“The fabrics are not acting as a sharp sieve,” said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech who is one of the world’s leading authorities on aerosols. “That’s not how filtration works.”
But rather than speculate, Dr. Marr worked with Jin Pan, a Virginia Tech graduate student who studies biological particles, to test two types of gaiters using methods similar to those required by the National Institute for Occupational Safety and Health for testing masks.
They decided to use foam heads to test gaiters as they are worn in real life, rather than tearing up a gaiter and testing just a small piece of fabric. One gaiter was a single-layer fabric made of 100 percent polyester. The other was a two-layer gaiter, made with 87 percent polyester and 13 percent elastane, a material often called spandex or Lycra.
The researchers used a liquid salt solution and a medical nebulizer to simulate saliva and to direct the particles through a tube in the foam head with a gaiter placed over the nose and the mouth. Special instruments measured the quantity and the size of droplets that were able to sneak through the mask.
The Coronavirus Outbreak ›
Frequently Asked Questions
Updated August 17, 2020
Why does standing six feet away from others help?
- The coronavirus spreads primarily through droplets from your mouth and nose, especially when you cough or sneeze. The C.D.C., one of the organizations using that measure, bases its recommendation of six feet on the idea that most large droplets that people expel when they cough or sneeze will fall to the ground within six feet. But six feet has never been a magic number that guarantees complete protection. Sneezes, for instance, can launch droplets a lot farther than six feet, according to a recent study. It’s a rule of thumb: You should be safest standing six feet apart outside, especially when it’s windy. But keep a mask on at all times, even when you think you’re far enough apart.
I have antibodies. Am I now immune?
- As of right now, that seems likely, for at least several months. There have been frightening accounts of people suffering what seems to be a second bout of Covid-19. But experts say these patients may have a drawn-out course of infection, with the virus taking a slow toll weeks to months after initial exposure. People infected with the coronavirus typically produce immune molecules called antibodies, which are protective proteins made in response to an infection. These antibodies may last in the body only two to three months, which may seem worrisome, but that’s perfectly normal after an acute infection subsides, said Dr. Michael Mina, an immunologist at Harvard University. It may be possible to get the coronavirus again, but it’s highly unlikely that it would be possible in a short window of time from initial infection or make people sicker the second time.
I’m a small-business owner. Can I get relief?
- The stimulus bills enacted in March offer help for the millions of American small businesses. Those eligible for aid are businesses and nonprofit organizations with fewer than 500 workers, including sole proprietorships, independent contractors and freelancers. Some larger companies in some industries are also eligible. The help being offered, which is being managed by the Small Business Administration, includes the Paycheck Protection Program and the Economic Injury Disaster Loan program. But lots of folks have not yet seen payouts. Even those who have received help are confused: The rules are draconian, and some are stuck sitting on money they don’t know how to use. Many small-business owners are getting less than they expected or not hearing anything at all.
What are my rights if I am worried about going back to work?
What is school going to look like in September?
- It is unlikely that many schools will return to a normal schedule this fall, requiring the grind of online learning, makeshift child care and stunted workdays to continue. California’s two largest public school districts — Los Angeles and San Diego — said on July 13, that instruction will be remote-only in the fall, citing concerns that surging coronavirus infections in their areas pose too dire a risk for students and teachers. Together, the two districts enroll some 825,000 students. They are the largest in the country so far to abandon plans for even a partial physical return to classrooms when they reopen in August. For other districts, the solution won’t be an all-or-nothing approach. Many systems, including the nation’s largest, New York City, are devising hybrid plans that involve spending some days in classrooms and other days online. There’s no national policy on this yet, so check with your municipal school system regularly to see what is happening in your community.
Both gaiters prevented 100 percent of very large, 20-micron droplets from splattering another foam head just 30 centimeters away. Both masks blocked 50 percent or more of one-micron aerosols. The single layer gaiter blocked only 10 percent of 0.5-micron particles, while the two-layer gaiter blocked 20 percent. Notably, when the single-layer gaiter was doubled, it blocked more than 90 percent of all particles measured. By comparison, a homemade cotton T-shirt mask, recommended by the Centers for Disease Control and Prevention, blocked about 40 percent of the smallest particles.
Tests show wide variation in how much protection cloth masks provide. Some homemade masks perform far better than the gaiters tested in the Virginia Tech study, and some perform worse. Over all, tests of fabric masks have shown that two layers are better than one, and that a snug fitting mask with no gaps is best. Most experts agree that the average mask wearer doesn’t need medical-grade protection, and that any face covering, combined with social distancing, probably offers adequate protection for the average person against spreading or contracting the coronavirus.
“I’ve been recommending neck gaiters, and my kids wear neck gaiters,” Dr. Marr said. “There’s nothing inherent about a neck gaiter that should make it any worse than a cloth mask. It comes down to the fabric and how well it fits.”
