In a proof-of-concept study appearing online Aug. 7 in the journal Science Advances, Fischer, Westman and colleagues report that the simple, low-cost technique provided visual proof that face masks are effective in reducing droplet emissions during normal wear.
“We confirmed that when people speak, small droplets get expelled, so disease can be spread by talking, without coughing or sneezing,” Fischer said. “We could also see that some face coverings performed much better than others in blocking expelled particles.”
Notably, the researchers report, the best face coverings were N95 masks without valves — the hospital-grade coverings that are used by front-line health care workers. Surgical or polypropylene masks also performed well.
But hand-made cotton face coverings provided good coverage, eliminating a substantial amount of the spray from normal speech.
On the other hand, bandanas and neck fleeces such as balaclavas didn’t block the droplets much at all.
“This was just a demonstration — more work is required to investigate variations in masks, speakers, and how people wear them — but it demonstrates that this sort of test could easily be conducted by businesses and others that are providing masks to their employees or patrons,” Fischer said.
“Wearing a mask is a simple and easy way to reduce the spread of COVID-19,” Westman said. “About half of infections are from people who don’t show symptoms, and often don’t know they’re infected. They can unknowingly spread the virus when the cough, sneeze and just talk.
“If everyone wore a mask, we could stop up to 99% of these droplets before they reach someone else,” Westman said. “In the absence of a vaccine or antiviral medicine, it’s the one proven way to protect others as well as yourself.”
Westman and Fischer said it’s important that businesses supplying masks to the public and employees have good information about the products they’re providing to assure the best protection possible.
Read more: https://www.sciencedaily.com/releases/2020/08/200811152916.htm