Face Masks Down Spread of COVID-19; Types, Duration of Use Vital

Face masks help slow the spread of COVID-19. The physics of face mask use and disease transmission, materials, design, and other issues affect the way face masks work. In Physics of Fluids, researchers looked at face masks and their use and summarized what we know, to date, design about the way face masks filter or block the virus.

Main aspect of face mask function involves the size of fluid droplets expelled from the nose and mouth when a person talks, sings, sneezes, coughs, or even simply breathes. Larger droplets, with sizes around 5-10 microns, are the most common. These droplets are still quite small.

Those below 5 microns, are more dangerous. These can become aerosolized and remain suspended in air for long periods. Among the many types of masks in use (cloth masks, surgical masks, and N95 masks), only N95s can filter out aerosol-sized droplets.

Performance of face masks worn, affect how effective overall mask wearing can be. Thermal comfort is an important issue, especially in hot and humid environments.

Researchers concluded that face masks made of hybrid polymer materials could filter particles at high efficiency while simultaneously cooling the face. The fibers used in these special masks are transparent to infrared radiation, allowing heat to escape from beneath the mask.

"There could be some relation between breathing resistance and the flow resistance of the face mask which will need to be studied for a face mask-wearing interval," said author Heow Pueh Lee. "Also, the environmental condition in the compartmental space within the face mask will need to be more accurately quantified using miniaturized sensors and the development of human replicas for such studies."

The team of researchers also looked into various epidemiological studies aimed at discovering whether face masks reduce the effective reproduction number. If the reproduction number drops below 1, the epidemic stops spreading. One study used COVID-19 data from New York state.

"The results suggest that the consistent use of efficient face masks, such as surgical masks, could lead to the eradication of the pandemic if at least 70% of the residents use such masks in public consistently," said author Sanjay Kumar. "Even less efficient cloth masks could also slow the spread if worn consistently."



Source-Medindia