18 ms·

A paradigm shift to combat indoor respiratory infection

147 points by edward 5y ago

sebmellen 5y ago
So the idea is to make every room a negative pressure room of sorts? I think this is probably long overdue, but I'm afraid I don't really see the paradigm shift. Haven't all of these steps been taken on airplanes already, to some extent? From what I see, the "personalized ventilation" idea is substantially similar to what aircraft ventilation does, just adapted for a workspace/building setting.
- skohan 5y ago
  What would be the cost implications of this? I assume we're talking about a massive energy requirement/climate impact to implement this for all public indoor spaces.
- mjevans 5y ago
  It's more important to think about FLOW and also the quality of air exiting an air-handling system. BTW, how often are those ducts cleaned, if ever? I would personally love a well designed slightly positive pressure dwelling with particle scrubbed inflow and egress (some kind of circulated water system like industrial sites have). Get rid of that pollen and everything else please.
  - sebmellen 5y ago
    There's an interesting system called "Phenomenal Aire" that I recently installed. It sort of achieves what you're talking about, but uses a very different mechanism called "Cold Plasma Generation" (caused by dielectric barrier discharge). The air smells noticeably "fresher" though that might just be due to the ozone. It does seem to have a dramatic neutralizing effect on VOCs [0]. Interesting article re: use in meat packing plants [1]. [0]: https://www.sciencedirect.com/science/article/abs/pii/S0308814621004088 https://www.sciencedirect.com/science/article/abs/pii/S03088... [1]: https://pubmed.ncbi.nlm.nih.gov/33876887/ https://pubmed.ncbi.nlm.nih.gov/33876887/
    - sgerenser 5y ago
      Isn’t ozone supposed to be very detrimental to indoor air quality though?
      - TheAdamAndChe 5y ago
        It is. It's a strong oxidizer and damages your lungs. It makes the house smell better because it oxidizes volatile organic compounds in the air, but it's horrible for you.
      - goldenkey 5y ago
        It's an extremely strong oxidizer. It will poke holes in your lungs. But sure, it'll also oxidize the other crap in your air.
edward 5y ago
Also here: https://science.sciencemag.org/content/372/6543/689 https://science.sciencemag.org/content/372/6543/689
breck 5y ago
What a good read. Shame on the authors for putting such an important article behind a paywall. Thanks someone for filesharing it. #AbolishCopyrights #AbolishPatents #EndIntellectualStupidity
prof-dr-ir 5y ago
From the article: "It is not known exactly what fraction of infections could be prevented if all building and transport ventilation systems on the planet were ideal (in terms of controlling airborne infections), or the cost of design and retrofitting to make them ideal." I think this is the key question. Surely better ventilation would have prevented some infections in the covid pandemic. But how many? And to decide that we need not just manifestos by civil engineers (like this article) but convincing research results, probably in collaboration with people who actually know some things about viruses as well. And without it, could organizations like the WHO or CDC have plausibly recommended building upgrades?
- zargon 5y ago
  The WHO and CDC have had their head in the sand for 60 years when it comes to airborne pathogens. They have only acknowledged aerosol transmission of covid in the last couple weeks. It was physicists who had to figure out why they were domatically denying reality. https://www.wired.com/story/the-teeny-tiny-scientific-screwup-that-helped-covid-kill/ https://www.wired.com/story/the-teeny-tiny-scientific-screwu...
  - ddxxdd 5y ago
    Apparently the CDC has yet to catch up to 19th century physics. The physics of small particles moving in the air ("Brownian motion") was completely figured out by Einstein back in 1905. Given a virus' size and weight, it should be trivial for a physics graduate student to simulate how long it will be airborne.
    - techdragon 5y ago
      The thing about medicine is they like to test. Theory and simulation are nice but it’s just not medicine and therefore not suitable for a doctor to tell to someone as “medical advice” with all of the legal burden of malpractice that the term entails. “What if I’m wrong?” is a question that keeps good doctors awake at night and bad doctors have forgotten to ask themselves… when this kind of question weighs on you, it’s natural human behaviour to become more cautious, to become risk averse and question the validity of newly presented information due to the potential that regardless of if their current understanding is wrong, there’s no inherent guarantee that the new information is any less wrong. And so medicine is understandably a slow moving science, and the practice of medicine moves even slower as it represents the slow filtration of the cutting edge of medicine the science, through a complex web of human interaction. Which with a dash of “social capital” theory, makes it easy to see why we have unfortunately often ignored sound advice like this. The mistaken assumptions of people viewing a person who’s expertise bridges two disparate fields, as being unable to understand things as deeply, clearly or fully, as the people dedicated to just one of those fields.
colechristensen 5y ago
It seems overly complicated. Just raise the air exchange per person and or per volume by a significant factor and mandate a very fine particulate filter. You could do many measurements and lots of theory but nobody is going to engineer their buildings like cleanrooms anyway so the results of a lot of science wouldn’t be so good regardless.
- londons_explore 5y ago
  I'd like to see "air quality inspection" be part of a fire safety inspection. Just have the inspector crack out a CO2 and PM2.5 meter during the inspection. Set legal limits and have a fee for exceeding them. Make it apply to existing buildings too, so building owners can choose to trade off increased HVAC costs Vs reducing the fee Vs costs of retrofitting better ventilation. Obviously the measured numbers vary a lot day to day, so if a building owner isn't happy with values measured on the day, let them take an average over a week or something.
  - cam_l 5y ago
    Agree and love the idea about testing.. there are no other inspectors (in oz at least) as incorruptible as fire safety inspectors. I had the experience a couple of years ago of working in an office with visible smoke from a meat smoker working downstairs. The owner and employer had 'independent' tests done with no issue found. Fuckers. I do reckon there is a rather disgustingly unequal relationship between people that own or build a building and people that have to deal with sickness from working in a building. Overwhelmingly, upfront costs for systems which prioritise airchange, occupant health, and energy savings are more expensive to install but cheaper in the long run.
- shalmanese 5y ago
  That has significant costs on the energy efficiency of buildings and would blunt a lot of the progress we're making on combating climate change. Not saying it shouldn't be done but it should be done in a smart way that balances between tradeoffs.
  - 5y ago
fiachamp 5y ago
dont need all this complexity to prevent airborne illness from going exponential, just masks + contact tracing. the results have spoken for themselves in asia
chiefalchemist 5y ago
Overall air quality is an issue. We "consume" more air than anything else. Every day. All day. Day after day. Pathogens are a concern. But conditions and elements that have negative impact on the lungs - and help prime such tissue for invaders and disease - should be addressed as well.
- x3iv130f 5y ago
  I find it regrettable that the things we eat and drink get so much more attention than the air we breathe in regards to health.
  - chiefalchemist 5y ago
    It's funny (not) cause bad air is a known killer. Yet it gets crickets. I'd add noise to that list as well. Something we should be more aware of.
mhb 5y ago
Sounds swell. Have we started rebuilding our stockpile of N95 masks yet?
- auxym 5y ago
  From industrial suppliers, they are available but about 20X more expensive than pre pandemic. We used to buy boxes of 160 count 3M 8210 for 20$ CAD.
deleted 5y ago
[deleted]
N5Air 5y ago
At https://n5air.com/ https://n5air.com/ we are formulating a quantitative "VIRUS INFECTION THRESHOLD" theory while fully recognizing it may already exist. Any leads? Also, is there a way to share its outline in a PDF file? Lev
renaudg 5y ago
Here's a fascinating Twitter thread about the history of aerosol transmission denial in the medical community, going back to the early 20th century : https://twitter.com/jljcolorado/status/1391111720526024708?s=20 https://twitter.com/jljcolorado/status/1391111720526024708?s... (It's 100 tweets long, here's a more readable version : https://threadreaderapp.com/thread/1391111720526024708.html https://threadreaderapp.com/thread/1391111720526024708.html) The tl;dr is that 20th century health authorities went too far in their rejection of the 19th century "miasma" theory of disease transmission, and now the pendulum is swinging back again.
Huiokko 5y ago
I thought about something like this for the last 10 years when taking public transport. It came again into my mind when I heard about tesla's biohazard filter system. It's just ridiculous how we accept the status quo. It can't be okay to be sick every year for 5-12 days and covid showed me no I don't have to be sick every year and don't get me wrong, clearly I'm not getting better in fighting this shit of if I have it every fucki g year. What are long-term effects of being sick every year?
rurban 5y ago
No more open office plans? Managers are not rational enough, sorry.
throwawaysea 5y ago
You could also use a decidedly low tech solution - putting UV bulbs in the way of air flow (like fans): https://www.cnet.com/home/smart-home/uv-light-and-the-coronavirus-big-ass-fans-might-have-a-solution-haiku-uvc-covid-19/ https://www.cnet.com/home/smart-home/uv-light-and-the-corona...

147 points by edward 5y ago

So the idea is to make every room a negative pressure room of sorts? I think this is probably long overdue, but I'm afraid I don't really see the paradigm shift. Haven't all of these steps been taken on airplanes already, to some extent? From what I see, the "personalized ventilation" idea is substantially similar to what aircraft ventilation does, just adapted for a workspace/building setting.

skohan 5y ago
What would be the cost implications of this? I assume we're talking about a massive energy requirement/climate impact to implement this for all public indoor spaces.
mjevans 5y ago
It's more important to think about FLOW and also the quality of air exiting an air-handling system. BTW, how often are those ducts cleaned, if ever? I would personally love a well designed slightly positive pressure dwelling with particle scrubbed inflow and egress (some kind of circulated water system like industrial sites have). Get rid of that pollen and everything else please.
- sebmellen 5y ago
  There's an interesting system called "Phenomenal Aire" that I recently installed. It sort of achieves what you're talking about, but uses a very different mechanism called "Cold Plasma Generation" (caused by dielectric barrier discharge). The air smells noticeably "fresher" though that might just be due to the ozone. It does seem to have a dramatic neutralizing effect on VOCs [0]. Interesting article re: use in meat packing plants [1]. [0]: https://www.sciencedirect.com/science/article/abs/pii/S0308814621004088 https://www.sciencedirect.com/science/article/abs/pii/S03088... [1]: https://pubmed.ncbi.nlm.nih.gov/33876887/ https://pubmed.ncbi.nlm.nih.gov/33876887/
  - sgerenser 5y ago
    Isn’t ozone supposed to be very detrimental to indoor air quality though?
    - TheAdamAndChe 5y ago
      It is. It's a strong oxidizer and damages your lungs. It makes the house smell better because it oxidizes volatile organic compounds in the air, but it's horrible for you.
    - goldenkey 5y ago
      It's an extremely strong oxidizer. It will poke holes in your lungs. But sure, it'll also oxidize the other crap in your air.

edward 5y ago

Also here: https://science.sciencemag.org/content/372/6543/689 https://science.sciencemag.org/content/372/6543/689

breck 5y ago

What a good read. Shame on the authors for putting such an important article behind a paywall. Thanks someone for filesharing it. #AbolishCopyrights #AbolishPatents #EndIntellectualStupidity

prof-dr-ir 5y ago

From the article: "It is not known exactly what fraction of infections could be prevented if all building and transport ventilation systems on the planet were ideal (in terms of controlling airborne infections), or the cost of design and retrofitting to make them ideal." I think this is the key question. Surely better ventilation would have prevented some infections in the covid pandemic. But how many? And to decide that we need not just manifestos by civil engineers (like this article) but convincing research results, probably in collaboration with people who actually know some things about viruses as well. And without it, could organizations like the WHO or CDC have plausibly recommended building upgrades?

zargon 5y ago
The WHO and CDC have had their head in the sand for 60 years when it comes to airborne pathogens. They have only acknowledged aerosol transmission of covid in the last couple weeks. It was physicists who had to figure out why they were domatically denying reality. https://www.wired.com/story/the-teeny-tiny-scientific-screwup-that-helped-covid-kill/ https://www.wired.com/story/the-teeny-tiny-scientific-screwu...
- ddxxdd 5y ago
  Apparently the CDC has yet to catch up to 19th century physics. The physics of small particles moving in the air ("Brownian motion") was completely figured out by Einstein back in 1905. Given a virus' size and weight, it should be trivial for a physics graduate student to simulate how long it will be airborne.
  - techdragon 5y ago
    The thing about medicine is they like to test. Theory and simulation are nice but it’s just not medicine and therefore not suitable for a doctor to tell to someone as “medical advice” with all of the legal burden of malpractice that the term entails. “What if I’m wrong?” is a question that keeps good doctors awake at night and bad doctors have forgotten to ask themselves… when this kind of question weighs on you, it’s natural human behaviour to become more cautious, to become risk averse and question the validity of newly presented information due to the potential that regardless of if their current understanding is wrong, there’s no inherent guarantee that the new information is any less wrong. And so medicine is understandably a slow moving science, and the practice of medicine moves even slower as it represents the slow filtration of the cutting edge of medicine the science, through a complex web of human interaction. Which with a dash of “social capital” theory, makes it easy to see why we have unfortunately often ignored sound advice like this. The mistaken assumptions of people viewing a person who’s expertise bridges two disparate fields, as being unable to understand things as deeply, clearly or fully, as the people dedicated to just one of those fields.

colechristensen 5y ago

It seems overly complicated. Just raise the air exchange per person and or per volume by a significant factor and mandate a very fine particulate filter. You could do many measurements and lots of theory but nobody is going to engineer their buildings like cleanrooms anyway so the results of a lot of science wouldn’t be so good regardless.

londons_explore 5y ago
I'd like to see "air quality inspection" be part of a fire safety inspection. Just have the inspector crack out a CO2 and PM2.5 meter during the inspection. Set legal limits and have a fee for exceeding them. Make it apply to existing buildings too, so building owners can choose to trade off increased HVAC costs Vs reducing the fee Vs costs of retrofitting better ventilation. Obviously the measured numbers vary a lot day to day, so if a building owner isn't happy with values measured on the day, let them take an average over a week or something.
- cam_l 5y ago
  Agree and love the idea about testing.. there are no other inspectors (in oz at least) as incorruptible as fire safety inspectors. I had the experience a couple of years ago of working in an office with visible smoke from a meat smoker working downstairs. The owner and employer had 'independent' tests done with no issue found. Fuckers. I do reckon there is a rather disgustingly unequal relationship between people that own or build a building and people that have to deal with sickness from working in a building. Overwhelmingly, upfront costs for systems which prioritise airchange, occupant health, and energy savings are more expensive to install but cheaper in the long run.
shalmanese 5y ago
That has significant costs on the energy efficiency of buildings and would blunt a lot of the progress we're making on combating climate change. Not saying it shouldn't be done but it should be done in a smart way that balances between tradeoffs.
- 5y ago

fiachamp 5y ago

dont need all this complexity to prevent airborne illness from going exponential, just masks + contact tracing. the results have spoken for themselves in asia

chiefalchemist 5y ago

Overall air quality is an issue. We "consume" more air than anything else. Every day. All day. Day after day. Pathogens are a concern. But conditions and elements that have negative impact on the lungs - and help prime such tissue for invaders and disease - should be addressed as well.

x3iv130f 5y ago
I find it regrettable that the things we eat and drink get so much more attention than the air we breathe in regards to health.
- chiefalchemist 5y ago
  It's funny (not) cause bad air is a known killer. Yet it gets crickets. I'd add noise to that list as well. Something we should be more aware of.

mhb 5y ago

Sounds swell. Have we started rebuilding our stockpile of N95 masks yet?

auxym 5y ago
From industrial suppliers, they are available but about 20X more expensive than pre pandemic. We used to buy boxes of 160 count 3M 8210 for 20$ CAD.

deleted 5y ago

[deleted]

N5Air 5y ago

At https://n5air.com/ https://n5air.com/ we are formulating a quantitative "VIRUS INFECTION THRESHOLD" theory while fully recognizing it may already exist. Any leads? Also, is there a way to share its outline in a PDF file? Lev

renaudg 5y ago

Here's a fascinating Twitter thread about the history of aerosol transmission denial in the medical community, going back to the early 20th century : https://twitter.com/jljcolorado/status/1391111720526024708?s=20 https://twitter.com/jljcolorado/status/1391111720526024708?s... (It's 100 tweets long, here's a more readable version : https://threadreaderapp.com/thread/1391111720526024708.html https://threadreaderapp.com/thread/1391111720526024708.html) The tl;dr is that 20th century health authorities went too far in their rejection of the 19th century "miasma" theory of disease transmission, and now the pendulum is swinging back again.

Huiokko 5y ago

I thought about something like this for the last 10 years when taking public transport. It came again into my mind when I heard about tesla's biohazard filter system. It's just ridiculous how we accept the status quo. It can't be okay to be sick every year for 5-12 days and covid showed me no I don't have to be sick every year and don't get me wrong, clearly I'm not getting better in fighting this shit of if I have it every fucki g year. What are long-term effects of being sick every year?

rurban 5y ago

No more open office plans? Managers are not rational enough, sorry.

throwawaysea 5y ago

You could also use a decidedly low tech solution - putting UV bulbs in the way of air flow (like fans): https://www.cnet.com/home/smart-home/uv-light-and-the-coronavirus-big-ass-fans-might-have-a-solution-haiku-uvc-covid-19/ https://www.cnet.com/home/smart-home/uv-light-and-the-corona...