The Astounding Physics of N95 Masks
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- Опубліковано 17 чер 2020
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This video was written in collaboration with Aatish Bhatia - aatishb.com
To learn more about using & decontaminating N95 masks: www.n95decon.org
Thanks to Manu Prakash for useful discussion and feedback (Manu is involved with the N95 decontamination project)
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Link to Patreon Supporters: www.minutephysics.com/supporters/
The physics & engineering of N95 mask design is pretty incredible.
REFERENCES
10X efficiency of electrically charged fibers
"The electrostatic charge of N95 masks is a major contributor to their filtration efficiency, improving it at least 10-fold over uncharged fabric" (Tsai et al., Journal of Electrostatics 2002; Peter Tsai, personal communication).
Prakash Lab COVID-19 Response Group Working Draft Document on N95 masks: docs.google.com/document/d/1a...
“Electrostatic charge contributes as much as 95% of the filtration efficiency”
Molina, A., Vyas, P., Khlystov, N., Kumar, S., Kothari, A., Deriso, D., ... & Prakash, M. (2020). Project 1000 x 1000: Centrifugal melt spinning for distributed manufacturing of N95 filtering facepiece respirators. arXiv preprint arXiv:2004.13494. arxiv.org/pdf/2004.13494.pdf
Tsai, P. P., Schreuder-Gibson, H., & Gibson, P. (2002). Different electrostatic methods for making electret filters. Journal of electrostatics, 54(3-4), 333-341. www.researchgate.net/profile/...
History of Electrets
Jefimenko, O. D., & Walker, D. K. (1980). Electrets. The Physics Teacher, 18(9), 651-659. aapt.scitation.org/doi/abs/10...
Physics of Air Filtration
Hinds, W. C. (1999). Aerosol technology: properties, behavior, and measurement of airborne particles. John Wiley & Sons. www.wiley.com/en-us/Aerosol+T...
Scientific consortium for data-driven study of N95: www.n95decon.org/
N95 & virus particle sizes
Bałazy, A., Toivola, M., Adhikari, A., Sivasubramani, S. K., Reponen, T., & Grinshpun, S. A. (2006). Do N95 respirators provide 95% protection level against airborne viruses, and how adequate are surgical masks?. American journal of infection control, 34(2), 51-57. citeseerx.ist.psu.edu/viewdoc/...
Harnish, D. A., Heimbuch, B. K., Husband, M., Lumley, A. E., Kinney, K., Shaffer, R. E., & Wander, J. D. (2013). Challenge of N95 filtering facepiece respirators with viable H1N1 influenza aerosols. Infection Control & Hospital Epidemiology, 34(5), 494-499. www.ncbi.nlm.nih.gov/pmc/arti...
Liao, L., Xiao, W., Zhao, M., Yu, X., Wang, H., Wang, Q., ... & Cui, Y. (2020). "Can N95 respirators be reused after disinfection? How many times?. ACS nano. www.ncbi.nlm.nih.gov/pmc/arti...
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4:24 - Facial hair causing imperfect seals in masks led to the decline of facial hair in militaries in WW1. Before then, soldiers were generally *required* to grow a moustache if they were able to. But when gas masks became necessary due to chemical warfare, a clean-shaven face was needed to maximize the effectiveness of the seals.
Why was it required ?
.
@@elejelly3986 "From 1860 to 1916, the British Army imposed mandatory dress regulations on their soldiers, including the requirement to have a mustache."
Elejelly According to this article, it was in Britain and came from the French, who typically wore mustaches to “boast...virility and strength.” So apparently it was to make everyone look more manly. No beards tho, just mustaches
www.google.com/amp/s/www.thevintagenews.com/2019/03/01/mustache-law/amp/
When I trained as a fire fighter I had to shave as well because the breathing apparatus must have a closed seal.
Henry you really need to put your footnotes up for longer than a 10th of a second.
you can always use periods and commas if youre on pc to switch from frame to frame
@@sebastianstark3224 i had to put it on .25 to read that (mobile)
Wait, there were footnotes?
I can appreciate some videos may do that as a stylistic choice, but I watched this on my phone during a lunch break and youtube’s video ui on the phone is super imprecise. It was frustrating to try and catch all the little footnotes.
Exactly 😂
**sigh*, *turns comments to newest first**
As a scientist always using N95 but had no clue about its mechanics, thanks a lot for preparing the video and explaining it explicitly!
Bad
@@truthseeker7815 what
If you live outside the US and never heard of N95 (like myself), it's because N95 is an American standard.
In Europe for example we use the FFP1, FFP2 and FFP3 masks.
N95 are about as good as the FFP2 masks
In Australia we call them P2, still have a couple left over from the fires. We've had a great year, out of the fire,into the frying pan.
@@shorebreak69 I love how half of the idiom is actually true and the other half is an actual idiom
in India its also n95
401st like!
In China we call it mask
The most outstanding explanation I ever heard of N95
Yep it’s me
Aren’t you the time traveler??
@Alejandro Vizcarra Congratulations here is your award for being the most gullible brainwashed citizen of whatever country you currently reside. P.s. this channel is corporately owned. Why would you let them tell you how to think? Start to think for yourselves or you are all in deep shit. Peace.
X onerate goddamn this is why people hate people like you
How many have you heard
such a great explanation
pretty rare for a new comment from a verified and on the top sort comment section
15 minutes after found
@@fiferplayeralt7118 LOL well creators don't always watch stuff as it comes out, most of them use youtube just like you and I :)
@@fiferplayeralt7118, indeed
No, it is not. You are godless. That explains much more
I consider this video very educating and allows non technical people to understand how disposable masks can protect them. I would like to ask for your permission to translate it into Spanish to be able to share it with my contacts.
You can just add captions here on the official UA-cam video :)
@@lyde9272, it says: "No captions available for this video".
I just checked the captions, and Spanish is an option. Not auto-generated, too.
I remember about 6 months ago when Australia dipped into its supply of n95 masks to help people cope with the bushfire smoke, believing it was unlikely there'd be a pandemic requiring them any time soon before they could be restocked. The universe has a great sense of dramatic irony.
Yeah nah, she'll be right mate - Scott Morrison, Australian Prime Minister.
Fatal Now shake my hand!!!!
Around 8 months back, Delhi residents were fighting severe pollution and smog.
Yep “the universe”🤔
Ditto for the Philippines. Five months back we had a volcanic eruption and it was fairly near Manila. Ashfall made everyone buy N95 masks.
I have never heard about electrets before. I demand a video on how the physics of them works ASAP.
An electret is a dipole where the north and south poles are electrically charged.Typically there will be positive ions on one side of the bar, and negative ones on the other side.
@@InXLsisDeo yes, but how do they maintain that charge? Normally a charged particle loses its charge from daily interactions with other air particles, like a temporary magnet. So what makes an Electret more like a permanent magnet?
*+*
Well, one way is to take an insulator, melt it, put some dipolar molecules in it, then solidify it in a strong electric field, causing the now secured dipolar molecules to generate their own electric field. en.wikipedia.org/wiki/Electret For n95 masks, after filtering material is melt blown, it is bombarded by electrons from a corona discharge mechanism. www.lisungroup.com/products/mask-produce-and-test-machine/meltblown-cloth-electrostatic-electret-generator.html However, this charge can dissipates over time.
Another way is to bombard an insulator with electrons, causing them to get caught inside the insulator, which gives it a fairly permanent electric charge. For fun, some people bombard acrylic plastic with 5 million volt electron beam to near the dielectric breakdown, then ground the ~2 million volt electret acrylic plastic, causing neat lighting tunnels : ua-cam.com/video/xlzIUKyA1eQ/v-deo.html
@@jophmac Mask against Corona virus
Brought to you by
Corona discharge
Btw great info.. Thanks
I've been wearing an N95 since the start of this horrific ongoing pandemic and have not had Covid, Flu, Cold, Respiratory Infection for the last 4 years. They work. And yes, dudes with beards who want to avoid Covid may have to reconsider their facial hair as per @TheSecondVersion ↙
still getting boosters?
That’s awesome
@@7QHookThe mRNA were a scam, but thankfully we have Novavax now, which actually works!
They weren't but go on. @@thomase13
I have gotten sick the last 3 times I’ve been on a plane, so I just ordered some n95 masks for future trips to hopefully reduce my chance of getting sick.
Welcome to fluid dynamics class 101. I am a medical and aerospace engineer and this is spot on.
How the fuck is one so smart to do these two subjects simultaneously holy shit...
@@monkeycousin3382 its been VERY difficult. Alot of classes over lap though. The ones that disnt are the medical classes. Juat an example of what i have taken. Started when i was 23. Had a bachelor's in cybersecurity then switched. Have 13 semesters of math, 7 of physics, 3 chem, 3 of materials, machining, and a bunch more haha.
@@LT72884 Just a curiosity: do you "believe" in stuff like chronic fatigue syndrome or fibromyalgia?
@@monkeycousin3382 as in they can be caused by viruses? Viruses can trigger auto immune stuff
Yes, the Nokia N95 was genius.
Makes phone calls AND protects you from COVID-19! 😷
Stop bruh
ua-cam.com/video/AQdYOvQBuU0/v-deo.html
It really was. My first big kid phone a decade ago and I still miss it. Way ahead of its time. Smarter than a few smartphones I've had after it. Nokia's fall from glory soon after was very unfortunate.
I loved that phone
In this case the 95 means, invulnerable in 95% of cases.
Footnotes
00:15 technically "N95 respirator"
00:50 *some straining of the very largest particles DOES happen, but it's not the main filtration mechanism
2:07 on the relevant time scales, gravity doesn't have much effect
2:13 this is called "capture by inertial impaction"
2:28 this is called "capture by diffusion"
2:42 if they do happen to get stuck while following streamlines, it's called "capture by interception"
2:50 called "capture by electrostatic attraction"
4:08 the mask has to pass quality control and breathability tests, too
Thanks for taking the time to write this comment. Now I can die in peace
The hero we don't deserve
Thanks!!
Careful, he's a hero.
Thank you! The only thing I don't like about this channel is how brief those notes are. Leave em up for about 2 seconds so people have time to pause to read them if they want
Thank you for the brilliant video. Straightforward and easy to understand.
fascinating!! thanks for all the hardwork put into researching, writing, and animating this!
2:57 Turn on the subtitles.
A B U S E D C A T
Who wrote that?
wtf man
Wtf he didnt even say anything close to "abused"
Allu71 it looks like it’s written, not auto-generated like how UA-cam sometimes does it.
I caught 95% of this video.
You comment has 95 likes as of 20:22 BST 21 June 2020
I interest in the subject is only medium but somehow I was still attracted to this video ...
Well, now you gotta catch em all
🤣
Ahhh 😆 🤣 got em
I think this is the best explanation of how the mask works, and the info about how to properly clean them for decontamination is the best bit of the video.
That's incredibly awesome engineering!! And this video probably does the most perfect job of explaining it
The cat: what have you done
Me: give you armor
1st law of the internetz: there is always a lolcat photo to illustrate your idea.
@@InXLsisDeo wish I had known this in high school, my presentations would have been more amusing
I will so do this to my best friend's cat xD
I am currently studying ferroelectricity in my solid state physics class and I would have never imagined that it could be used in a mask. Really good video!
Yeah! It's really awesome
This is so interesting! We watched it in my physics class
Oh wow, I didn't expect this, thank you so much for educating me!
I would like to know more about the process used to "electrotize" plastic fibers.
Typically a process called "corona charging" is used (no relation to coronavirus). As the nonwoven fabric is made, a static bar imparts a charge.
@@crazedaze10 coincidence lmao
Yeah the video really should've explained one of its most important parts.
@@crazedaze10 Is that the same mechanism used in an ionizing air purifier? My air purifier has three needles on top of it making a cricket-like sound and in the user manual they're referred to as "corona needles".
@@timbergroeneveld1287 I am not super familiar with the air purifiers, but that sounds like the same idea. I will be curious to check these out more since the first article I read said they charge the air to cause the particles to attach to each other to weigh them down. I'm wondering if there are models that charge a filter and cycle air through to trap the particles. One issue with charging fabric or a filter as it is made is that the charge will eventually dissipate, so effectiveness is lost even if it is not in use and just in storage.
I definitely thought they were like a strainer before this, thanks!
Very interesting and worthwhile video on N95 masks. Many people don't appreciate the modern technology involved with these masks. This video will help a great deal.
did know electric fields, but categorizing three sizes, any then talking about the easy part, physical filtering and sticking tiiiny sized particles(also with brownian motion) was really easy to understand. thank you!
obviously the best way is to have 7 pairs of mask that u wear only once a week and have 6 days to decontaminate between usages
Add one or two for spare, in case one is lost or damaged.
Did you actually mean 7 pairs?Just asking.
@@lifeofphyraprun7601 Maybe one for the intake and one for the exhaust.
Life of Phy,rap,run!!! Saying pair of masks is commonly used. Same as a pair of underwear, pair of pants, etc.
Or - let your immune system do what it is designed to do, and like any other system in the body, strengthen it's ability to do what it does.
Man all y'all are such sheeple.
Everybody gangsta till the N101 mask exists
Said no one ever
You're literally replying to someone that said it
P100 is called lol 99.98% and they can reuse 100 times per filter
error
How bout the n95 with the respirator attached lmao
Best explanation ive gotten about n95 for now thanks so much :)
In the past 2 years of this pandemic, this the first video that actually explains the N95 mask clearly. Not even the news channels did a good job
You might be interested to know that HEPA filters works on the exact same principles.
The written comments at the bottom of the screen, such as the one at 0:51 are unreadable when watching the video with captions.
Nillie I always watch UA-cam with the captions on and this annoys me about a lot of UA-camr's videos. Minutephysics write their own captions rather than the auto generated ones, but sadly UA-cam doesn't allow for the option of choosing which place on the screen the caption appears. An option by UA-cam to move the captions to the top of the screen (for when there's comments) or even left or right (for when there's two people with dialogue) would be such an appreciated addition.
tip: type "c" to quickly toggle caption on/off
Nillie just watch the video in full screen.
also they come and go too fast
just make it transparent. also, it works fine in my mobile. :p
Pls footnotes for longer than 0.0001 seconds lol
Amen
+1
press , or . on a pc to go frame by frame
I did not know a lot of this even though I'm in the medical field. Awesome video!
Hey Minute Physics, i have a request. I know this video is a great explanation for the science behind the N95 masks but I keep seeing people arguing other masks don't help and was wondering if you could make a similar style video for other types of mask so I can just pop your link when people keep fighting masks. Thanks!
I like your profile pic
Hey, i hope this helps ua-cam.com/video/Y47t9qLc9I4/v-deo.html
This acct just posted that video days ago.
It's about the effectiveness of mask in droping the transmission.
Heh. I feel like someone arguing "other masks don't help, therefore I'm not wearing one" is kinda like saying "boots that aren't steel toed don't help against a jackhammer, therefore I'm going to jackhammer barefoot".
@@nafion112 nah! Your logic is flawed! 99.7 survivability rate! Jackhammering your foot is a 100 percent loss of foot rate without steel toes! Do more research! Wear a mask if you want to, but don't force others!
@@rhuttrho88
1. It wasn't logic, it was an anecdote.
2. "99.7 survivability rate!" is a sentence fragment.
3. Jackhammering your foot without steel toed boots does not necessarily precipitate a 100% "loss of foot".
4. It doesn't take tons of in depth research to know that face masks diminish spread of contagions, just like it doesn't take tons of research to know that wearing a coat diminishes loss of body heat in the cold.
5. I'm not forcing you to do anything, be a dickhead all you want.
yall complaining about him going too fast in a minute physics video lmao
I wish they could explain why exponential growth had failed and how measures taken to fix the problem are actually what's more harmful than the virus itself.
This isn't even fast.
I watch this at 1.25x speed xD
@@MrKoval-nm9ky rookie numbers. X2 here.
Yeah…weird flex, I know.
Great video, except for one thing: footnote text is only present for a fraction of a second (4:08).
I see this a lot with UA-cam videos.
You, editing the video, will have seen and read it many times. But if I watch the video at normal speed, it is impossible to read. It's even difficult to pause the video at the right time.
Just slow down the speed of the video.
Use the full-stop (period) and comma buttons to move the video frame by frame if you miss your pause. Comma goes backwards, full-stop goes forwards.
@@HyperS13 on mobile, we don't have that luxury unfortunately...
The footnotes are just extra bits of information that stop people from saying "Actually it's [insert pedantic technicality]." They aren't necessary to understand or enjoy the video. Other channels use them as easter eggs.
regardless of importance, many people will feel like they are missing something and will try to read it anyways
Valuable insight into the N95 mask working.
Neat, I had some idea, but not to such specificity, great video.
I know you put disclaimers in the right hand corner in the intro but can you please site the sources in the description too?
Did the second link work for you? I'd like to read the source on that, but the link is somehow invalid for me.
F
@@justinsommer8141 Maybe it's because COVID-19 isn't racist and doesn't actually choose to kill more black people, because it can't.
@@xenockz about 15% of the people infected by COVID-19 require hospitalization and would die without proper medical care; COVID-19 can't choose to kill people based on their race, but the doctors can choose not to give proper care to certain people based on race.
@@raydai3708 what bullshit, doctors can't do that, they give ventilators to whoever needs it first
Wait a minute, electret? What does that remind me of...? Of course, electret microphones! They’re capacitative microphones, except that they don’t need an external power supply to charge the capacitor because they have a permanently charged foil.
Very interesting! I was wondering how could a N95 mask keep its filtering properties under high relative humidity? Does it keep its properties in this case? The electrostatic aspect of the mask is not very clear. If mask have a net electrostatic charge. Can't they be charged back? The problem of the cleaning process is linked to loss of electrostatic properties? I feel like I'dlike to know a bit more physics of N95 masks.
thanks for citing sources at the start!
The N95 was one of the BEST matric style smart phones of the mid-2000s
Thanks for the video, as a physics student I found it very interesting and definitely learnt something new!
One thing: I can't help but not find the cause behind the usage of rapid subtexts, that are impossible to read. :) Keep up the good work!
Thanks for the lesson. I wish my school lessons are as interesting as this.
The notes you have on some of the pics aren't shown nearly long enough.
Really great vid! INformative.
Really good video but the small text that briefly appears is really distracting and frustrating to read, everytime I have to stop the video, go back around 5 seconds, stop the video when the text appears, read it and continue.
Great video! But I feel like the footnotes are a bit too short this time around...
The caveat title slides too reeeeee
He seems to think that people normally watch his videos with their eyes glued to the screen and their finger hovering around the spacebar ready to pause in an instant in case text appears on the screen for like 4 frames.
Dope video : very well presented ideas and very easy to follow . Thank you!
I'd like to think that the first 10 seconds are a clever, sarcastic take on a certain other statistic that includes the same parties and involvement numbers.
2:57 Because that's what Schrödinger do...
Well, 50% of the time.
😹=😷
The best way to decontaminate a N95 is to leave it in "quarantine" for a week. So if you have seven masks you can use one each day of the week, store it at the end of the day and reuse that same mask in the same day of the next week.
Might kill the viruses, but the bacteria will thrive there.
There's already a shortage and limited supply of masks.
@@manashejmadi so this way you will only be using 7 masks for months.
What if you quarantine the mask outside in sunlight?
I do this by leaving masks in my car, in the sun, that cooks the viruses.
“This is why neutrally-charged styrofoam sticks to an abused cat-“ 2:57
Abuse magnetises its victim. That's why 50 years later my little brother still sets off the metal detector.
Abuse is not the main criterion for styrofoam to stick to a cat. Eg, if you punch a cat, then it is an abused cat, but this will not make styrofoam stick to it. So the statement that "neutrally charged styrofoam sticks to an abused cat" is not always true.
You guys, this was in the captions...
@@allpinksakura That's just my way of the ninja!
This is an excellent video - I am wondering if you would be willing to make a version that leaves off the information at the end about the shortage of N95s? There is no longer a shortage, and I am hoping to include a link to this video in a campaign raising awareness about better masks to protect against COVID-19.
Are you still alive after your 13th booster?
Here in the UK, we have FFP1/2/3 masks. I am using FFP2 masks, as this is what was recommended (FFP1 is mostly just useful for filtering dust and FFP3 are not easy to get hold of). I assume they work in a similar way to N95. This is very interesting info.
Regarding the initial opening statement I believe a part of those differences might be correlated with vitamin d deficiencies of the overall black community. Their socioeconomic backgrounds and lifestyles might entail low to none sunlight exposition (plus their diet also lack proper vit d ingestion). This is fundamental considering the fact that people with darker skins have, in general, lower production rates from sunlight (compared to lighter skin colors) and thus actually need more exposition to balance this out.
For what I understand Vit D is closely related in helping prevent respiratory deseases plus there's already some strong correlation with current covid deaths and sunlight exposition.
I'm unaware about the general education in the US, but if you're black and/or have friends under this conditions suggest them taking some complements (no more than the daily recommended estimates). Plus this will definitely help them in the long run as some most probably they are already getting sick quite regularly due to this.
Even if you're not black and you're lifestyle involves not being exposed to sunlight or while doing so you're mostly covered (or for example nursing homes), your diet isn't as good, do consider taking vitaming d complements.
Of course with this I don't want to downplay any racial inequalities the US has with the black community, and any other minority!
PS: Considering the influence and exposition your channel has you might want to do some research of this and cover this subject.
Interesting take, would love to see sone research on this idea!
Im no expert and not American, but I thought that bad health care for the black community also plays a role
Nope covid 19 is racist and you are the problem BLM✊✊✊
@@notasian7620 Not helpful. This is a genuine discussion on the causation of a disproportionate death rate. Please leave if you don't have something to add.
Looking at the data, it seems Black/Hispanic have higher rates of infection generally, with roughly the same trends between races across non-hospitalized/non-fatal/fatal cases.
So it would seem the outcomes after infection are approximately equal (likelihood of an individual case proving fatal), but the infection rate (and therefore total case number) shows a clear disparity. This would indicate that quality of care is likely nearly equal between races or insignificant to determining outcome.
Transmission within communities seems a likely culprit for infection rate disparity. I would venture a guess that higher population densities in Urban environments are at least a part of the equation.
I learned a lot of new things from this video! :) The N95 masks that I use the most are those made by Protect Life.
I agree! this video is very helpful and the masks from Protect Life are great!
And where can I find Protect Life masks?
@@davidblaine1994 from firstaidkitsurvival . com
For EU: N95=FFP3, and KN95=FFP2
this is so great!!! using electricity *field in a mask? wow never knew n95 is that advance, thanks for sharing
*electric field, by inducing a charge dipole.
Electricity need a conductor.
@@phrodite3882 yup
@@phrodite3882 yess that's what i want to say, thank your for the correction
@@dustyserenity ur welcome :)
Anyone can misshear something
Wow, this is so eye opening for me. Thank you for doing what you’re doing. Really thank you.
That was so awesome man!!,
Thank you so much for the video. I would show this in my class.
Well that was a lot of pausing
Wow, this was much cooler than I expected it to be! Big props.
so well explained...thank you so much.
I find it fascinating how they have so many tricks! (I think the van der waals force is actually chemistry btw)
van Der Waals was a physcist, but regardless, it is totally irrelevant whether a phenomenon belongs to physics or chemistry since the two fields have such a large overlap.
Really informative! I have 2 questions after watching the video
1. Are the electret properties of N95 masks related to ferroelectricity?
2. Wouldn't attaching an additional medium filter to an N95 mask then make a supereffective mask? (Since N95s have difficulty filtering medium particles?)
.
Thank fucking goodness there is a comment discussing the video and not a meme.
I would think that maybe adding an aditionaly filter might caus eit too hard to breathe through? Don't quote me on this though
Presumably there’s a trade-off between the number of layers & the breathability of the mask?
@@thunderlightning4347 cat go brrrrr
Useful places to pause for footnotes (on mobile - pause, then click timestamp)
0:01 Intro card
0:15 "technically a respirator"
0:51 "some straining..."
2:08 "on the relevant...."
2:14 "this is called..."
2:43 "if they do happen..."
2:50 "called 'capture by....'"
2:57 image source
4:08 "the mask has to..."
4:39 data source
4:55 decon 1
4:56 decon 2
5:00 decon 3
5:05 decon 4
5:19 decon 5
Thank you!!
Thanks a lot🙏
How generous, sacrificing some of your time to give it to others.
I've been looking everywhere for this kind of explanation
I like how the way the N95 mask is numbered means
No mask is an N0 mask
How to explain perfectly clear and understandable for all, the uses of a mask, how it works and how to use it, in 6 minutes... Respect
Particle size of 0.1 to 1 micron is very hard to be filtered.
N95 for medical staff is a bit different from regular one. It is resistant to blood splash.
The caption at around 2:56 is different from Minute's voiceover by exactly one word, and it's perfect.
You're doing humanity a great service by releasing this
Nope
True.
Do P3, or N99 masks work the same way just better, or does it have some additional features to do the 4% extra?
I have absolutely no idea, but my guess is that they're the same and works kinda like CPU binning or battery grading, where you find defects and simply sell it as a cheaper / lower grade product.
They are thicker, that's it. Or in the case of reusable respirator cartridges, they are "paper" HEPA filters.
for N99 they use a very special additional material for the fibres, it's called 'your mums ass hairs'.
No do this
ua-cam.com/video/AQdYOvQBuU0/v-deo.html
Finally Henry after soooo many days!! It's Physics Time!!!
Very interesting, informative, and worthwhile video.
Too bad I didn’t see this earlier… very interesting and well done, thank you!
Now do a video on why _any_ mask is recommended over no mask, so it can be shared with the people that claim non-N95 masks do nothing. Please, I'm tired of explaining why any mask is better than no mask to my moronic family, your type of videos are simple enough for their smooth brains to understand.
perhaps your family is right?
Meta-analysis indicated statistically significant superiority of N95 respirators over medical masks against laboratory-confirmed upper respiratory tract bacterial colonization (BRI) (RR = 0.46; 95% CI: 0.34-0.62) but not laboratory-confirmed influenza (RR = 0.84; 95% CI: 0.36-1.99) or other viral infections."
masks should work on paper, but in every single RCT of masks (including N95) they just don't stop viruses.
@@satoau1 I mean, he said no mask over any mask
@@satoau1 having a mask on is better than no mask at all, so their family is wrong
@@satoau1 For one thing, anything that stops or reduces your the droplets you breathe out is a huge help to everyone around you. Even just a handkerchief can help.
@@Merlincat007 you'd think, but it turns out no it's worse. most droplets go upwards past your nose which is worse than straight out, and the ones that do get stuck in the mask only get stuck there temporarily. they dry out and then the virus flies off anyway.
there have been tons of CRTs testing this, and they always show no difference between mask and no mask, and also no difference between surgical mask or N95 mask. it only takes 100 virions to cause an infection, and we breathe out thousands of tiny breath droplets time, and each one of them contains over 1000 virions.
it's no wonder every study shows they have no effect. how could they possibly stop you getting infected when it only takes 1/10 of one droplet?
Cool video, thanks for that. How about a video, that explains the differences between FFP2 and FFP3 masks and regular surgery masks?
It's exactly the same as the N95, except there are different progressive thresholds of the amount of particles captured, and they don't put them into their name
FFP2 = N95 and FFP3 = N99. From what I understand, surgery masks are good for stopping cough particles, thus protecting others from you, but not great at stopping airborne virus/bacteria.
ChillySunny Yep surgical masks protect others, not you. There are also many gaps between mask and face, so you are inhaling an amount of unfiltered air. When you breathe out though, your breathe at least makes contact with the mask before escaping through it or around it. They’re used to protect patients from doctors and nurses, not vice versa
This is wrong. Stop spreading this bogus idea that a mask is to protect others, it's not. It has been shown that surgical masks protect on a level similar to N95 regarding influenza virus. And yes of course a surgical mask also protects yourself. Surgical masks also have those meltblown layers like N95.
3:01 This video features our dear Schrödinger's cat!
Thankfully its collapsed wavefunction reveals that it is alive
Re your intro screen: correlation is not necessarily causation. The referenced JHU article offers hypotheses for the cause of higher health risks among lower income groups but does not offer data to validate these hypotheses. You make a strong statement based on hypothesis rather than established fact.
It's actually well documented that groups like black americans have higher mortality rates than say white americans, form all sorts of diseases. The difference is mainly attributed to lower incomes and lack of opportunity because of (historical or present) systemic racism. It is then not unscientific to assume a similar pattern would be present for COVID-19.
more black americans are dying from covid because poorer areas tend to have worse air quality, increasing your risk of covid. Check out this video ua-cam.com/video/XAFD-0aMkwE/v-deo.html
Phoe Nix I do not dispute the higher mortality rates, that data has been documented. It is the cause of those higher mortality rates that has not been verified with data. “Has been attributed to” is not the same as “has been demonstrated to be caused by” with citations to validated data. There may be a large number of underlying influences that contribute to the end result of higher mortality, disease, and impact of Covid. I do not presuppose the answer or deny the possibility that the hypotheses are correct. But until proven they remain hypotheses, not fact
@@dangreen7709 "help! we're dying" "okay but can you prove it?"
Kenji Bomar that is a very good point. Others have observed that regions with high levels of air pollutants had more detrimental reactions to Covid than regions with lower air pollutant levels. www.bbc.com/future/article/20200427-how-air-pollution-exacerbates-covid-19. China, Italy New York City are examples. But air pollution may be only one factor
When I saw there is a Minute Physics video about N95, I thought N95 is a name of some star or something.
Same
I thought of Nokia
The title specifies N95 MASK...
There is a galaxy called "M95", which is the 95th Messier object.
Yes it was the one they were all fighting over in the Star War.
Awesome video and great educational opening
Outstanding video and clear description. Does anyone knows of a version in Spanish or with Spanish captions? thanks
I love how Physics concepts are incorporated in the explaining of how N95 masks work!
Question: for how long do the fibers keep “electrictized”?? How long can I keep a N95 at home before it becomes useless?
You having an N95 mask reduces the supply of healthcare workers in your country.
In other words, if you have them you are selfish.
@@NLTops What if he had it way before the covid crisis e.g. for home renovation, does that still make him selfish?
Would be a wise move if you would stop assuming stuff about strangers on the internet.
Edit: Forgot to answer the main question, usually these masks last 5 years, meaning they can't garantee a filtration ratio above 95% beyond 5 years after the production date. But there are exceptions, just like for food it should be printed somewhere on the mask
@@sunl8363 I feel electretized by this answer! Good on you SunL 👍
NLTops wtf dude
NLTops Either a bot or you’ve been watching too much propaganda new networks.
It sounds like, from your excellent description, that an N95 mask is basically a very small precipertron electrostatic dust filter that runs on the van dear waals force
*This is probably the most outstanding explanation of N95 masks*
You should do a video on the filtering efficiency of cotton and homemade mask for comparison.
That'd be nice!
Without a proper seal around the face, the filtering properties of the material itself are kinda irrelevant.
I just bought a supposed N95 mask today and the little metal shaper around the bridge of the nose won't hold its shape, which means no seal. I exhale, and all the hot air goes right up through the gaps on either side of my nose, and over my eyes. It's useless. I still have a few good N95 masks from before (3M, valved), but I'm trying to find some more, because these things have to replaced occasionally, and so far, no luck.
@@austenhead5303 That lack of seal makes normal mask cumbersome for eyewear users, it causes condensation.
I think the best that a homemade mask can do is stop some of the particles from sneezing and coughing. It wont however do much to protect yourself in most cases but you should probably listen to the recommendations of the health ministry where you live because they probably took all of this into account.
Because of the shortage of N95s, rigorous lab tests have been done on different homemade mask designs. The data shows that well designed cloth masks can approach N95 effecitveness. (2 layers of tight cotton plus a layer of staticky material like dryfit poly or silk). It’s always better to have mask than no mask, but fit and design play a big role. Poor homemade masks can be as low as 10% effiective, while good ones can be 95 to 97%.
I get recommendations from this channel regularly and just want to say, I find the interestingness of the topics, the clear and easy-to-grasp way of the presentation and the charisma and likability of Henry Reich is just incredible! Thank you!
Excellent. Thank you very much.
Love the video(s)!
Small request to make the *text* you add last longer. I find it hard to even pause the video at the right spot to read them.
Especially if you are watching at 1.25x to 2x speed.
This channel has just gotten shockingly good.
They've been extremely informative since the very start, but the animation became top-tier in the past year or so. There's a reason why this is one of my favorite channels.
Heh, shocking. As in, electricly shocking...
I love how the subtitels added the "abused" part to the cat.
2:55
Good video, thank you. Could you please leave up the footnotes longer? Good explanation and break down of information!
0:07 what the fwck
Thanks, I learnt something. One thing not covered much that I would of dug is the amount of restriction on the air passing through. It must be a big factor, as you alluded to in the follow up. Obviously we can easily make a mask 100% 'effective' by covering it in plastic but it would be filtering out 0% as no air would get through. That relationship between the amount of restriction vs the amount of filtering would be a big part of the challenge in making n95 masks I imagine.
The big thing about the electrostatic charge is improving breathability, by allowing much bigger holes.
Air is a lot smaller than a virus. We do just fine breathing in an N95 mask.