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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

#221

Post by mathgeek »

lelanthran wrote: post #181
noja wrote: post #145

Earlier quoted context omitted.

I don’t think we actually care about co2 levels. I think we use them as a proxy for o2 levels (same as our bodies do). So your idea would be great.

> I think we use them as a proxy for o2 levels (same as our bodies do). Probably. ISTR that depriving a body of oxygen results in a different response than overloading the body on CO2. It's why if you completely displace all air in the room with CO2, people choke, panic, etc, but if you use Nitrogen, people just keel over dead without realising it.

The evolved response to CO2 is part of the human body’s ability to filter and remove CO2 via the respiratory system. AFAIK we don’t have similar capacity for Nitrogen because it’s not a primary waste product of that system.

Re: The bottleneck might be the air in the room

#223

Post by Scroll_Swe »

microtonal wrote: post #111
nok22kon wrote: post #109

Earlier quoted context omitted.

if you just want to know if CO2 is too much, 300ppm precision is fine. I dont need to know the exact level, just give me a green/yellow/red LED and make it cheap so I can have a sensor in every room

No, it's not. You generally want to ventilate an office when you reach 1000ppm, but then the IKEA will often warn you already at 700ppm. 700ppm is fine.

But if I open a window at 700ppm, so what?

Re: The bottleneck might be the air in the room

#224

Post by foobarbecue »

vintermann wrote: post #183
noja wrote: post #145

Earlier quoted context omitted.

I don’t think we actually care about co2 levels. I think we use them as a proxy for o2 levels (same as our bodies do). So your idea would be great.

I'm pretty sure that in a room where we replaced nitrogen with co2, we would be dead even if O2 concentrations were the same. Something about partial pressure. I notice AI explanations agree with me (not going to copy and paste them).

EDIT: ignore this; I was confused / misinformed

It's about pH. CO2 creates carbonic acid when it dissolves in water. Your blood pH, in turn, controls how much you feel like you need to breathe. So with high CO2, your respiration rate slows down, and that can lead to low oxygen levels.

Note that the physiology and biochemistry of this is complicated (e.g. blood is a very good pH buffer and it's actively regulated by kidneys etc) and it's very much a nascent field of research, so I think AI will be overconfident and hallucination-prone.

Source: I worked in high-co2 caves for my PhD so have read about this a lot. I always carried a CO2 monitor. Our rule was to get out if we saw 20,000 ppm or greater. I spent thousands of hours above 10,000ppm.

Re: The bottleneck might be the air in the room

#225

Post by bhouston »

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…

There is one in the EcoBee Premium and we use it to automatically drive our HRV (heat recovery ventilation.).

It is better to have it in the HVAC system than in your phone anyhow:

https://ben3d.ca/blog/upgrading-hvac-control

Re: The bottleneck might be the air in the room

#226

Post by xg15 »

deanc wrote: post #13

I’m not saying this isn’t a legitimate concern but this really seems to have exploded amongst the tech community as the next obsession. I see this pop up on X every few weeks. Is the concern about this really based on actual science? Is there empirical data proving people are less productive or are damaging themselves as a result of heightened CO2 levels? And I don’t mean observational epidemiology studies.

[dead]

Re: The bottleneck might be the air in the room

#227

Post by bell-cot »

dgellow wrote: post #179
deanc wrote: post #13

I’m not saying this isn’t a legitimate concern but this really seems to have exploded amongst the tech community as the next obsession. I see this pop up on X every few weeks. Is the concern about this really based on actual science? Is there empirical data proving people are less productive or are damaging themselves as a result of heightened CO2 levels? And I don’t mean observational epidemiology studies.

Worst case people open windows without effect, no?

Nope. Opening windows is very often disallowed - whether socially, or you'd need a hammer, or the space doesn't have windows. Or opening windows would have other downsides - letting in rain, or too-hot/too-cold air, or pollution, or ...

Re: The bottleneck might be the air in the room

#228

Post by cassianoleal »

Scroll_Swe wrote: post #223
microtonal wrote: post #111

Earlier quoted context omitted.

No, it's not. You generally want to ventilate an office when you reach 1000ppm, but then the IKEA will often warn you already at 700ppm. 700ppm is fine.

But if I open a window at 700ppm, so what?

Suddenly there's not enough CO2 in the room and you get overly awake! Bummer! /s

Re: The bottleneck might be the air in the room

#229

Post by throw0101a »

vertnerd wrote: post #186

As a high school teacher, I first noticed this effect when I started using a CO2 monitor in my classroom as a proxy for air freshness during COVID. The CO2 levels in our supposedly "no problem with the air" classrooms shot up to 2000 ppm within minutes of the start of school and stayed there all day. Kids weren't checked out ONLY because I teach mathematics. They were breathing bad air, too. Worse, when I brought the…

> The good news is that I stopped worrying about making my house "tight" for the sake of energy efficiency. I keep some windows cracked all year and don't worry about how tight the door seals are.

The point of having "tight" houses is not (just) about energy efficiency but about air quality as well. The general mantra is build tight, ventilate right. It's why modern building codes mandate air tightness and having ERV/HRVs.

By having a leaking house you do lose efficiency because in summer the air you paid to cool goes out and the hot-humid comes in, and in winter the air you paid to heat escapes and the cold comes in. But in addition to temperature (and humidity/moisture) you also get things like pollen, brake dust, (depending on your region) wildfire smoke, etc.

By ventilating right with ERV/HRV, you remove stale air and bring in tempered fresh outside air that you filter before distributing throughout the building. Air quality is also why 'spot ventilation' is also generally mandated at certain locations like over a cooktop/range in the kitchen, and in bathrooms (where the primary purpose is not taking care of smells (though helpful), but rather moisture from showers/baths).

* https://www.youtube.com/watch?v=CIcrXut_EFA

* https://www.youtube.com/watch?v=UTBNNhUH5V8

* https://www.greenbuildingadvisor.com/app/uploads/sites/defau...

* https://www.youtube.com/watch?v=lFfH1ljQgN07&t=3m14s

Re: The bottleneck might be the air in the room

#230

Post by xg15 »

A bit OT, but was anyone else amazed by the bad UX of that CO2 monitor in the picture?

If you notice, that monitor has a "traffic light" gauge at the bottom to tell you if the current CO2 level is critical. That traffic light is currently showing RED, i.e. highly critical.

The thing is essentially sounding the alarm and prompting immediate action. However, became the traffic light colors are printed on and static and the only dynamic indicator is a small e-paper bit above the color gauge, the effect gets lost completely.

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