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Everything you need to know about masks: What kind to get, where to buy them, and how often you can reuse them

A 3M Co. 8210Plus N95 particulate respirator.Angus Mordant/Bloomberg

With the highly contagious Omicron variant driving a nationwide surge in coronavirus cases and hospitalizations, the discussion over the most effective face coverings to stave off infection has again been elevated in the headlines.

Between its apparent ability to evade immunity to a greater degree than previous mutations of the virus to warnings from public health experts that “just about everybody” will become infected with the variant, Omicron has fueled a manhunt for the most optimal protection.

But shifting guidance and shady online retailers marketing masks that turn out to be counterfeit have left many scratching their heads. Here we try to break down some of the most common questions surrounding masks — from learning how to detect frauds to knowing when to toss them out.


What kind of masks are experts recommending?

The arrival of the fast-spreading Omicron variant, which now constitutes more than 98 percent of cases in the country, has spurred public health experts to recommend that people switch their face coverings to a three-layer surgical mask, KN95, KF94, or N95 respirator.

According to a graphic from the Centers for Disease Control and Prevention, surgical masks and respirators have some key differences.

While a surgical mask, for instance, does not provide the wearer “with a reliable level of protection from inhaling smaller airborne particles,” an N95 respirator filters out at least 95 percent “of airborne particles including large and small particles.” Both offer others protection from the wearer’s respiratory emissions.

While KN95s are made and tested in China, KF94s are manufactured in South Korea. KN95s masks are considered to be the Chinese equivalent to N95s — they are made of the “same synthetic material and [also] filter out and capture 95 percent of particles in the air,” Dr. Ravina Kullar, an infectious disease specialist, told the Strategist. She added that the “KF” in KF94 stands for “Korean filter” and that the 94 represents its 94 percent filtration efficacy.


Cloth masks, meanwhile, are only able to filter larger droplets, according to the Johns Hopkins Bloomberg School of Public Health.

It is also particularly important that the mask fits well as gaps between the mask and face may provide an opportunity for the virus to enter. The University of Washington has listed a number of steps to help prevent airborne particles and respiratory droplets from leaking in or out of the mask.

Where can these masks be found?

One of the ways to identify the right mask to buy is to check a list of respirators that have been approved by the National Institute for Occupational Safety and Health. Links to the manufacturers are also provided.

Major hardware store chains including Lowes, Home Depot, and Ace Hardware — or even your local supply shops and pharmacies — are also likely to have masks available.

Some may be quick to jump online and make the first purchase they can find. But before you buy anything, particularly on websites you are unfamiliar with, the CDC has provided a number of tips for spotting counterfeit respirators.

Possible warning signs to look out for include listings that claim to be “legitimate” or “genuine” and any poor grammar or typos. If you are able, also take a close look at any reviews posted and the transaction history.


But if you do not wish to purchase directly from a company, the nonprofit Project N95, which verifies suppliers of personal protective equipment and vets the products offered, from respirators to face shields, is an option. The shop is open to the public — enabling them to purchase only what they need as opposed to having to make a large order of supplies.

How can I tell if my mask is certified or fake?

Although NIOSH does not certify KN95s, the research agency does certify N95s. The CDC has provided a list of respirators approved by NIOSH on its website, along with one that has counterfeit versions.

Respirators approved by NIOSH have an approval label on or within the packaging of the respirator, according to the CDC. An abbreviated approval is also on the respirator itself. There may also be warning signs indicating the mask is fake by the packaging, such as if it is not tamper-evident or if there is no expiration date.

The signs that a respirator may be counterfeit, according to the CDC, include it having no markings at all, no approval number on the respirator, and no NIOSH markings. The health agency also noted that a mask is likely fake if it has claims for approval for children as NIOSH does not approve any type of respiratory protection for children and if the respirator has ear loops instead of headbands.


For KN95s, you can look up the filtration efficiency and test results of various models in a database from the National Personal Protective Technology Laboratory. About 60 percent of KN95 respirators in the United States are counterfeit and do not meet NIOSH standards, according to the CDC.

How much use can I get out of it?

Although disposable masks can get more than one use out of them, experts said their reuse comes with caveats — and that they should eventually be disposed of.

“Often masks are meant to be used for a certain number of hours and should be stored, following instructions, until either they have been used for the maximum hours or before that if they are soiled or worn out,” Amira Roess, a professor of global health and epidemiology at George Mason University, said in a question and answer about the variant.

Cloth masks can be cleaned frequently. Surgical masks can also be washed and reused. Although surgical masks lose “some effect of the electrostatic charge,” when cleaned, they will still outperform cloth masks, Dr. Stephen Luby, a professor specializing in infectious diseases at Stanford University, told KHN.

Dr. Sabrina Assoumou, an infectious disease physician at Boston Medical Center, said it is recommended that N95s are switched every day, but added that they can be rotated.

“If you have three masks, you could number them and switch them around,” Assoumou told USA Today.

Despite N95s and KN95s being characterized as one-use, they can be worn more than once unless used in a health care setting, Dr. Leana Wen, a professor of health policy and management at George Washington University, told KHN.


But at a certain point, the mask should be disposed of.

The CDC says that N95 respirators cannot be washed and that they should be discarded when they are damaged, dirty, or difficult to breathe through. The more the mask is worn, the more stretched out it becomes, which prevents a tight seal from being created. You should also avoid touching your mask too often.

Shannon Larson can be reached at shannon.larson@globe.com. Follow her on Twitter @shannonlarson98.