Time to put on an improved mask, experts say
22 February, 2021
As new, even more transmissible variants of the coronavirus spread, experts say it is time to consider by using a medical-grade respirator, or sporting a medical and cloth mask together.
Scientists experience agreed for quite a while the main method the virus is spread is through the atmosphere, instead of surfaces, and there's growing evidence that little droplets from standard breathing and speech that may travel many meters are a common mode of transmitting.
Added to this is the increased contagiousness of emerging variants, just like B.1.1.7, which takes a smaller sized viral load to reason symptomatic COVID-19 when compared to more common strain.
When authorities first recommended persons wear face coverings, proper masks were in incredibly short source and the public was encouraged to fashion makeshift solutions away of T-shirts or bandanas. But they are far from ideal.
Linsey Marr, a good professor of civil and environmental engineering at Virginia Tech, who research airborne disease transmission, told AFP: "How very well a mask functions depends on a couple of things: filtration and fit.
"Good filtration gets rid of as many particles as possible, and an excellent fit means that there are not any leaks around the sides of your mask, where air -- and viruses -- may leak through," she said, adding even a small gap could bring about a 50 percent decrease in performance.
The best resources for blocking small particles include non-woven polypropylene, which is employed to generate N95s and several surgical-type masks, and the HEPA filters in planes. Among fabrics, tightly woven cotton works best, she added.
"In the event that you wear a cloth mask, choose one which provides multiple layers, ideally one with a pocket that you could slip a good filter materials into," said Marr. "Or you can double mask by using a surgical-type mask with a tight-fitting cloth mask over it."
Medical masks are created from materials that filters things out well, but they have a tendency to be loose, so adding a cloth mask at the top holds downward the edges and reduces leaks.
Adding yet another layer improves filtration -- if one level traps 50 percent of all particles, combining two gets to 75 percent.
But, she added: "We do not recommend using a lot more than two masks. Adding more layers proves diminishing returns and will compromise breathability. It must continue to be simple to breathe through the layers; otherwise, air is much more likely to leak in around the sides of the mask."
Masks which may have a metal nasal area bridge help ensure a snug fit, as carry out straps that tighten around the top, not only the ears. Braces that enhance the fit of surgical masks are now in the marketplace.
"You should think the mask sucking inward when you breathe, and in the event that you hold the hands around the sides of the mask, you should not feel any air flow leaking away when you breathe away," said Marr.
Another option gets hold of N95s, or perhaps their international equivalents such as for example KN95, FFP2 etc.
"They all give a similar degree of filtration, meaning coverage of particles moving in and away," Ranu Dhillon, a worldwide health medical professional at Brigham and Women's Hospital and Harvard Medical University.
Dhillon, who features been advocating in favor of better masks since last spring, is frustrated by the lack of apparent messaging to the general public on the worthiness of better masks.
What's more, "there's not been a good concerted push to essentially mass make and mass distribute these higher caliber masks."
Health care staff have their masks professionally fit-tested yearly to ensure they're making the right seal, but Dhillon doesn't find this as a significant obstacle.
"To teach people to match a mask, regardless if not completely perfectly, but more effectively, is something that's very doable."
The key to conceptualizing the threat is to think about cigarette smoke, said Donald Milton, a professor of environmental health at the University of Maryland.
Ventilation definitely helps, but if you're between somebody who is breathing and a great exhaust vent, the virus might still reach you -- making good masks as a result crucial, he said.
Milton and Dhillon are cautiously optimistic that their pleas could quickly become policy beneath the administration of President Joe Biden, and CNN reported last week the U.S. government was focusing on the first established mask standards.
Before the pandemic, Milton and other aerosol scientists learning the flu concluded it also is transmitted from very small droplets from regular speaking and breathing, and that the function of sneezing, coughing and transmission from surfaces was more compact than thought.
Their findings stirred controversy at that time, but Covid-19 has renewed interest in the study -- meaning masks could be a common sight during tough flu seasons, long following the pandemic has receded.
Source: japantoday.com