Here's What Scientists Say Makes for the Most Effective Face Masks

Since April 3, 2020—nearly two years ago—the Centers for Disease Control and Prevention has been recommending the use of face masks to slow the spread of COVID-19. That's around the time that scientists confirmed that, similar to other flu viruses, this novel SARS-CoV-2 virus is a contagious respiratory illness that's passed from person to person through respiratory droplets. (ICYMI, we recently spoke to medical experts about if you need to wear a mask if you're vaccinated.)

Any mask, including those ubiquitous light blue disposable masks that are now found at nearly every business entrance, can offer some protection. But what makes a face mask the best of the best?

The CDC recommends using face masks that:

• Cover the nose and mouth completely
• Are composed of two layers of fabric that is breathable and washable
• Fit snugly along the sides of the face with no gaps
• Feature a nose wire to keep the mask tightly secured along the top

On a mission to determine even more about which face masks reign supreme (and, more importantly amidst the current spike in easy-spreading Omicron variant cases, are most effective at blocking respiratory aerosols), scientists conducted a study about the effectiveness of medical- and consumer-grade face masks.

Double masking with a well-fitting multilayer cloth mask and a medical mask, such as a N95, is your best bet, according to the study published December 15 in the journal American Journal of Infection Control, a publication from the Association for Professionals in Infection Control and Epidemiology.

The research team turned to a source many of the rest of us would—online shopping—to purchase two models of medical masks (both of which had elastic ear loops and adjustable metal nose strips) and three models of cloth masks (one two-ply polyester blend, one three-ply cotton mask with earloops and an adjustable metal nose strip, and one four-ply polyester blend with ear loops and an adjustable metal nose strip).

Testing the face masks as designed and with different modifications, such as crossing over the ear loops for a snugger fit and earloop toggles, the scientists put these masks through the paces in a breathing simulator. This tool was designed to measure how many aerosols (the microscopic particles forced into the air when you cough, sneeze or even breathe) each mask style allowed to escape during normal breathing and coughing.

The medical masks alone blocked about 42% of aerosols during normal breathing and about 56% of aerosols from coughs. A cloth mask plus a medical mask, by contrast, caught about 91% of aerosols during normal breathing and about 85% of aerosols from coughs.

The ultimate winner in their mask-off was a medical-grade mask with a nose brace and ear loop toggles (to create a custom fit) topped with a cloth mask. This combo created the best seal and blocked about 99% of exhaled aerosols and 95% of cough aerosols.

The study team, led by Francoise Blachere, a research biologist with the The National Institute for Occupational Safety and Health, say that ensuring a proper fit and double masking when possible is wise.

"Respiratory droplets and aerosols are expelled in a broad range of particle sizes. Our research shows that to be effective as a source control device, a face mask must be a good filter, but it also must fit well," Blachere tells Medical News Today. "Moving forward, it is important that the filtering properties of the materials used in the construction of a face mask are taken into consideration. Likewise, the design of the face mask should ensure a snug fit without any gaps or face seal leaks."

What mask is important, as is how you wear it, adds Fady Youssef, M.D., a board-certified pulmonologist, internist and critical care specialist at MemorialCare Long Beach Medical Center in Long Beach, California. We need to be informed users and wear with care, he tells Medical News Today.

"The modifications offered significant step-ups in [the] protection that the masks at baseline offered. It just highlights the importance [of] paying attention—it's not just wearing a mask, but how the mask fits. And taking these little steps to make sure you're optimizing your own protection, whether it's by adding a brace or tie behind the ears," Youssef says.

In the future, the scientists hope to dive into what, if any, details are different when coughs are especially strong. They also are curious about how often reusable masks need replacing, plus hope to someday develop a tool or test that would allow mask-wearers to quickly and easily assess the fit of their own face masks prior to heading out into the wild.

6 of the Best Face Masks to Buy Online

Until we know more, consider investing in one or more of these multilayer or medical-grade masks that each offer ample adjustments to make it your own.

• Good Mask Co. Good Comfort KN95 Face Mask (buy it: $39.99 for 25, Amazon)
• MagArt Reusable 4-Layer Anti-Fogging Cloth Face Mask with Nose Wire (buy it: $19.99 for 6, Amazon)
• Triple-Layered Protective Black Floral Print Face Mask (buy it: $24, Profound)
• EarthandLightCo 3-Layer Cotton Adjustable Face Mask with Nose Wire (buy it: $11.99, Etsy)
• Oura Air Mask 2.0 with Self-Sterilizing Travel Pouch (buy it: $63, Oura)
• HannahCanvasDesign 3-Layer Cotton 3D Face Mask with Nose Wire and Anti-Fog for Glasses (buy it: $7.74, Etsy)

The situation surrounding COVID-19 continues to change quickly; it's possible that information or data has changed since publication. While EatingWell is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations by using the CDC, WHO and their local public health department as resources.