[ptliddle]

The title is misleading. The study found duckbill N95 masks "blocked 99% of large virus particles and 98% of small ones". This is important because the issue with masks was always to do with fit and longterm ware habits, not that N95 material was ineffective at blocking viral particles.

[delecti]

> To reflect the general public's use of masks, study volunteers were not fit-tested for their masks or trained how to properly wear them

I think your cynicism is not supported by the study.

[ptliddle]

Read further down in the study. It discusses exactly what i'm referring to in that air was pushed out the sides with KN95 masks and one of the reasons cloth masks performed better then KN95s was a better fit.

[mikehodgson]

The title is still not misleading. You're conflating the results from two different masks. Both N95 and KN95 were tested.

[ptliddle]

And it showed that KN95s are NOT perfect at blocking COVID. This is why the general public now distrust scientists, because the media presents it to them inaccurately and tells them results the study never found. Science is about precision. The study did not find all N95s where nearly perfect at blocking covid, that's flat out inaccurate.

Also let's be really precise here. I'm not conflating anything and i think you don't realize you are.

1) KN95 and N95 use similar filter materials they both have to filter 95% of particles down to 3 microns, the difference is to do with certification N95 is a US certification and KN95 is a Chinese certification. So the material is essentially the same between them. The fits tend to be different.

2) What i'm getting at is the title said all N95s, that's not what the study found, it found that a specific fit style "duckbill" was "Nearly Perfect at Blocking COVID" the non duckbills did not.

So to be accurate what the study did NOT find which the title suggests is that all US certified masks that filter 95% of particles down to 3 microns were nearly perfect at blocking COVID.

[cameldrv]

Generally speaking, N95s fit better than KN95s, because earloops aren't allowed in the N95 standard, and headbands provide more tension so there's a better face seal. This study only evaluated one brand of N95, but there are many other people that have tested various respirators with generally the same conclusions.

[ajross]

> the issue with masks was always

No it wasn't. It was "I don't want to wear one"[1]. And the frame of the argument was fit to the desire. It was true then and remains true now that the single best protection for You Personally (absent isolation) is to put on and wear a mask. That remains true whether or not the "fit" is ideal or on the state of "longterm wear habits" of the rest of society.

[1] Though eventually the politically reframed corrolary of "You can't make me wear one" got more play.

[legitster]

And an important clarification: even if a virus particle is too small to make it through the mask - it is always riding some sort of host to transmit - water partical or something that help it transmit through the air.

Everything was moot though if you ripped off the mask and wiped your hands all over your face when you were done.

[ceejayoz]

> Everything was moot though if you ripped off the mask and wiped your hands all over your face when you were done.

No, probably not. There's very little evidence of transmission via surface contact; you have to breathe a significant amount into the nose/lungs, and the surgical and N95 masks are additionally statically charged to keep viral particles stuck to them; this is how they block viruses much smaller than their own pores. (https://www.wired.com/story/the-physics-of-the-n95-face-mask...)

[legitster]

I think the thing with the N95 masks is they could stay moist all day from your breath's condensation. Covid was very dependent on moisture to spread, and much of the evidence about surface contact implied that the surface was dry or dried out between contacts.

Though to your point it was probably a lower risk than what might have been implied.

[cameldrv]

To my knowledge there's never been a case of COVID conclusively proven to have resulted from surface contact.

[aredox]

Exactly. And this absence has never been as debated as masks, showing the huge biases in the public debate around the means to control the epidemic.

[jvanderbot]

Honest question: Why do we need it to block _viruses_. Surely the virus isn't flying around with wings. Doesn't it travel on water droplets? Doesn't the mask do most of its good work by keeping water droplets in (or out)?

[bee_rider]

Generally the design and testing of the masks tries to take that into account.

I only looked into it informally during the early pandemic, so recollection is a bit hazy. But IIRC different amounts of virus travel on different sized droplets. Different sized droplets also can have different behaviors. Big enough and it doesn’t get through the mask. I think there’s also a “small enough” point where they don’t penetrate very well because they basically bounce around with brownian-like motion, don’t really create much flow. Also, IIRC larger droplets carry more viral load, but I’m pretty sure the smaller ones stay suspended in the air longer.

It is a pretty complex space I think.

[ceejayoz]

This varies from virus to virus; some generate droplets, some generate smaller particles ("aerosols" / airbone transmission). Measles is so infectious because it travels in smaller particles that linger in the air longer.

[lesuorac]

That's generally what people mean.

However, it doesn't matter how good the N95 material is if the virus travels on a water droplet _around_ the mask. This is what all the comments about fit means.

[thsksbd]

Depends on the virus. Not all need a droplet

[jvanderbot]

Well aren't we talking about COVID here?

[thsksbd]

Sure, but check your sentence's grammar; it implies you're asking as a general rule of biology.

As to COVID, dunno.

[bena]

IIRC Covid is airborne so it doesn't need to travel on droplets.

But feel free to double-check that one. Everything surrounding Covid is so tied to politics and identity, it's easy to get things mixed up between actual studies that have actually demonstrated a thing and people just spouting off whatever just came out of their assholes.

In other words, I believe I read an article on how we know now that Covid doesn't need droplets to transmit, but it honestly could have just been someone saying that there was an article claiming that and I've just conflated being told there's an article with actually reading the thing.

[wordofx]

The main issue is people think masks prevent you getting sick. Rather they are designed to prevent you making others sick.

[leptons]

>Rather they are designed to prevent you making others sick.

Except N95 masks weren't designed for that at all. N95s and better masks have been worn for decades to protect the wearer from all kinds of airborne problems, from dust to virus particles. They have proven quite effective at that task. But maybe you think all those workers in the Ebola ward are just wearing masks as a fashion statement?

Masks do prevent the wearer from getting sick, far more than wearing no mask at all. Is it 100% protection? No, but nobody should be complaining about that. I'll take 95% protection or even 50% protection over no protection at all.

[Animats]

Right. The classic "3M 8210 Plus N95 Performance Sanding And Fiberglass Disposable Respirator (20-Pack)" sells for about $1 in boxes of 20 at Home Depot, Lowes, etc. That's a good mask.

Wearing one properly isn't rocket science, but is non-obvious. There's an instruction sheet in the box. You put it on, and then, using your palms, squeeze the part over your nose, which bends the mask and the metal stiffener. Check that you got it right by exhaling, then take a deep breath and feel the edges of the mask pushing against your face. If you don't feel the mask pushing, you did it wrong. Training video from OSHA: [1]

There's a serial number on the box. If you type it into 3M's web site, they will tell you if it's valid and if anyone ever queried that number before. This protects against counterfeit masks. Once you get an OK from the site, initial the box, so you don't ask the site again.

There's also a test kit you can buy, with a little bottle of a strong-smelling substance. If you can smell it with the mask on, you did it wrong.

The way these things work is subtle. There's an inner layer that's an electret, with a permanent electric field. Particles smaller than the mask mesh are caught and held by the electric charge. That's what makes these work against really small particles. They're actually more effective as particles get smaller. The "95%" is for the particle size for which they are least effective.

I've been wearing those since the beginning of COVID and never got COVID. I had a supply of those, because I used to use a water jet cutter at TechShop. This is all ordinary personal protective equipment, familiar to anyone who works around moderately dangerous industrial processes.

[1] https://youtu.be/pGXiUyAoEd8?t=149

[leptons]

Thanks for this detailed reply, TIL!

I've been wearing the 3M 8210 N95 masks when indoors with other people and I have avoided getting sick at all for 4.5 years. Before covid lockdowns, I would get sick at least 5 times a year and the only thing that changed was wearing the mask when in higher risk situations.

[wordofx]

Sure. Masks help the wearer. But the main purpose is to stop sick people spreading. And it’s more effective at preventing spread than preventing contraction.

[leptons]

>Masks help the wearer.

Yes, they do.

> But the main purpose is to stop sick people spreading.

No, the main purpose of an N95 mask is definitely to protect the wearer first and foremost. It's why they were created and sold in the first place. These masks were intended to protect people from all manner of workplace environmental hazards, and they've been used for that for decades.

>And it’s more effective at preventing spread than preventing contraction.

Citation needed.

Also, many people purposely choose not to wear a mask during a pandemic, so a mask not worn is not protecting anyone. Protecting myself from people without masks is 100% the purpose of wearing an N95 mask. We aren't talking about cloth masks in this thread, this study was about N95 masks - the two are different in that a cloth mask protects others more than it protects the wearer, but an N95 mask will protect the wearer more than others (who may not be wearing any mask).

[wordofx]

I haven’t even mentioned N95 masks. I’ve stated masks as a general thing. Surgical masks that are cheap and readily available are to prevent the spread of anything.

N95 masks to prevent you getting covid don’t help anymore than surgical when we know it was be contracted through skin and eyes etc.

If you’re wearing it in a workshop or some dusty place then obviously they are far superior to surgical masks as they are designed for the wearer.

And obviously wearing an N95 when you’re sick is more helpful than a surgical mask as they are much better fitting and don’t let as much through if you sneeze of cough.

[leptons]

>I haven’t even mentioned N95 masks.

This entire thread is about N95 masks.

>when we know it was be contracted through skin

Citation needed (you still didn't provide the previous citation I requested)

Yes, it can be contracted through eyes, so eye protection is another mitigation that helps. When I had to travel in 2021, we wore eye protection on the plane, as well as P100 masks. We were well protected and did not get sick.

>If you’re wearing it in a workshop or some dusty place then obviously they are far superior to surgical masks as they are designed for the wearer.

Guess what they wear in Ebola wards. Guess why they wear them.

[hollerith]

Not true of masks that comform to NIOSH's N95 specification such as the ones routinely worn in hospitals to provide care to COVID patients and which are readily available for $2 per mask without a prescription.

[monksy]

KF94s, (western tested)KN95s, and FFP2s were much better options for the general population rather than occupationally certified N95s. Yet, the US refused to acknowledge PPE for the commoner.

[leptons]

I'll stick with my P100, thanks.

[monksy]

The public health initive was a collective one that tried to incentivize widespread usage as opposed as personal protective equipment (as that good masks are).

Unfortunately the initiave was a (many)day(s) late, and $1(00000000) short. Other nations [that used a higher standard of mask] did not have nearly as bad of numbers as the US had under the mask usage policies/regulations.

[lesuorac]

Did you read the article? The issue of fit was addressed.

> (To reflect the general public's use of masks, study volunteers were not fit-tested for their masks or trained how to properly wear them.)

[ptliddle]

Read further down in the study. It discusses exactly what i'm referring to. The title says "N95 Masks Nearly Perfect at Blocking COVID" that's not what the study found. It found that duckbill N95s were nearly perfect at blocking COVID.