New Airflow Videos Show Why Masks With Exhalation Valves Do Not Slow the Spread of COVID-19New Airflow Videos Show Why Masks With Exhalation Valves Do Not Slow the Spread of COVID-19

New Airflow Videos Show Why Masks With Exhalation Valves Do Not Slow the Spread of COVID-19 ***@***.*** NIST

Many people wear masks in public to slow the spread of COVID-19, as recommended by the Centers for Disease Control and Prevention (CDC). However, masks with exhalation valves do not slow the spread of the disease, and now, new videos from the National Institute of Standards and Technology (NIST) show why. 

The videos, which show airflow patterns through masks with and without exhalation valves, were created by NIST research engineer Matthew Staymates. The videos were published, along with an accompanying research article, in the journal Physics of Fluids

“When you compare the videos side by side, the difference is striking,” Staymates said. “These videos show how the valves allow air to leave the mask without filtering it, which defeats the purpose of the mask.” ..

Exhalation valves, which make masks easier to breathe through and more comfortable, are appropriate when the mask is meant to protect the wearer. For instance, valved masks can protect workers from dust at a construction site or hospital workers from infected patients.  

The masks that the CDC recommends for slowing the spread of COVID, however, are mainly meant to protect people other than the wearer. They slow the spread of the disease by capturing exhaled droplets that might contain the virus. Even people without symptoms should wear masks, according to the CDC, because it is possible to be infected but not show symptoms. ...