from journal Physics of Fluids
Most studies on how the COVID-19 spreads by exhaled air have focused on coughing or sneezing, the force of which can send aerosols flying long distances. However, a study in the journal Physics of Fluids shows just speaking while near one another can spread the virus from asymptomatic but infected people. Researchers examined the patterns of exhaled air with and without a mask. You may already have guessed where this is going. A mask is beneficial in face-to-face contact. But, in certain situations, such as when a patient or customer is leaning back and the other person is standing over them, a face shield as well as a face mask helps prevent aerosols from traveling down to the patient or customer.