What Masks Can and Can’t Do, and Why You Should Wear One

As cases of COVID-19 decrease and states continuing opening, there have been more and more questions regarding mask-wearing. Should you still wear a mask? If so, should you wear an N95 mask, or will the more comfortable and fashionable cloth masks made at home or purchased from sellers like Disney, Old Navy, Banana Republic, Gucci, Fendi and a slew of others, be as effective?

Michael Bell, M.D., deputy director of the Division of Healthcare Quality Promotion at the Centers for Disease Control (CDC),  teamed up with the Pandemic Action Network to help answer such questions and combat misinformation. The most common misperception, he said involves who needs to wear a mask and why.

“COVID-19 shows up initially without symptoms, so we’re asking people to wear facemasks in public even when they have no symptoms,” Dr. Bell said. A facemask is a physical barrier that helps prevent the wearer from accidentally contaminating other people by containing the respiratory secretions inside the mask when they cough, sneeze or exhale. “Wearing a fabric mask makes a huge difference,” he told BioSpace.

Even though the SARS-CoV-2 virus particles are approximately .07 to .09 micrometers in size, the risk of those virus particles penetrating a cloth mask actually is quite low.

“When a person is coughing, the virus is wrapped in carbohydrates, mucus and what not,” Dr. Bell said.

That makes any particles carrying the virus larger. Exhaled particle sizes of 1 to 50 microns are typical.

“It’s unusual for a virus to be floating all by itself,” Dr. Bell explained. That risk usually is reserved for labs where these pathogen are studied. “Viruses in virology labs are purified and produced in large concentrations. That’s why lab technicians who work there wear much different equipment than those in hospital or community settings.”

In patient care settings, “healthcare workers wear N95 masks in combinations with goggles or face shields because they are in direct contact with infected people. A patient can literally cough in your face when you are examining or performing procedures,” Dimitar Marinov, M.D., Ph.D., assistant professor, Department of Hygiene and Epidemiology, Faculty of Public Health, Medical University of Varna, Bulgaria, told BioSpace. “The PPE also includes gloves, gowns and special footwear.”

N95 are designed to block penetration by 95% of particles 0.3 microns or larger. Some block particles as small as 0.1 microns. “You need careful fit testing,” Dr. Bell said, to ensure wearers aren’t breathing through breaks in the seals. If wearers are breathing air from outside the masks, it’s not doing its job.

For routine, daily wear, however, the CDC considers a cloth mask adequate to prevent an infected individual from inadvertently spreading the virus. The particle size emitted during a sneeze averages 50 microns, whereas those emitted during normal speech and breathing are 1 micron, according to a 2019 paper in Nature.

“Masks create a mechanical barrier that protects others from the wearer. If you are symptomatic, or a presymptomatic or asymptomatic carrier, it will significantly reduce the risk of spreading COVID-19 to others,” Dr. Bell reiterated. “Even walking on the beach, you never know when a Frisbee player will veer into you, or when a Girl Scout troop will hike around the bend on a hiking trail.” Therefore, carry a mask whenever you leave your home.

Cloth masks are an easy, inexpensive solution. Unlike N95s, they have the benefit of being able to be cleaned easily. “For a regular person it is enough to wash their mask daily. You can rewash and reuse the mask for 5-10 days and you should replace it with new one afterward,” Dr. Marinov said. Dr. Bell suggested that with casual, rather than constant, wear, a mask could be washed about as often as your pillowcase.

Since masks are made from many different materials and stitching patterns, “Bacteria may travel freely between the stitching,” Giuseppe Aragona, M.D., a general practitioner at the Prescription Doctor, told BioSpace. “You can always test the mask by simply blowing through it, and feeling how much air you can feel on the palm of your hand about 4-5 inches away from your face. The less you can feel, the better your mask is at protecting you from bacteria.”

The CDC recommends that people wear cloth masks, and says they can make inexpensive masks from old bedsheets, bandanas, scarves and T-shirts. In terms of design, cloth masks are like surgical masks. They’re loose-fitting and made from sometimes multiple layers of folded material to create a physical barrier between the mouth and nose of the wearer and the environment.

Cloth masks don’t protect wearers from fine aerosols, however.

These rarely are encountered in daily life, with a few notable exceptions. Dr. Bell referenced a 61-person choir practice Skagit County, Washington. Despite using social distancing, 31 people contracted COVID-19, and another 20 probably contracted the disease from this event, according to the CDC report. “Singing,” he said, “is one of the best ways to create very small aerosol particles.”

Earlier research into the spread of tuberculosis also found that singing emits six times more respiratory droplets than speaking.

The Hunta virus offers another example of how a virus may be aerosolized. Occurring in the desert southwest, this rodent-borne virus can be contracted when people use pressure washers to clean areas where the rodents have urinated, thus creating fine aerosols that carry the virus.

The bottom line is that masks are important, but should not be the only line of defense against COVID-19. Masks can prevent wearers from spreading the virus, but may not protect their wearers from contracting it. Social distancing and frequent hand-washing are essential in combatting the spread of this highly infectious disease.