I realize that I should have made the masks portion of yesterday’s wander its own post. What was supposed to be a casual collection of odd impressions of current events and what I’m up to turned into a mildly angry rant. That’s just how things work in the back of my head sometimes.
Anyway. I ran into some links this morning that are worth mentioning. The first one is a must-read: “Aerosols, Droplets, and Airborne Spread.” It didn’t answer all of my questions, but it answered a lot of them. It’s a very long, dense article. (I think it was intended for medical professionals.) Read it anyway. Yes, it’s almost three months old, but I sure don’t get the impression that we’ve learned much since that time. The big takeaway is that SARS-CoV-2 spreads via aerosols; that is, naked virus particles or droplets so small that they remain suspended in the air for a long time. (A lot of supposed experts deny this.) Ever watch cigarette smoke? It doesn’t drift toward the ground. It gradually spreads out until you can’t see it anymore. But take a whiff of the supposedly empty air, and you’ll know it’s still there.
Most droplets fall to the ground fairly quickly. But it’s true (as I mentioned yesterday) that in low-humidity environments, droplets evaporate quickly, and what may have been exhaled as a droplet large enough to fall can shrink to aerosol size before it hits the ground. We’re having a cool day here to close out June in Arizona. It won’t even break 100. The humidity is way up, at 16%. Tomorrow July comes in like a toaster oven (by most people’s standards) at 103. The humidity will be 10% or less. Even a 100µm droplet will likely give up its water long before it hits the ground in that kind of humidity. After that, it floats for what may be 30,000 hours; i.e., indefinitely.
People are still getting into fistfights about whether there are enough viral particles in airborne aerosol droplets to cause infection. It’s not a yes/no kind of question. Like a lot of other things associated with health, it’s about probabilities. I’m thinking that if you spend an hour in a crowded bar where everybody is talking loud, laughing, and drinking, you’re likely to get enough virus to become infected, even if everybody in the bar is wearing a mask. If you pass somebody in the baking aisle at Safeway, probably not. Why do I say this? Two things:
- There is something called “time in proximity.” The longer you spend close to an infected person, the more likely you are to get sufficient viral load to come down with COVID-19. I don’t go to bars much for the bar experience, but my writers’ workshop took place in a sports bar for over three years. When there were important games, people were draped all over each other, talking loud and cheering when their side made a good play.
- You can catch this thing if you get enough viruses in your eyes. A couple of droplets is all it takes. Masks don’t protect your eyes. Nor do I think masks eliminate all exhaled aerosols. Sit in a bar for an hour with hordes of people cheering into their masks, well, you’ll probably get enough of the bad guy in your eyes to come down with it. Why? Badly fitted masks allow exhaled air to flow out the edges. I tried singing with a mask on to see if they leaked out the edges when I sang forcefully. They did.
I’m sure I’ll get yelled at for my contention that masks don’t help us anywhere near as much as our supposed health experts claim, but I’m past caring. Which leads us to another and probably more controversial link, which is one MD fisking a rah-rah hurray-for-masks post by another MD. This is a guest post on Sarah Hoyt’s blog, and you’re free to dial it down if that makes a difference to you. I don’t agree with all the points made, but there are some solid numbers and good explanations about some of the downsides of wearing masks, few of which ever come up in the current debate.
Something else that I knew but forgot to mention yesterday: A real N95 mask filters inbound air only. N95’s have one-way exhalation ports that remain closed until pressure in the mask indicates that the wearer has exhaled. Then it opens and releases the wearer’s breath through the port. No filtering of exhaled breath is done. None. N95’s exist specifically to keep patients from infecting medical personnel. They protect no one but the wearer. The tiresome bleat that “You wear a mask to reassure and protect others” simply doesn’t apply for N95 masks.
So where do I sit in all this? I’ll give you a list:
- We do not know a lot of things, particularly involving viral load, antibody generation, asymptomatic carriers, etc. Everything we know about SARS-CoV-2 and its effects (COVID-19) must be regarded as tentative. We’ll learn more as we go, but right now there is a lot of arguing and handwaving over significant issues.
- Wearing a mask is no guarantee that you won’t catch the virus, nor infect others. Everything is a matter of probabilities. The type of mask matters, some being worthless (handkerchiefs & bandanas etc.) and some a lot better. But none are any guarantee, especially if you wear a mask the wrong way. (I’ve seen a lot of that in grocery stores.)
- Time in proximity matters. It’s the crowded bar thing again, or any dense meeting of bodies talking, laughing, or lor’ ‘elp us, cheering. Spend enough time cheek-by-jowl with virus carriers, and you will almost certainly get the virus, mask or no mask.
- Masks can be overwhelmed by strong exhalation. I’ve tried this myself, as I said before: Cheering or singing into a mask will just force air out the sides when the material of which the mask is made can no longer pass the volume of air presented to it. That air is not filtered.
- Masks don’t protect your eyes. This should be self-explanatory, but it’s rarely discussed. Getting droplets in your eyes is apparently less likely to lead to infection than breathing them in. However, after enough time in dense gatherings, your eyes could put your viral load over the top into infection territory.
- And my conclusion: Put as much distance between yourself and others as you can. Even that’s no guarantee. Furthermore, for some people it may be all but impossible. But for people in my age bracket (I turned 68 yesterday) it could become a life-or-death issue.
Carol and I wear masks, and we stay home a lot. We certainly don’t go to bars or political rallies or protests or anywhere else you have screaming crowds. If you pin me down on it, I’ll express my opinion that masks don’t protect you anywhere near as well as ten feet of clear air. But as with almost everything else about the virus, your guess is as good as mine.
Currently, the main reason for mandating widespread mask use is to flatten the curve of the COVID-19 pandemic. While masks won’t stop 100% of the spread of the virus, any reduction is definitely worthwhile. Even a simple cloth bandana stops approximately 50% of virus laden aerosols, a N95 mask is even better.
And if that argument doesn’t win you over, ask yourself…. Isn’t it the duty of responsible citizens to avoid harming others?
The duty of responsible citizens is indeed to avoid harming others. The kicker is that we’d better be sure that what we’re doing avoids harming others.
If masks worked as well as conventional wisdom holds–and what I’m seeing from medical people indicates they don’t–I would agree with you. A bandana or handkerchief actually stops about 5%-10% of exhaled virus. That’s basically nothing. Figures like 50% assume an airtight seal around the edges of the mask, which is impossible with a simple square of cloth. Most of the air exhaled under a bandana goes down and to either side.
And here’s the kicker: An N95 stops no exhaled viruses at all. Well, N95 masks are designed to protect the wearer, typically front-line medical personnel, and not the general public. N95 masks have an exhalation port that opens when the wearer breathes out, emitting an unfiltered jet of air that could contain thousands of infected droplets. This was in the post. If the idea is to protect others by wearing masks, N95s are worthless. Let’s leave the N95s for the MDs and nurses.
I feel that I’m helping protect others by reminding them that masks do not confer immunity to the virus. What they do is improve your odds a little, where the size of “a little” depends on what kind of mask, how carefully it’s worn, and what you’re doing while wearing it. My experiments show that shouting or singing force air out the sides of the canonical surgical mask, reducing its protective power to zero. A lot of people think, “Hey, let’s all mask up and go down to the bar!”
If this post has a primary point, that’s it: Masks are only part of the equation, and then only if made of something useful and worn properly. Distancing matters, especially given the crappy masks that people generally wear. And nobody is talking about infection through the eyes, even though in a masked but crowded environment, that might well be the primary infection path.
This reply is all for purposes of clarification. I’m not chewing you out; I’m trying to present a viewpoint that doesn’t get much play these days. I appreciate your taking the time to respond.
Magical thinking about masks helps no one, and allows people to imagine that they can get together in big, close groups in bars and in protests (etc.) without fear of infecting others or becoming infected themselves. That sort of thinking may in fact be more dangerous than not wearing masks at all.
Happy Birthday Jeff..belatedly. One note on masks. What I have read is the even if the mask are only say 50% effective, that still aids in slowing/reducing the transmission of the disease.
Thanks! Being 68 isn’t so bad. I’m going to miss weight training, though.
Now, I’m not arguing against masks as a general concept, but against bad masks like bandanas, and most of all, marginal masks in crowd situations, worn by people who consider themselves invulnerable when they put on a mask. That sort of thinking arose out of the protests, when even our supposed experts said, “Go outside and protest! It’s outside! Wear your mask and you won’t catch anything!” The crowd scenes I saw on video were like Napster for viruses. Being outside helped a little, I’m sure, but marching shoulder to shoulder with the same people for half an hour is asking for it. We’re expecting too much out of the masks we have, and not thinking through the ways that (as best we know) the virus travels.
I completely agree re the double standard on protests. Of course, those will spread the disease…and of course, crappy masks and close proximity to others are definitely like Napster for viruses. Even with good masks, close proximity to others will spread the virus.
Precisely. I put it this way: Distancing without masks will keep you better off than masks without distancing. Especially people our age or older.
Finally somebody remarks on the exhalation ports on N95s. I had to go in for a minor exam, and the physician was very considerately wearing a cheapie paper mask over his N95. For the reason you mentioned. It’s obviously not N95-level filtration of the exhalate, but it’s an improvement. Especially since the physician gets tested regularly.
Re: your hypothetical snot-to-aerosol droplet in your neighborhood. Note that the UV radiation in your neck of the woods would probably kill anything that small very quickly. Sure does a great job on human dermal tissue.
My guess (I don’t see much research on solar UV vs. microorganisms) is that direct Arizona sun kills viruses in seconds. This is why I didn’t worry about that much-retweeted photo of young people standing in a swimming pool at some resort in a southern state. None were wearing masks. Did a few get it? Sure. Did they die? No. Were the whole bunch contributing to eventual herd immunity? You bet. They were young. They were in bright sun, and standing up to their waists in chlorine sanitizer. The tans told me that they were unlikely to be vitamin D deficient. It looked like an antibody farm to me.
Much depends on how well droplets survive UV. Down here, I think droplets have very short lives as droplets. After that they’re aerosols, and all bets are off.
The N95 masks come in two types. I use them for woodworking, cleaning, and now during the SARS-Corona Virus 2019 pandemic.
The 3M Cool-Flow masks do indeed have a flexible flapper valve and provide protection against inhalation of dust and aerosols. They do ease the wearer’s breathing, reducing the buildup of warm exhaled air with excess CO2 around your face. They also reduce the back pressure as you exhale.
Other N95 masks do not have the flapper valve and are the type preferred for medical use. I have both types.
During outside trips with the potential for tight quarters, I wear the non-valve N95 masks and laboratory splash-proof googles to avoid eye exposure.
Jeff, I have a box of 3M #8000 N95 masks for doing fiberglass work. They do not have a valve, and fit quite tightly against my face. I can feel them bulge when I exhale, and suck in tight when I inhale. Little if any air escapes around the edges, unless I cough or exhale vigorously.
I was fortunate enough to have a box of surgical gloves, also for fiberglass work.
I re-purposed my old EPROM eraser as a mask and glove sterilizer. That’s allowed us to re-use them, since it’s so hard to boy replacements.
PS: There’s a silly covid-19 poem I wrote at my website link. http://www.sunrise-ev.com/poems/somelittlebug.htm 🙂
More grist for the mill: https://www.nytimes.com/2020/07/04/health/239-experts-with-1-big-claim-the-coronavirus-is-airborne.html
To stop transmission, it appears to be necessary to use Level C Hazmat suits – at least. Or, to use common sense and say “the heck with it”.
Yes. Saw that. A fair number of researchers have been saying that since the beginning, but as often happens, positions that don’t align with government narratives have a hard time getting traction.
Ayup; we have not come a long way since when Galileo had to recant for his attacking the government narrative.
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Here’s another take on masks.
https://medium.com/incerto/the-masks-masquerade-7de897b517b7
The best information I’ve seen on covid comes from osterholm: https://www.bluezones.com/2020/06/covid-19-straight-answers-from-top-epidemiologist-who-predicted-the-pandemic/
He predicted a coronavirus coming out of China from a wet market, he advises presidents and was an interim cdc head. He says cloth masks buy time, e.g. in an enclosed space you get infected in 20 minutes instead of 10. Distance and staying outside are the most effective.