New Study Confirms Face Shields and Valve Masks Can’t Be Trusted

Visualizations reveal these substitutes don’t measure up

A laser-illuminated horizontal and vertical cross-section of droplets escaping a face shield 16.6 seconds after a simulated cough. Image: Siddhartha Verma, Manhar Dhanak, John Frankenfield, Florida Atlantic University

Frustrated with the discomfort of face masks, some people have been using face shields, which have been promoted by some health experts to help prevent the spread of Covid-19. Other people are turning to masks with exhalation valves that make breathing out…