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A paradigm shift to combat indoor respiratory infection

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Re: A paradigm shift to combat indoor respiratory infection

#21

Post by londons_explore »

_y5hn wrote: post #18
londons_explore wrote: post #13

Earlier quoted context omitted.

I would put money on COVID not happening at all if all buildings had 10 air refreshes per hour, and that air either coming from the outdoors or going through a HEPA filter. I would guess an analysis of workplace COVID rates would see a strong correlation between workplaces with and without filtration in their AC systems.

The highest infection rates are still short range though. This, combined with being a new virus would still be similar to today.

Short range could be explained by airflow rates in most buildings being near nil. Someone talks in one spot, and pathogens hang around that spot in the air for many minutes.

With say 10 air changes per hour (injecting at the ceiling and extraction at the floor), and a 3m high building, you can expect airflow downwards at about 1 cm per second. That means there is perhaps only a 30 second window for a particular pathogen to hit someone else's nose before being pulled to below face level.

It's not nil, but I think that would lower transmission rates by a sufficient factor for COVID (and many other diseases) to become extinct.

Re: A paradigm shift to combat indoor respiratory infection

#22

Post by cam_l »

londons_explore wrote: post #11
colechristensen wrote: post #8

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.

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…

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.

Re: A paradigm shift to combat indoor respiratory infection

#23

Post by bellyfullofbac »

newsbinator wrote: post #19
zargon wrote: post #9

Earlier quoted context omitted.

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-screwu...

> EARLY ONE MORNING, Linsey Marr tiptoed to her dining room table, slipped on a headset, and fired up Zoom. On her computer screen, dozens of familiar faces began to appear. She also saw a few people she didn’t know It’s really hard for me to read a WIRED article for information. I mean I realize that’s not what it’s there for but it takes forever to get into the content of the article.

Hear hear. Maybe Wired should talk about the coffee she's sipping, made from beans harvested on the south coast of Java, where there is a legend of a queen who drowned...

Re: A paradigm shift to combat indoor respiratory infection

#25

Post by ur-whale »

prof-dr-ir wrote: post #7

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…

There is a "law of unintended effects" question as well: if we were to live - and presumably grow up - in such a sanitized environment, what would happen to our immune system.

There's a sizeable chance it would be extremely weak and that'd we'd be incapable of resisting many disease on our own and therefore would become completely dependent on the air cleaning infrastructure.

Re: A paradigm shift to combat indoor respiratory infection

#26

Post by andi999 »

bellyfullofbac wrote: post #23
newsbinator wrote: post #19

Earlier quoted context omitted.

> EARLY ONE MORNING, Linsey Marr tiptoed to her dining room table, slipped on a headset, and fired up Zoom. On her computer screen, dozens of familiar faces began to appear. She also saw a few people she didn’t know It’s really hard for me to read a WIRED article for information. I mean I realize that’s not what it’s there for but it takes forever to get into the content of the article.

Hear hear. Maybe Wired should talk about the coffee she's sipping, made from beans harvested on the south coast of Java, where there is a legend of a queen who drowned...

I need more detail... what happened to the queens relatives.

Re: A paradigm shift to combat indoor respiratory infection

#27

Post by hasmanean »

londons_explore wrote: post #13
prof-dr-ir wrote: post #7

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…

I would put money on COVID not happening at all if all buildings had 10 air refreshes per hour, and that air either coming from the outdoors or going through a HEPA filter. I would guess an analysis of workplace COVID rates would see a strong correlation between workplaces with and without filtration in their AC systems.

There’s a saying, earthquakes don’t kill people—buildings kill people when they collapse.

In the open air on a grassland, covid won’t kill a population. The design of our hermetically sealed buildings is what’s killing us.

Back in the 1970s the air outside was full of lead and smog, so the safest thing too was completely seal all office buildings.

Today the air inside probably contains more hydrocarbons (from volatile organic compounds offgassing from carpets and furniture) so the best thing to do is vent air to the outside and keep the windows open (assuming you live in a mild climate)

Of course, that flies in the face of all efforts to make things green…which involve better insulation, sealing windows against leaks, more air filtration systems and etc.

Here in Canada the temperature drops like 5 or 10 degrees when you walk into a forest. I’ve stepped into a traditional mud hut and experienced a similar cooling effect. The common denominator is that both environments have a high surface area compared to say concrete. This acts as an efficient radiator so that when water to evaporates it removes heat. In low humidity climates this is one way to reduce cooling demands. Beyond that if we cool micro zones or interstate cooling into clothing itself through hoses or something that might be the next step in efficiency…until it gives birth to the next problem.

Re: A paradigm shift to combat indoor respiratory infection

#28

Post by thrdbndndn »

lostmsu wrote: post #14
shalmanese wrote: post #12

Earlier quoted context omitted.

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.

Does it? I thought energy expenditure to maintain indoor temperature is mostly due to heating/cooling, not due to moving air to or from heat exchanger. E.g. it is cheap to rotate the air in the building in a closed loop through a filter.

Yeah, I can't see how the operating cost would be much different.

I do think the initial cost to install/upgrade to such system would be substantial, though (as in, existing systems may not have the capacity to ventilate that much.)

Re: A paradigm shift to combat indoor respiratory infection

#29

Post by ddxxdd »

zargon wrote: post #9
prof-dr-ir wrote: post #7

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…

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-screwu...

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.

Re: A paradigm shift to combat indoor respiratory infection

#30

Post by c7DJTLrn »

newsbinator wrote: post #19
zargon wrote: post #9

Earlier quoted context omitted.

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-screwu...

> EARLY ONE MORNING, Linsey Marr tiptoed to her dining room table, slipped on a headset, and fired up Zoom. On her computer screen, dozens of familiar faces began to appear. She also saw a few people she didn’t know It’s really hard for me to read a WIRED article for information. I mean I realize that’s not what it’s there for but it takes forever to get into the content of the article.

Nails on chalkboard.
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