It’s time to wear a better mask, experts say

As new, more contagious variants of the coronavirus spread, experts say it’s time to consider using a medical-grade respiratory system or wearing a surgical mask and a cloth mask together. I will.

Scientists have for some time agreed that the main way the virus spreads is through the air rather than the surface, and there is increasing evidence that: Small droplets It is a common mode of infection from normal breathing and speech that can move many meters (yards).

In addition to this, new variants such as B.1.1.7 are highly contagious and require less viral load to cause symptomatological COVID-19 compared to more common strains.

Fit and filter

When authorities first recommended people to wear facial masks, there was a great shortage of suitable masks and the general public was encouraged to make makeshift solutions from T-shirts and bandanas. Was there. But these are far from ideal.

Lindsaymer, Citizen and Citizen Professor Environmental engineering At Virginia Tech, which studies the transmission of aerial infections, he told AFP:

“Proper filtration removes as many particles as possible. Proper fit means that there are no leaks on the sides of the mask where air or viruses can leak,” she says. Just adding a small gap will reduce performance by 50%.

The best material for blocking Small particles Includes non-woven polypropylene used in the manufacture of N95 and many surgical masks, and in-plane HEPA filters. Of all the fabrics, tightly woven cotton is the most effective, she added.

Double

“If you’re wearing a cloth mask, choose one that has multiple layers. Ideally, choose one that has pockets that allow you to slip in a good filter material,” Ma said. Stated. “Or you can double the mask by wearing a surgical mask covered with a cloth mask that fits snugly.”

Surgical masks are made of materials that filter things well, but they tend to loosen, so adding a cloth mask on top will reduce edges and reduce leaks.

Adding a layer improves filtration. If one layer traps 50% of all particles, the combination of the two is 75%.

But she added: “We do not recommend wearing more than one mask. Adding layers can lead to diminishing returns and impaired breathability. You need to maintain good breathing throughout the layers. Otherwise, air will easily leak to the sides of the mask. “

A mask with a metal nose bridge helps to fit snugly, as well as a strap that tightens around the head as well as the ears. Brace is currently on the market to improve the fit of surgical masks.

“You should feel the mask inhaled when you inhale, and if you hold your hand over the side of the mask, you won’t feel any air leaking when you exhale,” Ma said. I will.

Medical grade respirator

Another option is to get an international equivalent such as N95, or KN95, FFP2.

“They all provide the same level of filtration, which means they protect particles in and out,” said Ranudiron, a global health physician at Brigham and Women’s Hospital and Harvard Medical School.

Dillon, who has been advocating better masks since last spring, is dissatisfied with the lack of a clear message to the general public about the value of better masks.

“There was no coordinated push to actually mass-produce and mass-produce these higher-caliber masks.”

Healthcare professionals perform professional fit tests each year to ensure that the mask creates the proper seal, but Dillon does not consider this a major obstacle.

“Teaching people to wear masks more effectively, if not 100 percent perfect, is very feasible.”

Our future mask?

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 will definitely help, but the virus will reach you even if you are between the person breathing and the exhaust. This makes a good mask very important.

Milton and Dillon are cautiously optimistic that their petition could soon become a policy under President Joe Biden’s control, and CNN last week worked on the first official mask standard by the U.S. government. I reported that there was.

Prior to the pandemic, Milton and other aerosol scientists studying the flu said that the flu was also transmitted from small droplets from normal speech and breathing, and the role of sneezing, coughing, and surface transmission was greater than expected. I concluded that it was small.

Their findings were controversial at the time, but COVID-19 renewed interest in research. mask It may be a common sight in the flu season, long after the pandemic recedes.

© 2021 AFP