You may need to start wearing better face masks

New coronavirus variants spread more easily than earlier versions of the virus. That means you may need to upgrade your face mask, experts say.

What does that mean? Many experts are recommending people wear fitted surgical masks, a cloth mask over a surgical mask, multi-layer cloth masks with a non-woven filter, or a well-fitted N95 mask.

"A surgical mask is better than a cloth mask, a tight-fitting surgical mask is better than a loose-fitting mask, and an N95 is better than a surgical mask," Dr. Tom Frieden, the former director of the Centers for Disease Control and Prevention, told Vox. 

This advice applies especially to those wearing single-layer cloth masks, bandanas or poorly fitted masks, which offer the least protection to the wearer and those around them. With more highly contagious virus variants now circulating, some European nations, including Germany and Austria, are ditching cloth masks altogether and requiring that citizens wear medical-grade masks in stores and on public transport, The Washington Post reported. 

Here's what to consider when selecting your own face mask.

Levels of protection 

Face masks block particles of saliva and moisture from spewing out of the mouth and nose. These particles can carry the coronavirus SARS-CoV-2 from one person to the next, so wearing a mask helps to cut down that transmission. While cloth masks protect others by keeping those particles out of the air, they may also protect the wearer somewhat as well, by blocking infectious droplets in the air from reaching the nose or mouth, Live Science previously reported. 

Still, highly protective N95s do a better job of protecting both the wearer and people nearby from SARS-CoV-2 particles than do cotton masks. Well-fitted N95s block at least 95% of small airborne particles, including particles as small as three-tenths of a micron in diameter, Scientific American reported. Surgical masks block less of the smallest particles, but they offer more protection to the wearer than single-layer cloth masks, according to a review of observational studies published in The Lancet in June. 

Related: Visualization shows exactly how face masks stop COVID-19 transmission

Multi-layer cloth masks with high thread counts consistently outperform single-layer cloth masks with low thread counts, both in terms of protecting the wearer and those around them, according to the Centers for Disease Control and Prevention (CDC). In some cases, these higher-quality cloth masks can filter out nearly 50% of fine particles less than 1 micron across. (The coronavirus itself is about 0.1 microns in diameter and can be carried in both aerosols smaller than 5 microns across and larger droplets.)

More contagious variant 

Early in the pandemic, both N95s and surgical masks were in short supply and the general public largely turned to cloth masks.

But although the public made do with those masks until recently, now there are more highly contagious variants of the virus to contend with. For example, early data suggest that the variant B.1.1.7, first identified in the U.K., is between 50% and 74% more transmissible than other dominant strains. And the strain first identified in South Africa, called 501.V2 or B.1.351, may be similarly contagious, experts say. 

Because these variants seem to be better at infecting people, some experts have recommended "doubling up" your masks by wearing one on top of another, The New York Times reported.

"If you have a physical covering with one layer, you put another layer on; it just makes common sense that it likely would be more effective," Dr. Anthony Fauci, the Biden administration's chief medical adviser on COVID-19, said on NBC News' "Today".

For the general public, placing a cloth mask over a surgical mask may be the best option, Popular Science reported. The cloth mask improves the fit of the surgical mask, by hugging it to the face, while the surgical mask acts as an additional filter and carries an electrostatic charge that traps respiratory droplets expelled by the wearer, and also helps repel infectious particles in the air.

Related: 20 of the worst epidemics and pandemics in history 

What about N95s? 

N95s, which offer the very best virus protection, are still in short supply for health care workers, CBS News reported. If you do go hunting for N95s, note that authentic ones are approved by the National Institute for Occupational Safety and Health and are listed online. 

Another option to look for is the KN95 mask, the Chinese equivalent of the N95. Many are available online, but these imported masks vary widely in quality; a recent study by the Emergency Care Research Institute, a nonprofit health care safety organization, found that up to 70% of KN95 masks it tested do not meet U.S. standards for an N95. To verify a KN95 manufacturer, check out the FDA's list of all surgical masks, including KN95s, that have been approved for emergency use in the U.S. during the COVID-19 pandemic. KF94s, the South Korean equivalent, are generally more consistent in quality, CBS reported. 

Avoid all masks with exhalation valves, because they release unfiltered air and don't protect those around you from the virus, according to NPR.

Whether you wear a heavy-duty mask or double mask, it's most important to practice these precautions in indoor settings, such as grocery stores and public transport. In outdoor settings, a multilayer cloth mask or a fitted surgical mask should still be adequate, since transmission is less likely in the open air, Popular Science reported.

"Based on the evidence, we still think risk of transmission outdoors is very substantially less than indoors, and there"s no reason to believe the new variants change that equation substantially," Richard Lessells, an infectious-disease specialist at the University of KwaZulu-Natal in Durban, South Africa, told Vox.

That said, masks should still be worn outdoors, and people should distance themselves from anyone outside their household. And just like in indoor spaces, the longer you spend with others, the higher the risk of transmission becomes. Physical distancing remains the best way to avoid catching and spreading COVID-19; masks are just another layer of protection to employ when you can't avoid being around other people.

Originally published on Live Science.