recommended period of use or reuse.
For now, here's a breakdown of respirators and masks based on current scientific knowledge, and what experts are saying about how to best use them.
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N95 type masks
Made from woven fibers with an electrical charge that can trap errant particles, like a sock sticking to your pants in the dryer, studies have shown that N95-type respirators are currently at the top of the line when it comes to filtering. large and small particles.
Masks in this category are also known as "filter facepiece respirators" or "disposable respirators."
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"It would stop the epidemic," Dr. Abraar Karan, an internal medicine physician at Brigham and Women's Hospital and Harvard Medical School, told Dr. Sanjay Gupta, CNN's chief medical correspondent.
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N95 respirators come in many sizes to fit various face shapes.
When fitted to the wearer's face and used correctly, N95-type masks can trap 95% of particles around 0.3 microns, studies have shown.
SARS CoV-2 can be as small as 0.1 microns in diameter, or about 4 millionths of an inch.
While it may appear that the N95 filters would lose the tiny covid particles, they are not.
Most of the virus fragments leave the lungs encased within larger respiratory droplets, usually much larger than 0.3 microns.
Even the ones that are aerosolized are easily captured.
Due to a natural phenomenon called Brownian motion, these tiny particles do not travel in a straight line.
Instead, they bounce back in a zigzag and easily get caught in the N95's electrostatic filter.
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While some experts are calling for a nationwide rollout of N95 masks, these masks are currently reserved for healthcare professionals on the first line of care for COVID-19 patients.
This is partly due to the shortage of such masks, which are designed for one-time use and disposal, but also due to the training required to properly don and wear the mask.
"In a healthcare setting, there is an advantage because there is a degree of sophisticated training to educate people on how to properly use respirators that do not exist in a public setting," said NPPTL's Szalajda.
According to the CDC, some other respirators also meet or exceed the 95% efficiency level: the N99, N100, R95, R99, R100, P95, P99, and P100 masks.
Some of these devices, which may resemble gas masks, have received an emergency use authorization and can be used in non-surgical settings during the N95 mask shortage.
The N95 mask, and its sisters and brothers, better conforms to the unique facial contours of a person on a bare face to maintain the airtight seal.
So the mask must be used correctly, even though such high filtration can make breathing difficult.
Type N95 masks have a much higher respiratory resistance than plain cloth or surgical masks.
"I've seen people with a full beard using the N95, or using the 95 backwards, or they just have it over their mouth and not over their nose and mouth because it's easier to breathe when you're not covering your nose," he said. Szalajda.
Note: Be careful with N95 masks with exhalation valves, as those valves return airflow to the environment.
Also watch out for knockoff N95s sold online and in some commercial stores.
The CDC's National Institute for Occupational Safety and Health (NIOSH) lists dozens of counterfeit masks sold as N95 or NIOSH-approved masks on its website, and offers the following tips on how to make sure you don't buy a fraudulent product:
NIOSH approved respirators carry an approval label on or inside the respirator packaging and on the mask itself.
NIOSH approved respirators will always have one of the following designations: N95, N99, N100, R95, R99, R100, P95, P99, or P100
You can check the approval number on the agency's equipment list or on the trusted sources page to determine if the respirator has been NIOSH approved.
Europe FFP2
In response to the spread of newer and more contagious variants of COVID-19, some European countries require the use of FFP1 and FFP2 masks, which stand for "filtering mask respirator."
Note: The "P" means that the mask is very resistant to oil and can be used to protect against non-oily and oily aerosols.
In comparison, the "N" in N95 means that the mask is not oil resistant and cannot be used in an oil droplet environment (such as drilling for oil).
An FFP1 filter has a minimum filtration efficiency of 80%, an FFP2 is 94% effective, and an FFP3 is 99% effective against airborne infectious diseases.
Last week, the German state of Bavaria ordered citizens to wear FFP2 masks when shopping in stores and riding public transport.
The German government then followed suit, demanding that everyone in the country wear FFP1 or FFP2 masks while at work, in stores, or traveling on public transport.
France also requires citizens to leave home-made masks behind.
Single-use FFP1 surgical masks and more protective FFP2 filtering facepiece respirators are now required in all public places.
France is also allowing people to use commercial cloth masks certified to filter 90% of particles greater than or equal to 3 microns.
Citizens are told to look for the "leak guarantee" logo when purchasing such masks.
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KN95 and similar filtering facepiece respirators
KN95 masks, which are certified to Chinese standards, also filter and capture 95% of 0.3 micron particles.
But there are differences: The filter layers of N95 respirators were "8 times thicker and had a dipole charge density 2 times that of KN95 respirators," according to a study published in December.
These KN95 masks are not NIOSH certified, but some KN95 mask manufacturers have received emergency use approval for use in healthcare settings in the USA.
The 3M company, which makes many filtering facepiece respirators, published a document comparing N95 and European FFP2 respirators with Chinese KN95, Australian-New Zealand P2, Korean First Class, and Japanese DS2 and found that they were all "similar. "Regarding" filtering of non-oily particles, such as those resulting from forest fires, PM (small particles) 2.5 from air pollution, volcanic eruptions or bioaerosols (eg viruses) ".
"However, before selecting a respirator," the 3M document read, "users should consult their local respiratory protection regulations and requirements or consult with local public health authorities for guidance on selection."
Surgical grade masks
Designed for use by surgeons and other healthcare professionals, surgical grade masks are loose, disposable devices intended to "help block droplets, aerosols or splashes of large particles that may contain germs (viruses and bacteria), preventing them from reach the mouth and nose, "according to the US Food and Drug Administration (FDA).
They do not "filter or block very small particles in the air that can be transmitted by coughing, sneezing or certain medical procedures," the FDA stressed.
"Surgical masks were not designed to perform the functions of the respirator," said NPPTL's Szalajda.
"They are not intended to protect against inhalation particles, but against contact with bodily fluids."
True medical grade masks are made from three layers of non-woven fabric, usually plastic.
The colored fabric top layer is made from medical grade spunbonded polypropylene, which is a heat bonded resin polymer in a web-like structure.
Surgical masks also have small wires that can be bent to help the mask stay in place and are often tied behind the head or secured with earmuffs.
This design doesn't make a particularly good fit, especially compared to the N95, according to Szalajda.
Surgical masks are single-use, and if they are dirty or breathing is difficult, the mask should be disposed of and replaced carefully, the FDA said.
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Homemade cloth face masks
The most commonly used mask among general people today is a cloth mask, often made at home.
The effectiveness depends on the type of fabric used and the number of layers of fabric.
These masks can be only 26% effective.
According to the CDC, "Multiple layers of fabric with higher yarn counts have demonstrated superior performance compared to individual layers of fabric with fewer yarns, in some cases filtering almost 50% of the fine particles smaller than 1 micron. ".
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That's good news: Studies have found SARS-CoV-2 in aerosols between 1 and 4 microns.
A study published last September examined the ability of cotton, polyester and silk to repel moisture when used in masks or as mask inserts.
"We found that silk face coverings repelled droplets in spray tests, as well as single-use disposable surgical masks," the authors wrote, adding that silk masks "may be more breathable than other trapping fabrics. moisture and are reusable through cleaning. "
Whatever the fabric, look for a tight weave, according to studies.
Use the light test to check the fabric - if you can easily see the outline of individual fibers when you hold the mask up to the light, it is probably not effective.
You can also add filters to your cloth mask, according to the CDC.
Some are made of polypropylene, the plastic that produces static cling;
others made of silver or copper, which have antimicrobial properties.
However, studies on the efficacy of inserts are rare, so guidance is limited.
To increase their odds, people have started putting cloth masks over surgical ones for added protection.
President Joe Biden has been seen wearing two masks numerous times.
On the day of the inauguration, the candidate for Secretary of Transportation, Pete Buttigieg, and her husband, Chasten Glezman, took a selfie with double mask and the poet of the inauguration Amanda Gorman wore a surgical mask underneath her version by Prada.
It's been an unforgettable and historic day.
Congratulations to @POTUS and @VP!
https://t.co/xrjIHkeNIt
- Pete Buttigieg (@PeteButtigieg) January 20, 2021
It's behavior advocated by Joseph Allen, associate professor at Harvard's TH Chan School of Public Health and director of the school's Healthy Buildings program.
"A surgical mask with a cloth mask on top can achieve a particle removal efficiency of greater than 91%," Allen recently told Dr. Gupta's team.
It makes sense to wear a double mask, according to Dr. Anthony Fauci, now Biden's chief medical adviser.
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"If you have a physical cover with a cape, you put another cape on, it just makes common sense that it's probably more effective and that's why you see people double-masking or making a version of an N95," he told her. Fauci to NBC's Savannah Guthrie.
But pay attention to putting on any masks, Allen told CNN last fall.
"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."
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Face shields, bandanas, gaiters, balaclavas, and scarves
Certain items do not provide a sufficient barrier against COVID-19 and other viruses and should not be used as a means of meaningful protection, according to the CDC.
Don't wear knitted scarves or balaclavas for protection, the CDC says.
Don't wear a face shield without a mask, the agency cautions, as it won't protect against the tiny airborne droplets that can float under and inside the shield.
And forget about scarves and leggings.
A 2020 study from Duke University examined 14 commonly available face coverings.
As expected, the fitted N95 was considered most effective, followed by three-layer surgical masks.
But the study found that folded scarves, knitted masks, and neck scarves didn't offer much protection at all.
In fact, gaiter masks, also known as neck fleeces, actually increased the transmission of respiratory droplets.
CNN's Keri Enriquez and Eliza Mackintosh contributed to this story.
Editor's Note:
This note was originally published in January 2021 and was updated in July 2021.
Covid-19 masks
