yes I do treat this site as my own personal extra-smart Siri.

I appreciate the nod to Columbo.

Also, that's a good question. I have no idea.

Chart!

https://www.sfgate.com/science/article/The-6-foot-rule-is-outdated-Researchers-devise-15520286.php

You said you wanted opinions, right? The part about wanting studies was just a typo? OK. Aren't cloth masks, like all inanimate objects, basically self-cleaning for virus? That is, if you leave a cloth mask on your desk overnight and put it on the next day, there won't be any virus left just because 12 hours have elapsed. That's what I'm assuming, unless someone is wiping or coughing big wads of snot on their mask. Launder them as you would normal clothing, but their protection doesn't expire, in fact it self-renews.

That's for cloth masks. I've heard that for the N95s which prevent inhalation as opposed to blocking outgoing droplets, the static charge does get used up and they do become less effective.

That image hurts me.

5, I'm asking about effectiveness for a single duration, like hours per day in a room... I agree that no special cleaning needs to be done between uses!

I think having the window open makes more difference than the specifics of the mask.

I guess if the cloth actually got moist all the way through it might start launching moist droplets, but that doesn't ever seem to happen? Not to me, anyway. I got nothing, basically.

4: I saw that, actually, and it made me nervous for how cavalier I've been about outdoor activities! Like, I'm in the habit of hanging out for hours outside, with other people, without masks. Sitting further apart than we used to before all this, but nevertheless prolonged time without masks.

9: Like, suppose they say that cloth masks are 70% effective. I assume that's for a 15 minute exposure. So if you're in a room, and your mask is being 70% effective every 15 minutes, over the course of two hours, are your covid germs effectively saturating the space?

Just don't talk or let them talk.

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Boy's Mom's COVID test was negative (she developed a mild fever after our older kid came home from first week of in-person classes with runny nose). Phew.
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That's good. None of us have been tested, but we now have an instant thermometer and a pulse oximeter. The later my wife bought without telling me because I told her that it reminded me too much of watching my dad with pneumonia. But she is of course right that if one of us gets sick, it could save a hospital visit or start a life-saving one.

The only studies I know are basically flow assessments of masks and particles, usually with laser illumination.
They don't examine the specific question you're asking (how many hours). All they get at is how a particul;ar mask type affects the number and distribution of expelled droplets.

https://advances.sciencemag.org/content/6/36/eabd3083

IMO one huge variable is speaking volume-- people yelling is worse than people talking, and crowded rooms run noisy unless everyone's socially agreeing to silence or muted speech to a neighbor. At the risk of sweeping generaliaztion, Americans like yelling, Japanese don't.

I think 11 is getting at the distinction between near-ballistic behavior of larger particles, which looks to be responsible for most infection, (those don't stay airborne long or travel very far absent ventilation currents), and small aeresolized particlez, which waft about and are probably responsible for a small fraction of infection.

IMO one huge variable is speaking volume-- people yelling is worse than people talking, and crowded rooms run noisy unless everyone's socially agreeing to silence or muted speech to a neighbor. At the risk of sweeping generaliaztion, Americans like yelling, Japanese don't.

Megan McArdle figured this out early on!

I agree that no special cleaning needs to be done between uses!

I recently read something in a reputable outlet - I can't seem to find, though - in which the quoted experts were urging people to wash masks between uses. You change your underwear every day, right? Apparently, this expert had never heard of the analogy ban.

I use my mask infrequently enough that I feel quite confident it decontaminates itself in its storage space in my car.

I remember the early mask advice that was pretty universal: Masks don't work, and we need to save them for medical professionals. News articles made little effort to reconcile the obvious contradiction.

Italians completely believe that explanation. But an aspect of Italian culture is that they like to blame any problems in Italy on Italian culture.

Do people really change their underwear every day if they aren't getting closer than six feet to anybody else?

hello world!
I have just cycled 180km in two days because we weren't going to get any other pointless exercise in this summer. My brain, like my thighs, is apparently made of rolled carpet, stiff, numb, and tingling oddly.

Two observations.
1)The Air BnB I stayed in completely ignored masks or any kind of track-and-trace regulation. People generally were not very good at any kind of social distancing in the provinces.
2) Pulse oxymeters are much less alarming if you read them the right way up. I do not in fact have a pulse of 107 and a blood oxygen level of 85%
3) We don't need Trump to screw up the postal service. It took me three tries to find a post office that actually sold envelopes to put things in that you might want to post.

Hello! Getting out sounds nice.

21.3): As someone who has had to deal with both the USPS and the Royal Mail recently, often using both with the same letter, going both directions: nah, Royal Mail's doing a lot better now. But I guess you're complaining about a Post Office problem. It's...slightly weird how it's done, isn't it? This is my understanding:

1. The Post Office and Royal Mail are separate entities, the former handling the physical locations, the latter doing delivery.
2. Royal Mail, despite the very governmenty-sounding name, is a publicly-traded company.
3. The Post Office is a state-owned private company. (A British SOE, basically.)
4. ...mostly operated on a franchise model. My local branch has been closed since the beginning of the pandemic, probably because the people who ran it were pretty old, so I've had to trek to adjacent postal codes to mail stuff. Upside is that sometimes you can buy beer at the post office. It brings tears to my Pennamite eyes.
5. The Post Office used to do real postal banking, but it apparently doesn't anymore. All the offices I've been to have ATMs that, due to agreements with most of the major banks, are free to use for most people (dunno if that holds for people using credit unions?).
6. ...in every case I've been to the ATM has been operated by Bank of Ireland, a foreign bank.

I'm not saying that's the craziest model, but it sounds hella contingent, probably involving a lot of locked-in bad decisions. Would love to hear how this is the model of just the right amount of deregulation, though.

(On the other hand, a package I ordered from Aotearoa went Auckland -> LAX -> Tennessee -> Stanstead -> St Albans -> two postal codes over in two days via Fedex. If shipping is massively overpaid, you can do amazing things.)

"Royal Male" is a stripogram company.

OP, 18: From CA's Guidance for Face Coverings document (PDF) -- It's a good idea to wash your cloth face covering frequently, ideally after each use, or at least daily. Have a bag or bin to keep cloth face coverings in until they can be laundered with detergent and hot water and dried on a hot cycle. If you must re-wear your cloth face covering before washing, wash your hands immediately after putting it back on and avoid touching your face.
https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/COVID-19/Guidance-for-Face-Coverings_06-18-2020.pdf
The masks and face coverings general page is -- https://covid19.ca.gov/masks-and-ppe/

From the little I understand, it looks like face masks are good for the initial interval and occasional spittle propelled Covid spread. Per the chart in 4, once you get into indoor spaces with long exposures, the effects of ventilation seems to dominate spread over proximity and masking. That seems to match the early reporting about poor HVAC in restaurants infecting people more than 15' away, due to the recirculation of fine particles. I think the idea is that aeresolized Covid is normally too small a dose to infect (or lead to anything beyond the mildest symptoms), but continuous exposure to the fine particles can cumulatively lead to a big enough dose for significant transmission.

It also sounds like some of the reluctance to assign "aerosol" transmission as a mechanism may be influenced by infectious disease researchers trying to live down the late 19th century miasma transmission associations. https://science.thewire.in/health/covid-19-pandemic-airborne-aerosol/

Every time I hear about "mail voting" I assume it has something to do with the anniversary of the 19th Amendment.

1. I think Bernie Sanders wanted to work on getting masks out that everyone could wear comfortably that would protect the wearer using filtration.

2. Trump may destroy our post office, but it has been a wonderful institution, and I do not understand why the British did what they did. You have the NHS - nationalized, socialized medicine (I know you had PFIs) - and they had to privatize mail service and make it more complicated by separating the mail service and the physical locations. Why?

From CA's Guidance for Face Coverings document

Sure, I get that this is the advice, and maybe it's legit for people who wear a mask all day, but if that's who they are talking to, they should say that.

lw @ 16: That division into "droplets with ballistic behaviour" and "aerosols that are wafted in the air" is a good one. And from the beginning, people new that the former were a real problem. That's where the 6ft rule originally came from. But the latter is also problematic, and recently there was a big kerfuffle about hundreds of infectious disease scientists petitioning the WHO to make this a major directive -- that aerosols are a major vector of covid transmission.

To heebie's question, it would be quite difficult to come up with any good quantitative method for answering it, because so much depends on (a) the efficacy of each mask at trapping exhaled aerosols, (b) ditto for inhaled aerosols, (c) the size of the room and possible drafts, and (d) the efficacy of ventilation at removing and replacing contaminated air.

It's just a really hard problem to answer, I'd think, though I have seen people doing simulations of smoke and how it travels in a room, gets evacuated by various ventilation methods, one or more doors, etc. It's mostly at the level of simulation, though there was also a paper where researchers recovered live virus (capable of infecting human cells in vitro, not just RNA) from surfaces far enough away from covid patients (in a hospital) that the only means of transmission could have been via aerosols. I forget the details of precisely where they recovered it, but they were clear that the only possible route was aerosol transmission. There was also a recent paper (in JAMA) about aerosol transmission on buses in China.

Honestly, given how little we know, and how every time you turn around there is further confirmation that aerosol transmission is such a problem, given that we know the pathogen is still potent in aerosol form for hours, and given that most masks are only weak barriers to inhalation of aerosols, I would assume that long-term exposure to possibly-infected people *indoors* is a bad idea.

I've been in a not-my-home building once in the last 6 months. I don't plan to repeat that experience unless community transmission is definitively squashed in our area, regardless of what mask-wearing practices are like.

26.2. Pure ideology.. Since the 1970s the Conservative Party has prioritised short term profit over any other consideration. Thatcher personally may have had a more sophisticated outlook, but none of her epigones have shown any ability to see beyond that.

re: 29

I think it's worse than that, since they went full on "klepto". They don't care about the economy (broadly speaking), or the specific short or long term profits of anyone except the narrow coterie of clients they have in their network of corruption.

Is "epigone" pronounced like "epitome"?

Does it mean you've lost your epinephrine?

31. More or less. It means the second rate followers who take over when the original great leaders have gone. I find it quite a useful term.