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'Better' face masks can mitigate spread of Covid-19 indoors: Study
The research found that N95 and KN95 face masks filter more than 50% of exhaled aerosols, as against just about 10% for common face masks.
A study conducted at Canada’s University of Waterloo has concluded that widespread use of “better” face masks is needed to mitigate the spread of the coronavirus disease (Covid-19) in closed spaces, according to news agency ANI.
For the exercise, engineering researchers used a mannequin which simulated a seated person breathing in a large room. The team observed a significant build-up of aerosols, over time, despite the use of common cloth and blue surgical masks. According to the researchers, the exhaled droplets were so tiny that these can remain suspended and travel through air.
The study finally showed that most common masks filter only about 10 per cent of exhaled aerosols primarily due to issues with their fit and filter. The remaining aerosols, it was found, are redirected in an unfiltered state, mostly out of the top of the mask covering the nose, and escape into the surrounding air.
By contrast, high-quality and more expensive masks such as N95 and KN95 filter more than 50% of exhaled aerosols that can accumulate indoors and, when inhaled, lead to the transmission of Covid-19, the study found.
Speaking on the exercise, Serhiy Yarusevych, its lead investigator, said, “There is no question that it is beneficial to wear any face covering, both for protection in close proximity, and at a distance in a room. However, there’s a reason that medical practitioners wear an N95 mask…these work much better. We have provided solid numbers and rigorous analysis to back our assumption.”
Yarusevych also recommended the use of N95 and KN95 masks in indoor settings, such as schools and work places, as much as possible.
An earlier research established that aerosols, when dispersed by people infected with coronavirus, can transmit SARS-CoV-2, the virus that causes Covid-19. The transmission can take place even outside the two-meter social distancing gap widely suggested by health authorities.
