[imagesource: here]

Today is the 160th day of our national lockdown, and some South Africans still haven’t figured out how to wear a mask correctly.

Under the nose, under the chin, or around the neck seem to be the popular styles.

All of these completely defeat the point of wearing a mask to prevent COVID-19 from entering your nose or mouth, or exiting your nose and/or mouth, thereby infecting someone else.

This really needs to stop now because, as you know, it has been drilled into us that wearing a mask is our best defence against transmission of the disease.

That said, as science studies PPE further, it is apparent that not all masks are created equal.

Even if you are a responsible citizen covering your mouth and nose, the type of mask that you’re wearing might not be doing the work that you need it to do.

We’ve covered the fashionable, but almost entirely useless scarf-masks already, and while we’ve looked at valve masks and shared Seth’s opinions on face shields before, we have even more compelling evidence that suggests these shouldn’t be your first choice when deciding on your preferred PPE.

A new study, conducted at Florida Atlantic University, and published this week in the journal Physics of Fluids, used lasers to show what happens to our exhalations when using the aforementioned face coverings.

Per Gizmodo, the researchers lit up the area around a mannequin designed to simulate a cough or sneeze, to capture a visual of how droplets spread.

These droplets, if they contained the virus, would be dispelled into the air putting others at risk.

You can see the results of the test on a valve mask here:

Here’s what happened when the test was performed using a face shield:

The results are plain to see, but let’s unpack them anyway.

When it comes to face shields, even though the concentration of droplets dissipated as they moved further from the mannequin’s mouth, they still covered a lot of ground before evaporating.

The valve masks were even worse, with the valve acting as an “easy escape hatch”.

“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 aerosolized droplets,” the authors wrote.

“Thus, despite the increased comfort that these alternatives offer, it may be preferable to use well-constructed plain masks.”

Face shields, used in conjunction with a standard mask, can be effective in limiting transmission, but aren’t great on their own.

We should probably avoid valve masks altogether.

Mask up, with a double-layered fabric mask, and stay safe out there.

[source:gizmodo]