11 ms·

What does in-plane 'slightly further sitting apart' accomplish when the air is recirculated and coughs travel at 50 MPH and sneezes at 100 MPH? I know they wil

by Zhenya 6y ago

What does in-plane 'slightly further sitting apart' accomplish when the air is recirculated and coughs travel at 50 MPH and sneezes at 100 MPH? I know they will screen for symptoms but this has to be "health theatre"

ses1984 6y ago
I was pretty sure airplane air is actually circulated fairly often, air from the jets is actually routed into the cabin.
badfrog 6y ago
> air is recirculated That shouldn't actually matter. As far as we know, coronavirus is not airborne. From the WHO: > According to the currently available evidence, transmission through smaller droplet nuclei (airborne transmission) that propagate through air at distances longer than 1 meter is limited to aerosol generating procedures during clinical care of COVID-19 patients. > as the droplets are too heavy to be airborne, they land on objects and surfaces surrounding the person. https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200326-sitrep-66-covid-19.pdf?sfvrsn=9e5b8b48_2 https://www.who.int/docs/default-source/coronaviruse/situati...
- dannyw 6y ago
  The WHO is the same organisation that has been telling people that face masks are not useful [1], repeating claims like no H2H transmission while ignoring warnings from Taiwan, discouraging travel restrictions and bans as late as Feb 29th citing trade and economic impacts (!!!) [2], and even fearmongering tweets like people can be infected with COVID19 twice (that they shortly retracted) [3]; so it's really hard to take this body as credible. [1]: https://www.sciencemag.org/news/2020/03/not-wearing-masks-protect-against-coronavirus-big-mistake-top-chinese-scientist-says https://www.sciencemag.org/news/2020/03/not-wearing-masks-pr... [2]: https://www.who.int/news-room/articles-detail/updated-who-recommendations-for-international-traffic-in-relation-to-covid-19-outbreak https://www.who.int/news-room/articles-detail/updated-who-re... [3]: https://reason.com/2020/04/26/world-health-organization-tweet-coronavirus-covid-19-antibodies/ https://reason.com/2020/04/26/world-health-organization-twee...
  - lsiebert 6y ago
    So basically they said the same thing as the CDC and the NHS? This seems to be something I hear a lot of in the anglosphere, ignoring that the WHO is arguably why things aren't way worse, especially in countries that don't have particularly robust epidemiological systems. This is a completely new virus that just crossed over from animals at the end of last year, and best practices evolved as everyone learned more, and recommendations evolved based on what they felt they could convince people to do at any specific point in time. Oh, and you may find this educational. It's about a pandemic preparedness exercise in october of last year https://www.forbes.com/sites/judystone/2019/12/12/how-prepared-are-we-for-the-next-pandemic-not-very-experts-show/#592e7c0b3524 https://www.forbes.com/sites/judystone/2019/12/12/how-prepar...
  - sneak 6y ago
    The fact that the WHO is sometimes wrong does not mean that they are always wrong. It also does not mean that any WHO-sourced fact should immediately spawn this reply. In general, the WHO gets more right than they get wrong. I’m critical of the WHO too but I don’t think it’s productive to make this kind of left turn in this kind of thread. Do you have any data that suggests the specific WHO-sourced claim in this thread and on this topic is not accurate? Otherwise it’s just ad hominem, which is noise. Let’s put it another way: There is no currently available evidence of airborne spread of ncov. That’s a fact regardless of whether the WHO says it or not. Please remember to keep in mind that the data and the messenger are separate.
    - dannyw 6y ago
      Absolutely. While this article does not come from a well known outlet, all of the evidence presented comes from peer-reviewed studies, universities, and organisations like the International Laboratory for Air Quality and Health: > The frustration lies with the fact that WHO is clinging to a 90-year-old medical dogma. The droplet dogma, articulated by William Wells in 1930 for tuberculosis, holds that contagion is largely limited to the distance covered by droplets that are larger than five to 10 microns in size. > Several types of studies now challenge that view. > A 2003 paper in The New England Journal of Medicine documented a flight in which one SARS case led to 16 possible infections – eight of whom were sitting within three rows of the symptomatic patient. Another study the same year suggested SARS transmission through an air shaft in a housing complex in Hong Kong. https://australiascience.tv/is-covid-19-airborne-dont-know-but-should-probably-assume-it-is/ https://australiascience.tv/is-covid-19-airborne-dont-know-b... Another scientific article directly on the airbourneness of COVID19: https://www.sciencedirect.com/science/article/pii/S016041202031254X https://www.sciencedirect.com/science/article/pii/S016041202... As an anecdotal evidence, I'd like to point to the Diamond Princess cruise ship. Infections continued to grow on the lockdowned cruise ship, where meals were individually delivered and people weren't allowed out of their rooms except for brief exercise with no contact. How could so many people have been infected if COVID19 is not airbourne? Air recirculation is a prime suspect. My view is that it is not reasonable to adopt a position that COVID19 is not airborne; and the position taken by the WHO should be discounted (not that we should always take the opposite of WHO; but that should NOT be the end of it given all the failures they have had to date).
- brianchu 6y ago
  The WHO is no longer a trustworthy source. But this is still (mostly) correct, and it's not that hard to dive into the studies directly instead of appealing to authorities. All indications are that it is possible for SARS-Cov-2 to be airborne but it is rare. The main study from Wuhan that people cite for airborne SARS-Cov-2 only found high levels of airborne SARS-Cov-2 in poorly ventilated areas of a hospital setting (where certain medical procedures like intubation are known to generate aerosols): https://www.nature.com/articles/s41586-020-2271-3 https://www.nature.com/articles/s41586-020-2271-3. Well-ventilated areas had very low levels. A separate study in Singapore found no airborne samples in a hospital setting (https://jamanetwork.com/journals/jama/fullarticle/2762692 https://jamanetwork.com/journals/jama/fullarticle/2762692). Documented spreading events are consistent with the disease not being aerosolized (one example: https://twitter.com/zeynep/status/1251556084424347649 https://twitter.com/zeynep/status/1251556084424347649).
- mannykannot 6y ago
  I am willing to be pursuaded, but the quote you have given us contains the caveat "at distances longer than 1 meter", while, in the scenario being discussed here, distances of less than one meter are relevant. The quote also presents its case as 'absence of evidence' rather than 'evidence of absence'. In the early (and not-so-early) pronouncements about HIV/AIDS, there were a number of significantly harmful false claims (notably, about it not being transmissible heterosexually) being made by health organizations as a result of confusing the former for the latter. Also, let's take a look at the text surrounding these quotes [my emphasis]: "In all other contexts [i.e. other than the experimental setup being discussed], available evidence indicates that COVID-19 virus is transmitted during close contact through respiratory droplets (such as coughing) and by fomites. ... "As such, WHO continues to recommend that everyone performs hand hygiene frequently, follows respiratory etiquette recommendations and regularly clean and disinfect surfaces. WHO also continues to recommend the importance of maintaining physical distances and avoiding people with fever or respiratory symptoms. These preventive measures will limit viral transmission." The quotes have been taken from a passage discussing the significance of a specific experiment.
lxmorj 6y ago
It's surely not worthless. The air is filtered, the concentration of cough droplets drops off rapidly with distance (inverse cube, I'd guess).
sneak 6y ago
The idea that cabin air is recirculated is a widely held myth. The plane is pressurized from the engines, and the cabin air is entirely replaced with new, fresh, outside pressurized air every few minutes. There’s a bleed valve in the tail area where it blows out.
- caseyf7 6y ago
  So you should want the air vent blowing on you? Most people shut them all off as soon as they sit down.
  - throwaway3563 6y ago
    Those are in addition to the main AC.
  - chrisseaton 6y ago
    > Most people shut them all off as soon as they sit down. Why do they do that? I leave mine of full blast the whole flight to stay cool.
    - TheSoftwareGuy 6y ago
      Personally I've always found the constant airflow starts to dry out my eyes, making it very uncomfortable
      - chrisseaton 6y ago
        Ah I just close my eyes and go to sleep on flights.
  - benhurmarcel 6y ago
    Those don't matter for the ventilation, they are just additional small nozzles to the main one hidden behind the panels. Shutting them or not doesn't affect the quantity of air delivered to the zone.
- bamboozled 6y ago
asdfadsfgfdda 6y ago
The cabin air is about half recirculated, half fresh air from the engines. But the recirculated air is filtered. An N95 mask can filter >95% of .3 micron particles, this cabin air filter can capture 99.9%. https://www.ptitechnologies.com/news-event/pti-announces-the-introduction-of-cabin-air-filters/ https://www.ptitechnologies.com/news-event/pti-announces-the...
- always_left 6y ago
  To put it in perspective, air plane air filters are almost as good as surgical rooms :)
- ikeyany 6y ago
  Are these in operation the entire time passengers are on the plane, or only when the engine is on?
  - KMag 6y ago
    They either idle the engines / run the APU to keep air circulating the whole time, or else they pipe in fresh air. I think it's SeaTac airport where they paint a message about "Mister Pipe" or "Mister Air Pipe" right on the jetway air pipe, along with a message about how it reduces pollution by reducing engine / APU idling, ending with "Thank You, Mister [Air?] Pipe". This "pipe" allows the more efficient (and bulky / heavy) air filtration and industrial chillers in the airport to be used to supply fresh air to the plane while the jetway is extended. If this weren't the case, the plane would get very stuffy very quickly. Imagine your share of the cabin space. Now imagine yourself sealed in a cardboard box that size waiting for the plane to board. How many minutes before your cardboard box becomes unbearable? They're always pumping in fresh air while passengers are in the airplane.
    - deleted 6y ago
      [deleted]
    - ikeyany 6y ago
      But planes do get stuffy very quickly, especially when they don't turn on the engine for a long time.
shizcakes 6y ago
There was an interesting contact tracing case study where two busses took the same trip, one with a coronavirus carrier: https://www.sltrib.com/news/2020/04/24/what-you-need-know-about/ https://www.sltrib.com/news/2020/04/24/what-you-need-know-ab... (about halfway down the page)
- the-dude 6y ago
  Not available in the EU.
manigandham 6y ago
Air is completely renewed in airliner cabins... but this brings up a more important question of whether any of this lockdown / social distancing even works. I'm 99% sure it's completely ineffective. We breathe the same air, touch the same services, and overall interact way too much for any of this to really work against something that's supposed to be so contagious.
- jobigoud 6y ago
  > I'm 99% sure it's completely ineffective How do you explain the reduction in cases and deaths in Italy, Spain, France, NY?
  - deleted 6y ago
    [deleted]
- andybak 6y ago
  > but this brings up a more important question of whether any of this lockdown / social distancing even works. > I'm 99% sure it's completely ineffective. We breathe the same air, touch the same services, and overall interact way too much for any of this to really work against something that's supposed to be so contagious. This makes no sense. Lockdown/distancing is about reducing how much we're "breathing the same air, touching the same surfaces" I've managed to avoid touching the same surfaces as a non-household member for 5 weeks or so and I'm pretty sure none of the air I've breathed has come from anywhere within 2m of anyone else. And even if it had it's all about probabilities. I've massively reduced the chance of contagion. I'm just rolling those dice a lot less often.
  - manigandham 6y ago
    People are still going to work and coming back to their communities, including healthcare workers who are highly exposed. People are still going shopping, touching the same products while bringing them home. People are still getting deliveries of food and packages that have passed countless hands and surfaces. People are still walking around neighborhoods, touching gates, benches, doors, signs, tables, cars, mailboxes, etc. While I don't doubt your efforts, I do doubt how effective they are. I'm not sure why such a question is so controversial. People are messy, and we vastly underestimate our interactions with the world. EDIT: I'm reminded of the mythbusters episode about virus spread which shows just how messy we are: https://www.youtube.com/watch?v=UbQ9Kl9CqUU https://www.youtube.com/watch?v=UbQ9Kl9CqUU
Symmetry 6y ago
There's been a surprising lack of transmissions events on airplanes so far. We've even had a case of an airline steward who was a super-spreader at a party he went to but when they checked the passengers on the plane he arrived with didn't seem to have infected any of them, though he did infect other crew. From the article it seems wearing PPE when interacting with passengers was SOP so probably that's it. https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=12325198 https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&object... This couple was infected by the woman they were sitting behind https://www.theguardian.com/world/2020/mar/09/british-couple-contract-virus-on-flight-from-heathrow-to-vietnam https://www.theguardian.com/world/2020/mar/09/british-couple... And this is in contrast to other respiratory illnesses like swine flu where infected passengers have caused many other infections on a plane. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3810906/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3810906/ So it does seem that SARS-CoV-2 is really pretty droplet based and you'd not the virus doesn't say in the air long enough to circulate through the ventilation system meaningfully. You seem to mostly be in danger if someone in your row or the rows in front of or behind you talk or cough without wearing a mask.
- koheripbal 6y ago
  While you cite news reports of anecdotes, the truth is we have very little data one way or the other. Our best guess is that it's just the people immediately next to you ( plus any surface you touch)... but we don't have high confidence in that.
  - Symmetry 6y ago
    There's actually a remarkable lack of evidence for people getting it by touching surfaces too. That doesn't mean it literally never happens but it seems to be a small fraction of cases compared to the flu. https://today.rtl.lu/news/science-and-environment/a/1498185.html https://today.rtl.lu/news/science-and-environment/a/1498185....
- phyzome 6y ago
  > There's been a surprising lack of transmissions events on airplanes so far. There's an unsurprising lack of data on transmission events.
bikamonki 6y ago
There is no risk avoidance in this scenario, just risk reduction. Our ability to do non-bias, rational, effective risk assessment is very poor. Hence, this and many other marketing tools work all the time.
ashtonkem 6y ago
Airplane air is less recirculated than you think. The basic mechanism for pressurizing an airplane involves basically running a scoop at the front of the plane and a valve at the back, with the difference between the two controlling the pressure. This means new air is continuously entering the front of the plane and being exhausted out the back.
- benhurmarcel 6y ago
  No that's not how it works at all. Compressed air is bled from the engine compressors (or 2 electric compressors in the case of the 787), cooled down using ram air, and passed into an air cycle machine that uses ram air to get the desired pressure and a slightly low temperature. Then it's mixed with filtered recirculated air (taken below the floor around the center of the cabin). Then it's distributed by zone into the whole cabin, brought up to the desired temperature by injecting hot air from the beginning of the cycle, and delivered by nozzles all along the cabin. And excess cabin air is bled out of the cabin, which maintains the right pressure. However in the case of the virus, the biggest risk arguably doesn't come from the recirculation but the nearby passengers.
  - ashtonkem 6y ago
    Still, fresh air is being added continuously, which is more of the point I was going for.
- refurb 6y ago
  That was my understanding as well. Bleed air from the engine is fed into the cabin to maintain altitude pressure, but it’s constantly leaking out of the aircraft too.

by Zhenya 6y ago

ses1984 6y ago

I was pretty sure airplane air is actually circulated fairly often, air from the jets is actually routed into the cabin.

badfrog 6y ago

> air is recirculated That shouldn't actually matter. As far as we know, coronavirus is not airborne. From the WHO: > According to the currently available evidence, transmission through smaller droplet nuclei (airborne transmission) that propagate through air at distances longer than 1 meter is limited to aerosol generating procedures during clinical care of COVID-19 patients. > as the droplets are too heavy to be airborne, they land on objects and surfaces surrounding the person. https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200326-sitrep-66-covid-19.pdf?sfvrsn=9e5b8b48_2 https://www.who.int/docs/default-source/coronaviruse/situati...

dannyw 6y ago
The WHO is the same organisation that has been telling people that face masks are not useful [1], repeating claims like no H2H transmission while ignoring warnings from Taiwan, discouraging travel restrictions and bans as late as Feb 29th citing trade and economic impacts (!!!) [2], and even fearmongering tweets like people can be infected with COVID19 twice (that they shortly retracted) [3]; so it's really hard to take this body as credible. [1]: https://www.sciencemag.org/news/2020/03/not-wearing-masks-protect-against-coronavirus-big-mistake-top-chinese-scientist-says https://www.sciencemag.org/news/2020/03/not-wearing-masks-pr... [2]: https://www.who.int/news-room/articles-detail/updated-who-recommendations-for-international-traffic-in-relation-to-covid-19-outbreak https://www.who.int/news-room/articles-detail/updated-who-re... [3]: https://reason.com/2020/04/26/world-health-organization-tweet-coronavirus-covid-19-antibodies/ https://reason.com/2020/04/26/world-health-organization-twee...
- lsiebert 6y ago
  So basically they said the same thing as the CDC and the NHS? This seems to be something I hear a lot of in the anglosphere, ignoring that the WHO is arguably why things aren't way worse, especially in countries that don't have particularly robust epidemiological systems. This is a completely new virus that just crossed over from animals at the end of last year, and best practices evolved as everyone learned more, and recommendations evolved based on what they felt they could convince people to do at any specific point in time. Oh, and you may find this educational. It's about a pandemic preparedness exercise in october of last year https://www.forbes.com/sites/judystone/2019/12/12/how-prepared-are-we-for-the-next-pandemic-not-very-experts-show/#592e7c0b3524 https://www.forbes.com/sites/judystone/2019/12/12/how-prepar...
- sneak 6y ago
  The fact that the WHO is sometimes wrong does not mean that they are always wrong. It also does not mean that any WHO-sourced fact should immediately spawn this reply. In general, the WHO gets more right than they get wrong. I’m critical of the WHO too but I don’t think it’s productive to make this kind of left turn in this kind of thread. Do you have any data that suggests the specific WHO-sourced claim in this thread and on this topic is not accurate? Otherwise it’s just ad hominem, which is noise. Let’s put it another way: There is no currently available evidence of airborne spread of ncov. That’s a fact regardless of whether the WHO says it or not. Please remember to keep in mind that the data and the messenger are separate.
  - dannyw 6y ago
    Absolutely. While this article does not come from a well known outlet, all of the evidence presented comes from peer-reviewed studies, universities, and organisations like the International Laboratory for Air Quality and Health: > The frustration lies with the fact that WHO is clinging to a 90-year-old medical dogma. The droplet dogma, articulated by William Wells in 1930 for tuberculosis, holds that contagion is largely limited to the distance covered by droplets that are larger than five to 10 microns in size. > Several types of studies now challenge that view. > A 2003 paper in The New England Journal of Medicine documented a flight in which one SARS case led to 16 possible infections – eight of whom were sitting within three rows of the symptomatic patient. Another study the same year suggested SARS transmission through an air shaft in a housing complex in Hong Kong. https://australiascience.tv/is-covid-19-airborne-dont-know-but-should-probably-assume-it-is/ https://australiascience.tv/is-covid-19-airborne-dont-know-b... Another scientific article directly on the airbourneness of COVID19: https://www.sciencedirect.com/science/article/pii/S016041202031254X https://www.sciencedirect.com/science/article/pii/S016041202... As an anecdotal evidence, I'd like to point to the Diamond Princess cruise ship. Infections continued to grow on the lockdowned cruise ship, where meals were individually delivered and people weren't allowed out of their rooms except for brief exercise with no contact. How could so many people have been infected if COVID19 is not airbourne? Air recirculation is a prime suspect. My view is that it is not reasonable to adopt a position that COVID19 is not airborne; and the position taken by the WHO should be discounted (not that we should always take the opposite of WHO; but that should NOT be the end of it given all the failures they have had to date).
brianchu 6y ago
The WHO is no longer a trustworthy source. But this is still (mostly) correct, and it's not that hard to dive into the studies directly instead of appealing to authorities. All indications are that it is possible for SARS-Cov-2 to be airborne but it is rare. The main study from Wuhan that people cite for airborne SARS-Cov-2 only found high levels of airborne SARS-Cov-2 in poorly ventilated areas of a hospital setting (where certain medical procedures like intubation are known to generate aerosols): https://www.nature.com/articles/s41586-020-2271-3 https://www.nature.com/articles/s41586-020-2271-3. Well-ventilated areas had very low levels. A separate study in Singapore found no airborne samples in a hospital setting (https://jamanetwork.com/journals/jama/fullarticle/2762692 https://jamanetwork.com/journals/jama/fullarticle/2762692). Documented spreading events are consistent with the disease not being aerosolized (one example: https://twitter.com/zeynep/status/1251556084424347649 https://twitter.com/zeynep/status/1251556084424347649).
mannykannot 6y ago
I am willing to be pursuaded, but the quote you have given us contains the caveat "at distances longer than 1 meter", while, in the scenario being discussed here, distances of less than one meter are relevant. The quote also presents its case as 'absence of evidence' rather than 'evidence of absence'. In the early (and not-so-early) pronouncements about HIV/AIDS, there were a number of significantly harmful false claims (notably, about it not being transmissible heterosexually) being made by health organizations as a result of confusing the former for the latter. Also, let's take a look at the text surrounding these quotes [my emphasis]: "In all other contexts [i.e. other than the experimental setup being discussed], available evidence indicates that COVID-19 virus is transmitted during close contact through respiratory droplets (such as coughing) and by fomites. ... "As such, WHO continues to recommend that everyone performs hand hygiene frequently, follows respiratory etiquette recommendations and regularly clean and disinfect surfaces. WHO also continues to recommend the importance of maintaining physical distances and avoiding people with fever or respiratory symptoms. These preventive measures will limit viral transmission." The quotes have been taken from a passage discussing the significance of a specific experiment.

lxmorj 6y ago

It's surely not worthless. The air is filtered, the concentration of cough droplets drops off rapidly with distance (inverse cube, I'd guess).

sneak 6y ago

The idea that cabin air is recirculated is a widely held myth. The plane is pressurized from the engines, and the cabin air is entirely replaced with new, fresh, outside pressurized air every few minutes. There’s a bleed valve in the tail area where it blows out.

caseyf7 6y ago
So you should want the air vent blowing on you? Most people shut them all off as soon as they sit down.
- throwaway3563 6y ago
  Those are in addition to the main AC.
- chrisseaton 6y ago
  > Most people shut them all off as soon as they sit down. Why do they do that? I leave mine of full blast the whole flight to stay cool.
  - TheSoftwareGuy 6y ago
    Personally I've always found the constant airflow starts to dry out my eyes, making it very uncomfortable
    - chrisseaton 6y ago
      Ah I just close my eyes and go to sleep on flights.
- benhurmarcel 6y ago
  Those don't matter for the ventilation, they are just additional small nozzles to the main one hidden behind the panels. Shutting them or not doesn't affect the quantity of air delivered to the zone.
bamboozled 6y ago

asdfadsfgfdda 6y ago

The cabin air is about half recirculated, half fresh air from the engines. But the recirculated air is filtered. An N95 mask can filter >95% of .3 micron particles, this cabin air filter can capture 99.9%. https://www.ptitechnologies.com/news-event/pti-announces-the-introduction-of-cabin-air-filters/ https://www.ptitechnologies.com/news-event/pti-announces-the...

always_left 6y ago
To put it in perspective, air plane air filters are almost as good as surgical rooms :)
ikeyany 6y ago
Are these in operation the entire time passengers are on the plane, or only when the engine is on?
- KMag 6y ago
  They either idle the engines / run the APU to keep air circulating the whole time, or else they pipe in fresh air. I think it's SeaTac airport where they paint a message about "Mister Pipe" or "Mister Air Pipe" right on the jetway air pipe, along with a message about how it reduces pollution by reducing engine / APU idling, ending with "Thank You, Mister [Air?] Pipe". This "pipe" allows the more efficient (and bulky / heavy) air filtration and industrial chillers in the airport to be used to supply fresh air to the plane while the jetway is extended. If this weren't the case, the plane would get very stuffy very quickly. Imagine your share of the cabin space. Now imagine yourself sealed in a cardboard box that size waiting for the plane to board. How many minutes before your cardboard box becomes unbearable? They're always pumping in fresh air while passengers are in the airplane.
  - deleted 6y ago
    [deleted]
  - ikeyany 6y ago
    But planes do get stuffy very quickly, especially when they don't turn on the engine for a long time.

shizcakes 6y ago

There was an interesting contact tracing case study where two busses took the same trip, one with a coronavirus carrier: https://www.sltrib.com/news/2020/04/24/what-you-need-know-about/ https://www.sltrib.com/news/2020/04/24/what-you-need-know-ab... (about halfway down the page)

the-dude 6y ago
Not available in the EU.

manigandham 6y ago

Air is completely renewed in airliner cabins... but this brings up a more important question of whether any of this lockdown / social distancing even works. I'm 99% sure it's completely ineffective. We breathe the same air, touch the same services, and overall interact way too much for any of this to really work against something that's supposed to be so contagious.

jobigoud 6y ago
> I'm 99% sure it's completely ineffective How do you explain the reduction in cases and deaths in Italy, Spain, France, NY?
- deleted 6y ago
  [deleted]
andybak 6y ago
> but this brings up a more important question of whether any of this lockdown / social distancing even works. > I'm 99% sure it's completely ineffective. We breathe the same air, touch the same services, and overall interact way too much for any of this to really work against something that's supposed to be so contagious. This makes no sense. Lockdown/distancing is about reducing how much we're "breathing the same air, touching the same surfaces" I've managed to avoid touching the same surfaces as a non-household member for 5 weeks or so and I'm pretty sure none of the air I've breathed has come from anywhere within 2m of anyone else. And even if it had it's all about probabilities. I've massively reduced the chance of contagion. I'm just rolling those dice a lot less often.
- manigandham 6y ago
  People are still going to work and coming back to their communities, including healthcare workers who are highly exposed. People are still going shopping, touching the same products while bringing them home. People are still getting deliveries of food and packages that have passed countless hands and surfaces. People are still walking around neighborhoods, touching gates, benches, doors, signs, tables, cars, mailboxes, etc. While I don't doubt your efforts, I do doubt how effective they are. I'm not sure why such a question is so controversial. People are messy, and we vastly underestimate our interactions with the world. EDIT: I'm reminded of the mythbusters episode about virus spread which shows just how messy we are: https://www.youtube.com/watch?v=UbQ9Kl9CqUU https://www.youtube.com/watch?v=UbQ9Kl9CqUU

Symmetry 6y ago

There's been a surprising lack of transmissions events on airplanes so far. We've even had a case of an airline steward who was a super-spreader at a party he went to but when they checked the passengers on the plane he arrived with didn't seem to have infected any of them, though he did infect other crew. From the article it seems wearing PPE when interacting with passengers was SOP so probably that's it. https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=12325198 https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&object... This couple was infected by the woman they were sitting behind https://www.theguardian.com/world/2020/mar/09/british-couple-contract-virus-on-flight-from-heathrow-to-vietnam https://www.theguardian.com/world/2020/mar/09/british-couple... And this is in contrast to other respiratory illnesses like swine flu where infected passengers have caused many other infections on a plane. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3810906/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3810906/ So it does seem that SARS-CoV-2 is really pretty droplet based and you'd not the virus doesn't say in the air long enough to circulate through the ventilation system meaningfully. You seem to mostly be in danger if someone in your row or the rows in front of or behind you talk or cough without wearing a mask.

koheripbal 6y ago
While you cite news reports of anecdotes, the truth is we have very little data one way or the other. Our best guess is that it's just the people immediately next to you ( plus any surface you touch)... but we don't have high confidence in that.
- Symmetry 6y ago
  There's actually a remarkable lack of evidence for people getting it by touching surfaces too. That doesn't mean it literally never happens but it seems to be a small fraction of cases compared to the flu. https://today.rtl.lu/news/science-and-environment/a/1498185.html https://today.rtl.lu/news/science-and-environment/a/1498185....
phyzome 6y ago
> There's been a surprising lack of transmissions events on airplanes so far. There's an unsurprising lack of data on transmission events.

bikamonki 6y ago

There is no risk avoidance in this scenario, just risk reduction. Our ability to do non-bias, rational, effective risk assessment is very poor. Hence, this and many other marketing tools work all the time.

ashtonkem 6y ago

Airplane air is less recirculated than you think. The basic mechanism for pressurizing an airplane involves basically running a scoop at the front of the plane and a valve at the back, with the difference between the two controlling the pressure. This means new air is continuously entering the front of the plane and being exhausted out the back.

benhurmarcel 6y ago
No that's not how it works at all. Compressed air is bled from the engine compressors (or 2 electric compressors in the case of the 787), cooled down using ram air, and passed into an air cycle machine that uses ram air to get the desired pressure and a slightly low temperature. Then it's mixed with filtered recirculated air (taken below the floor around the center of the cabin). Then it's distributed by zone into the whole cabin, brought up to the desired temperature by injecting hot air from the beginning of the cycle, and delivered by nozzles all along the cabin. And excess cabin air is bled out of the cabin, which maintains the right pressure. However in the case of the virus, the biggest risk arguably doesn't come from the recirculation but the nearby passengers.
- ashtonkem 6y ago
  Still, fresh air is being added continuously, which is more of the point I was going for.
refurb 6y ago
That was my understanding as well. Bleed air from the engine is fed into the cabin to maintain altitude pressure, but it’s constantly leaking out of the aircraft too.