ReadiMasks are no longer NIOSH approved. And haven't been for over a year.

Voluntary Rescission of ReadiMask's NIOSH approval was granted March 25, 2025 at the request of Global Safety First, LLC.

This applies to both the small N1901S and the large N1901L models currently sold on ReadiMask dot com under the no longer valid TC-84A-8133 approval number.

Screen shot of the published NIOSH Voluntary Rescission notice for ReadiMasks.

https://www.cdc.gov/niosh/media/pdfs/2025/10/NIOSH-CA2025-1092-GSF-Final.pdf

ReadiMask continue to claim NIOSH approval on their website homepage and elsewhere. However, ReadiMask quietly memory holed their 2019 NIOSH approval letter that they used to link to on their website's disclaimer page. And their link to the NIOSH approval on the CDC website is now 404.

https://readimask.com/pages/disclaimer

It’s unknown at this time why GSF requested the voluntary rescission. It’s common for companies discontinuing a single model of respirator, or for companies getting out of the respirator market entirely to request a rescission. It's possible they are working on a replacement, such as the ReadiMask365 announced in 2022, but they haven't made any announcements about that mask since then.

The rescission does not necessarily mean the unapproved masks are bad, but they no longer qualify as OSHA compliant for workplace use.

Background

I was writing a post wondering if we'd still be able to buy ReadiMasks in the aftermath of the closing of ReadiMask reseller Aliant Biotech. When I tried to look up the original NIOSH registration for ReadiMask I couldn't find it on the NIOSH Certified Equipment List search page. NIOSH just memory-holes rescinded approvals and you get no returns when you try to search the number or even the company on the CEL search page. But the rescission notice turned up in a Google search of the TC number.

The no longer approved masks are still offered on the Global Safety First (GSF) / ReadiMask website, along with 2 sizes of full face masks that were never approved and not subject to rescission.

Screen grab from the ReadiMask dot com home page.

People have had issues with the ReadiMask adhesive no longer sticking well enough to give a good seal. That has lead to speculation that GSF / ReadiMask hasn't made any new production runs in years, and has instead been selling off outdated stock. Given that the masks haven't been NIOSH approved for over a year, that seems like a safe bet.

ReadiMask Warranty

Back in 2023 Aliant Biotech published a letter clarifying that they don't make ReadiMasks, there is no expiration date on them, NIOSH doesn't require one, but that Aliant Biotech would warrant them to be good for 3 years after date of purchase.

https://preview.redd.it/tjhyqu6dqd2h1.png?width=1474&format=png&auto=webp&s=25576f910749d4da45defadf49b2145bbb5a3cb0

The GSF / ReadiMask home page says "GUARANTEED TO FIT" and "Warranted to last 3 years on shelf". But it also still says "NIOSH Approved" even though that hasn't been true for a year. Will they still honor that warranty?

Has anyone had luck with getting that warranty honored? And, if so, did Readimask offer a refund? Or a replacement that worked?

I'd love to know when the last production run of ReadiMasks was made.

Did the Apparent Downfall of ReadiMask Start in 2022?

GSF entered a new nano filter version of the ReadiMask mask, the ReadiMask 365, in the US government's BARDA Mask Innovation Challenge. And they won Phase 2 in 2022.

ReadiMask's prospects seemed very promising, and that they were succeeding at continued innovations that would keep their business vibrant and healthy going forward.

Screen grab from the ReadiMask blog about their BARDA Phase 2 win for the nanofilter ReadiMask365 prototype.

GSF described the new nanofilter mask as "a fantastic mask" that "exceeds the moonshot criteria". And they said they were going to make the masks even better before selling them.

https://readimask.com/pages/readimask-wins-barda-niosh-contest

Crickets

It's been 4 years since they won but the ReadiMask 365 is nowhere to be seen, and hasn't even been so much as mentioned by GSF since then. 4 years of crickets.

That silence on the new product makes me wonder if GSF has made a single production run of original ReadiMasks since 2022. It feels like they have been coasting ever since that win, as the market for niche N95s radically diminished.

Conclusion

ReadMasks are a vital tool for respiratory protection that provide fit and functionality for people and situations where other respirators cannot be used. There is litterally nothing else like it.

It is extremely disappointing to find out more than a year after the fact that the ReadiMask NIOSH approval has been rescinded and that GSF may be leaving the market entirely, and doing so without notifying the public in a timely fashion..

Many mask companies have left the market as demand has tanked. This is likely especially the case for makers of niche masks such as the ReadiMask that are popular with people who need them, but are not necessarily successful in the general market for filtering facepiece respirators.

I still have some hope that maybe GSF / ReadiMask have something new and better in the works that they hope to get approved. But they haven't made any announcements about new masks in the last 4 years, so I don't have any confidence that is the case.

I should add that GSF / ReadiMask can legally make all the new masks they want, in any style or color even after the voluntary rescission. They just can't call them "NIOSH Approved" or "N95".

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Random Observations

The ReadiMask website says "average filtering efficiency of 99.7%" for their current mask.

Screen grab from the ReadiMask homepage.

But the nano ReadiMask365 tested at 98% filtration efficiency according to their blog page. The prototype mask was supposed to be better, and presumably more breathable at "<9.6mmH2O", but it doesn't filter nearly as well according to their own statements.

Screen grab from the ReadiMask blog on their BARDA win.

There may have been too many hurdles to cost effectively bring the ReadiMask 365 to market. Maybe they put too much hope into the 365 as the game changer that would finally make ReadiMasks mainstream.

This pinless wood moisture meter has a 4.6 rating by people who have no idea the product isn't giving them wood moisture readings at all.

https://preview.redd.it/4kqo6p258y1h1.png?width=1854&format=png&auto=webp&s=18d89e995317c7c2755123ce418a01386b47ff2d

https://www.amazon.com/dp/B0G133R83W

The meter seems to be simple to use. Touch the calibrate button while it isn't touching something, then touch the object to be tested with the ball sensor and it gives a moisture percentage. Easy!

NOPE.

It **looks** like it gives moisture percentage readings, and even has a percent symbol, but that number isn't a moisture reading or even a percentage. But you have to read the manual to find that out.

If you read the manual it turns out the meter displays non-standard "unitless" readings from 1-100 of the dielectric constant of the material - different materials have radically different dielectric constants, so the reading tells you nothing about moisture content on its own. Then you have to go to the conversion table in the manual, choose 1 of 3 substances (Plaster, Cementitious Material, Lumber), then convert from the "unitless" numbers the meter gives to moisture percentage.

A reading of "50%" on the meter for plaster = 1% moisture.

A reading of "50%" on the meter for lumber = 25% moisture.

All of the Viners praising this device have no idea that the percentages they think the meter is giving them are radically wrong, because they never read the manual and don't know that they need to use a manual look up table for moisture percentages.

The fact that so many people are completely unaware of the issue isn't entirely their fault. The meter is incredibly poorly designed in terms of the UI. You shouldn't have to read a manual to use a simple moisture meter, so it is understandable why an average person would not think to do so. But as viners, who are essentially professional product reviewers, they should have read the manual before praising how great the device is.

Edit:

As per usual in this sub, there are a bunch of weird downvotes, apparently by people who do not think people should give accurate product reviews or read the manual before posting a review.

I just got an ad on Facebook for a mask to wear while traveling on airplanes - it doesn't filter, it just retains humidity.

The company, Kuvola, says that the dry airplane cabin air is bad for you, so you should wear their humidity retaining mask to keep you healthy while flying.

Screen Shot of Facebook ad for the Kuvola humidifier mask.

Humidity Retention

The Kuvola mask has quarter mask fit, with the bottom seal fitting on the front of your chin instead of under it. It uses a "Heat and Moisture Exchange" (HME) foam insert you breathe in and out through. The HME foam is supposed to trap moisture from your exhaled breath on the way out, and then release the moisture back into the air as you breathe in. That actually can work, however...

A regular N95 retains humidity the exact same way *and filters air* at the same time, for less money than the $90 Kuvola mask. As do other respirators. But Kuvola don't want you do do that!

>Regular masks are not designed to humidify incoming air. In fact, many people find regular masks make breathing feel more difficult on long flights. Kuvola's patent-pending moisture exchange system is specifically designed to humidify air you inhale while remaining comfortable for 8+ hours. They're fundamentally different technologies.

-from the Kuvola FAQ

N95s are not *designed* to retain humidity. But they do. It's a side effect that works on the exact same principle as the fancy sounding Heat and Moisture Exchange foam. And many respirator grade masks such as the 3M Aura, Wellbefore 3D Pro and Zimi masks are very breathable.

I tested another brand of humidity mask, the GoBu from Armbrust USA, and found that it didn't seem to be any better at humidity retention than non-valved respirators.

Testing humidity retention of the GoBu | 3M Aura 9205+ | 3M \6200 | MSA Advantage 900. I've not tested the Kuvola, but the GoBu is based on the same thinking and principles as the Kuvola.

https://www.reddit.com/r/Masks4All/comments/1k64hqr/respirators_get_hot_and_stuffy_but_somebody/

It also turned out that the Armbrust GoBu was actually less breathable than a 3M Aura N95. But Kuvola claim this for their mask:

>... Kuvola is designed for unrestricted airflow. You breathe normally through the mask, just with humidified air.

-from the Kuvola FAQ

This is false. The Kuvola is engineered specifically to restrict airflow, so that it all goes through the HME foam. The question is how much pressure drop does this cause, not whether there is a pressure drop.

There is no pressure drop information I could find on the Kuvola website to quantify the breathability of their masks. They *say* their mask is more breathable than other masks, but they don't show any testing data. I would not be surprised if the Kuvola is more restrictive than they think.

Kuvola say it took **five years** to develop their mask. One would hope they took actual measurements of in mask humidity and pressure drops to validate their design iterations. But I would not be surprised if the didn't do that at all given that they don't seem to have posted any data. But who knows.

Conclusion

I don't think the Kuvola is a scam per se. I don't have one and haven't tested one. But I do think it is overpriced and that you can get much of the same humidity retention with a regular N95, which will also give you clean, filtered air for a lower cost.

It would take objective data to know how the Kuvola compares to respirators, but at $90 I'm not likely to be buying one any time soon to test it, especially since it is a one trick pony and doesn't provide any air filtration.

https://preview.redd.it/m2fowedhi91h1.png?width=2288&format=png&auto=webp&s=061787437c53145eb371f6f8e5fd2f1b3470db6f

Some "dust masks" are real particulate respirators, and some are comfort masks for nuisance levels of non-hazardous dust.

https://preview.redd.it/zgpb9t9od70h1.jpg?width=1400&format=pjpg&auto=webp&s=b196ae66ff4135e5cb3573336855ba7f9982d028

N95s are tested and approved by NIOSH to filter 95% or more of the most penetrating size of particle. Nuisance dust masks are not.

N95s are made to seal well on your face to keep unfiltered air out. They have two headstraps to help you to get that seal. Nuisance dust masks typically do not.

Using the same terms for both is confusing so I call N95s respirators and try to always remember to include "nuisance" when discussing "nuisance dust masks."

My take is that if you are going to wear a mask to protect against particulates, you might as well wear a good one that fits you well, such as an N95

Breathing cleaner air is better that breathing dirty air.

---

Mask fit is key to getting good protection from a respirator grade mask. You don't want unfiltered air getting in under the face seal. You might have to try more than one model of N95/KN95/FFP2/FFP3/P2 etc to find one that fits you well. You can search the masks4all sub for information or start a thread with a new post to ask what masks might work for you.

https://preview.redd.it/pdfi8a76mzzg1.png?width=863&format=png&auto=webp&s=23b1e1fa4ec05078cb3a006e62e85c905d8de98e

I kept thinking there must be something neat inside to justify the price, but nope...

https://preview.redd.it/thxxcspamzzg1.jpg?width=960&format=pjpg&auto=webp&s=5eac5086719d4e8fa1fc1e373f3b34ee73e8764f

https://preview.redd.it/94umx4uw7zzg1.jpg?width=3072&format=pjpg&auto=webp&s=7710af2aa017cb7b1d1a424de4b093cd303a11c9

Transmitting on FRS 1 with a UV-5G Plus. I'm not even sure which spike is FRS 1.

I recently got a spectrum analyzer and tried it on a couple of HTs, but when I tried the UV-5G Plus I was kind of stunned. This is a type accepted, FFC approved transceiver. Is mine an exception or are all of the Baofeng GMRS radios this bad?

https://preview.redd.it/an52rmryjtzg1.png?width=1556&format=png&auto=webp&s=d6bbc72935a20d3a02b7ab034cd4a19ee4f15f11

I mean, if you don't want RF from your router, **turn it off**. Don't wrap it in conductive fabric. So I'm taking a pass on ordering conductive fabric from Vine, but I still kind of want some even though I can't figure out what I would do with it that wouldn't be utterly stupid.

I'm not an IH. I didn't even know that the VOC filters in combo cartridges can have 1/2 the service life of a dedicated gas cartridge until I read a NIOSH report testing knock off filters that used different service life standards for the different cartridges. So I'm wondering why use combo cartridges at all unless you specifically need oil resistant 99.97% filtration in addition to the gas filtration.

Early in the pandemic a few companies were working on custom respirator mask from 3D face scans. In part, I think, because 3D printing was bad at making soft seals to make generic fit masks so they tried to custom fit their way out of that problem to use hard plastic for mask seals in ways that didn't necessarily work that well.

3D printing technology has grown since then and u/Innovation-Vitacore, makers of CAN99 9500 NIOSH N95s, has received licensing to product custom CPAP masks from 3D face scans.

https://preview.redd.it/joe1tztr9lyg1.jpg?width=1354&format=pjpg&auto=webp&s=ae647cb86ccb9f1f06d77517bfe5e00d59ec9b26

https://www.reddit.com/r/CPAP/comments/1t0z2mk/we_just_got_health_canada_approval_for_a_custom/

This is an interesting plot twist in custom masks from 3D scans, largely because of the economics. Companies won't pay extra to have custom 3D masks printed for employee respirators because they aren't required to so and regular respirators meet legal requirements and pass fit tests (mostly). And few consumers could afford to have custom respirator masks made with the near $500 Canadian price tag, so it wouldn't be a good business plan.

CPAP masks are medical devices that are expected to be expensive and are often covered by insurance. And CPAP mask fit is vital to getting good results from CPAP therapy. The masks need to seal well to maintain therapeutic pressure levels, and fit well to be comfortable when worn for a full 1/3d of the patient's life going forward. So custom CPAP masks seem like a better business case for 3D scanning and printing of masks.

All that being said, I still hope that some of this tech may get developed and eventually be used for respiratory protection in a cost effective way.

I have posted a number of breathability comparison tests using brand new filters, such as this duckbill breathability chart. My tests are "initial" breathing resistance, and think the same is true for those done by Lloyd Armbrust on his fancy TSI machine.

https://preview.redd.it/5fqs40e98fyg1.jpg?width=1080&format=pjpg&auto=webp&s=1da9f975f13dfc7b4cdb373ae73ead67d4c23d42

The rank order in these charts should remain accurate for new masks and filters used in relatively clean environments, such as for protection from airborne disease. But in dusty industrial environments, the breathability of particulate respirators can change over time as the filter gets loaded with particles. And different particulate masks and filter media can behave differently, in ways the manufacturers and NIOSH do not inform users of. Respirator filters do not come with performance data sheets that illustrate the loading curve.

Here is an example of how loading can change breathability of particulate respirator filters, from a 2014 3M sell sheet.

https://preview.redd.it/ngw2g5959fyg1.png?width=1466&format=png&auto=webp&s=6ae0093b2ffcc8e9bde592379fb4831629930c47

The "Competitor B" example starts with lower breathing resistance than the 3M 2091, but with a small amount of salt loading on the filter (0.02 grams) they switch places in terms of which is more breathable.

Different kinds of filtration media, such as mechanical, electret or combination, can have different loading curves. The loading response is one of the ways a testing lab can tell what kind of filter media is being tested. Doing loading testing takes $100,000+ machines that I don't have access to. But I'm always looking for opportunities to see and share advanced test data on current respirator filters that test for things I can't.

Conclusion

In practice, this is why companies like 3M say to use respirator filters until they are hard to breathe through. NIOSH filtration testing requires loading to insure the filters still work under loading. So you are still safe so long as the particulate filter is not damaged and your mask fits well. But which masks will be most breathable when used in dusty environments is still largely a guessing game.

The filter loading is a separate issue from how long you can effectively wear an N95, because in that case the effectiveness may depend more on how well the mask continues to hold it's shape well to make an airtight seal on your face.

---

Thanks to LazarusLong13 for the link to the sell sheet.

https://preview.redd.it/8s4ccyjoqeyg1.png?width=1466&format=png&auto=webp&s=74eb60e177b44eeb79f9cb06bae35cd7a8375a46

This filter loading graph from a 2014 3M sell sheet illustrates what I'm referring to. The filter loading properties of the 3M pancake filters are radically different than the unnamed competitors. Granted, it is a marketing claim, but variability under loading is a real difference between filters that NIOSH doesn't publish. NIOSH just make sure the filters meet minium standards and keep the details secret, even from FOIA requests.

So, since filters don't come with loading performance data sheets, how do you create optimized replacement schedules for filters that may have significantly different performance over time? Do you rely on workers to say the filters are getting hard to breathe through to account for filters that don't perform well under loading?

N95s can loose dimensional stability over time, potentially allowing seal leakage of unfiltered air into the mask.

A 2024 study found that 39% of N95s failed a fit test after a single full work shift. The failure rates varied by mask model.

https://researchgate.net/publication/377727761_Incidence_of_Fit_Test_Failure_During_N95_Respirator_Reuse_and_Extended_Use

https://preview.redd.it/17oe0vk9eeyg1.png?width=1740&format=png&auto=webp&s=d73996ec8637676109a4336c3a1ed75df19f95d2

By the end of 5 consecutive shifts, only 7.2% of masks could pass a fit test.

https://preview.redd.it/l2rnsf8leeyg1.png?width=1698&format=png&auto=webp&s=952db3ab24375d9a06a94a6769e1f4dc33558829

Cup-style 3M 1860/8210s held up better than tri-fold 3M Auras. The Halyard duckbills were in between. No 3M V-flexes were included in the study.

The authors concluded "Our finding of significantly higher fit failure rates among trifold N95s compared with other models has implications for their future reuse. Our findings suggest that reuse of trifold N95s should be avoided."

That is a pretty serious conclusion. The long term efficacy of 3M Auras should be studied more.

I'd note that since they studied 9205+ and 1870+ 3M Auras specifically, that is what they need to write in their conclusion, not "tri-folds". Their study doesn't have any data on any other tri-fold models, and they can't assume completely different mask models only sharing a general shape style will perform the same.

Study Limitations

The study lumped strap breakage in with "fit" failures and the 3M Auras they tested (1870+ and 9205+) have thin polyisoprene straps that are more prone to breakage than the straps on the cup-style 3M masks. I'm left wondering how common strap breakage was in the study.

Another issue is that the study apparently repeatedly fit tested people in the same re-used mask at the end of each subsequent shift. I'm wondering about cross contamination from successive qualitative testing.

Each test was a qualitative test where a highly concentrated sweet or bitter substance you can taste if it gets in your mask was sprayed around the mask for 7 minutes during different exercises. The saccharine or Bitrex would remain on the outside of the mask, and build up with each additional fit test.

I wonder how valid 5 successive full OSHA qualitative fit tests on the same mask are, with handling in between tests? Could cross contamination or other confounding factors contribute to the fit test failures?

There is a lot to unpack in the study, including that it used pass/fail fit testing so we don't have a good idea of how much the fit changed. As is so often the case, more studies are needed.

The study authors admit that quantitative (PortaCount) testing would have been better, but defaulted to saying qualitative (taste) testing is OSHA compliant and that using PortaCount testing "would have limited the study’s feasibility".

The study is a good reminder that N95s are great tools, but they aren't necessarily one and done. How long they are effective in practice can vary widely. If your mask feels like it is leaking at the seal after a while, there is a good chance that it is leaking and that you should change to a fresh mask for the best levels of protection.

That being said, some protection is better than none. So keep using what mask you do have if you don't have better alternatives. But avoid risk compensation, which is where you take on more risk than is offset by the level of protection your mask is giving you.

Some 3M filter cartridges are way more breathable than others, but 3M won't tell you which is which. So I tested them myself on a headform mask testing machine to rank them in order of breathability.

(I have no affiliation with 3M and there are no sales links to any of the filters I've tested.)

https://preview.redd.it/yiin5z9qn6yg1.jpg?width=1440&format=pjpg&auto=webp&s=0c2bc2970cae5c87ad0ca332742d367a7a73261a

The acid gas / P100 combo filter is way less breathable than all the other filters I tested. If you don't need a combo filter you can get better breathability with different filters.

If I just need to filter particles, I'm going to go with the 2291 Advanced P100 or the 2071 P95s. They both filter really well and are much easier to breathe through than the magenta 2091 P100s.

The particulate filtration results were all surprisingly similar between filters. That is largely because even though P100s filter at 99.97%, face seal leakage is the primary limiting factor for how protected you'll be. You may get better or worse protection inside your mask depending on how well your mask fits.

For particulate + basic VOC filtration, I may go with the 6001 VOC filter + 5N11 N95 pre-filter instead of a harder to breathe through combo filter. Gas filters like the 6001 have to last 2x as long under NIOSH rules before chemical breakthrough than a combo VOC/particulate filter. So they can be a better value depending on what your needs are.

If you need protection from VOCs and oily particles you'll likely need one of the combo filters because they are P100 rated for oily particles. The N95 pre filters you can put over gas-only cartridges are not.

To figure out what filter you need you can check the 3M respirator selection guides.

https://multimedia.3m.com/mws/media/639110O/respirator-selection-guide.pdf

https://multimedia.3m.com/mws/media/40744O/reusable-resp-cartridge-and-filter-selection-poster-english.pdf

To check how well your mask seals you can do a user seal check to get an idea of whether your respirator seals well on you. The method depends on the mask and filter models.

https://www.youtube.com/watch?v=DzIDhYGnDIM

3M 60923 Organic Vapor/Acid Gas/P100 combo filters on a 6800 Full Facepiece respirator being tested on a customized Scince SC-MBT-2032 filter testing machine. The measured pressure drop is 363 Pascals at 85.6 lpm of airflow.

3M Filter	Pressure Drop	Filtration including mask seal leak†
60923 Acid Gas/P100 Combo	363	99.2
2097 P100 NVOC	320.2	99.1
2091 P100	284.1	99.3
7093 P100	267	99.5
6001 VOC + 5N11 N95	260.8	99.0
2297 Advanced P100 NVOC	223.3	99.1
2291 Advanced P100	207	99.4
2071 P95	159.7	99.3
6001 VOC-only	150.7	75.1
5N11 N95	150.4	98.6

†Differences in filtration from test to test are largely due to variability of the faceseal on the heaform since the mask was repositioned between tests and the seal was not caulked to maximize seal integrity.

Test Method

Breathability is measured by how much vacuum pressure in Pascals it takes to draw 85 liters of airflow per minute through the filters and mask. Lower pressure drop numbers mean more breathable.

Filtration is measured in this set up by testing concentration of particles in the air before the mask is put on the headform, and then testing the particle concentration inside the mask after it has been put on the headform and purged. The total filtration efficiency is calculated from the difference, but my test results are approximate since this system is a relatively simple one that tests ambient particles, not calibrated ones. And I did not caulk the mask to the headform to try to perfect the seal, so there is some face seal leakage that reduces the filtration results somewhat.

These are "initial" inhalation pressure drops. The pressure drops can increase as the filter becomes loaded with dust particles. Different filters can have different changes in pressure drop when loaded.

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Made possible by a grant from #Kanro.

https://preview.redd.it/5zlz3npojxxg1.png?width=2290&format=png&auto=webp&s=e927b695dc623d9853eb64763e97d68489eac320

I'm not a chemist, but these don't really seem like Labware...

For my own use I much prefer a respirator with a lower pressure drop and I'm wondering if that's a consideration in workplace respirator selection?

There is a huge barrier to being able to select respirators with low breathing resistance: Both the manufacturers and NIOSH keep the approval testing data secret, even from FOIA requests. NIOSH just say the respirator passed, which isn't very helpful since the NIOSH maximum pressure drops are pretty high and there is a wide range of pressure drops in approved respirators.

So I ran some initial inhalation resistance tests with an SC-MBT-2032 Sheffield headform mask testing system - I don't have a set up that can do loading, so the pressure drops could change significantly, and even change rank order, with loading. I can't test exhalation resistance. I tested 3M filters on a 6800 FF. The mask was not caulked to the headform, but all P100 results had >99% PM 0.3 ambient particulate filtration, indicating that seal leakage should not be a large factor in the pressure drop results.

Clearly, sometimes needed protection levels will necessarily require more breathing effort when negative pressure respirators are used, but it also seems that in many cases there may be more breathable options available that still meet RPE requirements, but only if the breathability data is available. I wish NIOSH would stop hiding the pressure drop results.

https://preview.redd.it/kkac0r3zpvxg1.jpg?width=1440&format=pjpg&auto=webp&s=365b44bd15b6abb90c50a75cd6d527bdbf150fcf

Some 3M filter cartridges are way more breathable than others, but 3M won't tell you which is which. And neither will NIOSH. So I tested them myself on a headform mask testing machine at 85 lpm of airflow to rank them in order of breathability.

3M 60923 Organic Vapor/Acid Gas/P100 combo filters on a 6800 Full Facepiece respirator being tested on a customized Scince SC-MBT-2032 filter testing machine. The measured pressure drop is 363 Pascals at 85.6 lp of airflow.

Test Method

Breathability is measured by how much vacuum pressure in Pascals it takes to draw 85 liters of airflow per minute through the filters and mask. Lower pressure drop numbers mean more breathable.

Filtration is measured by testing concentration of particles in the air before the mask is put on the headform, and then testing the particle concentration inside the mask after it has been put on the headform and purged. The total filtration efficiency is calculated from the difference, but my test results are approximate since this system is a relatively simple one that tests ambient particles, not calibrated ones. And I did not caulk the mask to the headform to try to perfect the seal, so there is some face seal leakage that reduces the filtration results somewhat.

Breathability of Filters on a 6800 Full Facepiece Respirator

https://preview.redd.it/958g8wla9vxg1.jpg?width=1440&format=pjpg&auto=webp&s=2bcecd8aefb99b32a2fbfe55fd8e1db3e7e7039e

3M Filter	Pressure Drop	Filtration including mask seal leak†
60923 Acid Gas/P100 Combo	363	99.2
2097 P100 NVOC	320.2	99.1
2091 P100	284.1	99.3
7093 P100	267	99.5
6001 VOC + 5N11 N95	260.8	99.0
2297 Advanced P100 NVOC	223.3	99.1
2291 Advanced P100	207	99.4
2071 P95	159.7	99.3
6001 VOC-only	150.7	75.1
5N11 N95	150.4	98.6

†Differences in filtration from test to test are largely due to variability of the faceseal on the heaform since the mask was repositioned between tests and the seal was not caulked to maximize seal integrity.

Discussion

Based on the breathability results, I'm going to go with the 2291 Advanced P100s or the 2071 P95s (which filter way above the required 95% minimum) when I need particulate filtration for a 3M bayonet filter mask.

The particulate filtration results were all surprisingly similar. That is largely because even though P100s filter at 99.97%, face seal leakage is the primary limiting factor for how protected you'll be. You may get better or worse protection in mask depending on the mask and your personal fit.

Whenever you combine gas + a particulate filter the combination becomes harder to breathe through. You'll get the most breathability by targeting the contaminantes you need to filter instead of arbitrarily wearing the most everything filter you can get. Even the P100s with carbon for nuisance levels of VOCs (the 2097 and 2297) were harder to breathe through than their particulate only versions (the 2091 and 2291).

For particulate + basic VOC filtration, I may go with the 6001 VOC filter + 5N11 N95 pre-filter instead of a harder to breathe through combo filter. Gas filters like the 6001 have to last 2x as long under NIOSH rules before chemical breakthrough than a combo VOC/particulate filter. So they can be a better value depending on what your needs are.

If you need protection from VOCs and oily particles you'll likely need one of the combo filters because they are P100 rated for oily particles. The N95 pre filters you can put over gas-only cartridges are not.

To figure out what filter you need you can check the 3M respirator selection guides.

https://multimedia.3m.com/mws/media/639110O/respirator-selection-guide.pdf

https://multimedia.3m.com/mws/media/40744O/reusable-resp-cartridge-and-filter-selection-poster-english.pdf

To check how well your mask seals you can do a user seal check to get an idea of whether your respirator seals well on you. The method depends on the mask and filter models.

https://www.youtube.com/watch?v=DzIDhYGnDIM

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Made possible by a grant from #Kanro.

The company BreatheX has been advertising on social media telling welders to ditch respirators and use the BreatheX nostril filters instead. They even show blackened filters as "proof" they work.

A TikTok \"welder\" in a BreatheX ad contemplating nostril filters in his living room.

Do the filters work? BreatheX's own marketing tries to say "YES" in big letters, and "not really" in small ones you won't notice. So, no.

One of their Facebook ads gives filtration numbers for PM10 and PM2.5:

A BreatheX Facebook ad, touting pretty terrible filtration.

So:

BreatheX Nostril Filters PM 10 - 90%

BreatheX Nostril Filters PM 2.5 - 65%

That's pretty terrible filtration, and it gets worse as the particles get smaller. They don't even state the airflow rate for the measurements. The numbers match up with the filtration curve for O2 Armor brand nostril filters:

Filtration curve for O2 Armor nostril filters, which may or may not be the same as BreatheX Nostril filters.

That is crap filtration, and BreatheX knows it. There is a disclaimer buried on their website saying not to use the nostril filters instead of a respirator, even as their marketing literally shows a "welder" throwing away certified respirators in favor of nostril filters.

Welding fumes are mostly particles below 1 micron.

\"The fume particle size distribution generated during the arc welding of cast iron.\" From Fume particle size distribution and fume generation rate during arc welding of cast iron, 2020

https://pmc.ncbi.nlm.nih.gov/articles/PMC7417507/

A NIOSH P100 respirator filters PM 0.3 - 99.97% or better at 85 lpm of airflow (total filtration efficiency in mask will be lower due to imperfect face seal). So P100s filter welding fumes, including all the particles below 1 micron, very well. Even N95s do.

Could you use the nostril filters as a supplement? Or for voluntary use in non-hazardous environments for nuisance level protection from large particles? Sure, if you want to, but they are not a valid substitute for a well fitted, certified respirator in hazardous environments.

(And, of course, the nostril filters are not NIOSH approved and don't meet OSHA requirements for respiratory protection.)

TL;DR: Use a certified respirator for welding fumes.

There's a company called BreatheX telling workers on social media to ditch their approved respirators and use the un-rated BreatheX nostril filters instead.

A TikTok \"welder\" in a BreatheX ad contemplating nostril filters in his living room, while wearing the harness for his welding helmet upside down.

One of their videos targets welders, showing a "welder," wearing a cheap welding helmet with the harness upside down, throwing away certified respirators because the un-rated BreatheX nostril filters are supposedly so much better.

Still frame from a BreatheX marketing video telling welders to throw away their certified respirators and use the non-certified BreathX nostril filters instead

Weirdly, the "welder" is never shown welding, or even so much as holding a torch in any of the videos I've seen. But he does have a cosplay welding costume, including a cheap helmet and welding gloves.

Stunningly, BreatheX falsely claim their nostril filters filter dust and fumes but respirators do not.

A table from the BreatheX website falsely claiming BreathX nostril filters filter fumes but that respirators do not.

The company absolutely knows what they are doing, and that the nostril filters don't qualify as respiratory protection, even as they are telling workers to use them instead of respirators.

This marketing graphic from one of their Facebook ads is especially telling, in the form of a fake safety data sheet. No filtration efficiency is listed, just a misleading visual. But that isn't the telling part, the telling part is the the line buried in the document nobody will read that says: "Supplements or replaces N95 in voluntary-use environments".

A fake safety data sheet used as marketing for BreatheX nostril filters. Note the complete lack of any quantitative data for filtration efficiency. Showing black filters is not proof of efficacy, though it is a trick used by some oil change services.

Only someone who knows OSHA regulations for respirators would know about "voluntary use". Voluntary use is when you voluntarily choose to use a respirator for comfort in a non-hazardous environment, as opposed to required use in an environment that has contaminants above the permissible exposure level.

BreatheX aren't mentioning voluntary use as legit advice, just as legal CYA in small print while they are saying ditch your respirator in big print.

If you dig deep enough on their website they say the nostril filters aren't a replacement for respirators. They are trying to have it both ways. Telling people to ditch their respirators in their marketing but saying "oh, we never would suggest ditching your respirator" in their disclaimer:

The BreatheX disclaimer buried on their website where they say not to do the things they say to do in their ads.

The BreatheX nostril filter marketing may not trick workers at any company with a properly supervised respiratory protection program, but independent contractors and hobbyists may get swindled into buying these ineffective nostril filters in lieu of real respiratory protection.

So, how do I know the nostril filters don't work? I've not tested them, but I don't have to to know they don't work. BreathX published all the data we need to be sure they don't work sufficiently for welding fumes in one of their Facebook ads:

https://preview.redd.it/le6z525t1oxg1.png?width=864&format=png&auto=webp&s=d577cc2220f0738f2bbb59fbc3109b68268e9670

BreatheX Nostril Filters PM 10 - 90%

BreatheX Nostril Filters PM 2.5 - 65%

BreatheX Nostril Filters PM 1 - ??% (not listed)

BreatheX Nostril Filters PM 0.5 - ??% (not listed)

BreatheX Nostril Filters PM 0.3 - ??% (not listed)

At an unknown airflow rate.

Most welding fumes are below 1 micron.

\"The fume particle size distribution generated during the arc welding of cast iron.\" From Fume particle size distribution and fume generation rate during arc welding of cast iron, 2020

https://pmc.ncbi.nlm.nih.gov/articles/PMC7417507/

A NIOSH P100 respirator filters PM0.3 - 99.97% or better at 85lpm (total filtration efficiency in mask will be lower due to imperfect face seal).

Use your certified respirator for welding fumes, not un-certified nostril filters.

The BreatheX nostril filters look suspiciously like O2 armor nostril filters, and the filtration claims seem identical. Here is a filtration efficiency graph from O2 Armor. Note how the filtration levels start to head nearly straight down for lower particle sizes, hence why BreatheX doesn't mention filtration levels below 2.5 microns:

Filtration levels for O2 Armor brand nostril filters, which may or may not be the same as BreatheX nostril filters.

More on the O2 Armor nostril filters here:

https://www.reddit.com/r/Masks4All/comments/17f6m5a/can_tiny_nostril_filters_protect_you_from_covid/

So, again, BreatheX know their nostril filters are nowhere near respirator-grade, even as their marketing tells people to throw away approved respirators to use the nostril filters instead.

I'm not including any links to BreatheX since I don't want to promote the company, but they are easy to google if you want to verify their shenanigans.

What's more niche than a fan powered respirator? A fan powered respirator for 2 that runs off of vehicle's cigarette lighter power.

Screen grab from the joyrider dot fun product page showing their two person fan powered respirator on a mannequin.

When I first saw an ad for this I wasn't sure what was for. Motorcycle riders? But then I saw the Rugged Radio brand walkie talkie headphones on one of the mannequins and the cigarette lighter power plug and realized this is for 4 wheel off roading. The filtered blower outputs to two separate hoses and masks, with a 4 person version also offered.

Detail of the JoyRider Dustless Air System.

This is the first shared PAPR system I've ever seen. A bit like the O2 systems in private planes, but for dust instead of lack of oxygen. And not certified, so the performance is entirely unknown.

I asked the seller about the air flow rate and was told "more air than one mask would ever need. Probably more than 4 masks would ever need." I was hoping for liters per minute so I could know how it stacks up to industry standards.

I also asked about the effective filtration rate. They say their filters go "down to three microns". That's both good and bad. I want to know the total filtration efficiency in the breathing zone in the mask, not the lab rating for the filter media because that lab rating doesn't include system leaks and other confounding issues that can affect how clean the air is inside the mask. A loose fitting industrial PAPR should have a minimum air flow of 170 lpm. I have no idea if the JoyRider system meets that target for 1 or more persons. And it sounds like Joyrider don't know either.

The other "bad" thing about the answer is that they said "three microns," which could mean they literally don't filter particles under 3 microns, or that they meant .3 microns, which is the most penetrating particle size for mechanical filters such as N95s and HEPA, but those filters work even better on particles smaller than .3 microns. So, I don't really know what to think about that answer other than it isn't the answer I'd expect for a PAPR.

You can see in the images that the system is not a loose fitting PAPR like a 3M Versaflo that uses a hood or helmet. Nor is it a sealed, tight fitting PAPR like a 3M Powerflow PAPR. Instead, the the JoyRider "dustless air system" blows filtered air into generic "RZ Mask" type respirators through the hole were a valve normally goes, and the other valve hole has flange fingers that allow a radio boom mic to be stuffed in the mask, but are not air tight, presumably counting on positive air pressure to keep dust out of the mask.

Does it work? Dunno. It's plausible. But with respiratory protection, the devil is in the details. Execution makes the difference between ineffective and effective products. I suspect this device does reduce dust inhalation to some degree while providing cool airflow in the mask to reduce humidity, and it should be safe to use compared to no mask since they are using filtering facepieces, so even if the blower isn't able to keep up with respiratory airflow rates, users will still be able to get adequate air through the mask filter media.

It would take objective testing find out how well this works in practice. JoyRider haven't posted any testing at all, or even any specs other than amperage, which makes it seem like the device is engineered entirely out of assumptions rather than measured performance, in spite of it being patent pending.

Personally, I don't have a use case for this since I'm not an off roader. It runs off of 12v power from the vehicle. It is meant to be installed as part of the vehicle, not a self-contained device to be worn. It is a niche product in an already niche category. So I probably won't get a chance to test one. At $399 it's hard to justify acquiring one since I can't really put it to use since it is so specialized.

You can see the installation process into a vehicle in their video:

https://youtu.be/Ki7_7-fTRLY

It's good to see some innovation in the market place. That being said, I wish people developing innovative respiratory protection would look into quantitatively testing the performance of their products before bringing them to market.