Time to wear a better mask, experts say

As new, more transmissible variants of the coronavirus spread, experts believe it is time to consider using a medical respirator or carrying a surgical and cloth mask with you.

Scientists have long agreed that the spread of the virus is through the air rather than through surfaces, and there is growing evidence that tiny droplets of ordinary breathing and speech that can move many meters are a common mode of transmission.

In addition, there is the greater contagion of emerging variants, such as B.1.1.7, which requires a smaller virus load to cause symptomatic COVID-19 compared to the more common strain.

Fit and filter

When the government first recommended that people wear face masks, there was an extraordinary shortage of masks and the public was encouraged to make temporary solutions out of T-shirts or bandanas. But this is far from ideal.

Linsey Marr, a professor of civil and environmental engineering at Virginia Tech who studies the transmission of airborne diseases, told AFP: ‘How well a mask works depends on two things: filtration and fitting.

“Good filtration removes as many particles as possible, and a good fit means there are no leaks around the edges of your mask, where air – and viruses – can leak,” she said, adding even a small gap. leads to a 50 percent reduction in performance.

The best materials for blocking small particles include non-woven polypropylene, which is used to make N95s and many surgical masks, and the HEPA filters in levels. Between woven cotton works best, she added.

Double

“If you wear a cloth mask, choose one that contains more layers, ideally one with a pocket in which you can insert a good filter material,” Marr said. “Or you can double a mask by wearing a surgical mask with a dense mask over it.”

Surgical masks are made of material that filters well, but it tends to be loose. To add a cloth mask on top, keep the edges down and reduce leaks.

Adding an extra layer improves filtration – if one layer traps 50 percent of all particles, the combination will be from two to 75 percent.

But she added: “We do not recommend wearing more than two masks. If you add more layers, it seems that the yields decrease and the breathing can be endangered. It should remain easy to breathe through the layers; otherwise there will be more air in the sides of The Mask. “

Masks with a metal nose bridge help to ensure a good fit, as well as straps that wrap around the head, not just the ears. Support straps that improve the fit of surgical masks are now available in the market.

“You should feel the mask suck inward when you inhale, and if you hold your hands around the edges of the mask, you should not feel any air leaking when you exhale,” Marr said.

Respirators of medical degree

Another option is to get N95s or their international equivalents like KN95, FFP2, etc. Get your hands on it.

“They all offer a similar degree of filtration, which means protecting particles that go in and out,” said Ranu Dhillon, a global health physician at Brigham and Women’s Hospital and Harvard Medical School.

Dhillon, who has been a proponent of better masks since last spring, is frustrated by the lack of clear messages to the public about the value of better masks.

What’s more, “there has not been a real push to really manufacture these higher caliber masks and give mass distribution.”

Healthcare professionals have their masks professionally fitted annually to ensure they make the right seal, but Dhillon does not see this as a major obstacle.

“Teaching people to apply a mask, even if it’s not 100 percent perfect, but more effective, is something that is very feasible.”

Masks in our future?

The key to conceptualizing the threat is to think about cigarette smoking, said Donald Milton, a professor of environmental health at the University of Maryland.

Ventilation certainly helps, but if you are between someone who is breathing and an exhaust valve, the virus will still reach you – which makes good masks so important, he said.

Milton and Dhillon are cautiously optimistic that their pleas may soon become policy under President Joe Biden’s administration, and CNN reported last week that the U.S. government was working on the first official mask standards.

Prior to the pandemic, Milton and other aerosol scientists studying the flu concluded that it was also transmitted from droplets of normal talking and breathing, and that the role of sneezing, coughing and surface transfer was smaller than expected.

Their findings sparked controversy at the time, but COVID-19 rekindled interest in the research – meaning masks could be a common sight during difficult flu seasons, long after the pandemic receded.

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© 2021 AFP