The bottleneck might be the air in the room

https://blog.mikebowler.ca/2026/07/03/co2-and-decision-making/

by gslin • 19 days ago

833 463 19 days ago

blog.mikebowler.ca

kennywinker• 19 days ago

You gather your most expensive people into a room to make your most important decisions.

A terrible way to make decisions.

sixtyj2• 19 days ago

What should be a better way?

hahahaa2• 19 days ago

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.

217• 19 days ago

i love seeing things i saw on twitter two years ago at the front page of hn man like what are we doing

keiferski• 19 days ago

Yet another reason to have meetings while walking outside: air quality and a natural limit on time, and the mental benefits that come from movement.

sapiogram• 19 days ago

Requires an area around your office that isn't ugly or overrun with cars.

Scroll_Swe9• 19 days ago

Scandinavia wins again :)

vineyardmike• 19 days ago

It needs to be safe (including from pollution), but you could absolutely just walk around the parking lot.

gostsamo• 19 days ago

requires that everyone is comfortable walking and has no physical impairments.

Not to talk about the weather either.

gpt5• 19 days ago

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. Raising awareness is the only real solution.

scoot2• 19 days ago

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

oasisbob3• 19 days ago

I don't think that's true at all. Capnography, the measure of carbon dioxide partial pressure is wholly separate from pulseox:

Pulse oximeters have some limitations. They can only employ light at two wavelengths. Thus the devices can only distinguish between hemoglobin and oxygenated hemoglobin. When carboxyhemoglobin and methemoglobin are also present, there are two additional wavelengths required for differentiation. In the presence of elevated carboxyhemoglobin levels, pulse oximetry overestimates the true saturation of oxygen as carboxyhemoglobin binds with a higher affinity than oxygen. In the case of carbon monoxide poisoning, the absorbance spectrum of carbon monoxide is very similar to hemoglobin, which results in a falsely high level of oxygen (overestimation of oxygen saturation) ...

https://www.ncbi.nlm.nih.gov/books/NBK539754/

Terr_3• 19 days ago

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 problems.

Even if the watch could sample atmosphere directly, is it sensitive enough to detect a shift from 21.00% -> 20.79% oxygen?

As it's estimating oxygen in the owner's blood, it might not detect anything different at all... not if the owner's body has already compensated by breathing harder or by "underclocking" their brain to make dumber decisions.

[0] https://en.wikipedia.org/wiki/Asphyxiant_gas

scoot2• 17 days ago

I really must learn to quote the full context of a reply. OP said:

just due to lower oxygen levels in your blood

So my comment is in response to that.

PS. The downvote button isn't a disagree button. (Although how you can disagree with the fact that Apple watches have a blood oxygen sensor I don't know).

legulere• 19 days ago

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.

Gigachad12• 19 days ago

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. It also plugs in to home assistant great.

Liftyee• 19 days ago

I would hesitate to say the IKEA is worse. Inside the IKEA is a reputable Sensirion all in one sensor module. It's much cheaper and smaller because the CO2 sensor in it is using different (newer) technology that only released a few years ago from Sensirion.

(Upd: the IKEA does have lower accuracy, with ±100 ppm instead of ±30 ppm. From the SEN63C datasheet)

SideburnsOfDoom• 19 days ago

I also don’t know how much electricity they pull.

It can't be much, since the Aranet 4 can run for years on 2 AA batteries.

mdf• 19 days ago

Ruuvi Air[1] seems to be close to the middle in both price and CO2 measurement accuracy between aranet4 and the IKEA device. I don't have personal experience with Ruuvi Air specifically, but have been using their cheaper Ruuvi Tags (that don't measure CO2) for temperature, humidity and air pressure measurement at home and office.

[1] https://ruuvi.com/air/

stein1946• 19 days ago

Raising awareness is the only real solution.

You'd have to raise awareness on every single person in the room and them sustain pressure to the organization in order to have proper CO2 levels in the room/organization.

And then you have to align every other person on every other organization to do this as well and hope for the best.

Or, you can do the right thing and have the state introduce regulations

b1122• 19 days ago

I can just imagine the horrors and skin crawls that your last sentence has evoked in some people's minds. Not the state!!

But seriously, so much care needs to be taken here. OK, well "care" at least. Employers certainly would benefit from scrubbing CO2 from the air, in terms of productivity. I'm willing to bet that with central air it would be quite easy, and even with heat and AC off, lots of places still circulate the air regardless.

So the central place to scrub is already there.

But then you have other issues. Such as, will your body adapt to 8 hrs of reduced CO2, and then you become torpid and barely awake when not at work. Such a horrid thought, that is to me. And what if employers learn that the tiniest boost of O2 helps too! Now your body becomes accustomed to that, and what are the long term effects there?

I can personally envision myself being concerned. I guess the legislation could be crafted to "the same CO2 levels found just outside of downtown city core" or some such blather. Maybe even same for O2. So that you're at least pegged to something normal for the area.

Maybe that's where the state could come into play. A simple, highly accurate monitoring station which has an API to be polled.

Come to think of it, CO2 and O2 rates fluctuate during the 24 hour cycle. Trees need O2 to live, but only produce O2 during the day. And so differing amounts of light might mean up and downs in these numbers. It may be another circadian rhythm. Getting it the same as in a nearby forest, might be the healthiest thing of all.

Scroll_Swe9• 19 days ago

Can't you just open a window a bit?

dan-robertson• 19 days ago

I don’t think that’s right. If people have an easy way to measure the levels, and they can see something on their phone like ‘you spent 8 hours today above 2000ppm CO2’ then the room will care a lot more than it did before, and people will be able to quickly see whether they have improved things. At my employer, I think it took us around 1000 employees until we randomly hired someone who happened to care a lot about CO2 levels and I think they managed to cause a decent increase in the amount that the company cared / thought about levels (this was around the end of Covid though so part of this may have been due to using CO2 levels as an indication of insufficient ventilation/air filtration).

joenot443• 19 days ago

Depending on the state, newer buildings do have regulations on air ventilation and quality.

The rooms being discussed here are mostly ones which would have been built before this was taken more seriously. Classrooms, older office buildings, etc.

NYC is full of buildings which would never pass any code today but are still happily occupied. It’s a trade off, I think.

Ikatza• 18 days ago

It doesn't work like that. I've been made aware thanks to this post, and tomorrow I'll be placing CO2 sensors in every meeting room in the company I work at, and mandating an open-windows or air-circulating policy above 800ppm.

You don't need to make everybody aware, you just need to make the right people aware.

As for the State... Mine mandates that nobody can use the laptop's keyboard, they must use an external keyboard so the laptops' screens can be risen to eye level.

We have the external keyboards and the risers, and nobody uses them.

The State usually finds the worst and most wasteful solution available. Only fools trust the State to solve their problems.

zeafoamrun• 19 days ago

I was looking at CO2 sensor module boards this week and the sensors themselves are quite large and the floor price is $15ish.

bjackman6• 19 days ago

And I believe the accuracy is also not great on these cheap ones. The product in the OP's photo costs $200 where I live! And ISTR finding the sensor itself contributes a lot to this cost.

IIUC they also need fans. The one I have in my home has one that's actually integrated into the sensor unit.

Gigachad12• 19 days ago

Those $15 ones are also straight up scams. They just estimate (lie) for the readings based on other sensors.

microtonal15• 19 days ago

I think the issue is that the common tech requires sensors in an air-chamber. E.g. NDIR works by firing IR at a frequency that is absorbed by CO2. A sensor on the other side either measures the amount of IR light that got through (optical NDIR) or pressure/sound waves (photoacoustic NDIR). I guess that it's hard to use any existing sensors, because they are relatively large and probably water could easily get into the chamber.

Would be extremely cool if Apple, Samsung, and others can crack this, though I think they'd have done it already if it was easy.

londons_explore2• 19 days ago

Oxygen sensors used in car catalyst systems use a different effect based on electrochemistry. I see no reason that couldn't be minuaritized to grain-of-sand size.

The question is if oxygen levels are as good an indicator as CO2 levels... I suspect not.

kingkawn3• 19 days ago

Mesh with the other Apple/et al devices in the room to take multiple samples and aggregate the results for an overall picture of the ambient co2

NathanielK• 18 days ago

Sensiron STCC4 uses thermal conductivity sensing thats very compact (4x4x1.2mm). It's pretty new to the market, but maybe in the future it'll happen.

reddozen• 19 days ago

CO2 and all other air quality indexers have to be very carefully calibrated regularly. It's not some slop you can just throw into a consoomer cheap iot device.

Article author completely ignores this for the obvious reasons.

Gigachad12• 19 days ago

For the purposes of indoor ventilation monitoring you can calibrate by occasionally exposing the sensor to fresh air. Either taking it outside or just the room not having people in it. The sensor will treat the lowest reading it gets as 400ppm since this is what outdoor air is.

A sensor mounted in the office will get calibrated every night when the office is empty.

OutOfHere11• 19 days ago

Not really. For ventilation purposes, a good sensor remain within 10% variation for nearly ten years. We are not running a controlled science experiment here.

throw0101a8• 19 days ago

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. Raising awareness is the only real solution.

Not wrong, but it is perhaps worth noting that there are already standards for proper ventilation. Generally you're looking at 5–10 cfm/person (2.5-5 L/s), depending on the facility and purpose of the room; see Table 6.2.2.1 in ASHRAE Standard 62.1 for the US:

* https://www.ashrae.org/file%20library/technical%20resources/...

Maybe set up a monitor, but if the room/facility has recently been renovated and meets modern (>2013) building codes, this 'should' have already been taken into account.

wouldbecouldbe• 18 days ago

I think modern domestic houses its the opposite. At least in Netherlands insulation is such a strong focus, due to climate change I think, that modern appartments have terrible ventilation

II2II• 18 days ago

Building codes that address this are wonderful, however:

- Plenty of people live or work in older buildings, where are not up to standard. For example: my office probably violates the air quality sensibilities of the Victorian era, which is when it was originally built.

- Equipment breaks down, isn't operated properly, or wasn't installed correctly. Having monitors that measure air quality is an extra check. While you may not be able to get direct action upon a consumer sensor, it can help you push for action.

I've been in buildings of varying quality over the years. I've seen how it takes time to get people in to do air quality testing. Heck, I saw the government claim that the air quality was acceptable in schools during the pandemic because the schools had passive ventilation systems. That meant they could open windows. (To be fair, the air quality in most of those buildings was probably fine since that was how the buildings were designed. That said, such standards make it easy for some buildings to slip through the cracks.)

So yeah, sensors to the people!

xyzzy_plugh• 18 days ago

This is correct, but there's still a lot of opportunity to do better.

I've been involved with the build out of several office spaces in new and old buildings. We always took this sort of thing seriously and measured each room independently for a week (many at a time) ensuring we accounted for periods of high occupancy.

This let us tune the HVAC systems to operate more efficiently, ensuring comfortable temperatures and air circulation. Every time I've seen this done there were structural deficiencies that required remediation, some times it meant adjusting duct work.

Most modern office buildings are designed to be a platform for constructing spaces, as spaces usually evolve and change between leases and tenants. They're designed to accommodate this sort of thing.

However I've found that no build out nails this the first time. It's very hard! Often times things look fine but once you get people in the space things change drastically. It requires time and effort to address.

Several of my offices had such good air that I'd prefer being there over pretty much anywhere else -- even outside on poor AQI days.

I've also found that a lot of offices don't do any of this and their air quality is noticeably poor. And lastly I've found that the oldest buildings, including schools -- and I'm talking really old -- have very good air because they are so incredibly leaky. They're usually harder to cool and heat, though.

josephg2• 18 days ago

Should…

Whenever I travel, I bring a CO2 meter with me. It’s amazing how often the air is bad. Often in unexpected places. My meter hit 3100 in an uber once. I didn’t even notice until I got to my hotel room and looked at the data log. It was a fresh, hot day outside. The uber had windows closed and AC on. I bet he had no idea - but he was driving with significant cognitive impairment. Takeoff and landing in planes are always the worst. If you get sleepy as the plane is taking off, it’s not you. The plane’s ventilation doesn’t work properly when the plane is stationary. So before a plane is in the air, they often hit 2500.

bhouston• 18 days ago

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

alienbaby2• 18 days ago

Is it a tually lower oxygen in the blood that's the problem, or higher co2? I'm not sure if having high co2 automatically implies lower oxygen, I have no idea at all but feels like it may not necessarily be strictly. Linked. Also, are the cognitive issues of low oxygen the same as high co2 or do they produce different effects?

fhdkweig• 18 days ago

From what I learned from Apollo 13, even with O2 in the air, CO2 can still be poisonous.

jeffybefffy519• 18 days ago

This would probably be the biggest awareness thing tech could do for climate change as well.

misnome• 18 days ago

I built a conference badge with a proper, laser-based CO2 sensor.

It didn't work very well because just by virtue of being near me all the time, it didn't get a very good measure of the average room contents.

Aurornis8• 18 days ago

I really wish a Apple or another major OEM would integrate CO2 monitor into watches or smartphones

CO2 levels are locally elevated in the area where you exhale. Someone sitting at a desk with their hands on a keyboard exhaling through their nose would be producing a directed stream of elevated CO2 straight at the sensor on their wrist. Same thing if someone puts their phone on their desk.

Even with the IKEA and other cheap sensors that are becoming popular, there is a learning curve where users discover that putting it on their desk right in front of where they’re breathing produces higher numbers than having it even 5 feet away.

The false positives from having a CO2 sensor that close to everyone’s face would be causing unnecessary alarm all over.

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. Raising awareness is the only real solution.

If someone is falling asleep in this many different places I would suspect undiagnosed sleep apnea or another condition first and foremost. Spaces like movie theaters have very high volumes of air due to their size and commercial building HVAC has much higher standards for air circulation than even your home. If someone was falling asleep in so many different places then the most likely common theme is that person and it should be checked out!

This is another reason why putting CO2 sensors on everyone’s wrists would be a mistake: It would start getting blamed for every vague condition people experience. This has already happened with wrist-worn heart rate monitors. My friends in the medical field see people all the time who come in with vague complaints and they’ve self diagnosed as being related to their heart because they can see their heart rate now.

You also have the wrong idea about what elevated CO2 does. It doesn’t reduce the oxygen levels in your blood. It makes it more difficult for your body to expel CO2, which can produce subtle changes in many processes.

riquito• 18 days ago

CO2 levels are locally elevated in the area where you exhale.

That's the same area we inhale from... Wouldn't be right to measure there then? It's not like we're interested in the amount of CO2 on the ground (in this discussion)

cotwo• 18 days ago

The air infront of you IS the air you breed in, why shouldn’t it be measured?

avazhi2• 18 days ago

CO2 does not stream out when you exhale like a fluid. It’s a gas. It dissipates quite immediately and behaves as all gases do - it expands to fill its container via something like Brownian Motion.

Melatonic2• 18 days ago

Mostly agreed but with that much data couldn't we easily have an adjusted CO2 number for local sensors ?

I would imagine it's still relative unlike temperature on the wrist (which is too affected by body temp)

tzs• 18 days ago

Wouldn’t it still be useful because you could look at changes in the measurement? E.g. if I can’t draw any conclusions when my phone says 800 at the start of a meeting because it might be where I’m breathing, but an hour later in the same place it says 2500 couldn’t I conclude we need to take a break and let the room air out?

pedalpete• 18 days ago

I always come at this angle.

If you had the data, what would you do to change it? Would you recommend everyone go outside? You can do that without the data.

Would you wear your own oxygenated supply of air? You can do that without the data.

Would you make recommendations that the office should improve air quality? You can do that without personalized real-time data.

I'm not against data in general, but the idea that if only we had data we would make changes in our lifestyle is not valid. We see it all around us.

We had bathroom scales for over a century, but the data or insights didn't put a dent in the obesity epidemic.

You're right about "the problem will solve itself", but it isn't the data that will help to solve the problem, it's creating a simple and obvious solution.

A friend has a start-up in the commercial air quality space which solves for this problem (in some ways). But the benefit isn't the air quality, it's the cost of maintaining the healthy levels required in commercial buildings. Air quality is the secondary benefit of reduced electricity demand in air circulation.

0ckpuppet• 18 days ago

This sounds like a solution in search of a problem. If you feel dizzy at random moments, see a doctor soon.

throwaway81523• 19 days ago

Don't forget too, if the CO2 is 1000 ppm, then half of the air in each breath you inhale was recently exhaled by someone else. Yes, airborne viruses are still spreading. I still wear an N95 mask whenever I'm in an indoor space with other people outside of home.

IKEA now has a remarkably cheap ($35) air quality monitor that measures CO2 as well as PM:

https://www.ikea.com/us/en/p/alpstuga-air-quality-sensor-sma...

I don't have one yet but plan to pick one up soon. A CO2 sensor alone from Adafruit is $50+, though that one is more precise. I bought it a while ago and it's still sitting in my todo bin.

boernard• 19 days ago

could you observe an effect on your health after starting to wear the mask? like sickness days per year?

hypfer2• 19 days ago

Doing that all the time might not be the best idea for your immune system and neither for the respiratory one too.

The first needs to occasionally see new threats to stay up to date and healthy. The second will not like the constantly restricted airflow.

a1371• 19 days ago

The building science community has not buy and large came to the agreement that the CO2 itself is the cause of the cognitive decline. It could be the Canary in the coal mine telling us there is an accumulation of compounds causing the decline.

Why that matters? You need good ventilation regardless, but instead of just thinking of CO2, try to minimize compounds in your air by selecting things for the room that smell less and off-gas less.

jwpapi• 19 days ago

Buying one of these gadgets killed my brain fog

Tossrock• 19 days ago

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...

brookst• 19 days ago

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.

threatripper• 19 days ago

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

Robin_Message• 19 days ago

If that study was of submariners, is it possible long-term high-level exposure causes the body to adapt?

I am suspicious of 0.1% having a significant effect though, given oxygen is around 20% and we naturally exhale a couple of percent CO2.

pishpash• 19 days ago

I mean that can't be right, as the body's breathing response is triggered by that amount of CO2 buildup. It's not about what's in the air. It's about what the body can take up. Maybe submariners are self-selected to be more physically fit, e.g. larger heart, lung capacity etc. to compensate.

culturestate• 19 days ago

One key difference is that submariners are rigorously trained to operate effectively in less-than-ideal environmental conditions, whereas Bob from accounting probably is not.

w-m2• 19 days ago

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.

hahahaa2• 19 days ago

O2 is 200000ppm so if co2 goes up 400 to 2000ppm does o2 go down to 198400ppm?

KerrickStaley• 19 days ago

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.

nok22kon4• 19 days ago

could be a selection effect at work

dev1ycan• 18 days ago

Submarineers also are hand picked due to their great lung capacity...

mppm• 18 days ago

... which is entirely unsurprising given that exhaled air is about 50.000 ppm CO2 and can vary by several 10.000s depending on depth and rate of breathing. I actually consider the recent wave of findings that CO2 levels as low as 500-1000 ppm measurably affect cognitive performance and well-being to be a great example of how you can prove literally anything with statistics and a sufficiently small sample size.

amluto2• 18 days ago

A major confounding factor is everything else in the air. Humans produce lots of different gases, and CO2 is usually a proxy for the overall concentration of our effluent gases. But in a submarine, or in some buildings, there are gas filters (usually carbon, possibly with various modifications) that can remove or destroy some of these gases but have no effect on CO2. So the air in a submarine at 15000ppm CO2 could be very different from the air in a an unventilated room that reaches 15000ppm CO2.

dr_dshiv• 18 days ago

The first person to deal with this may have been Cornelis Drebbel in 1610 when he deployed the first submarine. With 4 oarsmen submerged in a leaky wooden sub, they’d have too much co2 and too little oxygen. Somehow they were able to stay for hours at a time.

Robert Boyle describes Drebbel’s use of a “chymical liquor” to refresh the air.

“Paracelſus, indeed, tells us, that "as the ſtomach concocts the aliment, "and makes part of it uſeful to the body, rejecting the other; ſo the "lungs conſume part of the air, and reject the reſt." Whence, according to him, we may ſuppoſe a little vital quinteſſence in the air, which ſerves to refresh and reſtore our vital ſpirits; for which purpoſe, the groſſer, and far greater part of the air, being unſerviceable, it is not ſtrange that an animal ſhould inceſſantly require fresh air. This opinion, indeed, is not abſurd; but it requires to be explain'd and prov'd: beſides, ſome objections may be made to it, from what has been already argued againſt the transmutation of air, into vital ſpirits. Nor is it probable, that the bare want of the generation of the uſual quantity of vital ſpirits, for leſs than one minute, ſhould be able to kill a lively animal, without the help of any external violence. And, upon this ſuppoſition, Cornelius Drebell, is affirm'd, by many credible perſons, to have contrived a veſſel to be row'd under water: for Drebell conceiv'd, that it is not the whole body of the air, but a certain ſpirituous part of it, that fits it for reſpiration; which being ſpent, the remaining groſſer body of the air, is unable to cheriſh the vital flame reſiding in the heart. So that, beſides the mechanical contrivance of his boat, he had a chymical liquor, which, by unſtopping the veſſel wherein it was contain'd, the fumes of it would ſpeedily reſtore to the air, foul'd by reſpiration, ſuch a proportion of vital parts, as would make it again fit for that office; and having made it my buſineſs to learn this ſtrange liquor, his relations conſtantly affirm'd, that Drebell would never diſcloſe it, but to one perſon, who himſelf told me what it was.“

https://sourcelibrary.org/book/philosophical-works-vol-2-boy...

deanc3• 19 days ago

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.

kashishgrover4• 19 days ago

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

Krutonium• 19 days ago

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

deanc3• 19 days ago

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

ifwinterco• 19 days ago

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)

raffael_de3• 19 days ago

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

eastbound• 19 days ago

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.

puttycat• 19 days ago

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.

dgellow6• 19 days ago

it makes no secret to me that they grew bigger

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

nkrisc• 19 days ago

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

throw0101a8• 18 days ago

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

bjackman6• 19 days ago

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.

Gigachad12• 19 days ago

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.

nok22kon4• 19 days ago

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

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

raffael_de3• 19 days ago

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.

u1hcw9nx• 19 days ago

The article links into two controlled experiments.

Scroll_Swe9• 19 days ago

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.

dgellow6• 19 days ago

Worst case people open windows without effect, no?

bell-cot2• 18 days ago

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 ...

joezydeco2• 18 days ago

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.

bluerooibos• 19 days ago

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.

rahimnathwani• 19 days ago

And window.

mft_• 18 days ago

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

romaniv• 18 days ago

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.

paufernandez• 19 days ago

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.

losvedir• 18 days ago

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.

ip26• 18 days ago

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.

foobarian• 18 days ago

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.

wodenokoto• 18 days ago

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.

sixtyj2• 19 days ago

A lot of CO2 is bad for thinking.

CO2 is just a tip as office or home is toxic environment anyway. Plastic (e.g. carpets), formaldehyde in furniture, air fresheners… add home office and cooking at home (-> small carcinogenic particles)…

If you start reading How not to die by Michael Greger, you find out that dust, soda and sitting - not CO2 - are real killers…

It's similar to how people think sharks and airplanes are the biggest killers - when in reality it is coconuts, mosquitoes, and motorcycles.

_def2• 19 days ago

How do you avoid/reduce exposure to dust? Genuine question

throw-the-towel• 19 days ago

Use an air purifier, wear a respirator outside if you live in a polluted place.

Dove• 19 days ago

Air filters, decluttering, regular deep cleaning, replacing dust-friendly surfaces and furniture (such as carpet, drapes, and upholstered sofas) with things like wood, vinyl, or leather. HVAC maintenance, cleaning, and filters. Washable allergen covers for things like pillows and mattresses.

hobofan• 19 days ago

HEPA-filter air purifier and a robot vacuum that is scheduled to run while your are not in the apartment (to reduce baseline dust) are probably the most simple/cost-effective measures.

_def2• 19 days ago

Then, somewhere in the second hour, the room quietly gets worse at making them.

Maybe it's not just the air but also the multi-hour meetings that drive people to a sense of "oh god let this finally end now", which leads do decisions that fall short.

Scroll_Swe9• 19 days ago

I am able to open the windows at home and at work but have to be reminded to air out, but I always feel much clearer when I do.

Also, take walks. I am lucky to be able to walk to and from work and it helps immensely.

oasisbob3• 19 days ago

There needs to be a meter for the amount of AI writing in blogposts. Same physics, same climb, same afternoon fog.

stavros• 19 days ago

Yeah, it's really tiring reading Claude's output all day, every day. Nowadays I yearn for a different style.

naet• 19 days ago

This reads to me as AI generated. Apparently it's still good enough to the general audience to be the #1 post on HN right now though. Which is honestly a troubling signal for the state of the world...

LordDragonfang3• 18 days ago

Yeah, I clocked it as AI the moment I read "Here is the uncomfortable part". FWIW, Pangram detects it as 100% AI-generated.

https://www.pangram.com/history/c410d4b4-abfd-4ca0-b52d-db0d...

salahadawi4• 19 days ago

I've actually been tracking the front page of HN for AI posts for a while now: https://www.salahadawi.com/hacker-news-ai-detector

This post evaluates to 99% AI generated.

jsnell• 18 days ago

Nice! Have you considered doing a Show HN for that?

That's valuable in at least three different ways: public education, showing that most of the articles are still human-written which can be easy to forget about sometimes, and as an easy way to cross-validate my intuition when flagging something as AI-generated without having to manually run Pangram.

I despair a little bit about how many HN voters either seem to want to read slop or don't understand when they're reading it. This post is obviously AI generated from the first paragraph on, and still has 480 votes.

JonathanRaines• 18 days ago

Pangram claims to be super accurate. Do you know how? I understood detection is a hard problem.

kashishgrover4• 19 days ago

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 in my opinion for cars to have CO2 monitors. We put so many sensors in cars these days that this seems to be a really cheap and fairly high value of life addition that could possibly prevent accidents on roads. I keep a portable CO2 sensor in my car at all times, because sometimes circulation is not something I can avoid when stuck in traffic or when passing by a drain.

npunt• 19 days ago

Got a firsthand experience with this. I was dropping off my girlfriend and we stopped to talk in the car, with all the windows up. Over the course of the conversation we got more and more agitated at each other until I had a thought and pulled my Aranet out from my backpack. It was >3000ppm CO2. We opened windows and within 2 minutes all the agitation went away.

hypfer2• 19 days ago

To be fair, that might not just have been the CO2 dropping, but also the pattern interrupt + giving you both an easy and face-saving way out of that situation.

the_gipsy• 18 days ago

Or, you became aware of the agitation and interrupted it. The CO2 was a placebo. You have invested already in the idea, it all clicked in your mind.

gblargg2• 18 days ago

I was amazed how quickly it rises in the car with windows up and recirculate mode for the fan. There's a reason it has a fresh air mode.

_thisdot• 19 days ago

Relevant video of someone experimenting with a CO2 monitor in a car: https://youtu.be/hr9w-ZixAqc

infofarmer• 19 days ago

Yeah, I measured over 5000ppm in a taxi with two passengers. Showed the driver how to enable air intake (he didn’t know about the feature) and tried to explain this is deadly. Pretty sure this is commonplace globally.

Generally it’s a miracle to me so many people survive traffic on public roads, statistically.

esikich3• 19 days ago

Cars aren't hermetically sealed vessel. This is hilarious.

kashishgrover4• 19 days ago

You think that’s stopping CO2 buildup?

ErroneousBosh4• 19 days ago

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

kashishgrover4• 19 days ago

Try it yourself. They really are

inigyou2• 19 days ago

Buildup of CO2 and reduction in O2 are two different effects. We're not in danger of running out of O2 in any everyday situation.

prodigycorp• 19 days ago

Your comment actually has me convinced that this isn't an issue. I've been a recirculation dude for my entire life, I literally don't drive any other way.

fuzzfactor4• 18 days ago

In the 1970's when factory A/C started to get widespread adoption in other than very expensive cars, it was common for more than one US automaker to almost standardize on a dashboard system of levers or knobs.

At the extreme was "MAX" which most people didn't realize was "recirculate" unless they read the owner's manual in those cases where it was well documented. The next notch over was "NORM" which as the name implied was intended to be the "normal" setting except under more challenging conditions. But with fresh air coming in constantly it only was passing through the refrigerant coils one time, plus sometimes the outdoor air is a lot hotter than others, so recirc is when you want the same interior air to pass through the coils more than once.

All this may go "out the window" when the exhaust fumes or worse in the outdoor air need to be excluded as much as possible.

I kind of miss the old '70's cars even though loads of them kept running long after the A/C had failed.

Regardless, I never felt alone even without a passenger, with my good buddies Max & Norm with me everywhere I went ;)

rikschennink• 19 days ago

“That number matters more than it looks.”, then the next paragraph starts with “Here is the uncomfortable part”, and then I closed the tab.

vasco• 19 days ago

Similar to this a closed motorcycle helmet without air circulation increases CO2 extremely rapidly, within 60s it's already at really high levels. Open your visor when you stop!

eitau_12• 19 days ago

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?

fer• 19 days ago

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

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

Terr_3• 19 days ago

I'm not a doctor, but I would consider it in terms of flow and throughput, rather than,—metaphorically—the amount of water the pipe can hold.

eitau_12• 19 days ago

Per Wikipedia, at rest 500 ml of inhaled air is diluted with ≥2500 ml [1] of residual air in lungs containing ≥40000 ppm (4%) of CO2 [2]. Other things being equal, increasing concentration of CO2 in ambient air 10x (500ppm -> 5000 ppm) would increase concentration of CO2 in the lungs after taking the breath by less than 2.5% [3].

I imagine it could easily be compensated by an equivalently minor increase of breathing rate or breathing depth.

[1] https://en.wikipedia.org/wiki/Gas_exchange#Alveolar_air

[2] https://en.wikipedia.org/wiki/Breathing#Composition

[3] 5/6 × 40000 ppm + 1/6 × 500 ppm = 33417 ppm; 5/6 × 40000 ppm + 1/6 × 5000 ppm = 34167 ppm; 34167 / 33417 = 1.0225

sohpea• 19 days ago

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?

JoshTriplett• 19 days ago

One easy way to fix this for many people's bedrooms or home offices: look at your HVAC system, and there's probably an option to have the fan run all the time, even if the heat or air isn't running. Turn that on, and your home's CO2 levels will drop substantially.

udfalkso• 18 days ago

This. I have mine set to run the fan 15 min every hour. Circulates air nicely.

red75prime• 19 days ago

Does it work the other way around? Does breathing air with 0% CO2 improve human cognitive performance? I haven't been able to find any research on the effects of lower CO2 concentrations.

zh3• 19 days ago

For the DIYers, it's simple to get an SCD4x sensor and hook it to a pi, arduino, ESP32 etc (then use CC to create a live web interface). I did this after trying an Inkbird CO2 monitor, which gets reasonable scores in reviews and wanting a live web report in the office.

Interestingly the Inkbird and the SCD4X quite often diverge by anything up to hundreds of PPMs; I kind of back the SCD4x (on a Pi in my case) for accuracy after lots of experimentation, reading the datasheet and ensuring the correct calibration procedurs are followed (basically expose the sensors to outside air once a week).

It's also interesting how much it varies day to day in my one-person office - possibly down to how windy it is outside, even with windows closed one day it never goes about 800ppm, other days it'll hit 1500ppm by lunchtime if I don't open a window.

N.B. Quite possible the Inkbird uses an SCD4x internally, seems reasonable kit so I have no explanation for the differences in readings.

jofzar• 19 days ago

You can also get the IKEA one which uses a good sensor

https://www.ikea.com/au/en/p/alpstuga-air-quality-sensor-sma...

ludicrousdispla• 18 days ago

I've been using an Inkbird CO2 monitor for a while, and it's definitely accurate enough for my needs.

gwd• 19 days ago

I noticed this effect really strongly at university. There was one particular lecture hall that was effectively buried in the side of a hill; I can't count how many times I had an early afternoon lecture in there (so it had been in use since 8am), where I just could not focus or stay awake. Assuming sleep deprivation was the problem, afterwards I'd head out and lie down on a bench to take a nap, only to find myself wide awake. I have no trouble taking cat-naps when I'm actually tired, leading me to eventually conclude it was CO2 / O2 in the room that was the culprit.

hanspagel• 19 days ago

Not gonna happen in Germany. I don’t think I‘ve ever seen a windowless room here and it’s common to open all windows at once for a few minutes, just to replace as much air as possible:

Stoßlüften.

em-bee• 19 days ago

when i read the article i thought that maybe this is where german ingenuity comes from.

but then germany hasn't been doing so well lately, and people who do most of their work outside should also be doing better...

aurelwu• 18 days ago

Take a look at indoorco2map.com and you will find plenty of places in Germany with bad air measured in a crowd data collection effort. Most notably doctor‘s offices are often very bad. Many supermarkets too. Schools are not well measurable this way but academic research shows they often are at 2000-3000 ppm or even higher. (Disclaimer: I built the website/App)

Aperocky• 19 days ago

This article is rated 100% on my AI smell meter, making it less trustworthy despite convincing arguments.

For instance, I'm now really only sure that author measured a 2000 ppm CO2 in a meeting room once. Everything else could just be LLM trying to invent convincing argument.

girvo• 19 days ago

Glad someone else is saying it. It has that exact LLM cadence to it, horrible.

The worst thing is, I'm pretty sure humans are starting to mimic that cadence too...

LordDragonfang3• 18 days ago

Yeah, I clocked it as AI the moment I read "Here is the uncomfortable part". Pangram detects it as 100% AI-generated:

https://www.pangram.com/history/c410d4b4-abfd-4ca0-b52d-db0d...

GreenWatermelon2• 15 days ago

Myeter started tingling at "Not the people. The room." On the first paragraph, and reached maximums level at the same part as you.

Feels like I wasted time reading bullshit.

ccozan• 19 days ago

I wonder if the corona times trend to WFH and jump to Teams/Zoom/etc meetings instead of physical meetings had/has a positive effect in regards to this.

marouen19• 19 days ago

Just open the door

lexoj• 19 days ago

I remember some years ago after coming from work at 6 pm I was dead tired at home thinking it was due to hard work during the day. Then one summer day decided to code side projects on my balcony and I was building until midnight full of energy.

microtonal15• 19 days ago

Two tips: if you want a stationary CO2 meter in a room, you can make one very cheap with a SenseAir S88 sensor (22 Euro) and hooking it up to an ESP board. Flash ESPHome and you can get live statistics in your Home Assistant dashboard. The S88 is a pretty good optical NDIR Sensor that auto-calibrates by putting it in the outside air or in a well-ventilated room every N-days (N is in the data sheet). A bit more info about hooking up the S88:

https://danieldk.eu/hardware/smart-home/esphome-senseair-s88

If you want something with a display that works on batteries without spending over 200 Euro for an AraNet, the SwitchBot Meter Pro CO2 is pretty good option. It is regularly on offer below 50 Euro. It uses photoacoustic NDIR, but does not deviate a lot from the S88. You can use it without a SwitchBot by configuring it with a phone on Bluetooth. The meter works on external power and battery, but even when on battery, you can set the reporting interval to 5 minutes, which is good enough in practice. The meter broadcasts the measurements with Bluetooth LE, so if you want to get the data in Home Assistant, you can place a ESPHome Bluetooth LE Proxy in the vicinity [1]. This is an ESP32 flashed with ESPHome that listens on Bluetooth LE advertisement and forwards them to your HA instance over WiFi. Of course, you could also get the SwitchBot Hub, but what is the fun in doing that? :)

I would avoid the Ikea ALPSTUGA, it uses a thermal conductivity sensor, which is a very indirect method for measurements and it's often several hundred ppm off.

https://esphome.io/components/bluetooth_proxy/

dgellow6• 19 days ago

Thanks for mentioning that, last week I got 2 SwitchBot hub mini, 3 temperature sensors each, for 70€ total, they are really neat. Even put one in our fridge, I didn’t expect the signal to pass but it’s working :)

Will look at adding the CO2 monitoring

Edit: actually, they only sell them as part of a 6-in-1 device, with a display, and a bunch of other sensors. That feels overkill, I wish they would just sell the CO2 sensor itself

ac292• 18 days ago

I have a SwitchBot Meter Pro CO2 that is just temp/humidity/C02. Works well and was inexpensive ($50 or so).

bjackman6• 19 days ago

As a middle ground I can also recommend this unit: https://apolloautomation.com/products/air-1

Looks like it's increased in price unfortunately but I like the idea, it's basically just what you would do as a DIY project but ready built. So you can either use it like a normal commercial product, or you can just fork the ESPHome config that's on GitHub and flash it exactly like any normal ESPHome project.

microtonal15• 19 days ago

Yeah, I have heard good things about them. There are some other options that are kinda in between DIY and a product, like those by Screek Workshop.

https://screek.io/ https://shop.screek.io/products/sco-b

No recommendation though, I haven't tried them.

originalvichy• 18 days ago

I would recommend Ruuvi Air, its sensors are high quality, and is quite open for devs to do pretty much whatever with it. Works by broadcasting sensor data over BLE, so if you have a smartphone or a home assistant server with BT connectivity, you can display or store the data live. The iOS app sends alerts when different custom thresholds are crossed, like for co2 ppm.

They do have a gateway product, but it’s not necessary if you have HA. If Apple homekit routers supported BLE as source it would work seamlessly in the ecosystem, but a bridge software is required on HA.

nenadg• 19 days ago

At some point I worked with a team of ~10 people, and we did sprint plannings in 20sq meters room from 10am to 5pm. It was like everyone was high

joshuaS98• 19 days ago

Why did your startup fail? The CO2 was sitting at 1.000 ppm

bambax• 19 days ago

Open a window.

In most office buildings (towers) that's impossible. You have to deal with what the A/C gives you.

materialpoint• 19 days ago

Goes a long way to prove that industrial air conditioning is absolutely abysmal. If air conditioning actually worked satisfactorily, opening a window should never be necessary unless you want the cold waft of air, while the air conditioning actually delivered high-quality, low-CO2 air without smell. Instead any room at > 20% capacity is quickly filled with CO2 and the putrid smell of bad mouth and body odour. I get it that perfect ventilation would be way more expensive, but at the current level it is just bad, and the windows are sealed shut. It does not make sense from a human perspective.

fractallyte• 19 days ago

Aranet detectors are superb, and – best of all! – made in Latvia.

Support European!

https://aranet.com/en/home

skrebbel• 19 days ago

I wonder how many high impact political decisions (eg EU treaties) have been made in rooms like these.

zerop• 19 days ago

I tend to agree with this observation. I started taking my evening calls (6:30 to 10:30 PM everyday) from my terrace in open air and my overall fatigue became quite less and I feel quite less tired compared to earlier time when I used to take these calls from my room.

swe_dima• 19 days ago

if I travel and expect to be working I now bring a CO2 meter

metalman• 19 days ago

open a window, wait, ok, ok, turn up the , wait, no, ummm, hmmmmm re, re, no forget that, hmmm anyway, as a person with a strong interest in civil engineering, systems, and the subset of air handling, I can say that there has long been disenting arguments about how things are built,that have been ignored due to cost, which are large in terms of internal volumes required, and the intractable issues around, noise, filtration, heating/cooling and maintenance. And as the climate warms, and in many areas pollution increases , the inadequate methods used to "calculate" requirements, get further from real world needs. You could try throwing a desk through a window, but as that is one of the things the planners and engineers have antisipated, it will prove to be surprisingly difficult.

teekert• 19 days ago

I also use my Aranet everywhere. The nice thing is you quickly develop a feel for when you need to ventilate spaces you know so you don’t need it there anymore. I also developed a feeling for new (to me) rooms a bit.

I once woke up with the fam in a hotel with airco at 5500 ppm. It is then that I learned the airco does not blow fresh air (logical after thinking about it).

jumploops• 19 days ago

Indoor air quality improvements were one of my “pandemic sourdough” activities.

After testing a variety of AQI sensors, I ended up acquiring multiple Airthings-branded devices.

They provided the best mix of CO2/VOCs/PM sensors in a single device with a decent enough app.

There may be better options now, but I have these at both home and office.

Highly recommend doing the research and learning about the environments you’re in, especially if you have little ones at home.

Edit to add: opening windows is usually the easiest/best solution!

londons_explore2• 19 days ago

Are there studies which analyze performance Vs artificial CO2?

Natural CO2 in a room probably correlates strongly with other things given off by humans... Farts, water vapour, viruses, etc.

The effect needs to be properly understood before totally redesigning the nations ventilation systems on a possibly wrong premise.

irdc• 18 days ago

There are. The article literally cites a publication describing just such a study.

Mistletoe• 19 days ago

The really uncomfortable part is that 1000 ppm isn’t that far off from how EARTH will be. A terrifying scenario that will be like Total Recall with people clamoring for and paying for fresh air. Those that can’t will be permanently in a stupor.

https://science.nasa.gov/earth/explore/earth-indicators/carb...

SunboX• 19 days ago

Great article! I did build a open source one years ago: https://andrefiedler.de/open-source-co2-ampel/

It's on my desk and I can confirm, opening the window if it gets orange helps a lot with thinking.

Some days in the morning it shows red and I barely can't think or get awake. Opening the window and it changes instantly.

carterschonwald• 19 days ago

i literally had a co2 sensor for my engineering team last fall cause the space was so poorly ventilated. just measuring it continuously radically changed how everyone approached using the space packing wise and ventilation. smelled better too :p

TonyAlicea10• 19 days ago

Topic must be very interesting to have this much discussion on an obviously AI-written article. I couldn’t get past the first few sentences.

smooc• 19 days ago

I do feel impaired around 1000ppm. I get headaches. At home I got a few Air Gradient Ones (no affiliation, but they are great) and connected those to my Home Assistant to turn up the ventilation in stages (above 650ppm go up, above 800ppm again, at 1000ppm max). I also do this for the bedrooms, cause in the night it goes up too.

The article talks about "within the hour". With four people in my living room doing normal things it jumps within 20min to around 1000ppm. If I am wrestling with my kids much sooner.

In offices companies often neglect it.

edit: if you are cooking on gas it also has an immediate effect on co2 of course apart from other small particles

lloydatkinson• 19 days ago

I can feel the AI in the text.

netsharc• 18 days ago

Yeah, I noticed it at "Here is the uncomfortable part. 1,000 ppm is not an extreme number."

Either AI, or LinkedIn brainrot.

vertnerd• 19 days ago

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 monitor home, I found the levels there were elevated even with no one home and surpassed 2000 with just two or three of us in a room.

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.

tsss3• 19 days ago

Your comment is suspiciously missing the part where your students performed measurably better after decreasing CO2 concentration.

wffurr• 18 days ago

Assuming they had any control over the ventilation in the room.

weberer• 19 days ago

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.

You could also install an energy recovery ventilation (ERV) system.

Cthulhu_• 18 days ago

Houses where I live were fitted with those. People turned them down to the lowest settings because they were loud. Then people developed health issues due to high CO2 and they had to refit the systems.

throw0101a8• 18 days ago

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

cucumber37328422• 18 days ago

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.

mort963• 18 days ago

I would not want to live in a city where I have to be careful letting in outside air or going outside because there's too much air pollution...

cryptonector2• 16 days ago

Uh, no, homes should not be airtight. You'd have a hard time closing exterior doors if they were, and anyways, houses need to be able to "breathe" to be able to keep humidity down (you don't want mold problems), oxygen up, CO2 down, etc.

Aurornis8• 18 days ago

Most studies don't register cognitive changes in the range of 2000ppm. A lot of the military and space studies used exposures multiple times higher than that without registering cognitive problems. It wasn't until you got to very high numbers that they registered any changes.

Only a couple studies purport to show cognitive changes at levels around 2000ppm, and the ones I know of all involve one controversial researcher named Usha Satish.

There are a lot of studies with CO2 levels at 10,000ppm or higher that have failed to find cognitive effect (an example https://pubmed.ncbi.nlm.nih.gov/29789085/). Your 2000ppm classroom air would have been like fresh air relative to the concentrations these studies are looking at.

Yajirobe• 19 days ago

I have a CO2 monitor and I don't understand one thing - it seems that CO2 increases more quickly during summer than during winter. If I close my windows it takes longer to reach 1000 ppm during winter than it does during the summer.

I didn't gather concrete data on this but this is just what I eyeballed over the last few years. Does anyone know why could this be the case?

hoppyhoppy2• 19 days ago

Do you have a forced-air heating system?

bad_username• 18 days ago

The speed of air exchange through openings in your room (windows, gaps etc) is proportional to the difference of temperature between your room and outside. The more different the temperatures are, the more intensive convection is, and convection is very effective at moving/exchanging air. In summer the difference in temperatures of your room and the outdoor space is much smaller than in winter, which subdues convection, and the stale air tends to stay.

pavlus• 18 days ago

Cold air is more dense, than hot air. In winter the difference between the room air temperature and outdoor air temperature is much bigger, so the density difference is much bigger, making Archimedes force stronger and the airflow stronger as well.

BTW, that's also how stove pipes work - vertical column of air hotter than surrounding accelerates well and creates a strong airflow feeding the fuel. But if the pipe is thermally conductive, that air will cool down and won't flow, for hydrocarbon fuels it can also condensate water, that could extinguish fire underneath it. So, pipes are made insulated enough for strong flow.

doginasuit• 19 days ago

I find it kind of funny that we've been low-key suffocating the higher order function of our brains ever since we started building structures to live in with very little awareness of it. My mom is one of those people who complains that the air is getting stale and opens a window, the hero we needed.

jeromechoo• 18 days ago

Not that we need more anecdotal evidence but I’ve long felt a certain restlessness and inability to think creatively somewhere in the early afternoon. I work from home with my wife. I’ve eliminated lunch, coffee, and a ton of other variables. The one variable that finally had a distinct effect to my mental state was opening a window.

lofaszvanitt• 19 days ago

Wow, what a revelation. People rediscover basic things in life :D.

tsss3• 19 days ago

You know what also impacts my decision making ability? Freezing my ass off because people are opening all the windows every five minutes.

xg152• 18 days ago

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.

layer82• 18 days ago

These CO2 monitors have a configurable audio alarm. The present model uses an e-ink display to conserve battery. Physical LEDs would also work, but really in practice you don’t look at the unit and instead are notified by the audio alarm.

xg152• 18 days ago

Ah, that makes more sense.

jickmao• 18 days ago

The practical bottleneck for most AI tooling isn't model capability anymore - it's the orchestration layer. Getting reliable behavior across edge cases requires more engineering than people expect from demos.

frigaardj• 18 days ago

Is this a bot?

bob1029• 18 days ago

I've noticed that cooking with gas is easily the worst thing for CO2 levels. Even with lots of ventilation my kitchen will hover around 1200ppm until it's over with.

I swear I can feel the 430ppm already. I was born into a world with 340ppm. I can't imagine what it's going to be like when we hit 500+ globally.

I'm in the market for an active CO2 scrubbing solution that I could deploy at home. Scrubbing the entire planet won't work but I could make a small room feel like 1960 again.

Schiendelman• 18 days ago

What have you found so far?

OutOfHere11• 18 days ago

Controlling indoor CO2 is important, but it's a proxy metric for the escalation in indoor bioeffluent VOCs which are a tiring subset of total VOCs. This is why scrubbing indoor CO2 will by itself never produce the pro-cognitive result you want. See https://www.aivc.org/resource/effects-carbon-dioxide-and-wit...

Also, when you cook on a gas stove, it produces numerous other toxic gases which too are critical to ventilate before they even escalate, failing which the lung cancer is risked.

Scrubbing indoor CO2 is sensible only when you want to go below the outdoor CO2 level, not at levels above it.

mikestew2• 18 days ago

I swear I can feel the 430ppm already. I was born into a world with 340ppm.

You’re probably about my age, then, and I’m old. It might not be the baseline CO2 levels. :-)

Kidding aside, that would be hard thing to baseline.

Retr0id• 18 days ago

LLM prose really sucks the air out of a room.

layer82• 18 days ago

My employer started using CO2 monitors in meeting rooms 15 years ago, it’s really a useful thing to have. As well as the meeting rooms having windows you can open.

teiferer3• 18 days ago

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.

throwaway27448• 18 days ago

Or just open the window for the world that doesn't have HVAC

mort963• 18 days ago

In most of the world outside of the US, having "an HVAC system" is extremely rare.

teiferer3• 17 days ago

But maybe it shouldn't.

I visit a friend in Sweden the other day. Her house was built in the 80s, nothing fancy, a simple one family house. There is a ventilation system integrated. Every room has an inlet and the air is sucked out of the bathrooms and kitchen. Even has a heat exchanger. It's a pretty simple system: no cooling and it's not really used for heating except for pre-heating the incoming outside air with the energy in the exhaust air. But it exchanges the houses air multiple times a day. She told me this has been standard there for decades. A few ventilation pipes integrated into the houses construction and that's it. It's even mandatory in multi tenant houses to check air flow every few years.

It's not just the AC crazy US where HVAC is standard. It's just common sense to have such a system if you care about your health.

ncrmro• 18 days ago

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.

Beijinger• 18 days ago

Ugo Bardi has an interesting take on CO2 and intelligence: https://senecaeffect.substack.com/p/a-new-interpretation-of-...

Qem• 18 days ago

That's scary if confirmed. It took 500 million years for complex life to find the right mix of atmospheric O2/CO2 to foster intelligent lifeforms. Then we are undoing it in mere centuries.

clbrmbr• 18 days ago

Matches my experience. Basement home offices are the worst offenders.

abalashov• 18 days ago

As a cyclist, I've heard a similar argument for years about indoor training, and particularly doing difficult indoor intervals beyond FTP.

alienbaby2• 18 days ago

Working from home next to my open window feels generally way better then being in the office. Perhaps this is contributing. Still, seems more of a case for WFH rather than against, as article mentions some people have tried to make the case for.

scrollop• 18 days ago

Interesting.

Perhaps using non-ozone negative ionizers would also help.

ck2• 18 days ago

if price is no object get the AirGradient PM2.5+CO2

but Ikea now makes the most affordable PM2.5+CO2 sensor, at $35 a no-brainer

https://www.ikea.com/us/en/p/alpstuga-air-quality-sensor-sma...

in there is a very nice/expensive Sensirion SN63C sensor that costs nearly as much as the Ikea itself

https://sensirion.com/company/news/press-releases-and-news/a...

unfortunately Ikea requires Matter network not plain wifi for communication so I've been looking for a cheap Matter hub or DIY SPR

chrisweekly2• 18 days ago

I bought a $30 CO2 monitor a couple months ago, and it confirmed my suspicion that my home office (a normal room about 12' x 18') reaches unhealthy levels over 1000ppm after just a few hours; opening a window quickly restores levels to the 400-700ppm range. Afternoon mental fatigue solved. Highly recommended.

abixb• 18 days ago

Fantastic, did you go for a particular "trusted" brand or just went on vibes? How should one rationally approach shopping for a CO2 monitor for home office use?

chrisweekly2• 18 days ago

I didn't do much research, got a really basic "Temtop" model from Amazon.

machined_gray• 18 days ago

Get a sensor with NDIR system and it should be good. I myself have felt cognitive functions decline during my remote work sessions at home. I have smaller room that gets filled with CO2 when my family visit the room.

Comprehensive AIR monitor system is must to get most efficient output. Author is right here!

tmp147963• 18 days ago

Having CO2 sensors is mostly useless.

In Quebec province in Canada, they added CO2 sensors in all the classes in all the schools after covid. Now what? Having data does not change anything if nothing is done.

If instead all the millions invested would have gone into adding air exchangers, now that would actually do something.

And that is assuming that CO2 levels really have an impact. From the last time I researched the subject, I found that there were few studies showing an impact.

For context, from what I remember, in submarines the CO2 levels are usually between 10 000 ppm and 20 000 ppm. Very far from 1000 or 2000 ppm.

Also, CO2 sensors are usually pretty bad. I work in HVAC and I hate calibrating them, the readings are not very consistent. Leave them alone for a few years and a good percentage will simply output bad readings.

Then you see things like a teacher leaving the windows open in winter because the sensor says 2000 ppm all the time instead of realizing the problem is the sensor. (CO2 levels should go back to atmospheric levels over the weekend for example at about 450 ppm)

shawabawa3• 18 days ago

I very much doubt submarines operate that high

The ISS runs at 3000-6000ppm CO2. over 7000 is dangerous

a3w• 18 days ago

over 7000 is dangerous[citation needed]

I found 3-11k as regular levels, with no impairment known of. So acclimatization can happen?

Hikikomori4• 18 days ago

Having CO2 sensors is mostly useless

I got one because old apartment and bad ventilation. Was able to open a window when I felt the effect before, but now I can get an alert earlier. Since getting it I could consistently feel the effect at around 11100-1300.

spixy• 17 days ago

Not useless.

You cannot solve a problem when you don't know you have a problem.

xyzelement2• 18 days ago

I'm in the indoor air quality business. This is real.

A good way to think about CO2 is as a proxy for dirty air. CO2 is easy to measure but what it really means:

The next breath you take has: - already been inhaled and exhaled by others several times. - contains remnants of their farts, burps, off-gasing from everything they are wearing, have, everything in the room, etc. - may have presence of other gases like radon in the winter, mold spores, g-d knows whatever else. - co2 itself has negative effects but mainly it's a signal of what else is probabilistically in your air, poor ventilation.

Florence nightingale the inventor of modern nursing wrote that making indoor air as close as possible to outdoor air (without freezing the patient) is the best and most overlooked input to wellness. I believe this is still true.

Weirdly there are people who for some reason are hell bent on denying the air quality as an input to health and cognition. The simplest way to reason about it is: the argument for organic food is the less toxin-like stuff in it the better. Same for filtered or spring water. We often fail to quantity the impact exactly but we (logically) know that less toxin is better. For some reason we hold a much higher bar for "blaming the air" which doesn't make sense.

By volume we consume exponentially more air than food or water, and it enters the blood stream faster and more directly so obviously it impacts us. The EPA ranks indoor air quality as a top risk.

Ironically we are obsessed with outdoor air quality and if you have allergies to things like pollen that's a real concern but in most cases outdoor air is the baseline for what's indoors + other shit is added.

I find that there are people who say "wow air quality here is bad" and there are people who say "oh man I'm tired lately" without being able to attribute it, but I don't ever see anyone thriving in what is objectively bad air.

xyzelement2• 18 days ago

Sorry forgot the thing most directly related to the article. Harvard did a study on air and cognition (Google Harvard cogfx) - here's the Gemini summary which tracks with my research:

Study 1 (Simulated Office): Participants in optimized "Green" and "Green+" office environments scored 61% and 101% higher, respectively, on cognitive function tests compared to conventional office environments.

Study 2 (Buildingomics): In a real-world analysis, occupants of high-performing, green-certified buildings had 26% higher cognitive scores and slept better than those in high-performing but uncertified buildings.

Home/Work Study: Researchers tracking remote workers found that suboptimal indoor temperatures and elevated CO₂ (indicating poor ventilation) directly harmed creative problem-solving and cognitive processing.

Aaron_NW• 18 days ago

Very interesting. It would be nice if HVAC monitored this and helped adjust for optimum performance.

I heard a Freakonomics podcast recently with similar takeaways - that air pollution has a direct effect on cognition skills.

LordDragonfang3• 18 days ago

Hey, just FYI to everyone:

Even though this article is conveying good (and useful) information, it seems to be completely AI-generated.

Pangram clocks it as 100% AI: https://www.pangram.com/history/c410d4b4-abfd-4ca0-b52d-db0d...

Someone else in the thread lists it as 99%: https://www.salahadawi.com/hacker-news-ai-detector

Also, it sort of jumps out at you if you're used to reading AI writing. Claude loves to start paragraphs with "Here is the uncomfortable part".

I'm not necessarily saying this automatically makes it bad, but everyone should be aware of the source of their information.

gdilla• 18 days ago

People don't understand ppm like they do temperature units. These rebreathed stickers can help drive home the point. Especially when the next respiratory virus season rolls around. https://naltic.com/product/aranet4-rebreathed-percentage-sti...

You will take ~ 1000 breaths per meeting hour. really gross!

Royce-CMR• 18 days ago

I’ve had a Co2 monitor for years. I get headaches from increased Co2 levels plus the lethargic state. It’s been revolutionary - including on long drives where it’s def saved me from crashing.

Personal opinion, you can see cognitive decline at 1000 ppm. Not “ur a zombie” but it’s there. Airflow has vastly improved my life.

Another personal opinion - the coporate stupidity and inane behavior we all see tracks back in part to Co2 levels turning people into quasi zombies. It’s a lot easier to just not care, and things don’t click like they should, when in higher Co2 environments - pushing everyone to rote, process, unthinking approaches. Sounds familiar?

txoria• 18 days ago

Sherlock Holmes disagrees: "I find that a concentrated atmosphere helps a concentration of thought. I have not pushed it to the length of getting into a box to think, but that is the logical outcome of my convictions."

As other commenters noted, it's more about dirty air than CO2 levels - so, logically, should not be a problem for everyone.

If article is really written by AI though, then what if it's PSYOP? The question to ponder then is: why AI wants low CO2 levels? Maybe, for people like Sherlock Holmes to lose a concentration of thought?

rcr-anti• 18 days ago

After digging around, it looks like this area has some replication trouble. And as other commentors have pointed out, submarines operate well beyond these levels and the results failed to replicate in those contexts. Doesn't rule out CO2 as proxy for other components of air though, and most of the studies that failed to replicate added pure CO2.

ButlerianJihad• 18 days ago

When I was homeless, I often battled extreme sleep deprivation. I would often play tabletop games in a coffeehouse during the nighttime hours, and of course I found myself nodding off in there, even with the hubbub and the smell of fresh-roasted coffee brewing all night long.

I also attended liturgies at church all the time, and let me tell you, there is no CO2 machine like faithful Christians packed into a little chapel who are all singing for 90 minutes, and standing shoulder-to-shoulder. I was absolutely desperate to stay awake during those times, and I knew instinctively that it was an issue with the CO2/O2 mix in the room, and I was personally the most sensitive to it, being extremly sleep-deprived, but I am certain that many others felt the physical adverse effects, without being cognizant of what was causing them.

I still suffer from sleep deprivation today, and when I settle in to our chapel of silent prayer, I often find myself nodding off uncontrollably, and it's so frustrating because I want to be alert and actively praying, but the environment is just... so relaxing. There are only about 4-5 other humans in the room, so the genesis is basically just me relaxing in a sitting, quiescent pose for a significant amount of time. I believe that the room is well-ventilated, but are they constantly recirculating air? The air outside can be 115 degrees; are there active intakes that must cool this hot, dry, dusty air? That's a lot of work!

My father having worked in Environmental Health & Safety, I became fairly good at recognizing hazardous or troublesome situations, especially indoors and with large numbers of people. I try to avoid getting embroiled in them, and it usually does no good to try and alert any supervisor or management about the issues, but this blogger is right; we must raise awareness and take action.

relwin• 18 days ago

My local library displays CO2 level on an inconspicuous wall fixture as part of the HVAC system. If the level gets too high large shutters (near the ceiling) open directly to the outside, supposedly as a failsafe. The head librarian said he's never seen them open in the past dozen years. After 20 years of patronizing this facility I now know a little bit more on its operation.

cwoolfe• 18 days ago

I noticed this when comparing my experience in open offices with lots of airflow to the cramped spaces of our WeWork co-working space. I could feel the difference. Also one time I slept in a small basement room with no ventilation. I woke up at 3am feeling like I couldn't breathe. I opened the door and felt better.

sarchertech2• 18 days ago

If you want citations search my post history, but CO2 cognitive impact studies have a replication issue.

We’ve been studying the impact of CO2 for decades, at much higher levels than you see in office buildings and have never recorded any cognitive impact (until many thousands of PPM) until the Satish study in 2012 and a handful of other studies that Satish was involved in.

If you think about it for a second these studies can’t be accurate. If they were, you’d see differences on SAT scores of hundreds of points depending on building ventilation. You’d see huge variations between taking the SAT in the springtime when the windows are more likely to be open or in the winter.

You’d expect to see massive performance differences across nearly every metric between regions that use AC vs those that depend on opening windows.

And we do not see anything like that.

phyzome• 18 days ago

Yes, I'm a little skeptical as well. My apartment generally runs between 1000 and 1500 ppm, and I sometimes work outside, but I haven't noticed large differences in ability to work and concentrate between the two. (What does help is moving back and forth.)

I tried keeping my room well-ventilated (500-700 ppm) for a few weeks and didn't notice much impact on sleep and work. There was a burst of positive effects a few days into the experiment but it didn't last and was likely unrelated.

The air definitely starts feeling stale and gross around 2000 to 3000, so I try to keep it below 2000.

That's all personal anecdote, but it similarly drives me to ask: Where's the replication?

VygmraMGVl• 18 days ago

As an example of a negative result-- https://www.nature.com/articles/s41526-019-0071-6

Astronauts given two different batteries of cognitive tests showed no dose-response relationship to CO2 concentration

doctorpangloss• 18 days ago

I've only seen legitimate CO2 concentration studies with small impact on sleep quality (>1000ppm ie unventilated rooms can cause 1-5% decline in sleep efficiency, observable as more nighttime wake ups or longer sleep).

Aurornis8• 18 days ago

The difference between Satish-involved studies and other studies is extreme, too. Their first 2012 study tested levels at 600, 1000, and 2500ppm. In many categories they observed the 2500ppm group receiving "dysfunctional" ratings in their tests. Even their 1000ppm group saw significant drops.

This sparked the panic about CO2 levels that led to people buying CO2 sensors and thinking that not unusual CO2 levels were actually destroying their ability to think. Many conclude that this has been happening all of their lives and to everyone around them who is unaware.

It triggered a lot of follow-up studies. Confusing, some of those (like the Harvard one everyone cites) included Satish, meaning they weren't independent despite coming from different organizations.

The really interesting thing is that many of the follow-up studies that don't include Satish have even used CO2 levels much higher than the 2012 study that caused the panic. Here is one I grabbed at random that went all the way up to 15,000ppm and failed to find any significant changes: https://pubmed.ncbi.nlm.nih.gov/29789085/

There was also a lot of CO2 research before Satish come along that failed to find significant effects at these relatively low levels. It has been researched in the contexts of air quality for submarines and space shuttles by militaries and NASA because keeping the crew of those operating optimally is important, clearly.

schiffern• 18 days ago

CO2 on the ISS routinely gets up to 5 mmHg = 6,500 ppm, because the CO2 scrubber is more effective at that concentration. According to NASA it's "not practical from a hardware standpoint" to set the operational CO2 limit at 4,000 ppm.

https://ntrs.nasa.gov/api/citations/20100039645/downloads/20...

theshrike79• 14 days ago

In these studies, are the people told that they have less CO2 in the air?

My experience is more like being slightly drunk. If you know you need to be sharp (client meeting in a meeting room with shitty air), of course you can do it.

But when you have a relaxed team meeting in the same room, the jokes start getting really bad _really_ fast after the CO2 levels start going up.

utopiah• 18 days ago

I do free diving recreationally and I think the opposite is true. Air in the room is not the bottleneck, ever. Finding the right goal with the right people is. Even with very very little air a lot can be done, in fact constraints, even as fundamental as air, can help.

lalalandland• 18 days ago

"Opening a window or a door costs nothing."

Central ventilation system at my job can handle open windows. So that is prohibited :-(

Melatonic2• 18 days ago

The real bottleneck is the CO2 while you sleep. More CO2 means worse sleep means worse daytime performance.

tangenter• 18 days ago

You gather your notes about the article you’re to publish and you send them to your favorite LLM. Not your editor. Not your most helpful critic. The LLM.

GreenWatermelon2• 15 days ago

And Here is the uncomfortable part: The LLM smell in your article is obvious. Not only will people notice, but they will severely denounce the article. Absolutely Shame.

ducktastic• 18 days ago

Don't forget about a concept called 'sick building syndrome'

varispeed• 18 days ago

This triggers my PTSD. Had to work in managed office that was sealed and aircon was clearly not working properly. I had headaches etc. I didn't have such meter. Numerous complaints to management did nothing. They said everything is normal. That said it seemed like only myself was sensing this as other people said I am dramatising. It got to the point I decided to quit that job as I literally couldn't breathe properly there.

fuzzfactor4• 18 days ago

Maybe more like a catalyst than a bottleneck when you think about it.

A possible cayalyst for compromised decision-making during crowded meetings :\

reassess_blind• 18 days ago

I suspect there's a lot of placebo effect happening in this thread.

colinsane• 18 days ago

any tips for calibrating or even just validating these handheld CO2 meters?

i've taken a few Amazon-listed CO2 meters from $dirt-cheap to $150, tossed them in a ziplock, and then discharged CO2 from a canister into the bag & sealed it. none of them read notably differently after an hour, nor show any sort of range error, etc.

i've also done this without the ziplock: put them in a large pot, fill that with CO2. CO2's heavier than the rest of the air so the concentration should remain elevated within the pot, but same deal.

i like the idea of monitoring CO2, but it's hard enough to get certainty about the _effects_ of CO2 level; without confidence in my meter i fear the conclusions i draw from it are more noise than signal.

flawn• 18 days ago

I mean, I validate them by opening my window and seeing what the floor is. For me around 430ish usually - inline with what's in the atmosphere globally.

Henchman21• 18 days ago

Imagine if we applied this logic to climate change?

godot• 18 days ago

With so much work now remote, your people spend their days in small home offices with the door shut.

People should probably get used to opening doors and windows more. Sure for some people there's noise problems (kids in the house, or outside environment being noisy) but there's also a lot of people who just don't know better even if they are in a perfect environment to open windows in (e.g. no noise outside).

zftnb666• 18 days ago

2026: AI runs on GPUs. GPUs generate heat. Heat needs cooling. Cooling costs more than the GPUs

OutOfHere11• 18 days ago

The indoor CO2 level is important, but the article completely failed to discuss the correlated bioeffluent VOCs which also contribute to a good chunk of the adverse effects. Ventilation fixes both. Fwiw, my video covers it: https://youtu.be/26ENvFJK08E

zeristor• 18 days ago

I’ve wondered if we can do better, with my Aranet in Spring, and living close to the forest with the windows open on a breezy day my CO₂ reading went down to 410.

I’m guessing if someone had their air go through a conservatory first it could go lower.

In some climate YouTube videos people slip in the CO₂level of when they were born, an interesting point, mine was 325, but I guess there was more lead in the air then…

Is there much of an improvement, impractical as it is, to a far lower CO₂ level.

cryptonector2• 17 days ago

I carry an Atmotube with me to monitor VOCs and particulates, but it also measures CO2 and NOX. It's small, and it easily attaches to a backpack or belt loop with a carabiner it comes with. The only thing it's missing is different running average time scales.

wranglerjeans• 17 days ago

deleted

The bottleneck might be the air in the room

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