The CDC has issued its strongest mask guidance yet during the COVID-19 pandemic, calling for “universal mask wearing” in all activity outside of one’s home. The new guidance lists “universal wearing of face masks” as the first recommendation to help stop the spread of the disease. It says masks should be worn for all indoor activity outside of an individual’s home, as well as during all outdoor activity when at least 6 feet of social distancing can’t be maintained.
Fotis Sotiropoulos, the Stony Brook University Interim Provost and Dean of the College of Engineering and Applied Sciences addressed the importance of face coverings and social distancing in the midst of the pandemic during a virtual lecture “How Far Is Far Enough and Can Masks Curb the Spread of COVID-19?” on December 2. He also described the importance of fluid mechanics to the spread of a virus like COVID-19.
“Larger, heavy saliva particles can in fact settle within the recommended six-foot CDC guidelines and could contaminate surfaces. However, the greater concern is the smallest particles, or “aerosols,” that can be transported by the airflow several feet away from the body and stay suspended for longer periods of time,” said Sotiropoulos.
“A virus is primarily spread by respiratory droplets produced by exhalation. As we exhale, sneeze and cough it creates a range of particles at a range of scales,” said Sotiropoulos. “Airborne transmission occurs more easily when droplets are very small and stay suspended for a long period of time and can be inhaled and penetrate lung tissues, which is the case with coronavirus.”
These findings led a team in the Department of Civil Engineering, including assistant professor Ali Krosronejad, research associate Christian Santoni and PhD students Kevin Flora and Zexia Zhang, to study the effectiveness of social distancing and face coverings.
The research used computational fluid dynamics modeling for coughing and breathing, indoors and outdoors, with masks and without. High-fidelity numerical simulations of respiratory particulate transport on high-performance supercomputers provided strong evidence that even the simplest masks are effective in protecting others by dissipating the forward momentum of expiratory jets, especially in indoor environments. The details of the study were published in a paper, entitled “Fluid dynamics simulations show that facial masks can suppress the spread of COVID-19 in indoor environments,” in American Institute of Physics (AIP) Advances.
“The difference is stunning,” Sotiropoulos said. “Masks can modify the structure of a cough and dramatically diminish its energy and forward propagating momentum. The bottom line is: Wear a mask, any mask, and stay six feet apart to both protect yourself and others around you.”