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Comment by deanc | Hacker News Reader

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.

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IMO it's something where an intervention is often cheap enough that it's worth it even without great evidence.

But also bear in mind that regardless of "are we operating at max effectiveness", OSHA sets a legal limit of 5000ppm in a workplace, and that's about _safety_.

This article is talking about keeping levels below 1000 which is a very high standard IMO (still arguably justified given the studies mentioned). But if you are in a poorly ventilated home office you could easily hit 3000. At that point you are closer to "illegal in the US" than "earth's atmosphere".

So yeah even if you are unconvinced about micro-optimising your CO2 levels there's a very long established argument in favour of at least paying _some_ attention to it.

It's not even that hard to optimise at home. I've found simply leaving the door open to the rest of the house causes the room CO2 to not elevate much over baseline outdoor readings. Or just opening a window just a crack will rapidly remove all excess co2.

The real problem is offices and meeting rooms where you have 10 people in a small box for hours and windows that don't open.

That's interesting coz I found the opposite, at my place to keep the level below 1k I usually have to open a window in the room I'm in, or use a fan.

I live on a noisy street so I don't usually want to do that, if I open a window at the back and keep internal doors open it will stay reasonable but significantly elevated.

So yeah I think the lesson here is you probably need to buy a sensor, different homes are gonna differ.

My home is quite small (probably 80m²) and has literally zero ventilation built in (even in the bathroom!). I live in Switzerland where it's traditional to actively ventilate your home twice a day. But that doesn't do anything for CO2. Also it's such a fucking waste of time lol. Looking forward to moving into a modern building.

I think it’s just quite windy where I am combined with a not particularly airtight building so opening the window just a crack results in a lot of air blowing in

Yeah I was thinking airtightness might be the difference. My flat seems to be bizarrely hermetic (when you turn on the kitchen extractor fan, it struggles if you don't have a window open somewhere).

So maybe a few leaky cracks are enough that when you open a window you get a bit of a through-draft.

Anecdotal, but I'm convinced it screws up sleep quality. I'd just accepted for the longest time that waking up groggy with a slight headache and tired was the norm until I put a CO2 monitor in my room. With the door closed, it climbed up to 1500ppm in under an hour.

I'm certain many people are sleeping in similar conditions without realising and ventilating their rooms properly or leaving the door open.

And window.

An open window means kilowatts of energy wasted. All the air I spent money cooling will just leak out. It also means all the pollen will be let in.

If you’re cooling with whole house AC, you’re probably fine if there’s a register in your bedroom and the air is free to return.

Depends which way the wind is coming from.

Depends if you live where there is pollen.

Depends if you generate your power with solar.

Higher CO2 vs. free cat access at 4:17am. No win scenario!

I have this same challenge!

Also, moved all of my lovely oxygenating plants like lillies out of the room because they are toxic to kitty.

> Anecdotal, but I'm convinced it screws up sleep quality.

It absolutely does.

>I'd just accepted for the longest time that waking up groggy with a slight headache and tired was the norm until I put a CO2 monitor in my room. With the door closed, it climbed up to 1500ppm in under an hour.

Same experience here. Opening windows just a bit totally changed my sleep quality.

That is also my impression. CO2 build up provides a neat opportunity to carry around sensors, track something, display graphs and formulate quantifiable sets of rules. And also is a (more or less) interesting topic to discuss with others. Seems highly appealing to a large part of the crowd here. Personally, I only observed that some people are obsessed about having always one or more windows open but I never personally experienced any non-obvious problems with CO2 buildup. At some point the air is just smellably getting thick and then you just air out. Wouldn't need sensors for that.

I feel like it exploded after the cheap integrated sensors came on market that were easy to DIY with. It's nerd catnip, it makes you feel like you're discovering some hidden truth and makes it very tempting to blame the readings for all sorts of things. I don't even know how to trust the calibration on these things.

It kind of reminds me of the old joke where a drunk is looking for his keys under a street lamp even though he dropped them in a dark corner of the parking lot.

It's peak HN meme material because 1) it (allegedly) affects your intelligence which everyone here values highly 2) you can measure it, it's a number 3) requires tech to measure it

So perfect for HN, you can obsess over numbers and tech and how to measure it endlessly and overhype the significance to trick yourself into thinking you're doing something useful.

You get to have your cake and eat it, no wonder everyone loves this topic.

(Also if you're a doomer type you can link this in with rising atmospheric co2 levels for extra points)

Also this is finally a great reason to order a dozen Arduinos + sensors for a domestic IoT project.

Sounds like a positive thing :)

Not necessarily.

We assume sometimes that everybody experiences this in the same way, but a lot of people might be super-sensitive to it, and others completely immune. It is quite possible that the ones obsessing about it are the sensitive ones, because they feel it much more.

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

Yeah. But even when you can, how many bosses might forbid it - because there's already too many arguments over the thermostats, or it's kinda noisy outside, or HR warned 'em of lawsuits for doing that when the air pollution numbers are elevated, or whatever?

Perhaps HR should be warning them of reduced productivity and lawsuits when the CO2 concentration is elevated.

Opening windows can bring in pollen, dust, humidity, noise, and a lot of energy loss during cold winters and hot summers.

In a bedroom it might be worse than the elevated CO2 problem.

That’s a bit of a dramatic way to describe opening a window.

I've been designing my own ERV system for the house and have been weighing all the options, so I had this list in my head. Nothing dramatic, just the reality. We have allergies and like sleeping in a cooler bedroom.

As dramatic as having a runny nose and sneezing all day, having to overuse your asthma inhaler.

Is that really dramatic, or just the reality that needs to be considered in a cost-benefit analysis? Are you a hay fever truther?

I agree it seems like a concern fad. I talked about it once with my brilliant MIT-educated 20 year Navy submariner brother-in-law and he didn't commit one way or the other but did say submarines have CO2 in the low thousands.

You'd think (hope) if there was a big effect here on performance, the relatively cheap/easy solution of maintaining lower CO2 would be standard. I know people think of the military as dumb grunts who you don't want to think, but he was one of the four department chiefs onboard (Weapons, Nav, I forget the others) and they have pretty substantial responsibility to make decisions on their own.

https://www.youtube.com/watch?v=1Nh_vxpycEA

Somewhat unrelated, Tom also did a great video where he was put in a low oxygen environment. Similarish effects, differentish cause.

This is not a peer-reviewed study. It's a Tom Scott youtube video.

Are we not peers to Tom Scott?

Only if you watch it on Peertube. The link is explicitly YouTube.

I appreciate Tom as an educator, but he's not particularly an authority on anything.

And the sources he gives in the video's description are really bad.

The article links into two controlled experiments.

Any affect from CO2 specifically seems weak. Clean air in broadly good though, and high CO2 is a good proxy for stale air. So I’m always supportive of people caring and paying attention to their air.

Along the way they’ll either learn about or accidentally mitigate other ills like radon, nitrous oxide from stoves, diesel particulate’s impact on test scores, etc.

The level at which it is a concern might be skewed, but if you’ve ever sat in a room with “thick” air, trying to concentrate you know it is a real thing and just opening a window and a door for a few minutes to create a draft helps tremendously.

how can you detect without a study if CO2 meters are basically nowhere?

https://pmc.ncbi.nlm.nih.gov/articles/PMC4892924/

I mean try it for yourself... open a window a bit unless you live in a hellhole.

Also go for a walk, unless you live in a hellhole.

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.

Meanwhile in France we heat classrooms by stacking 35 kids in a confined space. It saves on heating, plus condensation that makes windows opaque helps pupils concentrate on the blackboard, as teachers said during my childhood.

France is indeed ridiculously bad at ventilation (not to mention air conditioning). Restaurants, offices, even gyms - most have bad to non-existing ventilation. Coming from the States this is just insanity.

> it makes no secret to me that they grew bigger

That sounds like something you made up to justify your beliefs…

So how does any of that relate to height? From what data I could quickly find, both countries are essentially equal in average height.

> 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

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