Cloth, surgical masks only 10% effective against COVID-19: study
In comparison, the higher-quality N95 and KN95 masks filter more than 50% of the exhaled aerosols that remain in the air
August 22, 2021
An alarming new study by the University of Waterloo in Canada has found that cloth and surgical masks are only 10% effective in protecting the wearer from aerosols dispersed by COVID-19 infected people, Daily Mail reported on Saturday.
"There is no question it is beneficial to wear any face covering, both for protection in close proximity and at a distance in a room," study leader Serhiy Yarusevych, a professor of mechanical and mechatronics engineering, said in a statement.
"However, there is a very serious difference in the effectiveness of different masks when it comes to controlling aerosols," he said.
The study involved experiments using a mannequin to simulate a person sitting in a large room and breathing.
It was found that there is a significant buildup over time of aerosol droplets — tiny particles exhaled by people that remain suspended and travel through the air — despite the use of common cloth and surgical masks.
A previous study had determined that these droplets dispersed by infected people transmit the virus even outside the two-metre social distancing zone recommended by health experts.
The new study found that common masks are not as effective, primarily due to problems with their fit. Resultantly, they are only able to filter out 10% of exhaled aerosol droplets. The remaining droplets escape out the top of the mask where it fits over the nose, and into the air, unfiltered.
In comparison, the higher-quality N95 and KN95 masks filter more than 50% of the exhaled aerosols that remain in the air indoors and can be inhaled by other people.
Yarusevych said the greater effectiveness of such masks versus cloth and surgical masks "makes a compelling case they should be worn in indoor settings, such as schools and workplaces, as much as possible", reported Daily Mail.
“A lot of this may seem like common sense,” he said. “There is a reason, for instance, that medical practitioners wear N95 masks — they work much better. The novelty here is that we have provided solid numbers and rigorous analysis to support that assumption.”
