As the pandemic continues, there has been a lot of confusion over face masks. Whether it’s their importance, how to wear them, or how to clean them, masks have caused a lot of discussions. The newest uncertainty revolves around the difference between a face mask versus a face shield. Well + Good consulted with an expert to bring some clarity.
To start to answer this question, Dr. Rand McClain, the chief medical officer of Live Cell Research, says you need to think in terms of germ level. The virus is believed to be transferred through droplets (coughing or talking) and aerosols (smaller sprays that travel with more ease). That’s why it’s important to have buffers.
So wearing a mask without a shield gives the wearer one less buffer between them and the virus. With a cloth mask, the droplets will likely hit the mask, while the aerosols will continue to disperse. This is helpful but not fully protective. “The masks aren’t 100 percent effective,” says Dr. McClain. “We’ve seen studies showing that a 10 to 30 percent increase in protection is available with a standard bandana cotton mask.” Medical-grade masks, meanwhile, circulate out between 60 to 80 percent of particles.
When you add the extra layer of a face shield, you’re creating another buffer of protection. “Just like you would expect with a shield, you’re going to block those droplets that are streaming directly towards you,” explains Dr. McClain. “They’ll hit the face mask and land—and that’s that.” The path for the aerosolized particles is a bit more complicated, though. “Some aerosolized particles could obviously just make contact with a mask and that’s the end of the road for them. With the aerosolized particles, though—because they’re light enough to float in the air—they could be drifting underneath, toward the mask. Someone inhales and you’d see the air pathway drop underneath the shield and then travel up toward the person within the shield,” Dr. McClain says.
A good metaphor to help you understand the levels of protection a mask and shield provide is sunscreen. The mask represents moisturizers that contain SPF. They are helpful but do not always effectively protect your skin against the sun. On the other hand, think of traditional sunscreen as the shield. It is more successful at guarding your skin against the sun, though potentially lessened by outside factors like long durations in the sun.
“The question, as usual with this virus, is ‘Is the juice worth the squeeze?’ In an environment where people are coughing around you and aren’t wearing masks and you’re exposed a lot—like in health care setting—it makes sense,” says Dr. McClain. So while you may opt-out of wearing a shield for a walk in your neighborhood, essential workers constantly facing the virus, like cashiers, delivery people, and medical workers, would likely benefit from the extra protection.