The rugged N95 and KN95 masks are best for protecting COVID-19, while commonly worn surgical and fabric face covers only filter about 10 percent of exhaled aerosols, according to a new study.
“The results show that a standard surgical mask and a three-ply fabric mask … filter at apparent efficiencies of only 12.4% and 9.8%, respectively,” according to the University study’s conclusion. of Waterloo.
But the KN95 and N95 masks offer “significantly higher apparent filtration efficiencies (60% and 46% for the R95 and KN95 masks, respectively) than the most commonly used fabric (10%) and surgical masks (12%). , and therefore are still the recommended masks. choice to mitigate indoor airborne disease transmission ”, reads a summary of the study, published on July 21.
The more expensive, high-quality N95 and KN95 masks “filtered out over 50% of exhaled aerosols that can build up inside and spread the COVID-19 virus when inhaled by other people,” he said. revealed the study.
The study was published in the journal Physics of Fluids. It took place in a large indoor and unventilated room.
One of the study’s authors said that there are significant differences in the effectiveness of various masks.
“There is no doubt that wearing a face covering is beneficial, both for protection near and far in a room,” said Serhiy Yarusevych, professor of mechanical and mechatronics engineering. “However, there is a very serious difference in the effectiveness of different masks when it comes to controlling aerosols.”
He explained that the study results followed “common sense” and prevailing healthcare practices.
“Much of this may sound like common sense,” Yarusevych said. “There’s a reason, for example, why doctors wear N95 masks – they work much better.
“The novelty here is that we have provided solid numbers and rigorous analysis to support this hypothesis,” he added.