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Brian Lehrer: Brian Lehrer on WNYC. In the latest mask wearing related news, the National Personal Protective Technology Laboratory, yes there's such a thing, and ASTM International, an international technical standards organization, are working on a set of actual standards so that Americans can easily identify how effective certain masks and other face coverings are against COVID-19. That's one story.

Last Monday, several democratic lawmakers sent President Biden a letter asking to increase the supply of better quality masks and to educate Americans about which masks are most effective. Everybody's talking about double masking now. In the meantime, questions about masking of all kinds still persist nearly a year into this pandemic.

Joining us now to break down mask wearing best practices is John Volckens, professor of mechanical engineering and director of the Center for Energy Development and Health at Colorado State University. Last spring, Professor Volckens converted his lab, which normally does experiments on air quality and pollution, into an official testing site for respirators and surgical masks for the State of Colorado. Dr. Volckens, welcome to WNYC. Thank you so much for joining us. Hi.

Dr. John Volckens: Thank you, Brian. I'm very happy to be here with you.

Brian: Listeners, we'll open up the phones right away for your questions on masks because I know you have them, for John Volckens, professor of mechanical engineering and director of the Center for Energy Development and Health at Colorado State. (646) 435-7280 with your single mask, double mask, high quality mask questions at (646) 435-7280 or you can tweet a question @BrianLehrer.

Let me start with these new standards being developed. ASTM and The National Personal Protective Technology Laboratory are testing whether certain masks can filter out particles measuring 0.3 microns. Why 0.3 microns and is that a number the average consumer should know?

Dr. Volckens: Well, 0.3 microns is the right choice of particle size because it is the most penetrating particle size through any kind of filter media in air, so it's the worst case scenario particle size. When we think about air filtration for particles, it turns out that particles smaller than 0.3 microns can be captured more efficiently by a filter, and particles larger than 0.3 microns all the way up to 10, 50, 100 microns, can be efficiently captured by the filter. It's that 0.3 micron size that gets through the filter most efficiently. If you design a filter to control against that size, you're setting a minimum efficiency for essentially all particle sizes around it.

Brian: ASTM, I see is also proposing a labeling system. According to their draft guidelines, which reported on by CNN yesterday, there will be different levels of performance. Level one being the lowest, which would require the product filters out 20% of particles, a level two, it require at least 50% of particle filtration, and both of those sound pretty low. In what scenarios would that be a standard that would make us happy?

Dr. Volckens: That's a really good question. My answer is, I don't really know. I don't see a situation where a mask that filters out 20% of particles is going to be protective of health in any situation. However, 50% we're starting to get a factor, that cuts down the particles in the air by a factor of two. That's good, but remember an N95, which is the standard we all hear about, that cuts out 95% of particles, or it reduces the particle concentration by a factor of 20.

If there are a hundred particles in air and you breathe in that air, an N95 would only let five of them through. An N50, if we were talking about a 50% efficiency, would let 50% or 50 of those particles though and to me, that doesn't seem high enough, at least when we're talking about a respiratory hazard like SARS-CoV-2 in air, especially with these new variants present.

Brian: All these masks that people buy on anywhere from Amazon to Etsy, on the street or in the corner drug store, do you think they should be labeled? A lot of people probably don't know, and maybe they were just learning as you said it, that N95 refers to filtering out 95% of particles. Should every mask that's sold commercially while the pandemic rages have to be labeled with a number like that, a percentage like that?

Dr. Volckens: I certainly think so. These are called conformity standards. What that means is that the industry that manufactures the product is required to conform to them. We have conformity standards for all kinds of safety equipment; Seat belts, airbags, and vehicles, the things that protect us. It turns out that industry actually likes conformity standards because it gives them a level playing field and they know what they're dealing with. Right now, we're in the wild wild west of masks. There are not a lot of rules out there.

It's very confusing for people to understand what's a good product and what's a bad product. Labeling goes beyond just talking about how efficient the mask is. It talks about how to wear the mask, how to use the mask, what are good techniques and bad techniques. If you're like me, you've probably walked in front of a mirror one day and noticed, "I put my mask on upside down. I put my mask on inside out." Does that matter? We need labeling and instructions so that we can make masks more foolproof.

Brian: One other thing on N95 before we take some phone calls. At the beginning of the pandemic, people were told to abstain from buying N95s because there wasn't enough supply for medical staff across the country who really needed them when they were dealing with COVID positive patients in the hospital. Do you know where we are in terms of supply? Should average Americans now try to procure a supply of N95, because I hear some people saying that?

Dr. Volckens: That's a really good question. It's an unfortunate reality we live in because we all should be wearing N95s. They have been designed for decades. They've been designed by manufacturers who specialize in protecting human health and they conform to a standard we all know and agree is a pretty good standard. However, like you said, when the pandemic started, we quickly ran out of the supply of N95s globally and there still is a shortage of them because if you're like me, you've been on Amazon or you've been to the hardware store, or you've been to any online retailer, and it's hard to find N95s and when you do, they're dubious quality.

You don't know where they're coming from and so we're still in this wild west of mask availability. The reason there's a shortage is that demand didn't increase by 10%, it didn't increase by 100%. It increased by like 10,000%. It’s really difficult to keep up with that kind of demand. Just think about how many Americans would need a mask, an N95, if you had a supply of 10 for the year. That's a billion masks that would need to be issued at least. We're not even close to meeting that demand right now.

Fortunately, we are getting close to meeting the demand in the healthcare industry so our front line workers in many cases are being better protected. They're still having to reuse masks in their workplace, and that's obviously not an ideal situation. An N95 mask is supposed to be a one and done mask. It's a disposable mask. You wear it for your work shift, you throw it away. There is good evidence that you can reuse an N95 multiple times, but we're still not even close to where we want to be as far as [inaudible 00:08:29]

Brian: Peter in Syosset. You're on WNYC. Hi, Peter.

Peter: Yes. Good morning. I'd like to know what the difference is between an N95 and a KN95. I've a got a package of KN95 that I picked up at the store and it seems like multiple layers, quilted on the inside, it's got like ear loops and everything. Can you tell me what that would be?

Dr. Volckens: Great question. The KN95 is a Chinese standard that is similar to our American N95 standard. Brian mentioned the NPPTL earlier in the call. That's the National Institute for Occupational Safety and Health Lab. They're the ones who certify N95s. The KN95 is a Chinese standard and the KN95 standard purports to say that the mask is 95% efficient, but in my opinion, there are some problems with KN95s out there.

For one, there's a lot of counterfeit KN95s coming into the country. Two, while KN95 do tend to have good filtration efficiency, we've tested hundreds of KN95 masks. We find that when a KN95 mask fails, it typically has 75% efficiency, 90% efficiency, not 95% efficiency, but pretty good efficiency. However, I'm not a fan of KN95s, wearing them by themselves, because they are ear loop style masks. Ear loop style masks do not provide a good seal to your face. The unfortunate truth is that an ear loop style mask just doesn't pull against your face hard enough to press that mask to form a seal. If you don't have a seal from the mask around your face, then the mask is going to leak. It's going to leak air around your chin. It's going to leak air around the bridge of your nose, and if it leaks air, that means that air is coming in and out of your body that is unfiltered. Unfiltered air does nobody any good.

Brian: What about KF94 masks, which is another one that people are running into commonly?

Dr. Volckens: The KF94 mask, that's a 94% efficient mask, is a Korean standard. KF94 masks tend to be a little bit better than KN95s, at least what I can see on the market, but most of them are still ear loop style masks, so they're pretty good masks, but they're not great masks because they don't seal well onto your face. You will never see an N95 mask, at least I haven't seen one yet, that has ear loops. N95s have headbands, and two of them, because those rubber bands that go around, one around your neck, one around the top of your head, efficiently pull that mask onto your face and close that mask down on all sides of your face so that all the air coming in and out of your body gets filtered.

This is one of the reasons why double masking has been advocated for. You put on one of those high efficiency masks, even the blue surgical masks we see have pretty good efficiency as far as their filters, but they leak. If you take a second mask and you tie that mask or press that mask harder on your face, you can hold down that high quality filter mask and provide yourself with better protection.

Brian: I've seen KN95s I'm pretty sure with the hand bands as opposed to ear loops, but I've also seen masks that have ear loops that are adjustable with little toggles so that you can tighten them around your ears. Does that solve the problem significantly in your opinion?

Dr. Volckens: It doesn't solve the problem significantly, but it certainly is a lot better. I've tried to tighten down an ear loop style mask to the point where it would make a good seal. Let me give you a point of reference. Many of us have actually worn probably an N95 mask before. When you're doing something in your backyard, maybe you're leaf blowing or doing something dusty, you've probably put on an N95 mask at one point because they used to sell them at the hardware store. When you wear an N95 mask for a couple hours and you take it off, your face looks like you've been snorkeling.

You have a literal ring where the mask pressed against your face, because that's the level of protection you need for the mask to seal. When you tighten down an ear loop style mask to that point, it becomes uncomfortable. It frankly hurts the back of your ears because there's just not enough contact area around your ears for that mask to be cinched down tight enough. What I worry about is that we get to the worst case scenario where it's like, "I can't wear this mask, so I'm just going to take it off."

Brian: Barbara in Manhattan, you're on WNYC. Hi Barbara.

Barbara: Hi, thank you. Two quick questions. I have a surgical mask that I use like day of the week mask, just for going out for a half hour, an hour to walk the dog, and I throw them away if they're soiled, but I don't touch them for the whole week. I just wear them for a short time. I'm wondering how safe that is. My other quick question is we keep hearing about N95 needing to be fitted to you, but if you happen to have N95s in the house from pre COVID, what's the mystery, how do we fit them?

Brian: [inaudible 00:13:45] [crosstalk] Go ahead professor.

Dr. Volckens: I wear a blue surgical mask but I walk my dog too, outdoors. I live in a suburb of Fort Collins, Colorado, so it's not a very populated area. My general rule of thumb is if I'm going to encounter more than say five people per minute, I need a better mask on, even outdoors. That's just my personal level of comfort. Everyone's different in what they're comfortable with, but that's me. But I will wear a regular cloth or surgical style mask when I'm outdoors.

When I go indoors and I do rarely these days, in public spaces, because it makes me nervous, I try and wear the best mask I can. I fortunately had about ten N95s in my garage. I'm an engineer. I like to work around the house. I like to cut wood and make dust and so I had a bunch of N95s before the pandemic. I'm still using those and I kind of reserve that for what I call high risk environments, and that would be being around strangers indoors. What was the second question?

Brian: Fitting an N95 mask, and a lot of people have heard this. I'm glad she brought it up because some people say, if you work in a hospital, they make sure that you have a well fitting N95 and without that, it's going to be gappy enough to be a risk to you. How do you fit them?

Dr. Volckens: That's right. NIOSH, which is the National Institute for Occupational Safety and Health, has known for a long time that even if you have an N95, that doesn't mean you're going to use it correctly or it's going to fit onto your face. So along within the N95 standard are requirements for doing what we call quantitative fit testing, which essentially means having a specialist teach you how to put on the mask, and then testing that the mask actually provides the protection of 95%.

There are lots of ways to do that. Unfortunately, that's a very technically involved procedure. It involves expensive equipment where we literally measure particles in the room and particles that get past the mask while you're wearing it. So it is a very personalized test, but it's the kind of test that really provides maximum protection to the wearer because you will know that if you put on that mask correctly, that mask, that size, that type for your face, you will be protected according to the N95 standard.

We're not all going to get quantitative fit testing done for ourselves because the equipment itself costs thousands of dollars, it's involved to do, but there are ways you can test fit at home. Let me go through a couple of those. Number one, if you breathe in or out and you feel any air around your cheeks or around your nose, you know that the mask is leaking. You shouldn't be able to feel any air moving around the sides of your face. Two, if you breathe out and your glasses or sunglasses fog up, that tends to suggest that air is not going through the mask. It's going up around the bridge of your nose. Where the mask meets your nose is one of the most common locations for the mask to leak.

Either on exhalations, you can breathe out, or on inhalation breathing in through that gap. In fact, when I'm out in the wild and I see people wearing masks, I cringe because I could take my pinkie and just slide it down between their nose and the mask. I think, well, air always follows the path of least resistance. Does it want to go through the mask or does it want to go around the hole between the mask and your nose?

I think the answer there is pretty evident, so we want the mask to be able to be sealed there. If you breathe out on a cold day, air goes- and there's been visualizations done of this. For surgical masks especially, the air shoots up the sides of your nose and hits your eyes and so that's why your glasses fog up, and it also shoots kind of out the sides of the mask around your cheeks, and so it goes kind of up and away from you.

Now, let me be clear that even these types of masks provide protection because you're not breathing out a cone of air right in front of your face. When we're in close respiratory contact with another person, say talking two or three feet away, that's where the risk is highest, because if you can smell someone's breath, you are breathing in the air they just exhaled. When you wear even a poorly fitting mask, it does at least push the air away from their face and upwards and out. That doesn't protect an indoor space but it does protect against close contact. This is one reason any mask is better than no mask. However--

Brian: Follow-- [crosstalk] Go ahead.

Dr. Volckens: I'll just finish up on the fit testing issue. If your glasses are fogging up, your mask isn't sealing well, and unfortunately most of the masks I see don't seal well. The third test, and it's the best one in my opinion, is what I call the blink test. Put on your mask, walk into the bathroom or stand in front of a loved one who's willing to get within a couple of feet of you and breathe out forcefully. Take a big breath of air and breathe out. Do you blink? If you blinked, that means that the air was going up around your mask and hitting your eyes. It's almost impossible not to blink when air hits your eyes. When I do this with an N95 properly fitted, I never blink. When I do it with almost every other surgical mask, I blink every time.

Brian: One more follow up on this. Listener tweets, something to ask about mask fit. My dad, he writes, heard from a doctor about using double-sided tape to create a better seal. I'll also add that I have a friend who makes masks and puts double-sided tape around the top of it so that that seal around the bridge of the nose is tighter, to prevent that leaking up toward your eyes let's say. Have you seen that? Do you recommend it?

Dr. Volckens: Yes. I'm fine with that. Anything helps make a seal. One of the issues with double-sided tape is it's going to run out of its stickiness, if you sweat or if you have an oily face, the tape's not going to seal well over time. It's not a perfect solution because it's going to degrade over time but it's better than nothing. Of course, once the tape degrades, getting it off the mask could destroy the mask. There could be issues with it, but it certainly isn't a bad idea. Many N95s have a little piece of silicone that is around the top of the mask that will seal. We'll eventually see a lot more masks featuring a silicone kind of ring. Very much like if you've ever put on a snorkel mask, that's the same material.

Of course, if you've ever been swimming in a pool wearing goggles or if you've worn a snorkel mask, you know real quickly if that mask leaks because anyone seeing water [unintelligible 00:20:45] the mask. It's hard to tell if a mask leaks in air, so the simple tips I gave on the blink test are a good way to check against that.

Brian: Dr. John Volckens, mask expert and engineer at Colorado State University. Juliana in Rockaway Beach, you're on WNYC. Hi, Juliana.

Juliana: Good morning to you both. Brian, I love your show and you have my favorite theme song on the radio, period.

Brian: Thank you.

Juliana: My question isn't pretty, but it's direct. If I double mask, I get not just sweatier but snottier and I don't know how that's any better protection for other people if I have COVID, or to me, if I don't.

Brian: I'll add to that Professor that I have heard, and tell me if this is true, that if your mask gets wet through snot or any other way, it's less effective.

Dr. Volckens: Those are good questions. When a mask is wet, then the little pores in the masks are getting filled up with liquid water. That makes the mask harder to breathe through and of course, a mask that's harder to breathe through, the breathability of the mask has lots of issues. One, if you have some sort of pre-existing condition like a respiratory disease, you don't want to put yourself under more duress.

I suffer from asthma. I can't exercise with a mask on, at least a mask that fits well. That's been a big issue for me. I haven't been to the gym in over a year and it's really a bummer. I tried to exercise outdoors. It's not as easy to do in wintertime but it's a toll that this pandemic has placed on me. If you're wearing a mask that's hard to breathe through as well, you're apt to take it off or it's apt to leak more around the sides.

The filtration ability of the mask can be affected by getting wet, but not to a huge degree. We don't see a massive decrease or increase in efficiency for wet masks, as long as air still goes through the mask. It is a good rule of thumb, if the mask gets very wet or very snotty, you need to take it off and replace it. When I go out in public, I'm always carrying a backup mask for any sort of mishap, whether if I'm snotty or if it gets wet because I'm sweating. I have a backup mask on.

Brian: Jacqueline in Englewood, you're on WNYC with Dr. Volkens. Hi, Jacqueline.

Jacqueline: Good morning and thank you. Being a woman, I like masks with different designs and fashion. I was wondering, the cotton or silk masks that are sold, and some of them have that pocket where you can put in that N95 filter. Are those masks effective, and the ones with that little respirator hole in the side?

Dr. Volckens: Good question. The little respirator hole is a vent to allow you to breathe out easier, which is not a good thing for protecting people around you because none of the air that goes through that outward-facing vent will be filtered. I advise against anyone using masks with vents for protecting themselves and their community and their loved ones from COVID-19. The question about, there was a second question. I'm sorry, I forgot it.

Brian: I forgot it too. Jacqueline, do you want to repeat it?

Jacqueline: Filter.

Dr. Volckens: Yes, inserting a filter into a mask. Inserting a filter into a mask can't hurt. It certainly doesn't hurt but one of the problems is for removable filters. You're putting the filter into a pocket in the mask, and if that filter doesn't cover the entire mask surface area, then just like leak pass around your nose, air that comes into the mask is probably going to try and go around the outsides of the filter, through the periphery of it, instead of through the filter itself. There's been some testing done on this. In general, for the removable filters you get some benefit, but you don't get maximal benefit because air will flow around the filter.

Air can make a right turn real easily inside a mask in a distance of millimeters or less. Insertable filters do provide some protection but not as much. I would rather recommend masks that have built-in filters or the mask itself is made of a filter material so that every part of the breathable space in the mask is filtering particles.

Brian: Dr. Volkens, I know you've got to go. We have so many people with so many questions that I hope we can have you back for a round two at some point. Thank you so much for such good information today. John Volkens, professor of mechanical engineering and director of the Center for Energy Development and Health at Colorado State University, where he has become an expert on testing masks. Thank you so much.

Dr. Volckens: You're welcome. My pleasure to be here.

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