4 ms·

With over a billion smokers on the planet, or ~20% of the population, it’s not that absurd to worry about urban smoke outdoors contributing to urban pollution.

by dahart 5y ago

With over a billion smokers on the planet, or ~20% of the population, it’s not that absurd to worry about urban smoke outdoors contributing to urban pollution. Nor wood burning house & backyard fires either, nor cars, but that’s a different debate… We aren’t around smokers once in a while, we’re around them constantly. Even urban outdoor second hand smoke really is a higher risk than air travel radiation. Yes I want the language to be specific about the levels of risk. I would agree that “no safe levels” is vague and less helpful than one or two percentile data points. That said, I completely agree with the CDC’s stance and language on both second hand smoke and air travel radiation.

lmm 5y ago
> Even urban outdoor second hand smoke really is a higher risk than air travel radiation. Isn't this exactly what's in dispute? What's the evidence that this is true?
- dahart 5y ago
  Not really. The actual topic of conversation underneath the smoke is the political neutrality of the CDC, and public mistrust of science and government funded sources of information. If you are really curious about the evidence, follow the thread up and click the links. I already posted links that have some stats and links to studies on the harms of second-hand smoke, and so did @dionidium too. :)
  - lmm 5y ago
    I didn't see anything in your links that addressed second-hand smoke specifically? I think there's a broad consensus that a) tobacco is a significant cause of premature death b) low outdoor air quality (e.g. high PM25) is a significant cause of premature death. But given that tobacco smoke does not show up in your link's list of major contributors to low outdoor air quality, that does not add up to a statement that second-hand smoke is significantly dangerous.
    - dahart 5y ago
      You’re talking about the WHO link specifically? You’re right, that link doesn’t mention secondhand smoke because it doesn’t have a list of major contributors (doesn’t mention cars or factories either). I’d agree it’s probably not a great example of what you’re asking about. I really only posted the WHO link because the WHO uses similar language to the CDC saying things like ‘there are no safe levels of exposure to pollution.’ Might not answer your question, but I think the WHO pollution guidelines published a few months are good reading (https://apps.who.int/iris/handle/10665/345329 https://apps.who.int/iris/handle/10665/345329). To clarify what I was talking about above, I’m saying the close exposure to smokers is high in urban areas -- in proximity, frequency, and density. There’s also broad consensus that the risks and harms of secondhand smoke are greater in proportion to proximity of the smokers, and that downtown urban areas where people congregate have higher concentrations of cigarette smoke than other places. I’m not personally claiming that average Pm2.5 air quality over time sees a measurable impact from cigarettes. (Even if true, I would expect cigarettes are dwarfed by cars --- but 6 trillion cigarettes a year isn’t nothing, right?) I’m really primarily claiming that being in an urban area like a downtown city center is high exposure to secondhand smoke, being very close to smokers is often a many times per hour occurrence in busy urban areas, walking and entering/exiting buildings. The CDC link does reference the Surgeon General’s report, which links to a whole pile of primary sources on secondhand smoke. You can also Google around for primary sources for links between smoking and general air pollution. I just tried and found a handful of papers studying outdoor smoke exposure levels, e.g., https://erj.ersjournals.com/content/48/3/918 https://erj.ersjournals.com/content/48/3/918. The main consensus that I see is that for a range of small distances like 10-20 feet, outdoor exposure is plenty high enough to be very concerned about the risks, and that high traffic areas can collect smoke and increase exposure.
      - lmm 5y ago
        > Even if true, I would expect cigarettes are dwarfed by cars --- but 6 trillion cigarettes a year isn’t nothing, right? I don't really understand this reasoning - the way I see it any effect that's dwarfed by cars might as well be nothing, there's no sense worrying about a splinter in a broken leg. > The CDC link does reference the Surgeon General’s report, which links to a whole pile of primary sources on secondhand smoke. You can also Google around for primary sources for links between smoking and general air pollution. I just tried and found a handful of papers studying outdoor smoke exposure levels, e.g., https://erj.ersjournals.com/content/48/3/918 https://erj.ersjournals.com/content/48/3/918. The main consensus that I see is that for a range of small distances like 10-20 feet, outdoor exposure is plenty high enough to be very concerned about the risks, and that high traffic areas can collect smoke and increase exposure. Hmm, sounds like there's a measurable impact which is honestly more than I expected. Still, it seems like a rather cherry-picked measurement; they compare levels in the evening when the traffic street is presumably mostly empty, and note that the traffic street had worse air quality after midnight. They notably don't compare levels in the morning or afternoon when traffic would actually be present and the traffic street presumably had overwhelmingly worse levels of pollution. And they jump straight to recommending a ban on smoking. To my mind to put that on any kind of rational basis you'd have to first set a safe level of PM25 and then propose banning the biggest contributors to PM25 on streets that exceeded it - but reading between the lines of that paper, I assume that once you measure PM25 over a full 24 hours that would mean banning cars long before banning smoking.
  - dionidium 5y ago
    To be clear, I don't think the CDC is full of political operatives intent on fighting a culture war. What I think is that almost nobody at the CDC smokes, that they don't know many smokers, that they (correctly, more or less) perceive smoking to be a lower-class-coded activity, that there is probably near-universal agreement within the CDC that smoking is an undesirable (maybe even "gross") activity (associated with low levels of educational attainment). On the other hand, they all fly in airplanes. They attach little or no moral weight to flying. Everybody they know flies on airplanes. Etc, etc. I think it's unlikely that this isn't influencing their language. The risk of smoking, in their view, isn't something to be managed or weighed or compared; rather, smoking is an abhorrent activity that should be stamped out of existence. How could that possibly not influence how they write about it?
    - dahart 5y ago
      That’s extremely heavy and unfounded speculation on your part. How do you know who flies, or what their morals are, or who they know?? You’re now attempting to move the goal posts to a different playing field entirely. Your beef was over radiation, which has extremely low levels of risk compared to air pollution, not the morals of flying. The questions about the environmental impacts of flying is certainly getting enormous amounts of exposure currently, why do you think people at the CDC are any different from the rest of us in that respect? You’re still trying to paint a picture of hypocrisy where none exists. The CDC is presenting facts on risks, not moral judgements. The fact is that the risks of smoking are large, it kills many times more people than all causes of flying related mortality combined, and that is the reason there is a lot of information decided to educating people about those risks. Smoking is also one of the easiest things to change, it’s a choice, and it’s a luxury, not necessary for anyone to do. Why not try to reduce it? They’re not judging people who smoke as low class, they’re pointing out correctly that smoking is something that statistically harms people of low SES disproportionately, not just health wise, but financially. The whole idea is to try to help those people escape. It seems strange to me to spend any energy complaining about the CDC’s language of smoking, while ignoring the vast amounts of social damage left in the wake of Big Tobacco.
      - dionidium 5y ago
robocat 5y ago
I wish it were acceptable to complain about stinky purfumes and body sprays. They fill the air with volatile organic compounds. Plenty of people are happy to chuck on something smelly while hypocritically complaining about other types of smells. Some cause allergies (hayfever) in me to the point I have to leave an enclosed space or suffer consequences. I know friends that get headaches from them.
- mc32 5y ago
  Hear, hear! Some are worse than others, some don't bother much, but lots of perfumes give me headaches.
- Brian_K_White 5y ago
  Right. And where is the "no safe level of exposure to perfume" PSA? It's entirely rational to suspect the motives and veracity of statements like this.
- nefitty 5y ago
  The harder you make it to engage a behavior, the more likely it is to become extinguished or reduce. These are nusges. It's basically how you influence people incrementally toward a desired outcome. I too, am bothered by some of the history of tobacco-related data. I am ok with the government using indirect methods to reduce tobacco deaths. Wearing perfume doesn't makebthe too of preventable deaths. Perfume smell may be as annoying as cigarette smoke to some people. There's a clear reason why there's societal pressure to address and regulate one I dustry as opposed to another. Whether a given government is using shit science and where it draws its concerns in regards to societal pressure valves to release, has a lot to do with who the leaders of the administration are. This is why politics needs to be a leading concern for any researcher or citizen that prefers effective methods of dispersing evidence-based knowledge.
- GoblinSlayer 5y ago
  I once encountered a smoker who smoked something seriously insane that smelled like burning shit. I could barely believe it's happening.
throwawaylinux 5y ago
It's not absurd to worry about it, it is absurd to say there is no safe exposure level and leave it at that. Especially because so many people smoke it is important to be informed about the actual risks of second hand smoke. If I'm walking down the street do I need to cross the street if I see someone approach with a cigarette? If I'm at a bar and smell smoke coming in should I leave?
- Brian_K_White 5y ago
  No safe level means one person a mile away is a problem. I bet they would say that's absurd, with a straight face.
  - enzino 5y ago
    A wise man I knew used to say "Dilution is the solution to pollution". In fact, once you think about it, that's also the only solution.
- dahart 5y ago
  I hear your point, and agreed already that more detail would be nice. To be fair, the CDC does not ‘leave it at that’. Their page that @dionidium linked to does not either start with or stop with the statement “there is no risk-free level of exposure to secondhand smoke.” It’s one statement among many that include actual statistics, and so incredulity over a line of summary taken out of context might be slightly misplaced. The CDC is in the business of setting guidelines, so the context of their statement that it’s not risk free is a suggestion that regardless of your situation, it would be better to not expose yourself to smoke. This happens to be in complete agreement with the message and recently updated guidelines by the World Health Organization, and with statements by the American Medical Association. Reasonable people are free to make reasonable choices. A little smoking and drinking isn’t going to kill anyone, and we all know that. So we don’t need to get upset when someone says a little is a little bit bad. That said, for someone with athsma, they might reasonably choose to cross the street, since smoke is a trigger and meeting someone on the street who smokes is a very common occurrence if you walk around in urban areas. If they go to a bar, then they’re probably asking for it. :P
tagoregrtst 5y ago
“ it’s not that absurd to worry about urban smoke outdoors contributing to urban pollution” Where do you live that second hand smoke is a significant urban level pollutant? Take a pack of cigarettes, 25g, divide it by 3 (your 30% of people are smokers) = 8.3 g per capita and burn it. Now consider all the diesel per capita that is burned in this dystopian city of smokers. No, we don't get to pretend these trucks have diesel particulate filters. Not if the city has 30% smokers. [1] Anyway, at 8g/person, pollution controls wont save the argument - smoking is a negligible urban level pollutant. [1] or propose a city with lots of smokers that has strict and enforced diesel rules. Tel Aviv? Israelis used to love to smoke.
cleansingfire 5y ago
Note the change from secondhand smoke to outdoor secondhand smoke, once you responded rationally. This poster may be a bot.
enzino 5y ago
Reminds me of a discussion at a students' senate meeting on campus a few years back, when they were discussing banning tobacco smoke everywhere including in the parks away from buildings. People who noted that PM2.5/PM10 emissions from construction sites (ubiquitous at the time), or even BBQs, where much greater than cigarettes, even if all people on campus were chain smoking (we maybe had 5% smokers), were ostracized. The times we live in lol.
- dahart 5y ago
  There are other large source of particulate emissions, larger than cigarettes, there is no doubt about that. Why would that mean we shouldn’t have rules about smoking in public places? Is it okay to try to address multiple issues at the same time, and do something about the ones we actually have control over, even if it only partially addresses the problem? It’d probably be ideal to eliminate the other sources of particulates too, it’s not necessarily a competition, though we all like buildings and BBQ. But out of curiosity - were the people noting that one BBQ is a bigger source of particulates than one cigarette also being fair about the averages, like the fact that there are generally many fewer BBQs running at far lower density and far less often than cigarettes? Are you sure they weren’t argued down because the point might be both somewhat misleading and also somewhat irrelevant? (I’m not certain about that, just suggesting it’s possible. It’s also a fact that there are people who like to ride on high horses and get uppity about their beliefs. I might be one of them sometimes.)
  - enzino 5y ago
    Exactly, you mention beliefs, while the point was (is?) one of science. By the way, have you ever heard of banning coal BBQs? I'm not sure at all that the exposure is less severe. Say you are at a party, there's a BBQ 20ft away, and some annoying guy lights a cig 10ft away. I'd bet you money that the BBQ harms you more, or at least emits more than 4 times (you need to scale by the square, diffusion of a fluid) PM2.5 than the cigarette.
    - dahart 5y ago
      Yes, I mentioned beliefs and was admitting that some of the behavior you saw might be based more on human beliefs than science. It wouldn’t be the first time it ever happened, right? ;) I have heard of banning coal BBQs. I’m sure you’re absolutely right that the instantaneous exposure per second can be worse if you’re close and downwind from one than a cigarette from the same distance. But how often do you go to a party? Is it dozens of times per day, every day? Because that’s how often I bump into smokers when walking around downtown. Part of the CDC’s point is that the damage is cumulative, and you need to integrate over time and space. Exposure to one big source for a short time can be a little bit bad, while exposure to many small sources for a long period of time can be much worse.
shard 5y ago
To bring it to the relevant topic of the day, I don't believe I will ever see the CDC issue a statement that "no level of exposure to the COVID-19 virus is safe", and recommend China level of quarantine.

by dahart 5y ago

lmm 5y ago

> Even urban outdoor second hand smoke really is a higher risk than air travel radiation. Isn't this exactly what's in dispute? What's the evidence that this is true?

dahart 5y ago
Not really. The actual topic of conversation underneath the smoke is the political neutrality of the CDC, and public mistrust of science and government funded sources of information. If you are really curious about the evidence, follow the thread up and click the links. I already posted links that have some stats and links to studies on the harms of second-hand smoke, and so did @dionidium too. :)
- lmm 5y ago
  I didn't see anything in your links that addressed second-hand smoke specifically? I think there's a broad consensus that a) tobacco is a significant cause of premature death b) low outdoor air quality (e.g. high PM25) is a significant cause of premature death. But given that tobacco smoke does not show up in your link's list of major contributors to low outdoor air quality, that does not add up to a statement that second-hand smoke is significantly dangerous.
  - dahart 5y ago
    You’re talking about the WHO link specifically? You’re right, that link doesn’t mention secondhand smoke because it doesn’t have a list of major contributors (doesn’t mention cars or factories either). I’d agree it’s probably not a great example of what you’re asking about. I really only posted the WHO link because the WHO uses similar language to the CDC saying things like ‘there are no safe levels of exposure to pollution.’ Might not answer your question, but I think the WHO pollution guidelines published a few months are good reading (https://apps.who.int/iris/handle/10665/345329 https://apps.who.int/iris/handle/10665/345329). To clarify what I was talking about above, I’m saying the close exposure to smokers is high in urban areas -- in proximity, frequency, and density. There’s also broad consensus that the risks and harms of secondhand smoke are greater in proportion to proximity of the smokers, and that downtown urban areas where people congregate have higher concentrations of cigarette smoke than other places. I’m not personally claiming that average Pm2.5 air quality over time sees a measurable impact from cigarettes. (Even if true, I would expect cigarettes are dwarfed by cars --- but 6 trillion cigarettes a year isn’t nothing, right?) I’m really primarily claiming that being in an urban area like a downtown city center is high exposure to secondhand smoke, being very close to smokers is often a many times per hour occurrence in busy urban areas, walking and entering/exiting buildings. The CDC link does reference the Surgeon General’s report, which links to a whole pile of primary sources on secondhand smoke. You can also Google around for primary sources for links between smoking and general air pollution. I just tried and found a handful of papers studying outdoor smoke exposure levels, e.g., https://erj.ersjournals.com/content/48/3/918 https://erj.ersjournals.com/content/48/3/918. The main consensus that I see is that for a range of small distances like 10-20 feet, outdoor exposure is plenty high enough to be very concerned about the risks, and that high traffic areas can collect smoke and increase exposure.
    - lmm 5y ago
      > Even if true, I would expect cigarettes are dwarfed by cars --- but 6 trillion cigarettes a year isn’t nothing, right? I don't really understand this reasoning - the way I see it any effect that's dwarfed by cars might as well be nothing, there's no sense worrying about a splinter in a broken leg. > The CDC link does reference the Surgeon General’s report, which links to a whole pile of primary sources on secondhand smoke. You can also Google around for primary sources for links between smoking and general air pollution. I just tried and found a handful of papers studying outdoor smoke exposure levels, e.g., https://erj.ersjournals.com/content/48/3/918 https://erj.ersjournals.com/content/48/3/918. The main consensus that I see is that for a range of small distances like 10-20 feet, outdoor exposure is plenty high enough to be very concerned about the risks, and that high traffic areas can collect smoke and increase exposure. Hmm, sounds like there's a measurable impact which is honestly more than I expected. Still, it seems like a rather cherry-picked measurement; they compare levels in the evening when the traffic street is presumably mostly empty, and note that the traffic street had worse air quality after midnight. They notably don't compare levels in the morning or afternoon when traffic would actually be present and the traffic street presumably had overwhelmingly worse levels of pollution. And they jump straight to recommending a ban on smoking. To my mind to put that on any kind of rational basis you'd have to first set a safe level of PM25 and then propose banning the biggest contributors to PM25 on streets that exceeded it - but reading between the lines of that paper, I assume that once you measure PM25 over a full 24 hours that would mean banning cars long before banning smoking.
- dionidium 5y ago
  To be clear, I don't think the CDC is full of political operatives intent on fighting a culture war. What I think is that almost nobody at the CDC smokes, that they don't know many smokers, that they (correctly, more or less) perceive smoking to be a lower-class-coded activity, that there is probably near-universal agreement within the CDC that smoking is an undesirable (maybe even "gross") activity (associated with low levels of educational attainment). On the other hand, they all fly in airplanes. They attach little or no moral weight to flying. Everybody they know flies on airplanes. Etc, etc. I think it's unlikely that this isn't influencing their language. The risk of smoking, in their view, isn't something to be managed or weighed or compared; rather, smoking is an abhorrent activity that should be stamped out of existence. How could that possibly not influence how they write about it?
  - dahart 5y ago
    That’s extremely heavy and unfounded speculation on your part. How do you know who flies, or what their morals are, or who they know?? You’re now attempting to move the goal posts to a different playing field entirely. Your beef was over radiation, which has extremely low levels of risk compared to air pollution, not the morals of flying. The questions about the environmental impacts of flying is certainly getting enormous amounts of exposure currently, why do you think people at the CDC are any different from the rest of us in that respect? You’re still trying to paint a picture of hypocrisy where none exists. The CDC is presenting facts on risks, not moral judgements. The fact is that the risks of smoking are large, it kills many times more people than all causes of flying related mortality combined, and that is the reason there is a lot of information decided to educating people about those risks. Smoking is also one of the easiest things to change, it’s a choice, and it’s a luxury, not necessary for anyone to do. Why not try to reduce it? They’re not judging people who smoke as low class, they’re pointing out correctly that smoking is something that statistically harms people of low SES disproportionately, not just health wise, but financially. The whole idea is to try to help those people escape. It seems strange to me to spend any energy complaining about the CDC’s language of smoking, while ignoring the vast amounts of social damage left in the wake of Big Tobacco.
    - dionidium 5y ago

robocat 5y ago

I wish it were acceptable to complain about stinky purfumes and body sprays. They fill the air with volatile organic compounds. Plenty of people are happy to chuck on something smelly while hypocritically complaining about other types of smells. Some cause allergies (hayfever) in me to the point I have to leave an enclosed space or suffer consequences. I know friends that get headaches from them.

mc32 5y ago
Hear, hear! Some are worse than others, some don't bother much, but lots of perfumes give me headaches.
Brian_K_White 5y ago
Right. And where is the "no safe level of exposure to perfume" PSA? It's entirely rational to suspect the motives and veracity of statements like this.
nefitty 5y ago
The harder you make it to engage a behavior, the more likely it is to become extinguished or reduce. These are nusges. It's basically how you influence people incrementally toward a desired outcome. I too, am bothered by some of the history of tobacco-related data. I am ok with the government using indirect methods to reduce tobacco deaths. Wearing perfume doesn't makebthe too of preventable deaths. Perfume smell may be as annoying as cigarette smoke to some people. There's a clear reason why there's societal pressure to address and regulate one I dustry as opposed to another. Whether a given government is using shit science and where it draws its concerns in regards to societal pressure valves to release, has a lot to do with who the leaders of the administration are. This is why politics needs to be a leading concern for any researcher or citizen that prefers effective methods of dispersing evidence-based knowledge.
GoblinSlayer 5y ago
I once encountered a smoker who smoked something seriously insane that smelled like burning shit. I could barely believe it's happening.

throwawaylinux 5y ago

It's not absurd to worry about it, it is absurd to say there is no safe exposure level and leave it at that. Especially because so many people smoke it is important to be informed about the actual risks of second hand smoke. If I'm walking down the street do I need to cross the street if I see someone approach with a cigarette? If I'm at a bar and smell smoke coming in should I leave?

Brian_K_White 5y ago
No safe level means one person a mile away is a problem. I bet they would say that's absurd, with a straight face.
- enzino 5y ago
  A wise man I knew used to say "Dilution is the solution to pollution". In fact, once you think about it, that's also the only solution.
dahart 5y ago
I hear your point, and agreed already that more detail would be nice. To be fair, the CDC does not ‘leave it at that’. Their page that @dionidium linked to does not either start with or stop with the statement “there is no risk-free level of exposure to secondhand smoke.” It’s one statement among many that include actual statistics, and so incredulity over a line of summary taken out of context might be slightly misplaced. The CDC is in the business of setting guidelines, so the context of their statement that it’s not risk free is a suggestion that regardless of your situation, it would be better to not expose yourself to smoke. This happens to be in complete agreement with the message and recently updated guidelines by the World Health Organization, and with statements by the American Medical Association. Reasonable people are free to make reasonable choices. A little smoking and drinking isn’t going to kill anyone, and we all know that. So we don’t need to get upset when someone says a little is a little bit bad. That said, for someone with athsma, they might reasonably choose to cross the street, since smoke is a trigger and meeting someone on the street who smokes is a very common occurrence if you walk around in urban areas. If they go to a bar, then they’re probably asking for it. :P

tagoregrtst 5y ago

“ it’s not that absurd to worry about urban smoke outdoors contributing to urban pollution” Where do you live that second hand smoke is a significant urban level pollutant? Take a pack of cigarettes, 25g, divide it by 3 (your 30% of people are smokers) = 8.3 g per capita and burn it. Now consider all the diesel per capita that is burned in this dystopian city of smokers. No, we don't get to pretend these trucks have diesel particulate filters. Not if the city has 30% smokers. [1] Anyway, at 8g/person, pollution controls wont save the argument - smoking is a negligible urban level pollutant. [1] or propose a city with lots of smokers that has strict and enforced diesel rules. Tel Aviv? Israelis used to love to smoke.

cleansingfire 5y ago

Note the change from secondhand smoke to outdoor secondhand smoke, once you responded rationally. This poster may be a bot.

enzino 5y ago

Reminds me of a discussion at a students' senate meeting on campus a few years back, when they were discussing banning tobacco smoke everywhere including in the parks away from buildings. People who noted that PM2.5/PM10 emissions from construction sites (ubiquitous at the time), or even BBQs, where much greater than cigarettes, even if all people on campus were chain smoking (we maybe had 5% smokers), were ostracized. The times we live in lol.

dahart 5y ago
There are other large source of particulate emissions, larger than cigarettes, there is no doubt about that. Why would that mean we shouldn’t have rules about smoking in public places? Is it okay to try to address multiple issues at the same time, and do something about the ones we actually have control over, even if it only partially addresses the problem? It’d probably be ideal to eliminate the other sources of particulates too, it’s not necessarily a competition, though we all like buildings and BBQ. But out of curiosity - were the people noting that one BBQ is a bigger source of particulates than one cigarette also being fair about the averages, like the fact that there are generally many fewer BBQs running at far lower density and far less often than cigarettes? Are you sure they weren’t argued down because the point might be both somewhat misleading and also somewhat irrelevant? (I’m not certain about that, just suggesting it’s possible. It’s also a fact that there are people who like to ride on high horses and get uppity about their beliefs. I might be one of them sometimes.)
- enzino 5y ago
  Exactly, you mention beliefs, while the point was (is?) one of science. By the way, have you ever heard of banning coal BBQs? I'm not sure at all that the exposure is less severe. Say you are at a party, there's a BBQ 20ft away, and some annoying guy lights a cig 10ft away. I'd bet you money that the BBQ harms you more, or at least emits more than 4 times (you need to scale by the square, diffusion of a fluid) PM2.5 than the cigarette.
  - dahart 5y ago
    Yes, I mentioned beliefs and was admitting that some of the behavior you saw might be based more on human beliefs than science. It wouldn’t be the first time it ever happened, right? ;) I have heard of banning coal BBQs. I’m sure you’re absolutely right that the instantaneous exposure per second can be worse if you’re close and downwind from one than a cigarette from the same distance. But how often do you go to a party? Is it dozens of times per day, every day? Because that’s how often I bump into smokers when walking around downtown. Part of the CDC’s point is that the damage is cumulative, and you need to integrate over time and space. Exposure to one big source for a short time can be a little bit bad, while exposure to many small sources for a long period of time can be much worse.

shard 5y ago

To bring it to the relevant topic of the day, I don't believe I will ever see the CDC issue a statement that "no level of exposure to the COVID-19 virus is safe", and recommend China level of quarantine.