DAVIS, Calif. (KTXL) — Researchers at the University of California, Davis have found that homemade, cloth masks could actually contribute to the spread of the coronavirus versus surgical and industrial face coverings, but the benefits of wearing homemade masks still outweigh going maskless.
The study was done by the same researchers who discovered that COVID-19 could spread through the air, not just from moisture droplets in a sneeze and a cough.
They found that microscopic particles called aerosols from the lungs can float around the air long after an infected person has left the room.
Test subjects spoke and breathed into collection devices wearing N-95 and surgical masks along with homemade masks — some of them double layered.
“Surgical masks and N-95 masks do a really good job of blocking the outward emission of these very small, micron-scale expirated particles,” William Ristenpart, a professor of chemical engineering at UC Davis, told FOX40.
Talking at a normal level could produce 10 times more particles than simply exhaling. Still, up to 90% of floating particles were screened out.
But the cloth mask results were harder to measure because dust and other particles were also emitted — particles that can potentially carry a virus.
“It turns out that those fabrics emit pretty large quantities of micron-scale dust particulates, the fabric itself. That dust can then move through the air and infect someone else,” Ristenpart said.
The ongoing advice about frequently washing homemade masks still holds true. There’s some value in keeping dust and fiber particles from floating into the air.
And then there’s that other piece of advice — any mask is better than none at all.
“You absolutely should wash your cotton masks,” Ristenpart said.
The study only measured particles exhaled. One test subject was a super spreader, emitting a hundred times more aerosol particles than others who were tested.
But researchers say masks can work both ways in allowing only 10% of microparticles to pass through, in or out, magnifying the benefits.
“So, basically, the 10% from the person emitting it and the 10% for the person wearing it, it’s multiplied. You’ve basically now reduced it by 99%, the probability of transmission,” Ristenpart said.
Another ongoing concern is that health professionals are still recommending that the general public not acquire N-95 masks because they are badly needed by medical and other essential workers who are more likely to come in direct contact with infected people.