When Aaron Collins sat down to talk, he’d just come from fitting workers at his child’s daycare with high-quality masks. He said they were skeptical at first, but he convinced them it would be a good way to market themselves to parents who are anxious about the coronavirus.
“That’s what I do. I look for ways to spread the gospel of KF94s, like I’m a Johnny Appleseed of protective face masks,” he said, referring to a type of mask made in South Korea.
Collins is a mechanical engineer for a technology company — a job that is unrelated to masks. But he also occupies a niche that government and industry haven’t yet been able to fill. Since August, the self-described “citizen scientist” has been trying to make it easier for Americans to find high-quality face masks that will protect them and others from COVID-19 without taking supplies away from frontline medical workers.
To do that, Collins set up an aerosol lab in his bathroom and started sharing the results with his YouTube subscribers. Some of his videos show him hooking up masks to testing equipment as he jots down numbers on a piece of paper next to the sink. In others, he runs down what he’s learned about different masks and which ones he prefers. He also breaks down the science of how masks work and how to wear them effectively.
Underneath the videos are links where people can buy the masks Collins recommends. He said he doesn’t get any money from those sales and hasn’t monetized his videos in any other way — and doesn’t plan to in the future. He currently has almost 800 subscribers to his channel.
“I’m just going to find as many good masks as I can and then publish all that,” he said. “And then people can kind of figure out which ones they like and what’s in stock and what their price point is.”
Getting many Americans to wear any mask at all has been an uphill battle. For weeks at the beginning of the pandemic, public health officials in the U.S. said that the highest quality masks, like surgical masks and N95s, should be reserved for health care workers, while insisting that homemade cloth masks would do little to stop the coronavirus from spreading.
In early April, the Centers for Disease Control and Prevention finally reversed course and recommended that Americans wear cloth face coverings in public. Meanwhile, masks had turned partisan. President Trump mocked Fox News host Laura Ingraham for wearing a mask at one of his campaign rallies as late as the end of October, and polls show there’s still a party divide in mask use.
Lost in the political debate was a scientific discussion over what sorts of masks people — outside of a health care setting — should wear.
That’s where Collins came in. He had written his master’s thesis at the University of Minnesota Twin Cities on the science of aerosols — tiny particles, like smoke or certain viruses, that can hang suspended in the air for long periods of time and travel far from their source. After graduating, he spent years building instruments to count and describe those particles.
He also read about severe acute respiratory syndrome, or SARS, a different coronavirus that emerged in Asia in 2003 and killed more than 750 people. So when COVID-19 started to spread around the world earlier this this year, Collins suspected it might also be spread through aerosols. If that were the case, then masks would provide an obvious benefit.
After health authorities in the U.S. began encouraging the use of cloth masks, he was hopeful that the general public would start to adopt better masks, like the N95s used by doctors and nurses, but those were in short supply. It soon became clear that N95s were not going to be widely available to the public. “So by July or August I was like, ‘Uh-oh, we’re in trouble,’” Collins recalled. “First of all, half the country doesn’t believe masks do anything. And there’s clearly no ramp-up of N95s.”
In the U.S., two kinds of disposable masks are used in health care settings. Surgical masks are loose-fitting, single-use masks that are regulated by the Food and Drug Administration. They don’t offer much protection from airborne particles. N95 masks — officially called “respirators” — form a tight seal on the face and filter out at least 95 percent of most airborne particles. They’re tested and certified by the National Institute for Occupational Safety and Health, or NIOSH, which is part of the CDC.
NIOSH also certifies other types of respirators, like N99s and P100s, that offer even higher levels of protection than N95s. “In normal, non-pandemic times, these are used by the guy or the girl in the steel foundry or the dust plant,” said Ron Shaffer, a scientist who spent over 15 years at NIOSH testing masks and other personal protective equipment.
The U.S. doesn’t have a mask standard that’s less than an N95 but more than a surgical or cloth mask, something that is widely available and will filter out small particles but doesn’t need to meet the high medical or industrial standards of an N95.
In other words, there isn’t a respirator for the people. That’s where Collins comes in with his work in trying to identify the best mask easily available for purchase.
What Collins focused on were KF94s and Chinese-made KN95s. Each country has different standards for respirator masks, so unlike the N95s, these aren’t certified to U.S. standards. But unlike cloth and surgical masks, they seal against the wearer’s face and are designed to filter out small aerosol particles. They’re also increasingly available in the U.S.
“It sits between a surgical mask and an N95,” Collins said. “Which is what I like to call, and I don’t know if it’s the best term, a ‘general population mask’ or a ‘general population respirator.’”
Collins said these masks came out of Asia’s experiences with SARS and another coronavirus called Middle East respiratory syndrome, or MERS.
While China and South Korea were hit hard by those epidemics, the U.S. was largely untouched. And with N95s readily available until this year, there hasn’t been demand for widely available protective masks that fill that gap — despite their potential usefulness during wildfire season.
Collins decided to start testing masks because he noticed, with KN95 masks especially, that it’s hard to know if what you’re buying is legit. When NIOSH started testing Chinese KN95s this year, it found wide variation between different brands of masks that were supposed to meet the same standard — and even between different samples of the same brand. In May, the CDC withdrew an emergency use authorization from several brands of Chinese KN95 masks because they didn’t filter out at least 95 percent of small particles, as promised.
NIOSH’s standards, like the N95, include quality controls to ensure consistency. “For some of the other standards out there, it’s just not as rigorous,” Shaffer said.
Luckily, Collins already had all the equipment he needed to test face masks in his basement. His setup looks complicated, but the basic idea is simple. A device called an aerosol generator spews out tiny particles using salt and water. (Collins does the tests in his bathroom because it’s small enough to fill up with a lot of particles quickly.) A second device called a condensation particle counter counts how many particles are in the room. Then it counts how many particles are inside the mask Collins is wearing, which is hooked up to the condensation particle counter through a plastic tube that allows the device to sample the air from inside the mask.
By comparing the number of particles inside the mask with the number of particles outside it, Collins can calculate how good the mask is at filtering particles out.
He said he’s spotted a number of knockoff masks since he started testing in July. Many of those tests never made it onto his YouTube channel, he said, because he wanted to focus on telling people where they can find good masks rather than proving he can find bad ones. But one KN95 mask he’s tested had a filtration efficiency of only about 67.4 percent, far less than the 95 percent they’re supposed to be rated at.
“Don’t buy random Amazon or eBay KN95s,” he said in the video after he tested the mask.
Collins isn’t completely opposed to KN95 masks; he recently released a video that included his top KN95 suggestions. But he said that the South Korean KF94 masks he’s tested have shown much more consistent quality. That’s one reason why his top recommendations are all KF94s.
“Every KF94 mask I’ve tested that has come out of South Korea has been legit, which is amazing to me,” Collins told Yahoo News. “And they’re not skirting by at 95 percent. I mean, these masks I’m checking are all at 99 percent-plus filtration efficiency.”
Many of the KF94s he recommends are imported by Be Healthy, a Korean beauty and health supplies store based in New Jersey that also sells masks on its website. Others come from specialty online retailers like Bona Fide Masks. But Collins said he’s been impressed with the KN95 masks carried at big box stores.
When it comes to protective masks like KN95s and KF94s, Collins also recommends against popular at-home tests like seeing whether water bleeds through the mask, whether you can blow out a flame while wearing it or whether you can smell with it on. A lot of bad masks will pass those tests, he said, while many legitimate ones won’t.
Collins said he recently bought 1,000 KF94s that he plans to donate to local food pantries — part of his mission to spread the masks far and wide.
While he recommends the KF94s, Collins is quick to say that a cloth face mask is better than no mask at all. One cloth mask he tested on his YouTube channel filtered about 52.6 percent of small particles.
As for him and his wife, they have two favorite brands of KF94s that they usually wear when they leave the house: the BOTN, which Collins says fits larger faces well, and the Bluna Facefit, which runs a little smaller. In a nod to style, they almost always choose the versions that come in black, rather than the clinical-looking white ones.
Different masks will fit better on different faces, and fit makes a big difference in how well a mask works. So Collins recommends trying one out to see how it fits before stocking up.
During a recent interview over Zoom, Collins said he and his wife may have found a new favorite, something he called “the future of protective face masks.” He held up a KF94 printed with a striking floral pattern that made it look more like a piece of brocade silk than a piece of personal protective equipment. He plans to feature it in a future video.
“It’s everything that we see with cloth face masks, right?” Collins said. “People want cool designs. People want something that’s comfortable. But imagine getting that and having the protection that comes with it.”
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