WASHINGTON: As new, more transmissible variants of the coronavirus spread, experts say it’s time to consider using a medical-grade respirator, or wearing a surgical and cloth mask together, reports AFP.
Scientists have agreed for some time the main way the virus is spread is through the air, rather than surfaces, and there’s growing evidence that small droplets from ordinary breathing and speech that can travel many meters (yards) are a common mode of transmission.Added to this is the greater contagiousness of emerging variants, like B.1.1.7, which takes a smaller viral load to cause symptomatic Covid-19 compared to the more common strain.
Back when authorities first recommended people wear face coverings, proper masks were in extremely short supply and the public was encouraged to fashion makeshift solutions out of T-shirts or bandanas. But these are far from ideal.
Linsey Marr, a professor of civil and environmental engineering at Virginia Tech, who studies airborne disease transmission, told AFP: “How well a mask works depends on two things: filtration and fit. “Good filtration removes as many particles as possible, and a good fit means that there are no leaks around the sides of your mask, where air—and viruses—can leak through,” she said, adding even a small gap could lead to a 50 percent reduction in performance.