Plastic face coverings rendered useless, new study suggests

TORONTO, Sept. 17, 2020-- A man wearing a mask and a face shield gets on a bus in Toronto, Canada, on Sept. 17, 2020. The number of COVID-19 cases in Canada rose to 140,539 on Thursday, with 9,199 deaths, according to CTV. (Photo by Zou Zheng/Xinhua via Getty) (Xinhua/Zou Zheng via Getty Images)

INDIANAPOLIS (WISH) – The average consumers may believe the most protective shield against the coronavirus are plastic ones. However, these masks do not prevent the spread of COVID-19 as well as one might hope. 

Japanese scientists conducted a study assessing data using a method known as a simulation study, which involves computer-based analyses. Researchers measured thousands of droplets–both small and large. Small droplets escaped the shield nearly 100% while large droplets escaped nearly 50% of the time. 

“Judging from the results of the simulation, unfortunately, the effectiveness of [plastic] faceguards from an infected person is limited compared to [other] masks.” said Makoto Tsubokura, PhD and lead study author in an interview with The Guardian

Although considered the most comfortable and best for communication, these shields are only effective outdoors or in an indoor environment with proper ventilation.

The findings are in line with the Centers for Disease Control’s recommendations (CDC). N95 masks offer the most protection but are reserved for front line workers. Surgical masks come in at a close second providing 98.5% protection at filtering large droplets and two-layer, non-woven masks come in third allowing an average of just 4% of particulates into the air. The CDC defines large droplets as those that travel one to three feet when a person coughs, sneezes, yawns, talks or burps before falling to the ground. Small droplets are ones that travel three to five feet.

Researchers from Duke University confirmed these same findings in a recent paper published in Science Advances, yet added three layered cotton masks are also a good option.  

News 8’s medical reporter, Dr. Mary Elizabeth Gillis, D.Ed., is a classically trained medical physiologist and biobehavioral research scientist. She has been a health, medical and science reporter for over 5 years. Her work has been featured in national media outlets. You can follow her on Instagram @reportergillis and Facebook @DrMaryGillis.