UCLA study says 70% reduction in risk for those who always wear a facemask

Originally published at: https://boingboing.net/2021/01/19/ucla-study-says-70-reduction-in-risk-for-those-who-always-wear-a-facemask.html


Let’s up those fines for people who decline to wear freely provided masks, then!


And/or add stimulus benefits for those who always wear masks.


Related, for those assholes who try to curbside-lawyer businesses about mask mandates, stating they’re not law…

According to University of Toledo law professor Evan C. Zoldan, there are technical differences between statutes, rules and orders, but to the average person, the effect is the same: they are all equally binding on the public and enforceable by the government.
The differences lie in where the authority to issue them comes from.



A year into this and we still don’t have a perfect mask for the masses that is ubiquitous. Cloth and surgical masks were always meant to be temporary measures. And there are so many N95 counterfeits it’s hard to know what to buy.


Sadly true. The US should have been all over this with a Manhattan Project level of focus and budget rather than leave the public to fend for themselves trying to figure out which random cloth mask, if any, works.

You can buy Korean certified KF94 masks that are likely to be genuine and effective. There are some good supply lines from Korea. YouTuber and aerosol scientist Aaron Collins tests masks with his condensation particle counter and provides test results, recommendations and links to where he bought the masks he tested.


To preserve the supply of N95 respirators for health care workers and other medical first responders, CDC recommends nonvalved, multilayer cloth masks or nonmedical disposable masks for community use.§


The CDC still recommends against n95 masks for non medical use. Maybe the presence of counterfeits self fulfills a supply of genuine masks for medical use?

I saw some sort of certification for cloth masks mentioned a few weeks ago but I can’t find any info on it right now.

But one of the things we’ve learned is that, with a few exceptions (face shields alone and masks with unfiltered outlets) it doesn’t matter. From surgical masks to DIY cloth masks to full-on respirators, it doesn’t fucking matter as long as you’re wearing a mask properly.

In this case, perfection is the enemy of public health.


I think both Razer and LG had mask announcements last week.

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Note that I recommended Korean certified KF94 masks, which are essentially a general population class of filtering face piece respirators originally used to protect people from the air pollution of “yellow dust” storms there. You are not taking away from any front-line providers by buying and using KF94 masks, but you will help reduce the load on medical providers by doing the best you can to stay healthy. Check Collins’ videos for explanations and tests showing the efficacy and fit of Korean KF94 vs. Chinese KN95 masks.

The whole reason we developed standards for respirators was because of what we are experiencing now in terms of the public having no idea how effective their masks are, if at all. But we are long beyond the time that we should still be using crude stop-gap cloth source control masks. We should be transitioning to certified masks for the general public and the Defense Production Act should have been used extensively to make that happen. Hopefully, Biden will make that a reality.

I don’t see a point in “certifying” cloth masks - they are not respirator grade and there’s not much worth testing. Instead we should be getting masks certified under current standards into peoples’ hands, not trying to create a new, substandard test and certification for crappy masks.


It totally effing matters. Better masks work better. Cloth masks are a stop gap that helps, but compliance x better masks is the best result.

Here’s a visualization of compliance vs. mask efficacy from the press release about the study referenced in in the OP:

Or, to to describe it in terms Collins mentions in one of his videos, if you are in an environment where you’d get infected after 10 minutes of exposure without a mask, it would take longer to get the same exposure wearing a mask as personal protection, and much longer with better masks. Here are some approximations based of the 10 minute arbitrary example:

No mask: 10 minutes
50% effective cloth mask: 20 minutes.
95% KF94, KN95, N95 mask: 200 minutes
99% KF94, KN95, N95 that exceed minimum standards: 1,000 minutes

Respirator grade masks are orders of magnitude better than cloth masks.

There are lots of variables, including how well the mask fits that affect their efficacy, but in general better masks work better. And respirator grade masks work much better than cloth masks at protecting you and at protecting others from covid. Cloth masks are just the start, not the goal.


I don’t care what it’s made of. Any certification would be for how effective it is. Personally, I would greatly prefer if it’s not one time use.

This study and most others show multi layered cloth masks are quite effective and can take the R-value below 1 without additional measures. The problem seems to be compliance and availability (and proper usage?) But I can’t argue with better masks perform better.


I know you didn’t comment on or against this, but emphasizing:


Good masks are good. Lots of people wearing any-old-mask is also good. The US is not in “lots of people are wearing masks” territory now, and is unlikely to arrive there soon. “Lots of people” in this comment means “more than half the people”. Unfortunately, this means that for masks to be effective in the US, they have to be pretty good masks, to make up for the lack of numbers.

Long answer

The graph shows that mask quality and participation levels both matter a lot.

In the US, politics made 45% of the population think wearing a mask was a bad thing. With the current public attitudes, it’s not possible to land in the top half of that graph where more than 50% of people wear masks. You have my sympathies.

In the bottom half of that graph, mask quality has to make up for mask quantity if you want to get any benefit. In this region, nothing short of N95 is going to get R < 1.0

If lack of N95 was preventing uptake, I’d say “it doesn’t matter, just put a damn mask on. Once everyone is wearing something on their face, we smash this.”

But that’s not the problem; you could deliver a jumbo sized box of N95 masks to every home in America and your adherence levels wouldn’t nudge much past 50% (unless something changes in the political tone). In this case, it might make more sense to say: “something is better than nothing, put this cloth one on and upgrade when you can”.

By contrast, in South Korea the mask-wearing adherence figure was around 70% when masks were voluntary. At 70% adherence, masks with 60% effectiveness would provide a similar benefit to N95 masks on 45% of the people (eyeballing roughly, well aware that there are plenty of nits to pick here). If less than 45% of US residents are wearing masks (say, 30%), then the benefits fall further, and no mask can catch up. Don’t get discouraged, and keep wearing them. But know that until the numbers pick up, masks are only for protecting yourself; if the virus is going to be eradicated, then masks alone won’t be thing that does it. Not with those numbers.

Now that there’s a mask mandate in South Korea, we can likely expect higher than 70% adherence, so even a 40% effective mask becomes very useful in a way it just can’t without cooperation of the general public.


Certification isn’t just testing a mask for filtration. There are a variety of design perimeters and minimum standards that samples of the mask have to meet for certification - nor do most companies making cloth masks have the consistency and resources to apply for and get certified under strict standards that would be meaningful.

Here are just some of the various parameters that various classes of masks are tested for to be certified (Comparison of FFP2, KN95, and N95 and Other Filtering Facepiece Respirator Classes, 3M Technical Bulletin May, 2020 Revision 4):

There are other details not shown in the table. N95s, for example, have to have head straps for a tight seal. There are no N95s with earloops. KF94s (Not shown on this 3M document because they aren’t industrial respirators, and they don’t have head straps) have to go through a certification with additional tests on subjects doing various tasks to verify the masks fit and filter under real conditions. It’s not as easy as test the filter media for efficacy.

Cloth masks don’t meet any current standards. Crappy standards would likely be more misleading than helpful. What we need to do is make better masks, not certify the bad ones we currently have an abundance of.

You can buy KF94s right now, no problem. That makes more sense than trying to, say, look up a certification of reusable cloth masks - a certification that wouldn’t be valid after the mask was washed because that would change the filtration.


This. Never underestimate how eagerly marketing departments will lie with a useless number.


Again, perfection is the enemy. How are you going to get compliance with more expensive masks when there is often poor compliance with free masks in some geographies and demographics?

The real-world calculation is low compliance x highly effective masks vs high compliance with moderately effective masks. And, unless you’re an ICU nurse, doc, or respiratory therapist, that does not come out in favor of perfect masks.


The thing is, I’m not advocating for perfect or nothing so that aphorism does not apply. I’m saying we need to transition to the best masks we can, even if that means giving them out free to the public. Just saying “Perfect is the enemy of good” can be a lazy way to argue for the status quo. There is no good reason not to try to improve the availability and distribution of better quality masks.


I didn’t interpret @Skeptic 's comments to be “only use the good stuff”. I read them as “the good stuff works better; please upgrade if you can.”


That would have been great, say, like 9 months ago. But masks have been deployed and are working where there is compliance. More focus needs to be put now on vaccine distribution and compliance. Yes, the government can do more than one thing at a time, but there is a limit to public attention, and trying to get the public to pay attention to deployment of better masks right now is like handing out binoculars to passengers on the Titanic after it hit the iceberg.

In the real world, an information campaign just to get people to wear masks would be significant and challenging.


Yes. But we didn’t because we had 40 years of one political party telling their voters that the government is the problem and if you get the government out of the way, the free market will magically take care of everything in the most efficient way. Half the damn country needs to be deprogrammed from neoliberal hogwash.