Masks for the face slow spread of Covida-19; types of masks, length of use of the substance.
The use of face masks to help slow the spread of COVID-19 is widely recommended by health professionals. This has spurred studies exploring the physics of using a face mask and the transmission of disease, as well as investigations into materials, design and other issues that affect the way face masks work.
in Fluid Physics, by AIP Publishing, investigators looked at research on face masks and their use and summarized what we know, to date, about how face masks filter or block the virus. They also summarize the design issues that still need to be addressed.
A key aspect of the face mask function involves the size of the droplets of fluid expelled from the nose and mouth when a person talks, sings, sneezes, coughs, or even simply breathes. Larger droplets, about 5-10 microns in size, are the most common. However, these points are still small. By comparison, a human hair is about 70 microns in diameter.
Even the smallest droplets, those under 5 microns, are probably more dangerous. These can be aerosolized and suspended in the air for long periods. Among the many types of masks in use (fabric masks, surgical masks and N95 masks), only N95 can filter aerosol sized spots.
The performance of face masks worn for many hours, such as by healthcare or other essential employees, affects how effective masking can be. Thermal comfort is an important issue, especially in hot and humid environments.
Investigators found that face masks made from hybrid polymer materials could filter out particles with high efficiency while simultaneously cooling the face. The fibers used in these special masks are transparent to infrared radiation, allowing heat to escape from under the mask.
“There may be a link between respiratory resistance and resistance to the flow of the face mask which will need to be studied for an interval wearing a face mask,” said author Heow Pueh Lee. “Also, the environmental condition in the partition space inside the face mask will need to be accurately determined using miniaturized sensors and the development of human replicas for such studies.”
Investigators also reviewed epidemiological studies aimed at finding out if face masks reduce the effective number of reproduction. If the reproduction number falls below 1, the epidemic stops spreading. One study used COVID-19 data from New York State.
“The results suggest that continued use of effective face masks, such as surgical masks, can lead to the eradication of the pandemic if at least 70% of residents use such masks in public consistently,” said author Sanjay Kumar. . “Even less effective clothing masks can slow down the spread if worn constantly.”
Reference: “The perspective of bringing the flow of fluid to the airways and aerosols through face masks in the context of SARS-COV-2By Sanjay Kumar and Heow Pueh Lee, November 24, 2020, Fluid Physics.
DOI: 10.1063 / 5.0029767