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"
I know they will screen for symptoms but this has to be "health theatre"
https://www.ptitechnologies.com/news-event/pti-announces-the...
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.
Large commercial buildings and aircraft have them. More expensive cars, sometimes. For homes, I think most people don't have it. However, I imagine it might be more popular in some colder areas with central A/C units.
I have purchased two Philips purifiers...
In October, I bought the AC3259. We use it in the bedroom. It's great, and you can use the Air Matters application on your phone to see how the air quality of your place is. At the end of March, I bought the Philips AC3829/10. It's a purifier + humidifier unit and is more practical, and I use it in the living room.
Our apartment is only about 78 square meters, so using both is a little overkill, but we have a fluffy dog, so definitely, it's making a difference to our health.
We (two people + dog) spent most of the time in the living room these days, and we have to clean the purifier in the bedroom every day, but the one in the living room only about a week or so.
I'd recommend getting a large purifier with a HEPA filter to anyone concerned about their health these days.
1. There is no way you’re getting a right seal all the way through the purifier because if you did it would cost orders of magnitude more. So there is air being sucked in around the filter and along the way that mixes with the filtered air
2. I seem to remember virus (and smells or VOCs) are way too small to be caught by a hepa filter so they just float right through
3. Some filters have a uv light in them. But they’re inefficient because not all the air is exposed, the exposition duration is too short, and it generates ozone as a side effect (probably not great to breath in large quantities)
4. They do an ok job at catching dust particles for allergy sufferers and some of the pollen
Orders of magnitude more? Are we talking about the same category of products?
What is your source saying HEPA filter doesn't filter viruses? Do you any data to back up your claims?
Regarding UV light, I agree that it might not be too effective... (but I had a great experience with using one on my aquarium a long time ago).
Whatever you think of the wirecutter’s picks and impartiality or lack thereof, I find the parts where they explain what matters in any given product category and how they picked helpful in educating myself.
I see they recently updated this particular one in light of the virus (I read this article a few years ago and there were no coronavirus concerns then)
2. HEPA filters and various other filter media claim to filter viruses. So I think your recollection is incorrect. See: https://www.epa.gov/indoor-air-quality-iaq/what-merv-rating-...
https://smartairfilters.com/en/blog/what-is-the-best-air-pur...
I own a mid-level, optical based counter and even it drifts without regular calibration.
I'd want to see citations showing that (absent serious allergies) there's any health benefit to "purified" air.
Not only do I have trouble seeing normal ambient air (like with my windows open) as a problem, but there is some reason to think that "impurities" may be beneficial, to a degree. For example, there are some studies showing that peanut allergies may be caused by failure to expose kids to allergens early-on. And others showing that giving your immune system something constructive to do can (a) help keep it strong (this evidence is probably weaker); and (b) help with some auto-immune disorders.
I don't say you're wrong, and I don't have anything against being out in the open, but not everyone lives in the middle of nowhere with good air quality (besides things such as allergies, dog fur all around, etc.).
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...
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/
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.
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.
https://today.rtl.lu/news/science-and-environment/a/1498185....
There's an unsurprising lack of data on transmission events.
https://www.kaggle.com/nhntran/vietnam-covid19-patient-datas...
Dataset collector's writeup: https://towardsdatascience.com/covid-19-what-do-we-know-abou...
https://wwwnc.cdc.gov/eid/article/26/7/20-0764_article
visual of transmission through air conditioning:
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.
Why do they do that? I leave mine of full blast the whole flight to stay cool.
Air comes in ducts, air goes out ducts. You get fresh air. Both the fresh fraction and the recycled fraction are HEPA filtered.
Edit: another comment here says the mean replacement time for air in an airliner is 4 to 5 minutes with a recirculating ratio of about 50%. I'm not sure if that's right, but it feels about right. Imagine your share of the space in the cabin. Think how long you could sit in a sealed cardboard box that size before the CO2 levels started making it feel stuffy. The airliners aren't carrying around hundreds or thousands of kg of lithium hydroxide to scrub the CO2. They're just dumping stale air overboard.
The recirculated air is filtered, so viruses and bacteria are not really a problem. What recirculation brings is better airflow and humidity.
On a plane, the outside air is incredibly cold and dry. The cold is not a problem: air is heated by the engines before it enters the cabin. Humidifying the air would be a problem however as it would require heavy humidifiers and water tanks.
The idea that 100% of the air is recirculated is obviously wrong, we would all die of hypoxia it it was.
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/situati...
[1]: https://www.sciencemag.org/news/2020/03/not-wearing-masks-pr...
[2]: https://www.who.int/news-room/articles-detail/updated-who-re...
[3]: https://reason.com/2020/04/26/world-health-organization-twee...
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-prepar...
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.
> 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-b...
Another scientific article directly on the airbourneness of COVID19: 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).
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. 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). Documented spreading events are consistent with the disease not being aerosolized (one example: https://twitter.com/zeynep/status/1251556084424347649).
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.
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.
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.
How do you explain the reduction in cases and deaths in Italy, Spain, France, NY?
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.
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
Norway has used lockdown and social distancing as the primary tool to fight COVID-19. On March the 12th we entered lockdown[1].
You can see the results on this page[2], where we clearly peaked at the end of March.
In the capital, certain groups are disproportionally infected by the virus[3]. In particular immigrants which does not understand Norwegian very well and come from cultures where visiting people, especially sick ones, is socially important.
These people are far less likely to have read about and understood the importance of social distancing, as information in their native language was lacking in the early stages[4].
[1]: https://www.nrk.no/norge/na-stenger-norge-1.14941623
[2]: https://www.nrk.no/korona/status/
[3]: https://www.fhi.no/nyheter/2020/status-koronasmitte-onsdag-1...
[4]: https://www.nrk.no/norge/smittevernoverlege-i-oslo_-_-meir-n...
It's pretty disingenuous to say this when the link only lists one group that they felt the need to make specific outreach to. Your link states that in general they are not seeing over-representation from people born outside of Norway.
Norway has also tested less than 3.7% of it's residents - we know they've done less than 200k tests, and we don't know how many people have been tested more than once, so it may be significantly less, so we really don't know how many people have had the virus or still have it.
Was a bit hasty with my attribution. See my [4] for more relevant quotes.
There are still precautions to take especially when touching surfaces, because the fallen droplets can then transfer onto the skin, and then later into the lungs when we touch our mouth, nose or eyes. But social distancing absolutely works in order to prevent the primary transfer of droplets from face to face through the air.
That is not a lockdown.
I haven't left my house for two weeks apart from a few small excursions where I stayed at least two meters away from everyone, while wearing a cloth mask. That is a lockdown.
Without lockdown, the daily increases in cases & deaths showed a doubling rate of every 3-4 days, sometimes faster. This is also what was reported in Italy earlier in the crisis.
Now, the doubling days in the locked down areas consistently exceeds 25 dsys.
This is not subtle, it is blatantly empirically obvious in the data. No need for theorizing.
I mention that the lockdown may be insufficient, or insufficiently implemented because the growth factor is still on a plateau generally exceeding 1.0,which means that we still have a net spreading, or positive growth rate, i.e., it is not yet being extinguished, only slowed.
So we will need to do more. From looking at other results, that will involve ubiquitous masks, glasses, gloves ang overwhelming program of testing, tracking, & targeted isolation.
Meanwhile, another MIT study (iirc) showed the effects of minor lockdown violations. With full isolation the societal exposure is limited to the essentworkets and their families, about 26% of the population. But if only one household member goes visiting others, the societal exposure increases to 90%++. Just a little casual 'it's no big deal' attitude screws up the whole thing.
Stay well out there, folks.
However, looking at the data, the death rate is only increasing; recent weekly series starting 06-April is: 3.0%, 4.1%, 5.4%, 5.7%, to 5.8% yesterday. This is actually low, since today's case count is the wrong denominator, as it has a certain amount of deaths built-in but not counted and this is still in a growth phase. Using [deaths]/[cases_on_day_-7] produces the most consistent numbers for a death rate of about 7.1%.
Neither the changes in contagion rate nor death rate, even with the half-baked lockdowns, even approximate support for your contention that lockdowns do not work.
They in fact support the opposite conclusion, even half-baked measures reduce the spread, and better measures would be better. The best are proper full testing coverage, tracking, and targeted isolation, as implemented well by South Korea.
As to your contention about the contagiousness, it is known that it is not nearly contagious as, say Measles, but is more contagious than Flu.