The science behind the masking

Written by By Philip Miller, DO, family medicine, Mount Nittany Physician Group


As the COVID-19 pandemic continues, even in the midst of vaccines beginning to roll out, it’s important that we all continue the safety measures we’ve been practicing. One of the most important of those safety measures is wearing a face mask.

COVID-19 spreads mainly from person to person through respiratory droplets that travel into the air when you cough, sneeze, talk, shout or sing. These droplets can then land in the mouths or noses of people who are near you or they may breathe these droplets in.

Masks are a simple barrier to help prevent your respiratory droplets from reaching others. Studies show that masks reduce the spray of droplets when worn over the nose and mouth. Masks also can prevent larger expelled droplets from evaporating into smaller droplets that can travel farther.

Early on when the Centers for Disease Control (CDC) recommended that everyone wear masks to slow the spread of COVID-19, a helpful phrase to remember was “My mask protects you, your mask protects me.” Evidence continues to show that masks help prevent the spread of COVID-19.

You should wear a mask even if you don’t feel sick. This is because studies have found that people with COVID-19 who never develop symptoms and those who are not yet showing symptoms can still spread the virus to other people. Wearing a mask helps protect those around you in case you are infected but not showing symptoms.

Because COVID-19 spreads mainly among people who are in close contact with each other, it’s especially important to wear a mask when you’re indoors with people you don’t live with and when you can’t stay at least six feet apart. And you should always wear a mask when caring for someone who is sick with COVID-19.

Choosing a mask
Although the purpose of wearing a cloth mask is mainly to protect others, it also protects you to some extent. How well it protects you from breathing in the virus depends on how tightly woven the fabric is, the number of layers of fabric, and how well the mask fits.

What kind of mask should you wear? The best mask is one you can wear comfortably and consistently. Fabric masks should be made of three layers of fabric: an inner layer of absorbent material such as cotton, a middle layer of non-woven non-absorbent material such as polypropylene, and an outer layer of non-absorbent material, such as polyester blend.

When choosing a mask, check for filtration, breathability and fit. Your mask should fit over your mouth and nose comfortably, and you shouldn’t have to be constantly adjusting it. Find a mask that fits closely over your nose, cheeks and chin. When the mask’s edges are too loose and they shift, air can penetrate through the edges. Masks with vents or exhalation valves aren’t recommended because they allow unfiltered breath the escape the mask. Surgical masks are generally more protective than cloth masks, and some people find them lighter and more comfortable to wear.

Doubling up

Earlier this month, the CDC released new research that found wearing a cloth mask over a surgical mask offers more protection against the coronavirus, as does tying knots on the ear loops of surgical masks. The findings prompted updated guidance on how to improve mask fit as concerns over a number of new variants of the virus are emerging. For optimal protection, the CDC recommends making sure the mask fits snugly against your face and to choose a mask with at least two layers.


A current guide to masks, including how to select, how to wear and how to clean is available at


No matter which mask you choose, the bottom line is that any mask that covers the nose and mouth will reduce the spread of the coronavirus. And remember, while wearing a mask, you should still keep physical distance from others.


Philip Miller, DO, is a provider with Mount Nittany Physician Group Family Medicine at its Green Tech Drive location.