Face shields are less annoying to wear than face masks.
They’re much easier to breathe in, they don’t fog up your glasses and you don’t need to awkwardly nod and squint to show someone you’re smiling.
But will they protect you and others from the coronavirus?
No, not unless they’re paired with a face mask.
“They don’t work,” said Professor Brendan Crabb, director and CEO of the Burnet Institute in Melbourne.
“Face shields don’t work in the absence of a surgical mask underneath.
“Bandanas, scarves, those things are not very effective either.”
Once again (during 1hr exercise) I saw someone wearing a face shield but no mask. This may be for valid health reasons, and it's not against the rules — but for general, healthy public please be aware: face shields, unless in combination with masks, are not effective. #covid19vic
— Dr Sandro Demaio (@SandroDemaio) August 31, 2020
To prove the point, a group of scientists at Florida Atlantic University in the United States created a visual representation showing why face shields were not best suited for preventing the spread of COVID-19.
In their study, published on Tuesday in the journal Physics of Fluids, the researchers simulated coughing by connecting a mannequin’s head to a fog machine and then using a pump to expel the vapour through the mannequin’s mouth.
Using a green laser pointer and cylindrical rod, the simulated cough droplets appear as a glowing green vapour flowing from the mannequin’s mouth.
During the face shield simulation, the shield initially deflected droplets toward the ground after a cough.
However, small droplets still hovered at the bottom of the shield and then floated around the sides, eventually spreading about 90 centimetres to the front and back sides of the mannequins.
“Overall, the visuals presented here indicate that face shields and masks with exhale valves may not be as effective as regular face masks in restricting the spread of aerosolised (sic) droplets,” the authors wrote.
“Thus, despite the increased comfort that these alternatives offer, it may be preferable to use well-constructed plain masks.”
