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.
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.
> 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
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.
I was looking at CO2 sensor module boards this week and the sensors themselves are quite large and the floor price is $15ish.
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.
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)
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.
Can it work with Zigbee network or is Matter/Thread required?
It’s part of the new range which is all matter over thread only. The existing ikea hub can do thread though.
I'm using a bunch of IKEA's "smart home" stuff, all via Zigbee+HA, works great. Look for the Zigbee icon on the package, and the pairing for Zigbee vs their own home controller might have slightly different pairing sequence on the device, otherwise it just seems to work.
> The thing runs on usb 5v so the power consumption is negligible.
There’s a huge leap from that to the power consumption being low enough to be integrated into a smartphone, as demanded by OP.
I don't think power use is the issue. I have this cheap CO2 sensor: https://www.domadoo.fr/en/devices/5882-heiman-zigbee-air-qua... which draws 0.5W. This includes thermometer and humidity sensor, Zigbee transmission, and acting as a Zigbee router, but it gives us an upper bound. It also measures continuously (picks up someone breathing on it within 10s), which is overkill. A phone could measure CO2 levels once every 10 minutes which would average under 0.01W, so that would work.
However, this assumes the sensor would fit in a smartphone, which is not a given. And these things need air flow. And they also wouldn't work while the phone is in a bag or a pocket.
> 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.
[dead]
Apple watches already have a blood-oxygen sensor so it's covered, albeit indirectly.
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) ...
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.
> The article references a study where the CO2 proportion going from 0.04% -to 0.25% causes mental problems. In other words, a difference in 0.21% of the air.
I'm finding that pretty difficult to believe, to be quite honest with you.
And before you say "aha, carbon dioxide brain fog!" consider that I'm about a mile from the sea with a 40mph onshore breeze. This air is about as oxygenated as it gets.
It makes a lot of sense actually. You get severe symptoms when CO2 makes up only a couple % of the air. And can become fatal at like 5%. There’s not like a hard line where you suddenly die, it’s a gradual thing. It very much makes sense that we’d notice minor symptoms at a few thousand PPM when it only takes like ten thousand to feel it severely.
1% (10,000 ppm) is enough for the person to become aware something is odd through drowsiness or an elevated heart rate.
I don't think it's too far-fetched for a quarter of that to cause subconscious cognitive effects, that could be measured in tests.
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).
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.
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
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.
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)
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.
This is not a peer-reviewed study. It's a Tom Scott youtube video.
Somewhat unrelated, Tom also did a great video where he was put in a low oxygen environment. Similarish effects, differentish cause.
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 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.
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.
Ok, fair points, including the sister comment, it's likely not a drop in O2 levels.
But then why can we see problems with concentration in studies of people in poorly ventilated rooms, but not replicate that when just adding CO2 to normal air? What is the CO2 that we can measure in meeting rooms actually a proxy for?
The Satish 2012 study that seems to have started this trend was a small cohort of 22 people split in 6 smaller groups where they also just injected pure CO2 in a small room. There have been several attempts to reproduce, which sometimes found no clear effect, or a significantly smaller effect.
This original study has been used to market these CO2 monitors for years, but the evidence is quite thin and doesn't support a strong effect. It seems likely that there is a small effect, and it has been wildly exaggerated thanks to a small study with N=22.
O2 is 200000ppm so if co2 goes up 400 to 2000ppm does o2 go down to 198400ppm?
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.
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.
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.
CO2 levels will rise much more slowly to such high levels even in a small room.
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.
> Open a window.
In most office buildings (towers) that's impossible. You have to deal with what the A/C gives you.
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
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.
There needs to be a meter for the amount of AI writing in blogposts. Same physics, same climb, same afternoon fog.
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.
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...
Yeah, it's really tiring reading Claude's output all day, every day. Nowadays I yearn for a different style.
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.
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.
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.
Relevant video of someone experimenting with a CO2 monitor in a car: https://youtu.be/hr9w-ZixAqc
Cars are not sufficiently sealed for that to make any kind of a difference.
Try it yourself. They really are
Cars aren't hermetically sealed vessel. This is hilarious.
You think that’s stopping CO2 buildup?
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.
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.
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.
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.
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.
I do not give a damm about masks, but yet another reason to prefer work from home.
Flu and other air transmited diseases should be treated as a workplace injury, with proper compensation!
could you observe an effect on your health after starting to wear the mask? like sickness days per year?
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.
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.
“That number matters more than it looks.”, then the next paragraph starts with “Here is the uncomfortable part”, and then I closed the tab.
> 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.
Why did your startup fail? The CO2 was sitting at 1.000 ppm
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?
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.
My previous employer had dogs shit on carpets, without proper desinfection! Just smearing excrements into carpet, waiting for it to dry out, so it can go airborne!
How do you avoid/reduce exposure to dust? Genuine question
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.
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.
Use an air purifier, wear a respirator outside if you live in a polluted place.
Air purifier is good for PM2.5 and other microscopic pollutants but it doesn’t do that much for dust unless it’s particularly light dust and very close to the purifier.
Dust is much more likely to just settle on the ground and be kicked back up than it is to move all the way to the purifier to get stuck in the filter.
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?
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.
It simply makes the baseline higher. If you want to go to extreme cases, check carbogen
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.
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.
Just open the door
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.
[dead]
Buying one of these gadgets killed my brain fog
[dead]
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 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.
i love seeing things i saw on twitter two years ago at the front page of hn man like what are we doing
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.
Requires an area around your office that isn't ugly or overrun with cars.
It needs to be safe (including from pollution), but you could absolutely just walk around the parking lot.
Scandinavia wins again :)
requires that everyone is comfortable walking and has no physical impairments.
Not to talk about the weather either.
> You gather your most expensive people into a room to make your most important decisions.
A terrible way to make decisions.
What should be a better way?
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.