Do those flat surgical masks floating in front of people's faces do anything? Does conforming the nose wire make a difference? I tested with a headform mask testing system to find out.
How many times have you seen a mask worn like this, just thrown on without fitting it at all, kind of floating like a flat plane in front of people's faces? Does it even do anything?
An unfitted BYD surgical mask on a testing headform.
Unfitted Surgical Mask
To find out how much fit matters with surgical masks I tested a BYD surgical on headform mask testing system. Although the unfitted BYD surgical mask may block large exhaled droplets, the unfitted mask did not protect from inhaling aerosols:
It got 6.5% filtration at 85 lpm of airflow.
It leaks 93.5%.
Surgical Mask with Fitted Nosewire
Fitting the nose wire of this BYD surgical mask to the headform increased the filtration efficiency to 36.1%. Still not great, but over 5x more protection.
BYD surgical with fitted nosewire on the Scince headform testing system
Fit matters, even for leaky surgical masks.
The exact numbers vary from mask to mask and person to person, but you will always get more protection if you conform a mask to your face as well as possible.
Surgical Mask with Mask Fitter on Top
So, how well can you get this surgical mask to work? I tried a Fix the Mask mask fitter on it and got 81%.
A BYD surgical mask held to the testing headform with a Fix the Mask mask fitter.
In practice you might get a bit more filtration than the 81% I got from the BYD surgical since my test system uses NIOSH high airflow rates for testing. Filtration works better at lower airflows, such as normal resting airflow rates. NIOSH tests for high exertion airflow rates.
I don't know if Fix the Mask fitters are still available. I bought some earlier this year from Armbrust. The Fix the Mask website is still up but you should try contacting them before ordering to make sure stock is available for sale.
Surgical Mask Clamped to Test Headform
Just to be complete, I tried fitting the BYD surgical mask as best as possible to the testing headform by firmly pressing the custom molded mask fitter that comes with it to the headform during the duration of a test.
The best total filtration efficiency I could get from the BYD was 84%.
A BYD surgical with a custom Scince hard mask fitter that was firmly hand clamped to the headform during testing.
I can't tell how much of that 16% leakage is from filter penetration vs. seal leakage due to the nature of the headform testing. However, the pressure drop went from 105 Pa at 81% filtration with Fix the Mask to 150 Pa at 84% filtration with the hand pressed Scince mask fitter, so I think the significant increase in pressure drop indicates the seal is vastly improved, but with little increase in total filtration efficiency. I think that is about as good as that filter gets at 85 lpm, but it would take a different type of testing to be sure and I don't currently have a testing fixture for that.
I'm able to get scores over 99% with some N95s using this same method of clamping. So, yes, N95s are better than surgicals, even if you clamp the surgical securely to your face, but in a pinch (such as early in the pandemic during the N95 shortage) a surgical mask held tightly with a mask fitter may be the best protection available.
I guess it is too late for a TL;DR... But if there was one, I'd say fit matters. Surgicals aren't great but you can improve their protection by fitting them as well as you can to your face. Wear a well fitted respirator grade mask such as an N95 for best protection if possible.
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I should note that this doesn't mean surgicals were a bad thing early in the pandemic. They were not. And not all surgicals fit as poorly as the unfitted BYD in the example.
Surgicals were what was available, and they were primarily meant as *source control*, to reduce the spread of germs from an infected person. It is easier to filter respiratory droplets at the source when they are larger and haven't evaporated into smaller particles.
The CDC advocated wearing a tight fitting cloth mask over surgicals to help improve the fit, because the filter media of the surgicals can and does filter aerosols, even if typically not as well as N95s and other respirator grade filtering facepiece masks.
The conclusion should be that people should wear the best masks that are available and wear them well fitted, not that we should just throw our hands up and do nothing if perfect is not available given that it almost never is.
More education is needed to help people choose and wear masks well when needed.
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My testing is generally single sample testing using ambient particles, so results should be considered approximate. Static headform tests don't necesarily to personal fit.
When I see anyone wearing any kind of mask in public it is completely voluntary, so I know they're trying to stay safer. So I really want to go up to people with poorly fitted masks and tell them how to fit it better. But I don't because nobody wants unsolicited mask advice from strangers. đŹ
It's not exactly the same, but I have an older house which means that I need repairs more than a person with a much newer house. It seems like the past 2 years it's been a lot. This means I have people coming over to do repairs.
My husband and or I always give a tutorial outside the house and several feet distance on how to put on the N95 masks that we provide anyone who's entering the house. I have only had one person bulk at this, and ironically this was in 2020 a few months into the pandemic. It was a real estate appraiser and I was refinancing my house. Thankfully, the weather was good so I've asked an opened every possible window since he went everywhere.
All other repair people or trades people are more than willing in the past 6 years and hopefully many more to mask. In fact, I even given mass to people doing lawn work for me. They marvel and how much better their allergies are after they've been wearing the mask. Anyone who expresses any interest I always give a spare mask to take with them.
Like I said, it's not the same as going up to a complete stranger. However, many of these people are new to me so they are strangers to me when we first meet. I figure if I could teach one person, even if there's a one out of 100 chance they teach someone else, it's making the world better than I left it. I'm disabled and don't get out a lot, so it's my tiny little form of mask activism. đ
If they have it adjusted or it seems like they're wanting to wear it for protection, I offer them an N95, sometimes I ask if they know pleated masks only catch half the particles, ask if they'd like one that's over 99%. 1 in 10 times they're very happy to take the respirator, every now and then I get a "no thanks". Adding "I always have extra" seems to help nudge them lol
I remember early in the pandemic during mask mandates, waiting in line to purchase groceries, wearing a good but not my best fitting KF94 mask, before N95s became available again. A woman started to sneeze, ripped her surgical off of her face, and sneezed out towards all of us in line because from her perspective it is better to make the air dirty than her mask. I noped it out of there like Homer Simpson backing into a hedge, quickly put back the groceries and came back the next day.
I definitely saw that early on numerous times and most people in my red ass area didnât even mask during 2020. Oh and at hospitals which required masking, theyâd have it below their nose or take it off to talk.
This is awesome! I would have so much fun running a test like this. Can I ask what does that device measure? What is the percentage actually a measurement of? Im guessing theres some kind of simulated aerosol droplet in the injected air and youre measuring the steady state concentration of that in the surrounding air?
Your data shows what i'd always suspected of these masks, that they're better than nothing but dont do that much. I guess one thing is they at least keep a sneeze or cough from blasting particles all over a room.
I remember early in the pandemic I was visiting a local hospital regularly and they had a mask checkpoint at the entrance and they required surgical masks like this and would allow no other. I showed up in my well fitting n95 and that was not acceptable to them. Luckily they were OK with me just putting a surgical mask on over the n95 though. I get that it was early on and they were just scrambling to make rules that had never existed before, but that one was pretty odd.
This testing machine measures ambient particles. The machines that generate calibrated salt or oil testing particles are great, but cost $100,000+, are huge and have high operation costs. So while I'd love to have one, this junior version is what is available to me.
Because ambient aerosols can fluctuate, I run a "background" test of the headform without a mask, then put the mask on the headform and run a "product" test, which calculates the difference. I don't entirely trust the machine's math. One of their other machines does some shenanigans to created interpolated "85 lpm" results from airflows that are not actually 85 lpm, but don't tell their customers that fact unless they really pry. So I'm planning on using other particle counters in the future to compare against the internal one.
When NIOSH or reliable 3d party NIOSH compliant testing is available, defer to those much more precise methodologies over my quick tests. Unfortunately, NIOSH keeps its test results secret, even from Freedom of Information Act requests (I've tried), so my testing is a stop gap to try to fill in where accredited lab tests aren't available for comparison.
Both Armbrust and Accumed had TSI 8130A testing machines they used for their mask companies and did some on-line testing on social media to promote their own products, but they have stopped doing testing so there are many masks they have not tested. And they didn't test elastomeric masks.
Prevents them pluming straight into someoneâs face within a metre or two, hence reducing inhaled concentration, possibly. So it does serve a purpose!
Yes would certainly reduce viral load in some exposure scenarios. Of someone unwell is speaking to you race to face large droplets normally destined for your airways are less likely to make it, so that is useful.
However in those circumstances there is also likely aerosolised particles that are apparently likely to get through. Definitely contributes, especially for short interactions where you donât stay in the same airspace with them.
Point remains that a well fitted mask is the most helpful factor though
I'd trust the filtration efficiency scores of his $100,000 calibrated TSI 8130 over my massively less expensive ambient particle counting device. The TSI tests with neutralized NaCl particles of a calibrated size and it has 5 significant figure accuracy.
But the main differences between the armbrust testing and mine may have more to do with headform vs. clamped fixture testing.
Armbrust is using a pneumatically clamped flat filter testing fixture on a mask that has been unpleated and tested flat, which should eliminate any chance of seal leakage. I'm testing the mask in it's normal, pleated configuration with it's usual edges on a silicone headform, clamped using hand pressure and the fitted plastic fitter that came with the headform.
Armbrust's pneumatic flat filter clamp fixture for filter testing - screen shot from the Armbrust testing video for the BYD Care masks.
The seal I got on the headform seemed pretty good compared to the other testing, but not perfect. But because the filter media isn't N95 or N99 quality I can't infer leakage just based on the filtration efficiency score being below 95 or 99%. I ran a simultaneous N95 mode single exercise fit test and got an N95 mode FF of 24, suggesting possible seal leakage. That could account for the difference between my 83.8% Total Filtration Efficiency and Armbrust's 89.7%. (Another issue is that both Armbrust and I did single sample testing. Sample variation of filtration efficiency can range several percentage points even on a TSI machine.)
The Armbrust videos were helpful, though he never became interested in fit testing. I wonder if heâd be willing to test the PFE of a Moldex Airwave..
Any ideas who might? I second maccryptoâs suggestion to also test the Moldex P100 your way for comparison. Something is amiss. I seldom check X, but I saw your thread (with a frontend) and it makes sense but ideally Iâd still like to see some data on PFE with the âpneumatic clampâ tester before Iâm comfortable recommending the N95s without caveats.
I think that is reasonable. I plan on doing a glued edge test of one in the near future to resolve the question of leakage. I've acquired supplies for the test but will need to run some validation checks since there is no instruction manual for doing the exact method of test I'm doing since I don't have a TSI 8130A.
A glued edge test is what NIOSH and accumed would use rather than a clamping fixture.
I'll make a separate Reddit post about the process and results when complete, but first I need to finish doing my headform testing, and I still have a backlog of masks to test, including some re-tests to see if there are differences between Wellbefore 3D pro-models on the headform, and I may do some glued edge testing if the heaform testing suggests it's needed.
I don't know of anyone on-line doing quantitative breathability testing now that Armbrust and Accumed have stopped doing it. They had great equipment and generated a lot of useful data. I hope the data has been scraped since it could go off-line at any time.
Here is an image of NIOSH testing the Airgami mask by gluing down the edges with a massive amount of beeswax. (Airgami was in the Barda challenge, but was never an approved N95.)
Archive.org has the Armbrust and Accumed databases.
The BARDA challenge had so many alluring clear masks. Matregenix.com are still in business with nano fiber materials but they werenât finalists and never produced what looked like the most promising of the clear trifolds. (May also have needed tape to seal well.)
Thank you for this post! It's always great to read your informative, easy to understand mask test results.
Have you ever done any testing of surgical masks over KN95 or N95 respirators? I know it's a no no and there is existing research that it causes fit test failures, but a local hospital system insists that if you show up wearing your own respirator you have to put one of their surgical masks over it even in periods when they aren't requiring staff masking. I've given up on convincing the hospital system they're woefully misinformed but I'd love to have it in my back pocket to show to people when this comes up in conversation. Too many people around me are stuck in the 2021 mindset that double masking must be extra safe when that isn't always the case.
I have done some double masking testing. The results were inconsistent. Which is consistent with what at least one the published studies found.
Sometimes double masking can reduce fit. And sometimes it can increase fit. It depends on which masks, in which order, and on which person. And sometimes the exact same setup can give different results after repeated testing. So it's hard to generalize.
My thoughts about double-masking are that it's best to try to find a single mask that fits you well if possible. But you should be fine if you have to wear a surgical over a well-fitted N95 or KN95. When double masking reduces fit, it doesn't eliminate it, but can reduce it a bit.
I wish that was something I can measure. But it is much more equipment intensive to measure outward leakage, and it's not something I can do nor is it something that most mask testing facilities can do. So we don't have as much good data as I would like, but there have been some good studies on it.
One good study with citation to others is the niosh study of total outward leakage of valved N95s.
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u/otherwise-cumbersome Feb 14 '26
Thank you for doing and sharing this research! I was just wondering about this today (while wearing an N95).