Resistant N95 and KN95 masks are best for protecting COVID-19, while surgical and fabric facial covers only leak about 10 percent of exhaled aerosols, according to a new study.
“The results show that a standard, three-layer surgical fabric mask … filters at an apparent efficiency of only 12.4% and 9.8%, respectively,” according to the study’s conclusion. University of Waterloo.
But KN95 and N95 masks offer a substantially higher apparent filtration efficiency (60% and 46% for R95 and KN95 masks, respectively) than the most widely used cloth (10%) and surgical masks (12%) and, therefore, they remain the recommended choices in mitigating indoor airborne disease transmission, ”a summary of the study, published on July 21, read.
The more expensive, high-quality N95 and KN95 masks “leaked more than 50% of the exhaled aerosols that can build up inside and spread the COVID-19 virus when inhaled by others,” the study found. .
The study was published in the journal Physics of Fluids. It was held in a large, indoor, unventilated room.
One of the authors of the study said there are significant differences in the effectiveness of various masks.
“There is no doubt that it is beneficial to wear any face covering, both to protect it very close and at a distance in a room,” said Serhiy Yarusevych, a professor of mechanical and mechatronics engineering. “However, there is a very serious difference in the effectiveness of the different masks when it comes to controlling aerosols.”
He explained that the study’s findings were traced to “common sense” and prevailing health practices.
“A lot of that may seem like common sense,” Yarusevych said. “There is a reason, for example, for doctors to wear N95 masks: they work much better.
“The novelty here is that we have provided solid numbers and rigorous analysis to support this assumption,” he added.