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N95 mask ranked the best among 14 face coverings to curb virus spread

WASHINGTON: Health experts have determined that face coverings are a vital tool in reducing the spread of coronavirus and now a new study has ranked 14 types of commonly available masks.

Here are the results of some of the more common masks.

Professionally-fitted N95 masks - hospital-grade protection worn by frontline workers in hospitals - reduced droplet transmission to less than 0.1 per cent.

Surgical or polypropylene masks were not far behind, bringing droplet transmission down by 90 per cent or more compared to no face-coverings.

Hand-made cotton face coverings provided good coverage, eliminating 70 to 90 per cent of the spray from normal speech, depending on the number of layers and the pleating.

BANDANAS

But bandanas only reduced the droplets by about 50 per cent and neck fleeces actually increased the amount of spray, probably by dispersing the largest droplets into many smaller droplets.

Finally, N-95 masks with valves - designed for industrial settings where the user's exhalation was less important than what they inhaled - performed roughly on par with cotton masks in terms of the amount of spray transmitted.

Health authorities have discouraged the use of valved N-95s.

The findings have public policy implications.

"We need to scale up surgical mask production and distribution," tweeted Dr Tom Frieden, former director of the US Centres of Disease Control and Prevention under then president Barack Obama, in response to the study that appeared in Science Advances.

Masks are important because some 30-40 per cent of people who are infected may not show symptoms but still unwittingly spread the virus when they cough, sneeze or just talk. - AFP

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