Is a Homemade Face Mask Better Than Nothing?

The best thing an amateur can do in times of crisis is to follow experts, specifically the expert consensus and not the hand-picked cherries who pander to one’s preconceived ideas. Not that the consensus is automatically true, but it probably is the best that human knowledge can offer at the moment. What we are seeing right now is a consensus shift regarding the wear of facemasks, as more and more countries recommend them or even make their wearing mandatory in some places.

This is accompanied by new research, and one such research in the Czech Republic focuses on comparing various materials. The findings are not published yet, but one such preliminary finding is mentioned in the Czech article – five layers of ordinary t-shirt fabric are effective at catching nearly all particles of the size that have droplets exhaled/coughed out. That is huge since it is nearly equivalent to a surgical mask. And since the main argument for widespread use of face masks is that they should slow the spread of disease from those who have it (especially those who might be asymptomatic), then yes, even such self-made masks are better than nothing, if everybody has them.

But the article mentions another thing, which is even more interesting. One layer of t-shirt fabric was able to stop 11% of the much smaller sizes, those that are expected for the dry incoming particles. And five layers would stop nearly 46% of such incoming particles at maximum breathing speed (i.e. during intensive exertion). Slow breathing increases their efficacy.

That might be significant. There is some evidence that the initial viral dose of SARS-CoV-2 might have an influence on the severity of the illness. That seems logical – the illness has several days incubation period during which the virus grows in the body exponentially. A smaller viral dose thus might give the immune system may be a whole day or even more to develop appropriate antibodies, as is the case with influenza. But I could not find any study looking at whether there is a correlation between the incubation period and the severity of the disease.

It is a work in progress, but to me, it seems the answer to the question in the title is “very probably yes, possibly even for your own protection”.

Before you submit any argument against wearing face masks, please consider whether said argument could be used with the same weight against the universal and non-controversial recommendation of washing your hands. For example, an argument that many people are wearing masks incorrectly is not an argument against wearing them, just like the fact that most people wash their hands incorrectly and insufficiently was never an argument against hygiene. It is only an argument for making an effort to educate the public.

Like this video, which educates about both.


  1. lochaber says

    I may be really wrong on this, but so far I’ve been thinking of most of this stuff in terms of probabilities and such, while I think there is a general attitude to treat things like this as a binary.

    I’ve been thinking if someone sneezes/coughs into their hand, and then touches a doorknob or public transit handhold, some of the virus particles will transfer to that object. If someone else then touches that object, some fraction of those virus particles will transfer to their hand, and then again another fraction will transfer to what that person touches. Then if I touch one of those objects, some fraction will transfer to my hand, etc., etc.

    Washing my hands for 10 seconds, or even 5, isn’t as good as 20, but it’s certainly better than not washing my hands at all.

    I figure the biggest thing with healthy(or seemingly healthy…) people wearing masks is that it makes it less likely for them to poke their nose/mouth with unclean hands/fingers. And, it would help prevent asymptomatic carriers from spreading the virus as much as they would without the mask.

    And, as to the probabilities, if something only reduces the rate by ~0.1%, that might not make a significant difference to me, but if it’s applied to a population of 1 million people, that’s another 1,000 who may be protected who would otherwise be exposed. And then, since it’s contagious, every prevented infection may also mean multiple other transmissions that won’t happen.

    Again, I might be wrong in my thinking about this. Admittedly, I was wrong in my thinking of this previously, I initially thought it was much less serious than it’s turned out to be.

  2. kestrel says

    Well, this is how I see it… and for what it’s worth (probably exactly what you are paying me for this) the Partner works in health care and a little of that splashes over to me as I receive daily lectures about these types of things. Sometimes hours long. Yes, I’m taking one for the team, here. You’re welcome.

    If everyone wears a mask, that is pretty cool. Not only are they stopping at least a little of your droplets we are concerned with here, they also stop some droplets from others. Something is better than nothing, in my view. Plus I don’t know about you, but it **really** makes me think about touching my face. If you happen to sneeze in one of these… not as big of a deal.

    Add to that: if masks make no difference, than why on Earth is it so important for health care workers to wear them? I mean, if they have no effect whatsoever, why did we even invent them? Why do we continue to make them and why is the supply so important? They must do SOMETHING. Sure, I’m willing to accept that they do not stop everything. Nevertheless, they seem to keep surgery patients a lot safer. (Surgery type masks are not nearly as effective as the N95 type.) That is not a zero at least in my book.

  3. says

    Re: dosage/severity
    While the article does claim there is a link between dose and disease severity, that’s not in the studies they cite. Nor am I aware of such data. There is a definite link between viral load/shedding and disease. But not dosage. The studies on healthcare workers, if anything, contradicts dosage having an effect on outcome. They are more likely to get infected, but the disease severity isn’t any worse than the general population.

    Re: masks
    wear em. the best you can get, unless they are N95s. Donate those to health care workers that need them more.

  4. Dauphni says

    The arguments that I usually see against wearing masks is that if you keep enough distance and observe proper hygiene, the added benefit of masks is basically negligible. That’s not saying masks are useless, obviously they’re necessary when you have to be in close proximity to other people. And considering that those people need those masks more than you do when you’re just out on the street, why should you be using up valuable resources? We still don’t produce nearly enough masks to supply the whole population, after all.

    Then there’s the argument that wearing the masks will increase risky behaviour because people feel safer so they think can get away with more. This is similar to what we see with bicycle helmets. It’s not just that cyclists wearing helmets will take more risks, but cars will drive closer to cyclists with a helmet than those without, increasing the rate of accidents. Is it worth taking the risk of people becoming lax on social distancing?

    And all of that is only considering disposable masks. Reusable cloth masks are a hygiene nightmare. They’ve been popular in Asia for years because they work for filtering out smog, but can you disinfect them well enough to get rid of viruses? Otherwise you’re just putting yourself at risk for infection as soon as you put it on again.

  5. says

    @Dauphni, my response to the arguments you put forth.
    -- distancing being better -- As you acknowledge, there are places and situations where closer contact with other people is unavoidable. Even during pandemic people need to buy groceries, visit a physician in person, etc.
    -- resources -- The talk is about whether it is worth making your own mask from spare cloth, not about using up valuable resources, so this argument is a non sequitur under this blog post.
    -- a false sense of safety -- That should and can be counter measured by appropriate education campaign.
    -- hygiene nightmare -- Just as people are being reminded about washing hands, they must also be reminded about washing the face masks. Although I am talking from the perspective of a country where nearly every household has its own washing machine, in the USA that is sometimes/someplace different, but even there people do wash their clothes, don’t they? At least in first-world countries, this is definitively a non-issue. And even if only some people care for the masks properly, it is still better than nothing.
    -- reinfection from putting a mask on later -- The main function of masks is to catch the droplets from the wearer. If everybody wears them, the risk of a healthy individual getting the mask contaminated with the virus on the outside is thus already reduced. And even if some individuals catch the disease later in this way, it is ridiculous to use it as an argument against mask-wearing altogether -- because at least some people will, surely, use the masks properly. Exactly as lochaber puts it, this is a probabilistic issue, to be evaluated from the POV of the population, not the individual.

    In short, these are not arguments against wearing masks, at best they are arguments for educating people on how to wear and care for them properly.

    Plus, they are all pure speculation without a shred of evidence behind them. I have found at least some evidence that facemasks help to slow the spread of respiratory diseases (I linked to some on Mano Sihgham’s blog), but none whatsoever that they make the situation worse as implied by the last argument in your post. That masks make people careless and thus more prone to catch the disease is pure conjecture.

  6. voyager says

    The reuseable cloth masks should be worn once and soaked in a bleach solution, washed and dried between wearing. I use one when I shop because it mostly reminds me not to push up my glasses or touch my face. I’m pretty careful about keeping at least 2m between other people, even when wearing a mask and so are most people I the same.

  7. lorn says

    As far as reusable masks goes cleaning in normal laundry should be more than sufficient.

    I keep a spare cloth mask, a pretty nice one, under the visor of my vehicle for spur-of-the-moment encounters. I have it on good authority, a local microbiologists backed up by CDC and WHO literature, that the way I use and store it it is pretty much self-decontaminating for COVID-19. A few hours at better than 75% humidity and over 100F inside with the windows up (welcome to Florida) and the cooties have all curled up their toes. That I’m only driving every third day guarantees enough time for the little bastards to die.

    Masks, pretty much any mask of reasonable quality, is going to go a long way in keeping droplets in and avoiding touching the face. As for keeping virus out? That’s gravy. It has to be better than nothing and every bit helps. As for people assuming they are protected and taking greater risks, that’s an attitude problem. Not the fault of any mask.

  8. says

    @lorn, it is however also important to not overfocus on Covid-19 to the extent that other pathogens get overlooked. Some very common molds (like Aspergillus niger) can cause pulmonary diseases as well, although not too often under normal circumstances. And then there are of course plenty of other bacterial and fungal diseases that can survive in the fabric much longer and better than the Covid-19, especially when the fabric is stored in shade and wet. So washing the mask with your clothes and ironing it now and then is probably still a good idea.

  9. says

    From Monday onwards, face masks are obligatory in public transport and shops in Germany. We’re currently mass sewing them for our pupils who will be required to return to school on May 4th. year 4 (my kiddo, not my school), years 9 and 10 and the final high school year (12 or 13 not my school either).
    This is going to be a nightmare anyway, but at least we all can have some protection. That’s also why I’ve been pretty absent these last days.
    In Germany the preferred type seems two layers of quilter’s cotton, not jersey and elastic has become the new toilet paper: nowhere to be found. Thankfully I ordered some before there was a mass run, so i still have some and I also instructed my sister to ask for elastic instead of money when she gives them to the carers of her elderly patients. Most grannys have a couple of yards they haven’t needed in ages.

    Re: desinfecting
    Machine washing is sufficient. Covid 19 has a fatty layer, which is why washing your hands is good protection. Washing your mask with detergent is sufficient as well.

  10. lorn says

    Charly @ 10:
    “So washing the mask with your clothes and ironing it now and then is probably still a good idea.”

    Basic cleanliness is always a good idea. Let’s not get carried away with talk of ironing stuff.

  11. says

    One layer of material at 11%. 4 layers for 45%, but really because you can’t breathe through that….

    And only if they are cleaned regularly.

    And, most people wear their face coverings very improperly, and in my opinion as a former hospital employee, full time outside in public is improper usage of even proper PPE.

    While I am supportive, this sounds like something to keep us busy, or give us false security. I really don’t like that kind of messaging, and know it will come back to bite us in the ass if the other side is smart enough to use it against us.

  12. says

    @ParaLess, 5 layers of cotton fabric from a T-shirt is breathable. The people working at the lab are not Donald Trump, they know they should only test things that can be breathed through. Otherwise, they could say that 1 layer of plastic shopping bag stops 100% of the virus both ways…

    The rest of what you wrote was addressed already, multiple times.

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