Study reveals a good reason to wear face masks instead of shields

We've all heard by now that you should be wearing face masks when in public to help curb the spread of the novel coronavirus, but what about face shields? Some people have turned to these shields as a more comfortable alternative to wear during the day, particularly while at work, but are they effective? Yet another study finds that you should avoid face shields unless you add one particular element to them.

The idea behind wearing a face mask is simple: when you talk, breathe, sneeze, yawn, and cough, you're producing small, invisible droplets of fluid that may contain the SARS-CoV-2 virus. If another person inhales these particles, they are at risk of developing COVID-19 — and even if they can recover without issue, they may pass it on to someone else who doesn't handle it so well.

It's quite obvious, then, that a face covering must be able to sufficiently slow down and block these droplets, reducing the amount in the air and how far they travel. Recent studies have demonstrated that properly fitted masks are better at reducing droplets than poorly fitted masks, and they've likewise called in question the usefulness of face shields.

Underscoring the latest guidance from the CDC, a new demonstration from Florida Atlantic University's College of Engineering and Computer Science shows what you'd reasonably expect from a face shield: the droplets are blocked in their forward motion, instead spreading out and dispersing from the sides of the shield.

As well, the study demonstrated that N95 masks featuring valves, which make it easier to exhale, are even less effective at reducing the forward motion of droplets. To change this, the study notes that one should use a mask that doesn't feature a valve or, in the case of face shields, also wear a mask underneath.