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.

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.

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.

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...

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.

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.

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/

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.

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

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

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.

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.

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.

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!

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.

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!

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

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.

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 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.

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.

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?

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

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?

> 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.

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.

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

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

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 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?

> Open a window.

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

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.

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.

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.

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.

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.

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.

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.

Interesting.

Perhaps using non-ozone negative ionizers would also help.

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).

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

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.

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

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

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.

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.

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.

LLM prose really sucks the air out of a room.

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.

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...

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.

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 can feel the AI in the text.

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

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

Buying one of these gadgets killed my brain fog

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

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

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

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.

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

Support European!

https://aranet.com/en/home

Just open the door

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.

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.

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

A terrible way to make decisions.