The U.S. Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) recommend for the most effective facial covering the N95 face mask because it’s a snug fit around the nose and mouth, and it’s property to best filter small airborne particles. What about face shields?
“It’s too complicated to compare a face shield to a face mask because people are not all wearing the same masks,” Dr. Veltman says. “In the community, some people are wearing bandannas, homemade masks or N-95 masks. There has not been a study comparing face shields to masks, and doing such study would be challenging since mask materials vary greatly in the community.”
Dr. Veltman argues that research has found that face shields are beneficial if someone cannot wear a mask. ”If someone coughs 18 inches from you while you are wearing a face shield, the immediate viral exposure is reduced by 96%,” Veltman says. ”If the person remains coughing and talking with you for 30 minutes, then the face shield blocks 68% of the small air particles,” she adds.
Prolonged exposure to the infectious particles from the cough or sneeze reduces the amount of protection that the face shield can provide, Dr.Veltman says. If combined with a face mask with a face shield, it can provide added protection. This is a reason why it is essential and widely used in hospitals and healthcare settings.