Aerosol pandemics/Facial
Please see Adjusters on how to improve designs collaboratively. And become an Appropedia editor to help with these pages. Thanks. -- User:LucasG
This page needs content from the Spanish version and lots of work.
Please see experts:
- twitter.com/jljcolorado
- Aireamos
- Sri et al [[patientknowhow.com]] bring in knowledge, not brands
- Fixthemask
- Etc
Cloth masks. Machine to make them, see somosrim.
Surgical masks.
Respirators N95, FFP2, etc. How they work video: https://m.youtube.com/watch?v=eAdanPfQdCA
Elastomerics.
Requirements.
...
Introduction[edit | edit source]
This page needs work: more links, better text, and maybe improvements to the structure. That said, it is hoped that it is already useful as it is. Please consider linking to this page to attract users, particularly contributors. Also, maybe look at the Spanish version: Proteccion respiratoria personal. Thanks, User:LucasG
Please go to Severe respiratory pandemics for a background understanding of a pandemic, a respiratory pandemic, and a severe respiratory pandemic and also for a framework for the tools needed to prevent, manage, or even terminate one if possible.
Clasification of PPE[edit | edit source]
Masks, face shields, helmets/hoods, excavator
Science[edit | edit source]
- Maths of massive use: what changes when many people use specific filtering-level masks?
- Fitting: air goes out through gaps. Three rubber bands for a better fit (video).
- Filter: N95 masks and how they work (video).
- In and out: when we breathe in, we move so many liters of air into our lungs through the mask's filter. So that filter has "things" (viral particles and other things). Those things go out when we breathe out. So we may "charge" our mask in room 1 and "empty" it in room 2.
Specifications[edit | edit source]
"Better" masks (or other face protection like shields) should achieve these parameters, all of which are achievable but not yet achieved:
- adequate protection: fit (sides) and filtration (front). For the user and others.
- Comfortable/wearable: It is away from the mouth and nose, not heavy, and easy to use.
- reusable: how often, how to clean them, how do we know they still work
- scalable: production in massive numbers, adapting other industries or relying on homemade masks.
- style: people want to wear it.
Designs[edit | edit source]
- improving fit: 3 rubber bands
- improving filtration: different materials
- crazy ideas: could we improve electricity with small (rechargeable) batteries?
Materials[edit | edit source]
- kinds
- combinations
- qualities: washable, breathable, light, availability
Testing[edit | edit source]
- testing for fit
- How to test filtration capacity with home tests
- How to test filtration capacity with industrial tests
- correlation (or lack of) between tests
- cheap and reproducible testing procedures
- https://www.washingtonpost.com/opinions/2021/01/26/n95-masks-safest-next-best-options/
- https://www.statnews.com/2020/04/16/n95-masks-training-needed-protect-against-covid-19/
https://twitter.com/enn_nafnlaus/status/1475267189477457921?s=20
Thread: Mask Fit Testing
This evening, I put all my masks to a proper qualitative fit test using a nebulizer, Bittrex solution, and an improvised hood. From the upper left, counterclockwise:
- HygoStar MP9017 surgical mask
- Demetech DT-N95-FH N95 mask (Amazon)
- Wisent BAU 4837 FFP2 mask (hardware store)
- 3M Aura 9330+ FFP3 mask (Amazon; used for ~20h)
- 3M Aura 9320+ FFP2 mask (Amazon; new)
- 3M Aura 9330+ FFP3 mask (Amazon; new)
- GVS Elipse SPR 644 P100 unvalved elastomeric respirator (Amazon)
- 3M 6800 elastomeric full face respirator (valved) with 3M 2135 P3 R particle filters.
Test setup:
A cheap portable nebulizer was purchased on Amazon:
While you can test with stevia or saccharin, bitrex is generally considered the easiest...
To detect this, so I also purchased a bottle of Ft-30 Bittrex solution:
(Bitrex (denatonium) is the most bitter compound known and is not hazardous to health)
While you can fit the test without a hood just by nebulizing near the mask, a hood can increase the...
... concentration and make detection of aerosols easier. This need not be complex—I used a loose transparent garbage bag, placed it over my torso, and left it open enough at the waste to not pose a suffocation risk.
Masks were tested individually, each going through initial...
I underwent basic breathing tests, speaking tests, tests with angling the head in each direction, and deep/rapid breathing tests. The airstream was directed across my tongue to aid in tasting. At the conclusion of each test, I removed the mask while still in the hood to make sure that I...
I could taste the aerosols easily. Between tests, I ate a small banana to cleanse my palate and avoid getting used to the Bittrex.
Results:
1) Surgical mask: You already know how this is going to go. I actually tasted the Bittrex before I even started the nebulizer.
It was just from putting on the hood that had been used in the last attempt. It was barely better than no mask. Rating: 1/10.
2) Demetech: the masks feel like they have a reasonable fit - certainly better than the Wisent cup mask - though the material feels light. But the bitrex taste came..
... disappointingly quickly, with no difficulty tasting at all. Rating: 3/10.
3) Wisent: This hardware store FFP2 mask is clearly intended for industrial rather than medical uses. Its fit felt poor, and expectations weren't high, but it still outperformed the Demetech. Rating: 4/10.
4) 3M Aura 9330+ FFP3, used: The Aura series is the gold standard in disposable medical FFP2/FFP3 masks, although there are some doubts about whether the ones you find on Amazon are legit. I had used this mask for maybe 20 hours. I was quickly disappointed—while better...
Then, the masks above, I was still very clearly getting Bittrex through it. Rating: 5/10.
5) 3M Aura 9320+ FFP2, new and...
6) 3M Aura 9330+ FFP3, new: I grouped these because I couldn't tell their differences. New, they performed much better...
... then the used Aura. I could still taste a bit of Bittrex through them at high concentrations in regular positions and a moderate amount of Bitrex when looking forward while directing Bittrex around the nosepiece. Rating: 8/10.
7) GVS Elipse SPR 644: What can I say? It aced the test. I might have imagined tasting Bittrex, but I think it was just my imagination. That said, it's certainly not the most comfortable of masks, though you do get used to it - and under prolonged wearing, I find I sweat in it,
... and then who knows how well the seal works. Rating: 10/10
8) 3M 6800: I'd put this in the same "may have imagined tasting something, but probably didn't" category as the GVS Elipse. This is an IMHO much more comfortable mask, but it is vented. Rating: 10/10.
Yet to test: I have an on-order 3M half-facepiece with an official vent filter attachment for source control; I will try it when it arrives, but I expect it to also ace the test.
These are qualitative tests and are not as good as quantitative ones (particle count measurements),...
... but we are still good enough to make some points quite clear:
1) Don't trust "N95" / "FFP2" / "KN94" masks without testing them.
2) A new FFP2 is better than a used FFP3.
3) Elastomeric rock.
Making[edit | edit source]
how to make them: links, keywords
Usage[edit | edit source]
Education for proper use: don, duff, clean situations in which they are most useful, strategies for facilitation (ads rules, teaching, games)
External links[edit | edit source]
- https://www.cell.com/med/pdf/S2666-6340(20)30072-6 recent commentary by @linseymarr and @MonicaGandhi9 in which a few different configurations of tight-fitting cloth masks can work to enhance the fit of a surgical mask (electro-statically charged filter) to get net higher filtration.
- https://hbr.org/amp/2020/10/essential-workers-need-better-masks
- https://christinajwilliamson.com/2020/09/25/cloth-masks-to-reduce-covid19-transmission/
- https://www.fastcompany.com/90542976/this-reusable-mask-is-designed-to-fix-the-28-major-problems-with-the-n95
- 28 problems with masks, pdf linked in the above article
- octosafety.com
- fixthemask.com plus videos
- Article 13 Aug 2020: http://built-envi.com/what-kind-of-mask-should-i-be-wearing-to-protect-against-covid-19/
- Science
- masks4all
- examples:
Copied with permission and not as endorsement because that's not what appropedia is for (plus needs work, as does the rest of the page) from https://x.com/zhouliang_mask/status/1864191052850319396
- Air pollution is divided into three categories: solid, gaseous, and microbial.
- Particle protection masks can absorb and filter solid and microorganisms, and for gaseous particles, activated carbon and other materials need to be added to achieve.
- Oily particles are more difficult to intercept than salt particles, and salt particles account for the majority of our daily life.
- It is not true that the N series cannot prevent oily particles, but the interception ability of the N series masks of the same level against oily particles is worse than that of the P series masks of the same level.
- As the wearing time of the mask increases, the filtering efficiency of the mask will slowly decrease regardless of the grade.
- Pure water is non-conductive and does not affect static electricity. When making water-electret meltblown, the purity of water is related to performance. There are all kinds of particles in the air, and continuous use of masks will slowly consume static electricity.
- The fit of a mask is often more important than the filtration level of the mask.
- Choose protective products of different levels and properties in different air pollution environments. In high pollution, eye and skin protection is also important, not just masks with high-level filtration capabilities.
- 0.3um is the most penetrable particle size, and particles larger or smaller than it are more easily intercepted and adsorbed.
- Whether it is 0.075um (counting median diameter CMD) or 0.3um (mass median diameter MMAD), they are different expressions of the same type of particles.
- "The mask is very simple, and you can tell at a glance whether the structure is easy to close, whether there is a separate or auxiliary closing structure, whether the ventilation area is large enough, whether the wearing and adjustment method is stable, whether the surface material is dense or loose, whether there is a special process, and the size of the cavity." The mask needs a separate closing structure, which helps to better close.
- There is no "N95" grade in China's mandatory mask standards. China's KN95 and the US N95 have the same capabilities. The difference lies more in whether the mask manufacturer provides a 60-point or 90-point product, which is related to the mask manufacturer.
- Please stay away from manufacturers that use 0.1μm or 2.5μm (PM2.5) as the filter efficiency of masks. If a mask manufacturer does not test masks according to standards, but tests them under conditions set by itself, then it must have a purpose. Testing under public standards can improve the technical level of the industry.
- The lower the mask test flow rate, the higher the filtration efficiency and the lower the breathing resistance. The protective mask standards of mainstream countries around the world use 85LPM and 95LPM for testing.
- Before China's GB19083-2023 came out, all medical masks had initial filtration efficiency, and all GB2626 masks had loaded filtration efficiency.
- Better mask wearing comfort cannot be achieved simply by having relatively low breathing resistance.
- In China, the annual national and provincial random inspections of GB2626 masks do not test the leakage of masks, which also leads to the biggest problem of KN95 masks being that manufacturers do not care about the tightness of masks. In order to save costs, the structure of masks is becoming simpler, which is not a good thing for tightness.
- VFE is the virus filtration efficiency, don't be intimidated by it. In fact, it is just like BFE (bacterial filtration efficiency), very easy to filter and intercept. In front of KN95 masks, it is easy to get a few "9s".
- Qualified KN95 masks can pass the blood penetration test of medical masks.
- The moment a sterile mask is put on your face, it is already covered with bacteria and microorganisms. Sterile masks are ineffective in daily environments, and EO is harmful to the environment.
- No protective mask is suitable for all people, but it must be suitable for at least 80% of people to be called "qualified". Therefore, masks with independent sealing structures are superior to masks without independent sealing structures in this regard.
- A leaky mask is not a breathable mask.
- The effective ventilation area of the mask determines its actual protection ability and the resistance of the mask after wearing, as well as the filtration efficiency after wearing the mask. However, the mask standards around the world will not tell you the real breathing resistance and real filtration efficiency of the mask. The mask standard test is tested under the same conditions, but masks with different structures are very different.
