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Gerard Hughes ( @ghhughes@zeroes.ca ) Profile picture
@ghhughes
Oct 23, 2023 • 8 tweets • 4 min read • Read on X
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Can tiny nostril filters protect you from Covid?

Lots of people would like unobtrusive respiratory protection, and nostril filters are an attractive option, or they *could be* if they work, and if you only breathe in through your nose.

🧵
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I was given these by Amazon to review. They are from O2 Armor, who provide more filter data than most companies. But check their wording and compare it to their filtration efficiency graph..."up to" is doing a lot of heavy lifting.
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You can see in these macro photos how loose the weave of the nostril filter is to make it breathable at such a small size. Compare that to the Drager N95 filter shown at the same magnification.

Electrostatic attraction can make a filter work better than it looks, however...
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I got the perhaps lowest filter-only score I've ever tested:

Fit Factor 1.2
17% filtration efficiency

(I made a jig to test the nostril filters directly with a PortaCount at 0.7 liters of airflow per minute. Penetration would be way higher at the 85 lpm NIOSH test airflow.)
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The 17% filtration efficiency score is consistent with seller's filtration efficiency chart and the sub-micron counting range of the PortaCount.

Better than nothing, but not much. So avoid risk compensation and don't take on any extra risks if you use these. Image
Wear a good respirator that fits you well instead of nostril filters when at all possible. The difference in protection is orders of magnitude.

3M Aura and Drager trifold N95s are good respirators to try that fit most, but not all, people well and are very protective. Image
I didn't test these in my nose because there isn't a way to sample the air above the nostril filters short of a big nose piercing, so I didn't test fit, just filtration. More on that in a later Tweet.
O2 Armor have a pretty detailed write up with test data. They seem to come to opposite conclusions about the utility of their nostril filters based on that data than I do.

static1.squarespace.com/static/6064fce…

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More from @ghhughes

Gerard Hughes ( @ghhughes@zeroes.ca ) Profile picture
Jun 30
Finally! Nice looking black tri-fold respirator masks that perform as well as 3M Auras, the Project 3 Trident FFP3s.

I tested the regular size and the regular size with extended strap length with a quick PortaCount test to see how well they fit and filter, and they scored higher than a 3M Aura 9205+.

I also checked out the strap tension to see how they differ from the 3M tri-fold masks. Turns out there is *a lot* more strap tension, even the "extended" straps version.

The straps are longer at rest than a 3M Aura, so it might seem like they would be looser, but the strap material is much thicker. And I found them to be a bit tighter than I'd like.

These black tri-folds are a collaboration between The Face Mask Store in the UK and Trident Safety in Australia to make nice looking black versions of Trident's existing masks. They are certified as FFP3 respirators, the EU's highest standard for filtering facepiece respirators, a standard that is more protective than the US N95 standard.

The Project 3 masks come in extra small, small, regular, regular extended straps and XXL. When in stock, The Face Mask Store offers a sample pack with 1 of each size.

I purchased these myself for review.Image
Test results in the video:



I'll be doing full OSHA fit tests in future.youtube.com/shorts/3knXamc…
I measured the upper and lower strap tension with a force gauge at the same length they extend when worn on my head, which for me is 18 inches for the top strap and 14 inches for the bottom strap. I let the tension settle and took readings after 30 seconds of extension.

You can see that both the regular and extended strap Project 3 masks have significantly more tension than a brand new 3M Aura.

The Project 3 straps are thicker, 0.5 mm vs. the 3M Aura 9205+'s 0.3mm. This could mean that the Project 3 straps will be less prone to stretching out and losing tension over time like Aura 9205+ straps tend to, but I've not yet done longer term testing.

What I can say is that the 1 kilogram's worth of tension from the regular Project 3 head strap is more than I find comfortable, and the extended version is pretty tight, too.Image
Read 6 tweets
Gerard Hughes ( @ghhughes@zeroes.ca ) Profile picture
Jun 13
222nm UV light, "Far UV", is a wavelength of invisible light that can sanitize air while being safe around people.

One company tried to monopolize the use of this frequency of light to sanitize air, in the middle of the pandemic. That company is Sterilray (aka "HEO3").

Sterilray had a patent for the use of 222nm UV light with other frequencies to sanitize air, and they broadly interpreted that idea in their own favor, filing lawsuits against multiple companies during the pandemic.

In 2022 they sued competitor Far UV Technologies for making and selling a competing product.

sterilray.com/wp-content/upl…

Before suing they not only demanded licensing fees from Far UV Technologies, but also from everyone who had bought lights from them.

Yeah, that's a thing. A patent holder can demand licensing fees and also sue *end users*, not just manufacturers, for patent infringement. That includes not only hospitals and venues who bought competing Far UV lights, but also the general public who bought them to be safer from airborne infection.

The pandemic was ongoing, and Sterilray decided there was money to be made by killing the development and use of Far UV by anyone other than Sterilray and their customers or paid licensees.

The thing is, their patent claims were BS. They claimed a legal monopoly on things they had no right to.Image
After Sterilray started suing over their patent, 4 UV companies collaborated and financed a challenge to the 8,975,605 B2 patent.

In October of 2023, the Patent Trial and Appeal Board found *all* of the challenged patent claims to be unpatentable and invalidated them.

quantadose.com/wp-content/upl…

Thanks to that win over Sterilray's specious patent claims, individuals, companies, and open source projects can design, innovate, manufacture and sell Far UV products without facing financially ruinous licensing terms or lawsuits from Sterilray.

Because there is no "non profit" or "open source" exemption to US patents, if Sterilray had won the patent challenge I'd expect even open source projects like @TheOSLUVProject would be dead in the water. It seems unlikely Sterilray would allow open sourcing of their patent after paying all that money to sue competitors over it. And even if they did agree, patent grant issues can complicate or ruin open source projects.

The over broad patent claims of Sterilray were antithetical to the public interest, and to open source development.

The Patent Trial and Appeal Board ruling against Sterilray's claims is a victory for the public in general, and public health specificallyImage
You can read more at the Quantadose website.
Quantadose received correspondence from Sterilray implying they'd be sued if they didn't enter into an agreement to purchase 222nm lamps and power sources from Sterilray.

quantadose.com/the-fall-of-a-…
Read 4 tweets
Gerard Hughes ( @ghhughes@zeroes.ca ) Profile picture
May 18
5 years into Covid some people are still arbitrarily trying to apply workplace respirator regulations to respirator use by the general public, even though they are different paradigms.

@kristinaEBP has experience running an industrial respiratory program, and pushes an absolutist occupational regulation approach to masking and mask fit testing in spite of the fact that the general public doesn't have affordable access to mask fit testing. Nonetheless, she calls community mask fit testing "criminal".

Stealthy Jess / @AdvancedTweaker does innovative mask testing and mask fit testing, including harm reduction testing by using a PortaCount to see how various masks are affected by things like getting them wet, or decorating them.

People are decorating masks anyways, so Stealthy Jess tests things people are **already doing** to see which may have more or less risk

It's institutional orthodoxy vs. innovation and harm reduction.Image
Getting people in to masks that fit them well is one of the best ways for them to be better protected from airborne hazards. In the US, only employees required to wear respirators at work get fit tested, at their employers expense.

The general public is left to fend for themselves, often told to forego respiratory protection entirely if they aren't fit tested, even though most fit testing companies won't fit test individuals, and the few that do may charge $75 - $150 *per mask* just to see if they fit.

So, volunteer community fit testers have stepped up to fill this void that should not exist. In the US, there is no training requirement or certification to perform OSHA compliant fit testing - so it would be defamation per se to claim that volunteer community fit testing in the US is "criminal".

To my mind, inflexibly applying workplace respiratory protection rules to the general public is harmful and counter productive.

The paradigm for mandatory workplace use is totally different than for voluntary use by the general public.

At work, if you don't get fit tested you don't get a respirator and you aren't allowed in the contaminated environment (this is part of the Hierarchy of Controls, where staying out of the contamination is the first, safest choice and masks are a last resort). In workplaces, those rules make sense to make workers safer.

But for the general public, we are already in the contaminated environment, so fit testing rules just prevent people from getting good protection for the situation they are already in.

More fit testing for the general public == more people getting better respiratory protection. And workplace fit testing rules and companies cannot and are not making that happen.

I see community fit testing as vital to helping the general public staying safer from respiratory hazards, including particulates from wildfires as well as airborne disease.

To find volunteer community fit test in your area you can check the Fit Testing for Everyone Discord server:

discord.gg/NwjecfB3S3
Ultimately, fit testing is more important than whether you decorate your mask.

I'm generalizing, so in some cases that may not be an accurate generalization, but based on test data the amount of difference in protection between a leaky, ill-fitting mask and a well fitted mask is orders of magnitude and more significant that the difference made by the types of decoration Stealthy Jess has tested.

The difference all depends on where are starting from. If your mask fits really well, a mod may reduce the protection. But if your mask fits poorly, a mod may not make a significant difference.

Some would say that means "don't modify masks", which I think is a safe take, but doesn't prioritize harm reduction if not accompanied by encouraging accesable fit testing get people fit tested since that makes the most difference.

Take a look at Stealthy Jess' results. The 3M Aura N95 fits her well and the mask chain slightly reduced the protection. But even if the chain massively reduced the Aura's protection the Aura would *still* be more protective than either of the two poorly fitting masks without a chain.

YMMV because fit is individual, which is the point. Fit is individual and mask fit testing is the best way to verify if you are getting the best protection. And it's also best to test your mask as worn, including any decoration.

x.com/AdvancedTweake…Image
Read 5 tweets
Gerard Hughes ( @ghhughes@zeroes.ca ) Profile picture
Apr 21
Most tri-fold masks I try don't pass a fit test on me because they leak at my nose bridge. The WellBefore 3D Pro KN95 is the first earloop tri-fold I've tested that fits me well enough to pass an N95 mode PortaCount fit test.

I compared the 3D Pro to a 3M aura using PortaCount Mask fit testing machines.Image
You can check the YouTube video for quick summary:

youtube.com/shorts/B7sQWzT…

A number of things stand out to me about the 3D Pro. The first is the sturdy nose wire. A good, strong nose wire is a key to sealing a mask well at the nose bridge. 3M Auras and Drager 1950s have excellent nose wires that seal well, but almost every other tri-fold I've tried has a weak nose wire that is reminiscent of twist ties. The 3D Pro nose wire, combined with the comfortable large nose foam, works well on my high nose bridge to give me a good seal.

Another good feature of the 3D Pro is that the earloops are adjustable. Normally I don't get a good seal from earloops - headbands are typically more comfortable and better for the tension needed for a good face seal. However, the individually adjustable earloops let me get a good enough seal to pass a fit test. But keep in mind that you do need tension on the earloops. If you make them loose, you may reduce the seal of the mask.

Overall I'm pleasantly impressed with the 3D Pro. Although the filter media isn't as good as a 3M Aura it is good enough to meet the 95% filtration requirement for KN95s. And the seal is surprisingly good for an earlooop mask.

This testing is preliminary. It will take more testing to see how repeatable the results are, and how the mask holds up under wear.

Fit is individual. Your fit with this mask may be very different than mine. Check below to see how you can do a home fit test to make sure you are getting the best protection from your masks.
The fit testing machines sample ambient air through a tube and sample air inside the mask using a second tube. It compares the concentration of particles outside the mask to the concentration inside the mask, and gives a ratio of outside to inside called a "Fit Factor". The fit factor essentially tells you how much cleaner the air is inside the mask. A fit factor of 10 can be thought of as meaning that the air inside the mask is 10 times cleaner. You need a fit factor of 100 to pass a fit test in an N95 mask.

The first machine, the 8020, measures all the submicron particles that get inside the mask, including ones that went through the filter and the ones that bypassed the filter. That's why the Aura got a fit factor of 278 and the 3D Pro got a fit factor of 33. The Aura has a really good filter, way better than required for an N95. The 3D Pro has a sufficient filter for an N95 or KN95.

Because a 33 isn't a passing score, I used a different machine that can measure just the particles that got in the mask under the seal, that way I could measure just the seal leakage. This test is called an N95 mode test. OSHA requires seal leakage to be under 1%. The machine does the N95 mode test by just counting particles of a certain electrical charge that can't get through filters, so if they are inside the mask they got in under the filter.

Both the Aura and the 3D Pro got N95 mode OSHA fit factors of 200+, the maximum score it can measure. An N95 mode fit factor of 200+ means that there was seal leakage of 0.5% or less.
Read 5 tweets
Gerard Hughes ( @ghhughes@zeroes.ca ) Profile picture
Apr 14
This is what we are losing when the government axed NIOSH and its National Personal Protective Technology Laboratory:

A 10 year plan "focused on novel hazards, PPE shortages, and advancing nationwide PPE expertise and capabilities"

NIOSH was making sure that the inadequate PPE issues from early in the pandemic didn't happen again.

The goals included:

• Conduct workplace exposures assessments & hazard evaluations to inform PPT policy, standards, & conformity assessment needs

• Develop, evaluate, and innovate PPE performance requirements & test methods by integrating advanced PPT & design guidance

• Develop & disseminate strategies & tactics to extend PPT supplies during emergencies, disasters, or PPT shortages

• Develop and disseminate guidance & best practices to inform PPT implementation & enhance user adherence

• Provide national leadership to inform the design & execution of NIOSH’s Respirator Approval Program (RAP) & other PPT conformity assessment schemes

•Expand U.S. capacity for PPT research and innovation

This is from an official presentation by Susan M. Moore, NPPTL Associate Director for ScienceImage
NIOSH was working outside the box, including using BARDA competitions to develop innovative respirators and ways to test how well masks seal and protect you. Image
They were working on using advanced robots with motion and simulated respiration to test how well respirators actually work in simulated workplace conditions, not just under ideal static conditions.

The robot has perfect repeatability, unlike humans, making it easier to isolate and identify design issues.Image
Read 9 tweets
Gerard Hughes ( @ghhughes@zeroes.ca ) Profile picture
Mar 13
Do clear face masks work?

I tested 4 clear panel face masks with a fit testing machine to see if they fit and filtered as well as a regular N95.

The results were mixed, but one mask stood out to me, the Optrel P.Air Clear.

youtube.com/shorts/JDuwPIS…

Clear masks can help people who read lips understand you better and may help in situations where masks are restricted on the claim that they obscure your identity. But to be useful they still need to offer protection from airborne particulates. Not all do.
One that was recommended to me as being popular in the lip reading community did especially poorly, the Safe 'N' Clear "The Communicator" mask. It is a procedural (aka surgical) mask, a design that was not created as respiratory protection & does not seal well.

My "Fix the Mask" N99 Fit Factor for "The Communicator": 3

What I mean by " 'Fix the Mask' N99 Fit Factor: 3" is that I sealed the mask to my face as tightly as possible with an elastic Fix the Mask brand mask fitter (a best case scenario) and the air inside the mask was only 3 times cleaner of sub-micron particles. Without Fix the Mask the N95 FF was 2.Image
The Savewo 3DMask Smile is has tons of pedigrees – KF94, FFP2, ASTM Level III surgical mask – but didn't give me great fit out of the box. With Fix the Mask I got a FF of 12, so the air was 12x cleaner when sealed as best I could. Your results could be better or worse since fit is so individual.Image
Read 6 tweets

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