If you’re alive and breathing, there’s a good chance you’ve noticed the overwhelming number of articles and tutorials on face masks suddenly appearing lately: how to make them, what materials to use, what materials to avoid, what type of inserts to consider, and more. That’s because the Centers for Disease Control and Prevention (CDC) did an about-face on April 3, telling all Americans they should be wearing cloth face coverings when out in public to help stop the spread of COVID-19.
To be clear: The CDC does not want you buying precious surgical masks and N95 respirator masks, which are both low in global supply and critical to protect healthcare workers on the frontlines. “We don’t want people to go out and use those types of masks because we need them,” says Kathleen Winter, Ph.D., assistant professor of epidemiology at the University of Kentucky in Lexington. The recommendation is that you make your own, or purchase homemade face masks sewn by someone else.
Before early April, the official line was that only healthcare workers needed to wear face masks, or people caring for loved ones with COVID-19 at home. Now, the CDC advises that regular civilians strap on cloth face coverings before mingling among other people, especially when you’re going to a place where it’s difficult to maintain a six-foot distance, like the pharmacy or grocery store. (New York Gov. Andrew Cuomo officially told New Yorkers to do the same on April 15.) It’s even more important to wear one while running essential errands if you live in an area with a significant amount of community spread (meaning hot zones of COVID-19 infections, with no known, direct cause of how the virus was transmitted). However, when you’re out in the open air walking or jogging solo, and you’re maintaining proper social distance at all times, it’s probably OK to skip the mask, according to the CDC.
Still, why the abrupt change? Because experts now know that people can transmit COVID-19 even when they’re asymptomatic (they have the virus but don't show any symptoms) or pre-symptomatic (they're carrying the virus and will eventually have symptoms), says Dr. Winter. CDC Director Robert R. Redfield, M.D., says that as many as 25% of people with COVID-19 may stay asymptomatic, potentially spreading the virus without knowing it, and those who are pre-symptomatic may be even more contagious, transmitting the virus for up to 48 hours before they have symptoms.
Plus, we all know by now that the evidence shows how COVID-19 is transmitted through respiratory droplets. “These can be in the air for a short period of time or [remain] on surfaces,” says Aaron Hamilton, M.D., quality and patient safety administrator at the Cleveland Clinic in Ohio.
With so much conflicting information floating around, it can be difficult to sort out what’s what. We drilled down to the basics on what you need to know about face masks, based on the information available right now:
1. You Wear a Mask to Protect Other People
The number-one thing you should know about cloth face masks? “A homemade mask is not intended to protect the wearer, it’s intended to protect other people from what the wearer might be spreading,” says Steven Q. Simpson, M.D., professor of pulmonary and critical care medicine at the University of Kansas in Kansas City.
Dr. Simpson points out that the droplets from a sneeze can potentially travel up to 26 feet—although Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, has stated on more than one occasion that in well-ventilated areas the famous six-foot rule still applies. (Still, kinda makes you want to bolt rather than stick around to say “gesundheit,” doesn’t it?) And while most of us don’t usually sneeze quite that forcefully, with the arrival of allergy season more of us are sneezing more often. “That’s the point of the mask,” Dr. Simpson says. “You never know when you’re going to sneeze, and if you happen to be an asymptomatic COVID carrier, you’re [possibly] spreading that for a good long distance.”
Still, "whether you cough, sneeze, or even just talk or breathe, you can release respiratory secretions that have virus,” Dr. Winter adds. “Wearing a mask helps contain that, so you’re not spreading it into the air. We call that ‘source control.’”
There is evidence that homemade masks might be helpful in this regard. A study in Disaster Medicine and Public Health Preparedness looked at how masks made from 100% cotton t-shirts compared to commercial surgical masks. While both types greatly reduced the number of respiratory droplets that came out when volunteers coughed, the commercial surgical masks were three times more effective than the homemade ones. However, researchers concluded that even though homemade masks should only be used if commercial masks aren’t available, they’re better than nothing at all to help prevent the spread of infectious respiratory droplets.
Both Dr. Simpson and Dr. Winter concede that homemade face masks may provide some protection for the wearer, too—though, that’s really not their purpose. “They may help a little to protect your nose or mouth from getting the virus directly into your openings if somebody coughs or sneezes right by your face,” Dr. Winter explains. The mask will probably also keep you from touching your mouth and nose, the primary way the virus appears to be spread, adds Dr. Simpson.
And, if you’re taking care of someone in your household with COVID-19, having the sick person wear a mask while you wear one, too, will likely help protect you from getting the virus, Dr. Simpson says.
2. The Material You Choose for Your Mask Matters
The same researchers also wanted to see how well a variety of household materials could block aerosolized organisms compared to material from a surgical mask. They tested material from:
a dish towel
a 100% cotton t-shirt
a cotton blend t-shirt
a HEPA vacuum cleaner bag
First, they shot high concentrations of aerosolized bacteria in 1-micron particles through each material. The surgical mask material blocked 96% of the droplets, but the vacuum cleaner bag was right behind it (95%), followed by the dish towel (83%), cotton blend t-shirt (75%), 100% cotton t-shirt (69%), and antimicrobial pillowcase (65%).
Next, they used a highly concentrated aerosolized virus in 0.02-micron particles—smaller than COVID-19—with the same materials. Again, the surgical mask material blocked the most particles (89%), followed by the vacuum cleaner bag (86%), dish towel (72%), cotton blend t-shirt (70%), antimicrobial pillowcase (69%), and linen (62%).
The researchers also tested the materials for breathability, an important factor when you’re going to be covering your mouth and nose with it. Even though the vacuum bag and the dish towel were the most effective at blocking particles, not surprisingly, they were the hardest to breathe through. The researchers decided the best items for homemade face masks were the pillowcase and the 100% cotton t-shirt, preferring the t-shirt because its stretchiness gives the wearer a better fit.
As you’ve no doubt seen by now, there are many ways to cobble together a cloth face mask at home using materials you probably have on hand. The CDC has instructions for face coverings you can sew, as well as no-sew mask tutorials for those of us who aren’t crafty. (If you happen to have a 3D printer, Rowan University has downloadable 3D patterns for face masks to make reusable masks in three different adult sizes, as well as a pattern to print a filter, if you’re so inclined. And while still too new to be studied for its effectiveness, this Montana doctor designed one for himself and his colleagues—and it’s already been downloaded thousands of times.)
3. Using a HEPA or AC Filter Isn’t Necessary
There are face mask tutorials out there that advise people to insert a HEPA or an AC filter into their cloth masks—but since some of these are made with fiberglass, could this be dangerous? Like so many other issues surrounding COVID-19, it’s not very clear, and people have different opinions.
Dr. Simpson says that it’s really the various chemicals involved in fiberglass production that are harmful. “Fiberglass fibers aren’t of a size that tends to get down in the lungs, and certainly not when it’s built into a filter the way that these would be,” he says. “It probably isn’t dangerous, but it isn’t necessary,” he says. In the goal to protect others, “a cloth mask is perfectly adequate,” agrees Dr. Hamilton.
4. Masks Are an Additional Tool—Not a Force Field
Wearing a face mask is never a replacement for social distancing—it’s another tool to help prevent the spread of COVID-19 in our communities. Frequent hand-washing is as critical as ever, especially since recent studies show that the virus can live on some surfaces (like plastic and metal) for days.
5. Carefully Follow Wear and Care Instructions
So, you have your homemade mask. Do you need to worry about fit and cleanliness? In a word: yes.
Make sure your mouth, nose, and chin are covered and that your mask goes to the backs of your cheeks. “Try to cover your mouth and nose completely, but any way that you can wear it without constantly having to adjust it and touch it is beneficial,” Dr. Winter says.
Your mask should fit snugly, but comfortably, and you should be able to breathe easily.
Though layering material does provide more protection, don’t overdo it. Check that you can still breathe comfortably.
Avoid touching the outside of the mask. “You don’t want to get anything that’s on the mask onto your hands,” says Dr. Winter. If you do touch it at any point, wash your hands well. When you get home, try to take your mask off without touching the outside as much as possible, and then wash your hands.
Launder your mask each time you’re done wearing it. “If you wash it with hot water or even just dry it on a hot cycle, that should be sufficient,” Dr. Winter says.
Make or purchase several homemade face masks so you always have a clean one available.
Don’t use face masks on children under two years old, or on anyone who is unable to take the mask off if they should have trouble breathing.
Homemade Masks vs. Surgical Masks:Disaster Medicine and Public Health Preparedness. (2013.) “Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic?” ncbi.nlm.nih.gov/pmc/articles/PMC7108646/