The bottleneck might be the air in the room

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.

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.

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.

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.

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...

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/

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

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.

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.

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.

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)

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.

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

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.

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

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.

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.

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.

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.

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?

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?

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!

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...

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.

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.

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.

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

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

> 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.

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?

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.

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!

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?

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.

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.

> Open a window.

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

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.

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.

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

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.