“The substances do not act as a sharp sieve,” said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech, one of the world’s leading aerosol authorities. “That’s not how filtration works.”
But instead of speculating, Drs. Marr teamed up with Jin Pan, a Virginia Tech student studying 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 because they are worn in real life, instead of scraping up a gaiter and just testing a small piece of fabric. One gaiter was a single-layer fabric made from 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 saline solution and a medical nebulizer to simulate saliva and direct the particles through a tube into the foam head with a gaiter placed over the nose and mouth. Special instruments measure the quantity and size of droplets that were able to sniff through the mask.
The coronavirus breaks out>
Frequently Asked Questions
Updated August 17, 2020
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Why does standing six feet apart help others?
- The coronavirus spreads primarily by drips from your mouth and nose, especially when you cough or sneeze. The CDC, one of the organizations using that measure, bases its six-foot recommendation on the idea that most large drops that expel people when they cough or sneeze fall within six feet to the ground. But six feet has never been a magic number that guarantees complete protection. Noses, for example, can launch drops much farther than six feet, according to a recent study. It’s a rule of thumb: you need to be the safest to stand six feet apart, especially when the wind is blowing. But always wear a mask, even if you think you are far enough apart.
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I have antibodies. Am I immune now?
- At the moment, that probably seems like at least several months. There have been horrific accounts of people suffering from what appears to be a second bolt of Covid-19. But experts say these patients may have a prolonged 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 only last two to three months in the body, which may seem worrying, but that is perfectly normal after an acute infection progresses, said Dr. Michael Mina, an immunologist at Harvard University. It could possibly get the coronavirus back up, but it is highly unlikely that it would be possible in a short window of time from initial infection or the second time safe.
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I am a small business owner. Can I get relief?
- The incentive bills introduced in March provide assistance to the millions of American small businesses. Those eligible for support are non-profit companies and organizations with less than 500 workers, including sole proprietorships, independent contractors and freelancers. Some larger companies in some sectors are also eligible. The assistance provided, which is managed by the Small Business Administration, includes the Paycheck Protection Program and the Economic Damage Disaster Program. But many people have not seen payments yet. Even those who have received help are confused: the rules are draconian, and some are stuck on money they do not know how to use. Many small business owners get less than they expected or heard nothing at all.
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What are my rights if I am worried about returning to work?
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What will school look like in September?
- It is unlikely that many schools will return to a regular schedule this fall, requiring the grinding of online learning, easy childcare and stunted workdays to continue. The two largest public school districts of California – Los Angeles and San Diego – said on July 13 that instruction will be remote only in the fall, citing concerns that growing coronavirus infections in their areas pose too great a risk to students and teachers. Together, the two districts enroll about 825,000 students. They are the largest in the country to date to abandon plans for even a partial physical return to classes when they reopen in August. For other districts, the solution will not be an all-or-nothing approach. Many systems, including the nation’s largest, New York City, are creating hybrid plans that include some days attending classrooms and other days online. There is no national policy yet, so check regularly with your municipal school system to see what is happening in your municipality.
Both hostages prevent 100 percent of very large 20-micron droplets from splashing another foam head just 30 centimeters away. Both masks blocked 50 percent or more aerosols of one micron. 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 measured particles. 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 much better than the gaiters tested in the Virginia Tech study, and some perform less well. Above all, tests of dust masks have shown that two layers are better than one, and that a smart fitting mask without holes is best. Most experts agree that the average mask wearer does not need medical class protection, and that any face covering, combined with social distance, is likely to provide adequate protection for the average person against spreading or contracting the coronavirus.
“I have recommended neck dressers, and my children wear neck dressers,” said Dr. Marr. ‘There is nothing inherent in a neck pin that should make it worse than a cloth mask. It comes down to the fabric and how well it fits. “
