Face masks can reduce the risk of spreading large drops of COVID-19 by up to 99.9 percent while talking or coughing, a new study published in the journal Royal Open Society claims.
The study was part of a laboratory conducted using mechanical and human subjects.
A woman standing two meters (yards) from a man coughing without a mask will be exposed to 10,000 times more germs than if he wore one, even if he is only 50 centimeters away, they said in the magazine Royal Society Open Science.
“There is no longer any doubt that face masks can significantly reduce the spread of potentially virus-infected droplets,” said lead author Ignazio Maria Viola, an expert in applied mobile dynamics at the University’s School of Engineering Edinburgh, to AFP.
Large respiratory droplets – which resemble projectiles before being dragged to the ground by gravity – are thought to be the main driver for the release of SARS-CoV-2, he noted.
Smaller ones, sometimes called aerosol droplets, can stay in the air for longer periods.
“We always put out a full range of droplets, from micro-scale to millimeter scale,” Maria Viola said by phone.
“Some droplets fall faster than others” depending on temperature, humidity and especially airspeed, he said.
The study focused on particles larger than 170 microns in diameter – about two to four times the width of a human hair.
Aerosol grains, which tend to follow airborne currents, typically less than 20 or 30 microns, are described.
Medium-sized drops can be polite, either, the study found.
Wear a universal mask
“If you wear a mask, you reduce the transmission of the virus by an order of magnitude – 10 times less,” said Maria Viola.
“In our study, for the larger drops we measure, we talk about 99.9 percent smaller.”
According to the Institute for Health Metrics and Evaluation (IHME) in Seattle, Washington, the adoption of a policy on universal mascara use could save 55,000 lives in the United States over the next four months .
The Institute’s models – which made a definitive prediction in mid-July that Covid-19 deaths in the U.S. would exceed 224,000 by November 1 – projected 561,000 deaths on the current trends by April 1, 2021.
Universal mascara consumption would reduce the global death toll by 400,000 over the same period, from 2.9 million to 2.5 million, they estimate. To date, the virus has claimed about 1.7 million lives.
Earlier this month, the World Health Organization (WHO) updated its Covid-19 directive on alien faces to recommend that they be consumed indoors in the presence of others if ventilation is not appropriate.
This guidance is particularly relevant in areas where community dissemination is known or suspected.
Masks in particular reduce the spread of viral droplets by people when coughing, sneezing, singing, talking or just breathing, but can also prevent droplets introduced by the wearer.
“Not only do cloth masks prevent most large droplets – 20-30 microns and larger – but they can also prevent infiltration and fine particles, known as also aerosolas, “according to the CDC.
(By submission from AFP)