The Best Face Masks for Kids, According to Experts

Fri, Aug 20 2021 — One essential back-to-school item for kids this fall is a face mask — the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics both recommend them — but finding one that's actually protective for a child is not a straightforward task, as many parents can attest.

There's little in the way of official guidance or research to inform evidence-based recommendations on what type of face masks works best for kids.

Search for children's face masks on Amazon and you'll run into a smorgasbord of options: masks with three, four, or five layers, different designs, and different materials. There's one company selling a mask it calls an m95 model, a term the company devised.

It's almost impossible to verify many of the claims being made by the manufacturers, or to know if they will fit your child's face until you order some, which can get expensive.

But it's worth looking for a good mask. A large study of more than 1 million people being conducted online by Facebook and Carnegie Mellon University found that students who wore face masks in school had a reduced risk for testing positive for the virus and getting sick with COVID symptoms. The study was published in June in the journal Science.

Delta More Contagious

The Delta variant of the new coronavirus is much more contagious than previous versions of the virus. Studies have shown that infected people carry 1000 times more virus in their nose and throat than with the viruses that circulated last winter and spring. They shed more viral particles into the air when they talk or yell or sing, making this COVID-19–causing virus much more transmissible that in the past.

What that means says Kimberly Prather, PhD, an aerosol scientist and distinguished professor at the Scripps Institution of Oceanography in La Jolla, California, is that if it once took about 15 minutes of proximity to an infected person to catch the infection, that window of risk is now much shorter.

"If you believe the 15-minute magical number, now if you take 1000 times the viral load, basically in 1 second you could inhale that same amount of virus. So it's gone from 15 minutes to 1 second," Prather said in an online seminar on school safety she helped to organize.

A Better Mask

What that means is that we need to upgrade our face masks, switching away from ill-fitting fabric masks, which can offer varying degrees of protection depending on the number of layers and type of fabric that's used, to more highly protective surgical masks or better yet, N95 respirators, which provide the highest level of filtration.

That's harder to do for kids, who have much smaller faces.

Any masks that gapes around the edges isn't going to work well, no matter how well it filters.

"N95s are not made to fit kids. They do not come in kid sizes, so I do not recommend N95s for kids," said Linsey Marr, an environmental engineer at Virginia Tech, who tests face masks in her lab.

Marr says parents need to consider the attributes masks in this order of priority:

1. Comfort: "If your kid won't wear it, it's not helping at all," she said.
2. Fit: "Leaks around the sides are like having a hole in your mask and aerosols carrying the virus can get right through," Marr said.
3. Filtration: How well the mask blocks small particles

One option to improve fit is to layer a fabric mask over a surgical mask. The fabric mask helps to hold the edges of the surgical mask more tightly to a person's face. The surgical mask creates better filtration.

Marr said KF94 or KN95 masks, which are being manufactured in Korea and China, are good choices. They offer nearly the same degree of filtration as an N95, and they fit closely to the face, to minimize leaks.

Check for Counterfeits

The KF94 and KN95 masks for children are widely available, but Marr said parents do need to watch out for counterfeits, which don't perform as well.

The National Institute for Occupational Safety and health (NIOSH) gives examples of counterfeit products here.

There's also a type of cloth mask that has a built-in, edge-to-edge filter layer that is made for children.

"Some of these filter out more than 99 percent of particles and those can be very effective, if they fit well," Marr said.

Marr has compiled and publicly posted a list of her recommendations for masks for children.

There's also a new voluntary standard for face masks. It's called ASTM F3502-21, and it's published by an international organization that sets voluntary standards for thousands of products. In order to claim that a mask meets this standard, a manufacturer has to have its mask tested and demonstrate that it provides a certain level of filtration and breathability.

Not everyone agrees that the standard is adequate, though.

“It's pretty much useless. The max category is 50% filtration efficiency,” says Aaron Collins, who calls himself @masknerd on Twitter. “That might have been OK for the original coronavirus but “now that we're talking about Alpha and the Delta on top of that, it’s not even applicable any more,” he says. “We’ve passed that standard.”

Collins is a mechanical engineer in Minneapolis, MN, with expertise aerosols who started testing face masks last year as a way to find a good, protective one for himself. The project soon grew. Now he posts the results of his testing and debunks common myths about masks (yes, if you can smell through it, it is still protective. Smells are vapors, not particles, he explains) on YouTube.

He had stopped his testing over the summer but said parents have been bombarding him with questions about masks for kids, so he started testing them again. He has a 5-year-old son.

“We have a huge problem in the U.S., and that is that here is no general population standard for face masks,” says Collins. “Now we have this problem, that we need kids with better masks, and we have no standard,” he says.

NIOSH sets standards for occupational masks, like the N95. But their standards don’t apply to people who need them for general use. Collins says it would likely fall to the FDA to set a standard like that and more importantly, enforce it.

Based on his testing, he recommends that parents try to find a KF94 mask, from South Korea. He says their performance is nearly equivalent to an N95, and he’s run into fewer instances of counterfeits with these kinds of masks. If KF94s are sold out, as they often are, he recommends looking for a KN95 mask from one of the companies that once had an emergency use authorization (EUA) from the FDA for healthcare workers. That EUA has been revoked as supply of N95 masks has increased, but he says the masks on that list are more reliable.