Here's Why You Shouldn't Wear A Mask With A Valve

When the UK’s chancellor of the exchequer Rishi Sunak was spotted buying lunch from Pret, all eyes were on him and his fetching grey mask.

The face covering fitted well to his face, covering his nose and mouth (top marks there), but it also featured a valve – and here lies the problem.

Valved face covers are banned in some cities and counties in the United States because they can expel the wearer’s germs into the environment.

People are told to wear face coverings to protect others. But when people wear face masks with valves, this doesn’t quite go to plan.

Experts say the one-way valve closes when a person breathes in and opens when they breathe out. This means while the valve doesn’t let germs in, protecting the wearer, it does allow a person’s exhalations to leave the mask – and therefore does not protect others and slow the spread of the virus.

Professor Trisha Greenhalgh, an expert in primary care at University of Oxford, told HuffPost UK: “The valve acts like an exhaust pipe, potentially spewing germs out to the environment.

“Cloth face coverings are the best thing. They stop droplets – that’s why they get wet of course, and you have to change them when they do.

“Droplets contain viral particles so the more droplets get caught in your face covering, the fewer germs get into the air. A valved mask bypasses the barrier and potentially emits the droplets in an explosive gas cloud.”

Some people argue that valved masks can have filters between the mouth and the valve – therefore, isn’t the air people...

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