Study shows N95 masks near-perfect at blocking escape of airborne Covid-19

https://sph.umd.edu/news/study-shows-n95-masks-near-perfect-blocking-escape-airborne-covid-19

by robtherobber • 2 years ago

160 105 2 years ago

sph.umd.edu

mozman• 2 years ago

More importantly, how’s it block the inhalation of covid?

sofixa2• 2 years ago

Why more importantly? For an airborne pandemic with very a long incubation period (if memory serves me right up to 2-3 weeks), lack of symptoms in many cases, preventing the spread is the number one priority on the level of a city/local/central government.

Quarantines and lockdowns are good old tested ways, but infeasible for prolonged periods of time. Having everyone wear a mask and drastically reduce the spread was such a no brainer I never understood all the panic around it.

AnimalMuppet• 2 years ago

"More importantly" because people seem to respond better to self-interest than they do to promoting the public good.

lettergram• 2 years ago

Not the original poster, but It’s probably more important because you can’t force people to wear masks. As such, the question is “can I protect myself?”

If you can, there’s absolutely no reason to force other people to mask anyway & you get the same benefit. That’s the ideal situation for everyone.

francisofascii• 2 years ago

It is a fair question for what one should do if healthy. Most people today are not wearing masks when sick. So how much protection does an N95 give us vs not wearing a mask at all? If we are healthy, should we bother with masks?

harimau7772• 2 years ago

Much of the US refuses to wear masks. If masks only prevent the virus escaping but not entering, then it is only the selfish segment of society that is being protected.

hurrdurr573• 2 years ago

I never understood all the panic around it

I think a good chunk of it was the CDC randomly changing its recommendations with no real explanation.

At the beginning of the pandemic in the US, from January to May of 2020, there was a big campaign by the CDC to discourage people from wearing masks. I remember seeing various guest "medical experts" on the news claiming that people who wore masks were actually MORE LIKELY to contract COVID. At the same time, virtually every other country was encouraging or mandating masking.

Then June of 2020 came around, masks quickly became encouraged and then mandated. Fauci only made vague and nonsensical statements like "the science changed!" and "we're moving at the speed of science!" to explain the abrupt change in policy. As if there was ever any scientific data to suggest that COVID-19 was not capable of airborne transmission or that masks wouldn't help limit said transmission.

I get that there was a shortage of masks early on and the CDC was probably just trying to prevent panic buying (which occurred anyway, there were N95s selling on amazon for $40 per mask). The ridiculous claim that "masks make you more likely to get COVID" followed by a sudden requirement to wear said "COVID causing" masks completely destroyed public confidence and fueled all kinds of conspiracy theories.

InDubioProRubio• 2 years ago

For many ordinary citizens its just panic when asked to perform something not within the usual cultural norms. In japan this is normal behaviour, whenever you feel under the weather.

Then there were obvious propaganda lies surrounding masks. One was that soldiers wear them- and i was a soldier, with a abc-mask and we "trained" marching with them and unscrewed them to get some air. Then some other world-unaware office worker suggested using them in freezers and cooled environments- which basically boils down to waterboarding yourself with condensing air-moisture. Good idea, pushed by panicy people into bad policy, communicated badly, resulting in massive resistance.

veidr• 2 years ago

LOL did you mean, "more selfishly"?

Not trying to be snarky, tbh that is more important to me personally, too... but probably not in the broader sense...

justin66• 2 years ago

It's not the sort of membrane that only works when air is flowing in one direction. It won't protect you from getting goober in your eyes, but when it comes to inhalation, N95 material is great.

It also helps that N95 masks tend to have better nosewires for fit, and specify real head straps, which makes them practically more dependable than some masks like most KF94s.

mitchbob• 2 years ago

Discussed recently (93 comments): https://news.ycombinator.com/item?id=40565561

robtherobber• 2 years ago

Thanks for that. Seems that I've missed it. I suppose this one can be removed.

InsomniacL• 2 years ago

@Dang the thread linked seems to be wrongly [Flagged]?

daghamm• 2 years ago

This is more and more being abused to kill discussions people don't like.

Seems like a vulnerability in the system.

skygazer• 2 years ago

Articles sometimes are flagged for poor or inflammatory content, but often it’s the uncivil squabbles that erupt in the comments for completely reasonable but somehow polarizing articles that triggers flagging. I think it’s seen as a regrettable cost of elevating civil discourse. Dang often appears early in such threads “don’t make me turn this car around”-ing, but his warnings are seldom heeded.

karol• 2 years ago

In females :D (check study)

DonnyV2• 2 years ago

Yes because men breath differently then women. {eye roll}

bluejekyll• 2 years ago

To be fair men in general are more likely to have facial hair. Facial hair absolutely impacts the effectiveness of masks.

elric• 2 years ago

Facial shape, size, and facial hair (as another commenter here already mentioned) can absolutely matter in mask fit and seal. This is a very common problem in CPAP masks, which use an inflated bladder to adjust to the face of shape. So I can't imagine this *not* being a problem in N95 masks which don't have a bladder but only an edge of slightly flexible material.

And if we're being pedantic, men typicall have ~10% larger lung capacity than women, which may well have an impact on mask performance as well.

So while the original commenter was factually incorrect, the concern doesn't seem terribly far fetched to me.

n4r9• 2 years ago

The study says it had 44 volunteers, 43% of whom were female.

caleblloyd• 2 years ago

It always baffled me that the US government had a program to send everyone free COVID tests, but they didn’t have a program to send everyone free N95 masks, so we ended up wearing random materials that were far less effective.

With all of the mandates to wear a mask everywhere I at least would have liked to wear one that worked well. You would have thought if they could produce 6 free tests per household per month, they could produce 6 free N95 masks per household per month.

baryphonic• 2 years ago

I guess Big Pharma was better at using lobbying dollars than Big Mask.

addicted• 2 years ago

That’s because the U.S. population was strongly against masks. In the beginning the US public was strongly in favor of the vaccines. In fact the complaints were around the delay in vaccine availability and the way the rich and powerful could access them earlier.

It was only in late 2021 where certain people realized vaccine skepticism was lucrative and the Republicans needed something to rile up their base for the upcoming elections did vaccine skepticism become a thing.

padjo• 2 years ago

It’s truly insane that vaccine deniers are now voting for Trump, when he was the one to take credit for them in the first place (and perhaps with some small justification!)

wannacboatmovie4• 2 years ago

It was only in late 2021 where certain people realized vaccine skepticism was lucrative and the Republicans needed something to rile up their base for the upcoming elections did vaccine skepticism become a thing.

This is revisionist history. I remember many Democrats being staunchly anti-"Trump's rushed vaccine" and it was only when their party came into power did they turn into human pincushions nearly overnight, "believing in science" and not being able to get enough jabs into them.

The vaccines, of course, were one and the same.

tomp• 2 years ago

You mixed up parties a bit.

Democrats were criticising Trump for rushing the vaccine, and flaming vaccine scepticism, helped by mainstream media.

https://www.reuters.com/article/idUSKBN2671R8/ September 17, 20201

Democrat Biden warns against rushing out coronavirus vaccine, says Trump cannot be trusted

throwaway484766• 2 years ago

On any issue some percent of the population will be contrarian. This is why there's much less resistance if policies are heavily encouraged instead of trying to punish dissenters. At the point where x issue becomes part of the culture war concensus becomes impossible.

ksherlock• 2 years ago

You know what else happened in late 2021? Vaccine mandates in the US (and Canada).

In the US, there were two - the first, via OSHA, affected all employers with > 100 employees. Employees would need to be vaccinated or tested weekly and required to wear a mask. This was overturned by the Supreme Court.

The second, via CMMS required vaccinations for all health care employees if Medicare or Medicaid money is involved. SCOTUS allowed that one.

chrismcb• 2 years ago

Maybe it has something to do with the the medical factors in government, like Dr Fauci telling us not to wear masks. It maybe it was all if the prior research that shows that masks fit the last person were mostly ineffective.

Someone1234• 2 years ago

They did have that program:

https://x.com/WhiteHouse/status/1483831305448173578

I personally received free masks. However, it was too late.

It was mostly early COVID when the masks were most needed and not available. Even the strategic stockpile essentially ran out after distributing them to vital areas. By the time they had enough to give them away, everyone had multiple masks of various qualities.

silisili• 2 years ago

I didn't even realize they did that, interesting. Sadly, two years late and not even nearly enough if it was on time.

Kinda telling and depressing that everyone was ordering random knockoffs of varying quality from overseas, because we couldn't seem to produce enough domestically.

beams_of_light2• 2 years ago

How would one even work toward positive results with leadership doing things like this? https://www.nbcnews.com/politics/congress/trump-white-house-...

dwighttk• 2 years ago

A) they did have that program eventually

B) money doesn’t magically turn into materials and finished goods. Someone had to make masks to distribute and they had to get their raw materials from somewhere right when the supply chain was disrupted.

bee_rider2• 2 years ago

N95s were in short supply for quite a while, and a result from this work is that cloth masks outperformed surgical and KN95s. People made pretty good cloth masks, so unless real N95s were distributed, distributing masks could have been a wash I think.

I’m not surprised that cloth beat surgical, but beating KN95 is kind of a shock. Of course, I’m sure there was quite a bit of variance in cloth mask quality. I wonder if anyone has done specifically a study on the home made cloth masks.

hnbad• 2 years ago

Problem is probably that the masks are supposed to be single-use when used as protection and you're meant to replace them even when moving between different places. You're also not meant to wear them for extended periods of time because they supposedly get less effective when they get wet from the moisture of the air you exhale. They also aren't washable so you would need to dispose of them after use.

throwaway484766• 2 years ago

The coronavirus particles are so small they go right through the filter so N95 masks have special fibers that use electrostatic charge to bind them. The electrostatic filter doesn't work effectively when damp, eg after prolonged exposure to humid breath. There's an incredible amount of engineering that goes into PPE.

wannacboatmovie4• 2 years ago

Because there was a massive shortage and they were being rationed for healthcare workers? Am I the only one that remembers collection drives for masks for doctors and nurses?

huygens6363• 2 years ago

There weren’t nearly enough of those to go around. Even medical staff had trouble procuring these.

DiogenesKynikos2• 2 years ago

The other baffling thing was how long it took cheap Covid antigen tests to reach the US market. In Europe, 1 Euro antigen tests were widely available, while in the US, they could easily cost more than $10 and were difficult to find.

At 1 Euro a test, you could easily test yourself every morning before heading to work or school.

freitzkriesler2• 2 years ago

About 3 to 4 years too late but cool to read nonetheless.

ceejayoz8• 2 years ago

The people who weren't convinced of "a good mask reduces spread of a respiratory illness" 3-4 years ago won't be convinced by this either.

It's like when Bill Nye debated creationist Ken Ham; when asked what would convince them they're wrong, Nye said "evidence" and Ham said "nothing".

cies• 2 years ago

For professionals (doctors) it works, we know that for a long time. It's not fail safe, but it works.

For the rest of the population it is hard to determine a mask measure works. Even with this study it's hard to determine. Regular people tend to reuse masks too much, not care for quality labels (N95, etc), and not adjust them well.

gunapologist99• 2 years ago

The other masks actually didn't work though.

Only disposable paper surgical masks (actually disposed of after single use!) worked (if the definition of worked was "reduced the transmission of at least droplets when coughing"), or real masks like KN95 or N95 certainly worked.

Those cloth masks that were reused every day did far more harm then good, especially if they were not washed. They did nothing against the pressure race of a cough, and most transmissibility was via aerosol anyway, not droplets.

The politics simply distorted the science, like when we saw Executive staff wearing logoed blue cloth masks more as a fashion statement than any real science, while subjecting the wearer to reduced air flow, exacerbating things like asthma or cardiac issues, and trapping some virus and random bacteria in a cess pool of saliva in a cloth mask that got saturated within minutes.

It's a real shame that people who knew better didn't say, "these masks work and these other masks are worse than no mask at all."

Politics took over and both sides were trapped by the nuance, and the result is a stain on the history of science and public health.

23B14• 2 years ago

Here's how the headline should read:

"The right mask, worn properly, can do a nearly perfect job of blocking COVID-19"

It's incredible to me that after all this, we still write and publish declarative headlines and articles like this.

ceejayoz8• 2 years ago

The article addresses fit.

Even without giving participants fit tests or training on how to wear masks correctly, all masks significantly reduced the amount of virus escaping into the air.

Including interesting results around cloth masks fitting better than surgical/KN95 masks:

Cloth masks also outperformed both KN95 and surgical masks. Milton theorizes that cloth masks with greater coverage, wrap around the face and give a better seal than either KN95 or surgical masks. With cloth mask filters, flow resistance is also lower, allowing breath to pass through the filter and not leak out the sides of the mask.

23B14• 2 years ago

Doesn't excuse the lazy headline writing. If we're talking about a serious public health matter, the press shouldn't shift the cognitive load to their readers ffs.

stuff4ben• 2 years ago

FWIW, now that N95 masks aren't hard to get, I bought some a few months ago and holy crap they're so much better than the KN95s I had to use during COVID. I basically went maskless at times because the KN95 mask just leaked so much that I couldn't wear them. No matter how well I adjusted the metal nose bar, air leaked up when I breathed and it "tickled" my eyes so much I just stopped wearing them. I have since stockpiled a few hundred 3M N95s just in case.

HPsquared• 2 years ago

Most masks I used, my glasses would steam up from the amount of leakage.

Edit: With all the statistics that were bandied around in that time, I wonder how many accidents were caused by steamed-up glasses due to leaky masks.

HankB992• 2 years ago

I used double stick tape (AKA "boob tape" on Amazon) to reduce leakage around the bridge of my nose. It helped reduce fogging of my glasses a lot.

I guess it's called boob tape because boobs like me use it?

I didn't see any need to wear a mask outdoors (except in a crowded circumstance) or when driving.

aredox• 2 years ago

The 3M "Aura" masks with their origami-like folds are really good in terms of fit and comfort. I switched to them also when sanding wood.

Springtime• 2 years ago

This is an interesting comparison, as there was a NIOSH study in late 2020 (released in 2021)[1] that used equipment to measure procedure masks, surgical masks, proper disposable respirators (with exhalation valves, since that was the main focus of the study) and cloth face coverings and T-shirt fabric (latter two more representative of common DIY masks).

These were sealed shut onto the test equipment using wax (ie: perfect fitment, so best case scenario). They found a much higher penetration through the materials per se for cloth coverings and procedure masks.

Particle penetration through the surgical mask ranged from 2% to 17%. Procedure masks were most variable and ranged from 1% to 85%
For the six cloth face coverings, the submicron particle penetration ranged from 24% to 92%. For the two types of fabric from cotton t-shirts, submicron particle penetration ranged from 45% to 91%. Although this sample size was small, these penetration percentages for the cloth face coverings and fabric from cotton t-shirts are comparable to the 40% to 90% penetration found by previous NIOSH testing of cloth face coverings and fabrics.

For the respirators with exhalation valves their finding was the particle penetration was <1% to 55% without any additional mitigation and under 5% when using the ECG pad mitigation strategy tested. Relevant since a common earlier critique (perhaps assumption) of valved respirators was they weren't as decent as even common masks for non-wearers.

[1] https://www.cdc.gov/niosh/docs/2021-107/pdfs/2021-107.pdf

instagraham• 2 years ago

the inexpensive “duckbill” N95 came out on top,

Inexpensive is not a word I'd use to describe a mask you need multiple of in a week and monthly replacements of thereafter. For a virus that affects the entire world, "developing" and "developed", it's not an easy sell.

But this rather harmless inference could've been promoted instead of the fake initial narrative of "masks are not that useful, save them for medical staff" that happened early on in the pandemic. Policymakers should never be gatekeeping information and acting like the public is too dumb to solve resulting supply-side issues.

presto8• 2 years ago

I've been wearing the same N95 duckbill for about 3 years now. It is getting a bit dirty but structurally it's fine. I don't wear it every day though, only in what I deem high-risk situations. Its construction is much more robust than the around-the-ears N95s.

I think one could reasonably stretch out a box of 20 duckbills for a whole year even if worn daily. They are about $1 each. While I could see that there would be places that $20/year would be too much, I don't think money is the barrier here. People just don't like wearing masks (especially respirators, which are bulkier) for many reasons.

throwaway484766• 2 years ago

You really should be replacing them as directed by the manufacturer. They're not effective after prolonged use.

hurrdurr573• 2 years ago

[flagged]

t0bia_s2• 2 years ago

Studies with different conclusions:

Wearing face masks as a potential source for inhalation and oral uptake of inanimate toxins – A scoping review https://www.sciencedirect.com/science/article/pii/S014765132...

Physical interventions to interrupt or reduce the spread of respiratory viruses https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD...

Possible toxicity of chronic carbon dioxide exposure associated with face mask use, particularly in pregnant women, children and adolescents – A scoping review https://www.cell.com/heliyon/pdf/S2405-8440(23)01324-5.pdf

Blackstrat• 2 years ago

Before you go drinking the kool-aid here, read the sponsoring list. Then go back and read peer reviewed studies on masks that occurred before the COVID pandemic. Or read the disclaimers on the masks. Bottom line, masks, even N95, offer limited mitigation. Numerous studies have demonstrated that. As for the vaccine, personally I know more people that died of vaccine side effects than died of COVID. In fact, I know exactly one person that was deemed a COVID death, despite dying of a hospital acquired staph infection. The government paid more for COVID deaths than dying with COVID. If you spent any time dealing with hospitals during the pandemic, the abuse was obvious. And since it's an election year, it's time to round the sheep up and scare them to death once again. Having lived through numerous pandemics down through the year and seeing how the sheep behavior was stimulated during COVID, my suggestion is that Fauci and the rest of his fascist cabal spend the rest of their lives rotting in jail, especially now that he has essentially admitted that he was making it up as he went along AND that the lab leak theory has gained more traction. Fool me once, shame on you, fool me twice, shame on me. Never again.

Study shows N95 masks near-perfect at blocking escape of airborne Covid-19

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