"Study shows N95 masks near-perfect at blocking escape of airborne COVID-19"
Fascinating results from a study published by the University of Maryland School of Public Health:
"Surprisingly, KN95 masks – the disposable masks used widely – were no more effective than cloth or surgical masks. The study found that a common brand of KN95 masks leak more air than duckbills or other studied masks, because they don’t conform to the face well. That flaw is compounded by a powerful filter with more flow resistance that pushes air out of the mask at the sides instead of through the filter, allowing more virus particles to escape into the surrounding air."
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"Cloth masks also outperformed both KN95 and surgical masks. Milton theorizes that cloth masks with greater coverage, wrap around the face and give a better seal than either KN95 or surgical masks. With cloth mask filters, flow resistance is also lower, allowing breath to pass through the filter and not leak out the sides of the mask."
Wow, this really is surprising! I've been wearing the KN95 masks because they seem like they'd be significantly more effective, given the better fit compared with surgical masks and tighter feel over cloth. This really does underline why we need these studies: what might seem obvious or logical is not always true in practice.
Study shows N95 masks near-perfect at blocking escape of airborne COVID-19 | University of Maryland | School of Public Health
COLLEGE PARK, Md. – In a head-to-head comparison of masks worn by people with active COVID-19, the inexpensive “duckbill” N95 came out on top, stopping 98% of COVID-19 particles in the breath of infected people from escaping into the air. Led by researchers from the University of Maryland School of Public Health (SPH), results showed other masks also performed well, blocking at least 70% of viral particles from escaping from the source – an infected person’s exhaled breath.