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The bottleneck might be the air in the room

blog.mikebowler.ca

241–250 of 499 posts

Re: The bottleneck might be the air in the room

#242
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.

I’ve lived in Australia and France and I’ve always attributed the taller size of Australians to the excellent state of their ventilation in buildings. Vents (and rooms themselves) are systematically bigger than in France, and if you live in a healthy environment, with meat, lots out outdoors during teen age, and correctly ventilated classrooms during their 20 best years, it makes no secret to me that they grew bigger…

> I’ve lived in Australia and France and I’ve always attributed the taller size of Australians to the excellent state of their ventilation in buildings. Vents (and rooms themselves) are systematically bigger than in France

The average male height in France is 178.60 cm, while in Australia it is 178.77 cm:

* https://worldpopulationreview.com/country-rankings/average-h...

Some sources even have France being higher than Australia:

* https://ourworldindata.org/human-height

Re: The bottleneck might be the air in the room

#243

Earlier quoted context omitted.

Can't you just open a window a bit?

In lots of modern office buildings you can’t.

ah, sadly that was in my last modern one. Thankfully we can open the windows in this one :)

Best solution.

Re: The bottleneck might be the air in the room

#244

Earlier quoted context omitted.

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 k…

Wouldn't high CO2 make you breath faster?

Interesting, the linked article does say that.

Pretty sure I learned the effect was the opposite (high CO2 --> slower respiration). Note that that was ~15 years ago when I would have read that. Maybe I just misunderstood, or thinking has changed.

edit: reading now I see I was wrong about this. Thanks for the correction!

Re: The bottleneck might be the air in the room

#245

Earlier quoted context omitted.

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 ...

Can't let those stupid workers open a window and ruin the efficacy of the precisely engineered hvac system that lets the building hit LEED Platinum or whatever

Re: The bottleneck might be the air in the room

#246

Earlier quoted context omitted.

> 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.

Dissolving CO2 in water creates some carbonic acid (H2CO3) that will decompose back to water and CO2 when the CO2 concentration drops. Blood has a fair bit of water, and carbonic acid is much easier to detect than oxygen or nitrogen gas

We evolved to detect CO2 because that's by far the easiest thing to detect that's still a reasonable proxy for the performance of our respiratory system

Re: The bottleneck might be the air in the room

#247

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 ER…

Not everywhere is LA.

How much does implementing all that cost? What degree of benefit does it offer over simple window in situations where those concerns are negligible? What other benefits to human life could be procured with that money?

It just boggles the mind that people feel emboldened to only look at one side of the equation.

Re: The bottleneck might be the air in the room

#248
That article's message is spot on.

If your CO2 levels are that high then you should fix the HVAC system and get it up to code or lobby for fixing the code. In many countries, a full air exchange in any office space every X hours is mandatory. In other countries that's optional and they need to get their act together.

Re: The bottleneck might be the air in the room

#249
At a career fair in an auditorium I was showing a sensor suite with OLED displaying current readings, one of which was the SCD41 CO2 sensor (they cost more than the esp32!)

I watched the sensor rise from 800 to 1700 PPM by the time the last group left the

It’s quite easy to build one and deploy with esphome and breadboard with stuff you can order on Amazon and have an LLM walk your through hardware and setup.

It is interesting where the rate of speech quickens as the co2 rises and the body starts to notice the co2, or maybe that was just the coffee.

Re: The bottleneck might be the air in the room

#250

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.

you assume that the error will always be in one direction and if sometimes you ventilate a bit sooner than required, at 700, what? businesses will not put $200 meters in every room

$200 is nothing compared to the lost productivity.
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