The Covid-19 Mask Wars : Hi-Fi Mask Asks


Effective yesterday, February 1, it is a violation of federal law not to wear a mask on a public conveyance or in a transit hub, including taxis, trains and commercial trucks (The 11 page mandate is here.)

The “mask wars” are a major source of disagreement and politicizing science during the current pandemic, but my interest here is not of clashes between pro-and anti-mask culture warriors, but the clashing recommendations among science policy officials and scientists wearing their policy hats. A recent Washington Post editorial by Joseph Allen, (director of the Healthy Buildings program at the Harvard T.H. Chan School of Public Health), declares “Everyone should be wearing N95 masks now”. In his view:

there’s no reason any essential worker — and, really, everyone in the country — should go without masks that filter 95 percent. The masks I’m referring to, of course, are N95s. These are cheap — pre-pandemic they cost about 50 cents — and easy to manufacture. Yet our country has failed to invoke the Defense Production Act to produce enough masks for health-care workers and other essential workers. That needs to change, as my colleagues at Harvard Medical School have written.

To see the true power of masks as a public health tool, we have to examine them in the context of everyone wearing them, where the power of each mask doubles. That’s because the particles have to pass through the material twice — once after being emitted and again before someone breathes them in. Take the example of two 70 percent efficient masks, which combine to reduce 91 percent of particles. Not bad. But two N95s result in greater than a 99 percent reduction in exposure. Think about that for a minute. We could reduce exposure by 99 percent for what should be $1 a mask. (Prices are higher now because of the failure to produce an adequate supply.)[i]

Wow. The cheapest I have found N95 masks going for is $3.95—provided you buy in quantity of 100. Generally, they’re around $5. Other high-filtration (hi-fi) masks, e.g., KN95 go for around half that—still prohibitive for 1-time uses.

Doctor Abraar Karan and colleagues have been calling for a “national hi-fi mask initiative” in the U.S. (Stat News Jan. 7, 2020), averring that the pandemic would be over in 4 weeks were everyone to wear N95s in public areas. It would be worth it, they say, for the government to provide monthly stocks of hi-fi masks to everyone in the country, especially with the new mutant Covid-strains we’re seeing. [ii] Anderson Cooper and Dr. Sanjay Gupta echoed this call in one of those town-halls the other day, questioning the new head of CDC, Dr. Rochelle Walensky, along with Dr. Anthony Fauci. Cooper asked, with a straight face: “Does the Biden administration plan on sending every household N95 or equivalent masks?” Restraining a chuckle, Fauci said “I’m not sure that that will happen”.  Walensky’s reply to this is that it wasn’t entirely clear to her that the reason people weren’t wearing masks is lack of access to them. Sure, but that’s very different from lack of access to hi-fi masks being the reason they’re mostly out of reach. N95 masks can only be extended for around 2 days even with life-extending contrivances, which individuals would not have available[iii].

Gupta asked Walensky two questions: first, should people be wearing high filtration (hi-fi) masks, such as N95s, in order to slow the spread of Covid-19? And, second, is the reason the CDC doesn’t recommend the public wear N95s that they have to be reserved for healthcare providers?  Remarkably, Wolensky says no to both.

CDC Director Dr. Rochelle Walensky: Yeah, it’s a really good question and one we get a lot. I have spent a reasonable amount of time in an N95 mask and they’re hard to tolerate all day every day. … I worry that if we suggest or require that people wear N95’s, they won’t wear them all the time. They’re very hard to breathe in, when you wear them properly.

The question, of course, was whether the public should wear hi-fi masks to slow the spread of Covid-19, for example on public conveyances, not whether recommending them would have the effect of decreasing the use of any masks. Besides, perhaps pointing out the advantages of hi-fi masks would cause more people to wear some kind of mask. They could use the information to upgrade their cloth masks (considered the weakest of the lot, even aside from the problem of infrequent washings causing bacteria build-up). The public should not be presumed incapable of making the kind of decisions they make every day about trade-offs of risks and benefits, maybe wearing the hi-fi mask in crowded situations—which for most people would rarely be all day—and less protective masks for other times. Even those pressing for N95s deny you’d need them for running outdoors, for example. In answering factual questions, especially ones they get all the time (which suggests people really want to know) CDC should provide the best information—in this case, about the efficacy of different masks, and we now have a number of studies on this–and not give obfuscating answers that are described as having been designed to avoid or ensure some behavior. “It is just for your own good that we’re not recommending them!” Going down that road makes us wonder what else they’re not being frank about.[iv]

The other possibility that springs to mind, of course, is that the CDC worries that if it recommended (not required) hi-fi masks, the public would urge that there be an effort to provide them at a reasonable cost. Why can’t they be manufactured for the 50 cent pre-pandemic rate?

As for denying that CDC is reserving N95s for healthcare providers, this is at odds with the CDC site itself, in several places. For example, under the CDC guide to choosing a mask

DO NOT choose masks that are intended for healthcare workers, including N95 respirators or surgical masks


N95 Respirators Not for Use by the General Public

The Centers for Disease Control and Prevention (CDC) does not recommend that the general public wear N95 respirators to protect themselves from respiratory diseases, including coronavirus (COVID-19). Those are critical supplies that must continue to be reserved for health care workers and other medical first responders, as recommended by current CDC guidance.

Weaving in and out of the discussion is an equivocation between not recommending the public do X and recommending the public refrain from doing X. Officials should be honest in admitting a shortage remains; and that they do not see a way to restore the 50 cent price-tag.[v]

The CDC recommendation for cloth masks, starting last spring was primarily intended to reduce the emission of virus-laden droplets (“source control”), especially relevant for asymptomatic or presymptomatic people with Covid-19. That was OK as a stop-gap measure, but we want to protect ourselves too. The electrostatic charges found in N95 caliber masks enable trapping aerosols, which we know go beyond 6 feet and can travel across a room.

Some say the general public cannot be expected to conduct the “user seal check” to test the fit of hi-fi masks, but it’s not clear why not. They’re worn by our government representatives in DC.

The push for high filtration (hi-fi) masks has been growing in Europe (Washington Post, January 20, 2021):

Germany on Tuesday night made it mandatory for people riding on public transport or in supermarkets to wear medical style masks: either N95s, the Chinese or European equivalent KN95 or FFP2s, or a surgical mask.

It follows a stricter regulation from the German state of Bavaria this week that required N95 equivalents in stores and on public transport. Austria will introduce the same measures from Monday.

Meanwhile in France, the country’s health advisory council on Monday discouraged the wearing of inefficient cloth and homemade masks, also arguing they may not offer sufficient protection against the more highly transmissible coronavirus variants.

… Markus Söder, the state premier of Bavaria, said that the decision to require [hi-fi masks] there was “very simple.”

“If the virus becomes more dangerous, the mask has to get better,” Söder said. He said he thought it was “absolutely necessary” to have a higher level of protection on public transport and in retail and work places. …

In the U.S., we not only lack affordable hi-fi masks, there has been little attempt at standards for mask adequacy. Dr. Nahid Bhadelia, an infectious disease physician at Boston Medical Center, says the U.S. needs a national effort to get hi-fi masks to the public, beginning with releasing a standard for the masks that are available.(The source is here.)

It’s unconscionable that we have the largest use of PPE by American public in history and the quality of these masks is not being moderated, standardized or regulated. (Dr. Nahid Bhadelia, Twitter, Jan 26, 2021, as quoted in this article.)

The new Feb. 1 mask law allows that wearing an N95 would satisfy the ruling; however aside from blocking face shields [by themselves], bandanas, masks with exhalation valves and masks that don’t fit properly, there are no specific standards. The edict says passengers and operators must wear their masks at all times except “for brief periods, such as to eat, drink or take medications”. But Covid-19 transmission doesn’t take food break, and when my neighbors have their masks off (as well as the rest of the time), I’d like hi-fi protection.

What do you think? Please share your comments. Check back for updates (which I’ll indicate in the title with (i), (ii), etc.).


[i] Without a federal standard, he recommends N95, then the KF94 from Korea, and next the KN95 from China, ideally one with a NIOSH certificate.

[ii] A measurement called the Fitted Filtration Efficiency corresponds to the concentration of particles behind the mask expressed as a percentage of the particle concentration in the chamber air. The overall percentage of FFE, measured in a number of positions, is calculated as 100 × (1 − behind the mask particle concentration / ambient particle concentration). (JAMA Dec. 2020)

[iii] When I wear the hi-fi mask, I get more life out of it with one of those blue masks over it which are around 25 cents).

[iv] A good discussion of this issue in relation to Fauci and herd immunity is by Dr. Vinay Prasad. What’s a good name for this fallacy? The fact vs nudge fallacy?

[v] There is something called a Thermoplastic Elastomer mask that comes up to hi-fi standards, for $15, and is deemed more comfortable than N95s. It still requires purchasing filters, but is sure to get you noticed, especially with goggles, which I’ve also taken to wearing. 


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27 thoughts on “The Covid-19 Mask Wars : Hi-Fi Mask Asks

  1. Tom Passin

    I read a lot of reviews of hi filtration masks including the Chinese and Korean variations. There were a great number of complaints of shoddy construction, very poor fit, poor filtration, and generally it seemed that many if not most on order via internet may be counterfeit or at least poorly made imitations.

    I haven’t ordered any of these myself, mostly because of reading so many adverse comments. I really want to wear a mask that’s better than what I use now (the so-called surgical masks you find in most drugstores but it’s doubtful they are really of that quality.

    One big problem with these common “surgical” masks is that the strip that’s supposed to mold to the nose just doesn’t work well. Anyway. most people I see wearing masks have not done any molding even if their mask would allow it. So there’s a big opening from nose to the middle of the cheekbone where the mask just goes straight.

    It’s almost beyond my comprehension how nine months after the pandemic got going, we still don’t have adequate (never mind N95) masks that most people can buy.

    • Tom: Thanks for your comment. I agree with you that it’s majorly disappointing that we don’t have hi-quality protective masks that are affordable, and that our health systems promote. It was because the responses from the new CDC head showed me that things were unlikely to change that I decided to write a blogpost on it. Where are the innovative individuals with resources who might move forward to get this done. privately?

  2. An N95 and a KN95 have the same filtration capabilities, but are markedly different in that the N95 is tight-fitting and the KN95 is not. Because air like everything takes the path of least resistance, the gaps along the circumference allow egress of air during exhalation and ingress during inhalation, and its worse the heavier you’re breathing and the larger is the gap in the first place. During exhalation, the gap will increase with positive pressure in the mask. N95 is difficult to fit properly with facial hair, and most of the time I see people in public with them, they’re not wearing them properly. I personally will enter a COVID patient room without thinking twice with a N95, but I would not enter with a KN95 – it’s just inadequate.

    However, I think a reasonable compromise, given that most people wouldn’t use the N95 properly and allow it to confer its special level of protection, would be to provide and require the cheaper KN95 masks, or at least surgical masks, something that meets a known standard, and require them to be worn properly over the nose (a pet peeve of mine, seeing them below the nose.)

    Finally, I personally have no qualms about wearing/recycling a mask for days or even weeks, depending on how soiled it gets.

    • Tom Passin

      The question is moot because I don’t seem to be able to get N95s, even over the internet – that is, the medical version without an exhaust valve.

      The fit problem is vexing because CPAP masks usually seal well, with only two or three sizes. True, they are kind of expensive for disposable use, but you would think the designs could be adapted for cheaper manufacture, plus a much larger volume of orders should reduce manufacturing costs in itself..

    • Scott:
      Do the KN95s also hav the electrostatistic charge capability?

      • Scott K. Aberegg

        Complicated and outside of my bailiwick. The circumferential seal difference is pretty much unequivocal, though. On airplanes and in airports I use N95 (and in patient rooms). Elsewhere (where exposures are shorter) in avocational settings, I use KN95 or surgical. At work, just a surgical mask. It’s harder to get, I think, than we originally thought. You need to be in a place with a person who is highly infectious (how do you know? you can’t, but the odds are in your favor), and close to them, or with very poor air circulation or both. And fomite/contact spread is, I think, mostly a canard, meaning all the “wipe down” infection control measures are wastes of time.

        • Scott: yes it would be good if we knew how people were getting infected, if indeed it’s harder to get than we thought. No one I know who got it knows how they got it, except likely from someone around them who was found to have it. If contact spread isn’t deemed problematic, then the whole fear of touching one’s mask would also seem an overreaction.

          • Scott K. Aberegg

            I am a habitual face/nose/eyes toucher. When this started I was scared poopless that I was gogin to get it from contact. I would use hand sanitizer on my hands then wipe my face and make my eyes burn with hand sanitizer. I have backed off completely from that, and now routinely touch my face and eyes with minimal worry in an actual COVID dedicated ICU. I have not been ill (except with the vaccine, which makes me think if I had been ill with COVID, I would have had symptoms). I let my behavior speak for itself: if I were worried about fomites, I would not behave as I do; if I were wrong, I would probably have gotten COVID by now. (True, I do shed my scrubs in the garage still, and immediately take a shower before interacting with my family.)

            • Scott: I know of other doctors who say they haven’t gotten it despite being exposed. Who knows, maybe doctors get some resistance from small amounts in their environment-is that possible?

              • Scott K. Aberegg

                Yes, this is the “variolation” hypothesis, and I think it has some good face validity and biological underpinnings, even though the later correspondents (letter to editor) were not kind to it.

                • Scott: Thanks for sending that link.
                  Let me take the opportunity to ask you, as a doctor, what you think of some concerns about generating mutant Covid-19 strains in immunocompromised individuals, and how that could be exacerbated by extending the time between dosing as being done (I believe) in the UK. I’d been reading about antibody dependent enhancements from vaccines for many months. When the issue of extending the lag time came up, I thought about whether it could be an issue for mutations, having subimmunized individuals. Just yesterday, I found something that linked some of these issues:

                  • Scott K. Aberegg

                    for that “rant” I’d say 1-4 are a political statement; 5 is absurd because the number of people getting convalescent plasma (and we don’t even know what, if anything that does) is minuscule and as he admits (I presume it’s a he for some reason), the potential for transmission from these people is nearly nil; and 6 is, as Alex Tabarak replied to the original tweet, remarkably one-sided – we would need to “model” the competing/opposing effects of (alleged, not proven) selective pressure for antibody resistance purportedly caused by one dose of vaccine against the (mostly proven) reduction in transmission conferred by partial immunity from the first dose. I’m all for speculation, I just don’t think we should take any of it too seriously, especially when it’s from an anonymous ranting pissed off virologist or whoever it was, who spends time on issues 1-4 to take a jab at what he considers a bungled public health response (not that I disagree, it’s just that it’s a given)

        • They’re giving 15 masks for the winter in Germany to people over 60, so clearly they’re intended to be reused. Pharmacists help with checking fit.

  3. Another place selling N95s. Small amounts are ~$6.

    • Tom Passin

      I found them earlier this afternoon. At least they will sell small quantities. Their standard time to ship is stated to be 10 days, but I suppose that’s OK since we’re looking at the long haul.

  4. Scott K. Aberegg

    well, even though I did basic immunology research 26 years ago, I’m not the right person for these nuances, because I don’t have enough background knowledge – I’m just a clinician working in ICUs and with pulmonary patients. I’d have to do some background research and see if there’s actual science behind this speculation, and if there is a precedent for the phenomenon. And it would have to be balanced by the fact that these “escape mutants” would have to be transmitted effectively to get a foothold. This may be partially or completely offset by reduced viral load in partially immune people, decreased transmission/infectivity from them, decreased pathogenicity or virulence of the resulting mutations, tons of known unknowns and unknown unknowns, to borrow from Rummy and the epistemologists. In the biological sciences this is the usual scenario, the systems are too complex to make predictions, you have to do empirical testing. And as I have mused on my blog in the past, I prefer “biological precedent” to “biological plausibility” because the latter is just too easy, vague, and fluid. A much higher standard is, “we’ve seen this same phenomenon in the past, here’s our precedent (or archetype) for how this is likely to play out.”

  5. They’re giving out free KN95 masks to attendees at the Super Bowl today.

  6. Another source of N95s, they say they have trouble buying them given that CDC recommends against them.

    • Tom Passin

      I have found a source for (apparently) good quality medical-surgical masks that are made in Texas. They are also not expensive: a box of 50 sells for $29.90, with free shipping. I ordered last Friday and just got my box today, Wednesday. The nose molding strip is a little better than on the masks I have been wearing, and I think they fit a little better and are more comfortable.


      Note that I’m just a new customer and don’t work for the manufacturer.

      I have also finally learned the difference between a “medical” mask – properly called a “procedure” mask, I think – and a “surgical” one. The surgical mask is rated to withstand high-pressure sprays of liquid – think a ruptured artery. The non-surgical ones are not. For normal everyday use I don’t suppose most of us need the surgical variety.

      These procedure masks are intended mainly to protect the patient (not the medical staff) in case the staff coughs, spits up mucus, etc., according to what I have read.

      The N95-grade “masks” are properly called “respirators”, it seems. They *are* intended to protect the medical staff from emissions by the patient. Again, the surgical grade is rated to protect against high pressure fluid sprays.

      I have also found a source of 3M N95 respirators, both surgical and not, that has not jacked up the price, and from which you can order small quantities, even singles. They have the famous 3M #1860 (surgical) and the non-surgical (but still N95) #8210. They even have the 1860 in small as well as regular sizes. I just ordered 5 of each to try for $15.00 total. From several other suppliers, I could only get about two masks for that, and not in the small quantities.

      I haven’t been notified about the ship date yet.

      • Tom Passin

        Let’s hope these 3M masks aren’t some of these counterfeit ones: see

  7. Here’s an article on mask studies I just saw on twitter. It claims the power of tests were often too low to pick up on genuine benefits.

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