5 ways to make your mask more protective

It’s time to improve your mask game.

With new, more contagious strains of coronavirus spreading in the United States, and transmission levels still very high in many places, some public health experts recommend that Americans update the basic cloth masks that many wore during the pandemic.

“A cloth mask can be 50% effective in blocking viruses and aerosols,” says Linsey Marr, a Virginia Tech researcher who studies the transmission of viruses through the air. “We are at a point now … that we need more than 50%.”

When you’re outdoors, where fresh air can quickly disperse droplets of viruses and smaller particles, a tissue mask is still appropriate, says Marr. But infectious particles can accumulate inside the home, and this is where you want a better mask. “Now I’m wearing my best mask to go to the supermarket. It wasn’t before, ”says Marr.

Ideally, we would all be using medical grade N95 respirators – so called because they block at least 95% of the particles when used correctly. But even now, the N95 remains scarce, and the Centers for Disease Control and Prevention still say they should be reserved for healthcare professionals.

Fortunately, there are other ways to seriously increase the protection your face mask offers. See how.

1. Use 2 masks

The double mask concept has received a lot of attention lately, especially after Dr. Anthony Fauci, America’s leading infectious disease specialist, publicized it on the “TODAY” program.

Start with a surgical mask closest to your face, says Marr, and then add a cloth over it. You want a surgical mask made of a non-woven material called polypropylene, because that material contains an electrostatic charge that allows you to capture particles. (Some surgical masks are made of paper.)

The disadvantage of surgical masks is that many of them fit freely – and the mask’s ability to filter out particles depends in part on how it sticks to the face. By placing a layer of cloth mask on top, you can get a tighter fit while adding an extra layer of filtering, says Marr, who co-wrote a recent review recommending the double mask.

But don’t keep accumulating masks, Marr warns; only an additional mask is sufficient. If the masks become too difficult to breathe, air will enter and exit through the sides. “So it’s like you have a hole in the mask,” she says.

Even if you start with two masks with about 50% effectiveness each in blocking particles, when you put one on top of the other, you can end up with a combination of 75% or more effective, says Marr.

This is how Marr explains this math: “If you have 100 viruses that are flying towards your mask with 50% effectiveness, 50 of them will be filtered and 50 will pass. When those 50 arrive at the second mask, 25 will be filtered and 25 will pass. So the overall efficiency is 75%. “

Dr. Monica Gandhi, an infectious physician at the University of California, San Francisco, says the double mask is especially important for people in specific circumstances: adults working in crowded indoor environments and clinically vulnerable people entering indoor spaces. in areas with high transmission.

2. Add a filter

If bending is not your thing, you can get a similar increase in filtering efficiency using a two-layer mask with a filter pocket, says Gandhi. The outer layers must be made of a tight weave fabric.

Marr suggests using a surgical mask in the filter bag. (You can cut the surgical mask to fit in your pocket, if necessary.) She says that the HEPA filters cut from the filters used in portable air purifiers work very well (here’s her instructional video); a PM2.5 carbon filter should also solve the problem, as long as it is flexible.

Another filter option: a material available at fabric stores called spunbond, also sold under the Oly-Fun brand. It is made of polypropylene, so it also uses the power of static electricity to retain particles.

Adding a filter made of two layers of polypropylene can increase the filtration efficiency of a cotton mask by up to 35%, Yi Cui, a researcher at Stanford University, told NPR last year.

And for a home-made option: Cui’s research found that two facial tissues, folded to form a four-layer filter, can also do a decent job of increasing the protection of a mask. But please don’t take a coffee filter: Marr and Zangmeister notice that these filters are difficult to breathe, so you end up breathing around the filter instead of through it.

3. Choose a better fabric mask

If you are still wearing a single mask, make sure that the one you wear is as protective as possible. Like Gandhi recently wrote on Twitter, “There is still a function for basic masks.”

When it comes to fabric masks, look for a fabric with a tight weave. Several studies have shown that 100% cotton is a good bet (think cotton shirt or quilted cotton instead of a shirt).

As Christopher Zangmeister, a researcher at the National Institute of Standards and Technology, explained to NPR last year, natural cotton fibers tend to have a more three-dimensional structure than synthetic fibers, which are smoother. And this 3D structure can create more obstacles that can stop an incoming particle. That said, filtration tests have shown that some masks made from other fabrics, such as a designed mesh, can be highly effective.

Also, look for three layers on your mask: Studies have shown that a three-layer mask made of tightly woven fabric works well.

For more detailed advice on choosing a cloth mask, refer to the NPR guide on choosing a more protective cloth mask.

4. Make your mask tighter

To maximize the effectiveness of the mask, make sure that it fits well over your mouth and nostrils, up to the bridge of your nose, and that you don’t see any gaps. And, please, don’t let your nose hang over the mask – it defeats the purpose!

The filtration efficiency of a mask varies depending on how well it adapts to your face, as a recent study in JAMA Internal Medicine illustrates. The researchers found that the tested surgical masks blocked only 38.5% of the small particles, on average, when used normally. But filtering efficiency increased when they tried several hacks to make the mask seal better.

A trick they tested: tie the rings as close as possible to the edges of the mask and then attach the side pleats to minimize any gaps that appear at the edges, as in the photo on the left, below. This increased the filtration efficiency of the surgical mask to 60%.

Another simple trick is to use a hair clip, as in the photo above, on the right, to hold the hair clips securely on the back of the neck – which increased the mask’s filtering efficiency to almost 65%.

And the final and most effective hack? It is a pair of tights. When the researchers covered the surgical mask with a 25 cm nylon stocking section, the filtration efficiency reached an impressive 80%.

material ring, about 20 to 25 centimeters from top to bottom, from one leg in a pair of pantyhose. Then, pull the ring over the head and over the mask to create a perfect fit on the face.”/>

It may sound silly, but it is effective – and quite comfortable. If you want to try this trick, cut a ring of fabric from the thigh area into a pantyhose – about 20 to 25 inches long, from top to bottom. (Professional tip: wear queen-size socks for a more comfortable fit.)

Then, pull the ring over the head and over the mask to create a perfect fit on the face. The socks should also work well, says Loretta Fernandez, assistant professor of civil and environmental engineering at Northeastern University who has conducted previous research on the power of pantyhose.

5. Consider KN95s and KF94s

While N95s remain scarce, KN95 respirators are very easy to target today. KN95s are regulated by the Chinese government and, like N95s, they must filter at least 95% of the small airborne particles, although testing standards are different in each country.

Be warned: the market is flooded with fake KN95s and tests have revealed that some of these fakes are practically useless. If you want to buy one, check the list of models and authorized suppliers from the Food and Drug Administration. (You will need to scroll down to Appendix A).

NIOSH also conducted limited assessments to assess the filtering efficiency of foreign-made respirators. Check this link for results, which are updated regularly.

Lately, another foreign-made respirator, the KF94, has also received a lot of noise. KF means “Korean filter” – the mask is made in South Korea – and 94 means it is designed to block at least 94% of the small particles. It looks like an N95, but with side flaps that adapt to the contours of your face and an adjustable band around the bridge of the nose.

As Stephen Morse, professor of epidemiology at Columbia University, told NPR recently, in South Korea, the KF94 is intended for public use. But, again, beware of counterfeits.

If you choose one of these respirators, make sure that they also fit your face well. And remember, no matter what you choose, the best mask is basically the one that you will use consistently.

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