Not to hide what is obvious: Experts urge a better approach to face coverage

Washington – As new, more portable variants of the coronavirus spread, experts say it’s time to consider medical-grade inhalers or the use of combined surgical and tissue masks.

Scientists have long agreed that it is the main way of spreading the virus through the air, rather than on the surface, and there is growing evidence that small drops of normal breath and speech can travel many meters. as a common method of distribution.

In addition, there is a greater susceptibility to emerging mutations, such as B.1.1.7, which gives a smaller viral load to cause symptomatic COVID-19 compared to the t. -sommon most common.

Fit and filtration

Back when authorities first proposed wearing face masks, proper masks were scarce and the public was encouraged to make portable solutions out of T-shirts or bandanas. But these are far from ideal.

“How well a mask works depends on two things: filtration and appropriateness,” said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech that studies the spread of airborne disease.

“Good filtration removes as many grains as possible, and good conditioning means that there are no leaks around the sides of your mask, where air – and viruses – can pass through,” she said. even a small gap could lead to a 50% reduction in performance.

The best materials for preventing small particles include nonwoven polypropylene, which is used to make N95s and many surgical-type masks, and the HEPA filters in airplanes. Among clothing, tight-knit cotton works best, she said.

Doubling

“If you’re wearing a cloth mask, choose one that has several layers, especially one with a pocket that you can slip in a good filter material,” said Marr. “Or you can double the mask by wearing a surgery-like mask with a tight-fitting cloth mask on it. ”

Surgical masks are made of a material that filters things out well, but they tend to be loose, so putting a cloth mask on top keeps the edges down and reducing leakage.

Adding an extra coating improves seeding – if one layer captures 50% of all grains, two combinations get up to 75%.

However, she said: “We do not recommend wearing more than two masks. Adding more layers ensures a reduced yield and can breathe. He needs to stay easy to breathe through the layers; otherwise, air is more likely to penetrate around the sides of the mask. ”

Masks that have a metal nose bridge help ensure proper snugness, as do straps that tighten around the head, not just the ears. Sewers that improve the suitability of surgeries are now available in the market.

“You should feel the mask flush in when you breathe in, and if you keep your hands around the sides of the mask, you should not feel any air leak when you breathe out, ”said Marr.

Medical grade reliefs

Another option is to grab N95s, or the like such as the KN95 or FFP2.

“They all provide the same level of filtration, meaning protection from incoming and outgoing granules,” said Ranu Dhillon, a global health physician at Brigham and Women’s Hospital and Harvard Medical School.

Dhillon, who has been advocating for better face masks since last spring, is plagued by the lack of clear messages to the public about the value of better masks.

Moreover, “no strenuous effort has been made to produce a large product and distribute these high-quality masks.”

Healthcare workers have their masks professionally tested every year to make sure they’re making the right seal, but Dhillon doesn’t see this as a major hurdle.

“It is very impossible to teach people to apply a mask, even if it is not 100% perfect, but more effective.

Masks in our future?

The way to conceptualize the risk is to think about cigarette smoke, said Donald Milton, a professor of environmental health at the University of Maryland.

Ventilation will certainly help, but if you’re between a breather and an air shower, the virus will still reach you – which makes good masks so essential, he said.

Milton and Dillon are hopefully optimistic that their pleas could become a policy in the U.S. under the administration of President Joe Biden, and CNN reported last week that the U.S. government was working on the first official standards on mask.

Before the pandemic, Milton and other aerosol scientists who studied the flu concluded that it is also transmitted from tiny droplets from normal talking and breathing, and that the task of sneezing, coughing and sneezing from the surface was less than expected.

Their findings raised controversy at the time, but COVID-19 has rekindled interest in the research – meaning masks could become a common sight during the difficult flu seasons, long after the flu transmission of pandemic disease.