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The bottleneck might be the air in the room

blog.mikebowler.ca

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Re: The bottleneck might be the air in the room

#51

Post by KerrickStaley »

w-m wrote: post #36
Tossrock wrote: post #12

Submarines operate in the 1000s of PPM CO2 range and the sailors aboard generally do not experience any ill effects. This was tested and no deficits were found even at 15,000 PPM: https://asma.kglmeridian.com/view/journals/amhp/89/6/article...

I don't think you can cleanly compare this: In the study, they added CO2 to the room, while keeping O2 at normoxic levels throughout the experiment. In your meeting room, O2 levels will be dropping in lock-step with the CO2-levels rising. It may be the lack of oxygen that leads to drowsiness, not the additional CO2. But it's the CO2 levels that you can measure as a good proxy of overall air quality.

I don't think this is correct. The concentration of CO2 in air is about 0.04%, whereas the concentration of oxygen is 20%, so the partial pressure of oxygen is about 500x higher. This means that if, for example, 10% of the oxygen in a room spontaneously disappeared, it would be replaced about sqrt(500) = 22x faster through leaks in the room than a 10% spontaneous CO2 increase would dissipate. (This ignores a small effect due to the different density of the two gases).

So in practice the oxygen level can never drift meaningfully far from the atmospheric pressure, whereas carbon dioxide easily can because the pressures involved are so low.

Re: The bottleneck might be the air in the room

#52

Post by threatripper »

brookst wrote: post #16
Tossrock wrote: post #12

Submarines operate in the 1000s of PPM CO2 range and the sailors aboard generally do not experience any ill effects. This was tested and no deficits were found even at 15,000 PPM: https://asma.kglmeridian.com/view/journals/amhp/89/6/article...

Though that study included a 45 minute acclimation period. Appropriate for submarines, but I wonder what the results would be in the first 1 / 5 / 10 minutes.

CO2 levels will rise much more slowly to such high levels even in a small room.

Re: The bottleneck might be the air in the room

#53

Post by hahahaa »

sixtyj wrote: post #5
kennywinker wrote: post #2

> You gather your most expensive people into a room to make your most important decisions. A terrible way to make decisions.

What should be a better way?

Make them mostly async, bringly only the very pointy details that need nutting down sync. If knowledge transfer is needed in a meeting that could be done seperately.

Put it this way do you need to book a 3h meeting with your spouse to decide if to buy a house? Nope all the research and decision criteria were in advance. That final minute of making the decision is a cross check over that work.

Re: The bottleneck might be the air in the room

#54

Post by ErroneousBosh »

Terr_ wrote: post #42
scoot wrote: post #18

Earlier quoted context omitted.

Apple watches already have a blood-oxygen sensor so it's covered, albeit indirectly.

I don't think that's safe to assume at all, for two reasons: 1. CO2 has effects on the human body of its own that aren't simply a lack of oxygen, and vice-versa. [0] 2. The baseline proportions involved aren't close, so even doubling CO2 isn't going to show up easily as a large swing in in oxygen%. For example, the article references a study where the CO2 proportion going from 0.04% -to 0.25% correlates to mental pro…

> The article references a study where the CO2 proportion going from 0.04% -to 0.25% causes mental problems. In other words, a difference in 0.21% of the air.

I'm finding that pretty difficult to believe, to be quite honest with you.

And before you say "aha, carbon dioxide brain fog!" consider that I'm about a mile from the sea with a 40mph onshore breeze. This air is about as oxygenated as it gets.

Re: The bottleneck might be the air in the room

#55

Post by fer »

eitau_1 wrote: post #49

Can someone provide an explanation why CO2 concentrations above 1000 ppm have such a negative influence given the fact that CO2 concentration in lungs (at rest) never falls below 10000 ppm?

It simply makes the baseline higher. If you want to go to extreme cases, check carbogen

https://en.wikipedia.org/wiki/Carbogen

Re: The bottleneck might be the air in the room

#56

Post by aaron695 »

gpt5 wrote: post #6

I really wish a Apple or another major OEM would integrate CO2 monitor into watches or smartphones. Suddenly, everybody would be aware of the CO2 level in the room, get alerts, etc. and the problem will just solve itself. There are so many rooms, classrooms, movie theaters and other places with poor ventilation where you just feel dizzy, or fall asleep, not knowing it was just due to lower oxygen levels in your blood…

[dead]

Re: The bottleneck might be the air in the room

#57

Post by p-e-w »

Gigachad wrote: post #37
legulere wrote: post #33

Earlier quoted context omitted.

I guess the problem is with the price of the sensors. Just look how expensive the Aranet 4 home shown in article is. There are worse devices for less like the IKEA alpstuga. I also don’t know how much electricity they pull.

I got the ikea sensor, I’d say it’s way more accurate than you need for personal use. I wouldn’t use it as a scientific instrument but it’s well good enough to see if the room is ventilated enough. I was shocked to see just how fast CO2 climbs while in a room, and how just opening the window just a crack was enough to restore the room to baseline co2. The thing runs on usb 5v so the power consumption is negligible. I…

> The thing runs on usb 5v so the power consumption is negligible.

There’s a huge leap from that to the power consumption being low enough to be integrated into a smartphone, as demanded by OP.

Re: The bottleneck might be the air in the room

#58

Post by sohpea »

A reasonably popular brand's product that uses an NDIR sensor revealed to me just how much the CO2 level increases each night in my two bedrooms.

One of them seems to have much worse ventilation to the extent that it reaches double the level. Opening the window slightly 24/7 keeps it low.

My fiance's chronic headaches/migraines/idk became noticeably less frequent after this change and when they do occur it's usually because the window was accidentally left closed.

Anybody who struggles with this kind of thing might want to try checking their levels. Or just open a window I guess?

Re: The bottleneck might be the air in the room

#59

Post by kashishgrover »

ErroneousBosh wrote: post #50
kashishgrover wrote: post #27

Oh this is absolutely so relevant and I wonder if there are any high quality studies that have analyzed driving performance against CO2 buildup in cars. Cars often ship with circulate air feature in the aircon, and people use it aggressively, nonchalantly at least where I live, having no idea about the dangers of possible hypoxia and sleepiness that might be inducing in them while driving. It is absolutely critical i…

Cars are not sufficiently sealed for that to make any kind of a difference.

Try it yourself. They really are

Re: The bottleneck might be the air in the room

#60

Post by Terr_ »

ErroneousBosh wrote: post #54
Terr_ wrote: post #42

Earlier quoted context omitted.

I don't think that's safe to assume at all, for two reasons: 1. CO2 has effects on the human body of its own that aren't simply a lack of oxygen, and vice-versa. [0] 2. The baseline proportions involved aren't close, so even doubling CO2 isn't going to show up easily as a large swing in in oxygen%. For example, the article references a study where the CO2 proportion going from 0.04% -to 0.25% correlates to mental pro…

> The article references a study where the CO2 proportion going from 0.04% -to 0.25% causes mental problems. In other words, a difference in 0.21% of the air. I'm finding that pretty difficult to believe, to be quite honest with you. And before you say "aha, carbon dioxide brain fog!" consider that I'm about a mile from the sea with a 40mph onshore breeze. This air is about as oxygenated as it gets.

1% (10,000 ppm) is enough for the person to become aware something is odd through drowsiness or an elevated heart rate.

I don't think it's too far-fetched for a quarter of that to cause subconscious cognitive effects, that could be measured in tests.

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