NIST engineer offers simple message on COVID-19 masks: Cover smart, slow the spread

Face masks are a hot topic lately, with the Centers for Disease Control recommending that people wear masks when outside their homes and when unable to keep a minimum of 6 feet distance between themselves and others to help combat the COVID-19 pandemic.

Matthew E. Staymates, a fluid dynamicist and mechanical engineer at the National Institute of Standards and Technology (NIST), created his own lab to show how face coverings can help to slow the spread of disease.

He brought scientific flow visualization equipment home during the pandemic quarantine and set it up in his woodshop. Staymates uses Schlieren imaging, a technique that shows changes in air temperature. He also used a sophisticated optical device with multiple lenses and components, as well as an 18-inch first-surface concave spherical mirror and built a home system with tripods and wood. 

After gathering 26 different homemade face coverings provided by Gail Porter, the director of the NIST Public Affairs Office, Jennifer Barrick, also of the Public Affairs Office, and Amy Engelbrecht-Wiggans of the NIST Material Measurement Laboratory, Staymates worked with Leon Gerskovic, of Public Affairs Office, who guided him through the project and his cinematography.

Staymates wrote his findings in an article published on NIST Taking Measure standard blog:

“After weeks of data collection, over 50 GB of video data [looking at yourself coughing over and over gets a little strange after awhile], and literally hundreds of fake coughs, we had a clear message — ‘cover smart, do your part, slow the spread.’''

"We learned that even the simplest face coverings [bandanas, ski neck warmers] stopped much of your cough from landing on someone else,” Staymates said. “We also learned that a good seal around the nose, chin and cheeks helps to prevent your cough from ‘leaking’ out of the covering. And pulling your face covering below your nose is not good — you would be surprised how much air comes out of your nose when you cough.”

The experiments discovered that fabrics with tight, nonporous weaves increase air leakage by the nose and chin, although they filter droplets better. Because these masks aren’t breathable, that defeats the purpose, Staymates concluded.