For CO2 specifically, one offline option is the "CO2Meter RAD-0301", also available as "TFA Dostmann AirCO2ntrol Mini" and possibly other labels. They have an unofficial USB interface too: https://news.ycombinator.com/item?id=22764488
Anything that moves the air is fine. And yes, opening windows would be a sensible thing to do in that context.
That said, I'm not sure I buy the thesis as a whole. As far as I am aware, last time this came up, the Navy has done pretty detailed tests on CO2 concentration as a result of submarine warfare and found no significant impairments up to 1200ppm.
Opening the windows is a solid choice. I keep a CO2 monitor in my office. So long as I keep the door open, levels usually stay below 800ppm, but if I close the door they can climb rapidly within an hour or two. I have a CO2 meter tied to an alarm to remind me to open the window if they get too high. I probably should have it set to 800, but I found that to trigger too often so I upped it to 1200.
I use a RAD-0301, which works fine as a monitor and an alarm by itself, but which I connect to a Raspberry Pi for dashboard purposes using the code shared here: https://news.ycombinator.com/item?id=22764488
If you have central heat/ac your thermostat might have a switch to convert it from 'auto' to 'on'. You can combine that with turning off the heat/cooling such that it's just a house/apartment-wide fan. I do that at night before going to bed to deal with poor airflow in my bedroom and according to my CO2 sensor, it works. It works correctly even if I leave it set to cool or heat, the thermostat still controls whether it's actually heating or circulating air. Likely what you have is the same.
I wish there was a freeway down the street. Then the cars would be here and gone instead of idling in our local streets for fifteen minutes waiting to merge. Here's a real-world study of before and after they tore down two exits of the Central Fwy and built the horrible Octavia Blvd that necessitated a bunch of sidewalk closures and keeps killing cyclists: https://archive.sfcta.org/sites/default/files/content/Planni...
I don't know about the awair specifically, but it's worth being cautious about cheap air quality monitors. There seems to be little good standardized testing of them, and sometimes even major brands can have abysmal accuracy. See for example the EPA study "Evaluation of Emerging Air Sensor Performance" [1], some of them have very low or even zero correlation with reference monitors. It'd be nice to see some more uniform independent lab testing and marking standards there, or maybe there already are? I've rarely been able to find comprehensive evaluations however. At least it does look like the EPA is looking at them more, last year there was a very interesting webinar overview [2] of research being done on them.
There are plenty of fully dumb plain monitors too, but since you picked a smart IOT one I'd personally really want to make sure it'd work LAN-only and supported a wide array of integrations. From a quick glance it's not clear the Awair does that, and it does not have HomeKit support for example.
Anyone getting an air quality monitor specifically because of an interest in CO2 needs to be a bit wary, a lot of them claim to have a CO2 sensor but are actually just predicting CO2 levels based on other sensors designed to measure human occupancy. CO2 sensors are/were very popular for HVAC systems to use as a proxy reading of human occupancy levels and general air quality to meet air quality requirements. Now more modern (cheaper) air quality sensors are available which measure a mix of VOCs exhaled by people instead of CO2 but have an output mode that emulates the reading from a CO2 sensor at a similar occupancy level so that HVAC systems wouldn't have to redesign their control systems / formulas, usually marketed as "equivalent CO2" (or eCO2) readings.
Because they're called eCO2 sensors while being cheaper and lower power than real CO2 sensors, many air quality monitors have been using them and then surfacing their readings as "CO2 levels" under the mistaken belief that they can use the sensor to measure CO2. But it won't measure environmental CO2 at all, just predict the amount of CO2 the humans in a room would typically generate. Which is all you need for air quality monitoring, but just be aware you're not actually measuring CO2 if that's what you're curious about.
There are monitors with real CO2 sensors, but you'll want to look for a teardown to see what sensor is actually being used before you purchase. The Awair 2 seems to have a real NDIR CO2 sensor (Telaire T6703), for example: https://wiki.liutyi.info/display/CO2/Awair+2+inside#Awair2in...
Kurtis Baute's full experiment from Tom's video was very interesting. He tried to seal himself in a green house with plants to generate oxygen for a few days.
https://youtu.be/PoKvPkwP4mM
If people want a more flexible, less crazy expensive option, it's fairly straightforward to build a WiFi-connected sensor with an ESP32 devkit [0], an off-the-shelf sensor like the SCD30 [1] and ESPHome [2]. This is simple to assemble, will give you fairly good, repeatable readings, auto-calibration that performs pretty well and an open-source platform with full access to your data rather than a proprietary cloud application.
Full cost should be ~$70, I'd expect assembly and flashing to take ~1h the first time. The most complicated thing you'll have to do from an electronics standpoint is solder on the pin header to the sensor, other than that it's just jumper wires and flashing over USB. No need for adding resistors or capacitors or anything like that.
If you're not comfortable with soldering, I _think_ the evaluation kit for the SCD30 [3] comes with pre-assembled headers. There's also a third-party variant [4] that comes with a cable header you can break out [5].
I strongly recommend that you use the SCD30. I've tested a variety of sensor components from a variety of manufacturers and the SCD30 was by far the best performing. Other sensors have problems with auto-calibration in a residential environment so either give nonsense readings or drift without periodic manual calibration.
However if you want something _really_ cheap, you can replace the SCD30 with the ~$20 MH-Z19 and the total price will be ~$30. The auto-calibration on these is utterly terrible however, so you'll need to manually calibrate it with fresh air every couple of months to compensate for drift.
And as others have warned, beware of retail products. A lot of them have fake "CO2" or "eCO2" sensors that don't measure CO2 but try to guess it based on other measurements. These are completely useless and are not at all indicative of actual CO2 levels.
Finally, a good explanation for the state of the world!
On a realistic note, this is a cause for concern for astronauts on the ISS. They experience chronic, significantly elevated ppCO2 levels (4 torr, vs 0.3 torr at sea level), which cases headaches and fatigue, and possibly what's known as the "space stupids," where very high-key, detail oriented people start messing up checklist items and don't perform nearly as well as they should.
You can buy a cheap sensor, like the MH-Z19B, connect it to a Raspberry Pi Zero W (or just about anything else), and set a reminder to open the windows once the value rises above some threshold.
Or just buy a finished product for this somewhere I guess.
> Oxygen concentration inhaled by healthy subjects wearing a surgical mask covering an N95 respirator decreases to about 17%, and the concentration of carbon dioxide increases to about 1.2% - 3% in a short period of light work (2-3). Although participants did not show any obvious changes in physical function and did not have any discomfort ratings, the average carbon dioxide concentration inhaled was far higher than the limit of 0.1% of indoor carbon dioxide concentration in many countries. With prolonged mask wearing, untoward reactions may gradually appear. In another long-term study, after wearing an N95 mask for 12 hours the CO2 concentration of subjects increased to 41.0 mmHg, far higher than the baseline value of 32.4mm Hg at the beginning of the test (4). The subjects mainly reported headache, dizziness, feeling tired and communication obstacles. In real life, the situations and time of wearing masks are much longer than the above experimental research settings.
That's for an N95 respirator combined with a surgical mask. Most of us are just wearing surgical-type masks, and I doubt they make any difference to oxygen levels.
(If they did, I'd be very worried about surgeons!)
You can take the mask off for a while if you're starting to get uncomfortable, but yes, it's probabaly not good to wear masks all day long, which is why the lockdown is important.
on the other hand, lockdowns have reduced CO2 emissions in significant levels
The solution is not rooms with air-filtration-conditioning or whatever, there are natural processes for that, the long term solution I see is just a reduced economic activity like during lockdowns, focused on essential sectors (so not luxury, entertainment, ..)
A drop in emission rates for a couple months doesn't mean that 100-200 ppm of CO2 magically drops out of the atmosphere. Locally it might help cities a bit.
But the backlog of CO2 to be removed to reach reasonable post-industrial levels (to say nothing of preindustrial) is tens of trillions of dollars if done artificially.
The solution is EVs + alt energy, and to stop industrializing every possible arable acre for agriculture and switch to vertical farming.
If rising CO2 levels trigger cognitive impairment, you should be wary of everything else you think is triggered by rising CO2 levels. Because you, and all scientists, and all politicians, and Greta: You're cognitively impaired.
TLDR: They seem to be talking about global levels over time and also mention that indoor levels can be higher, depending on how well air is exchanged with outdoor air.
Probably good to be thinking about the latter, and in my well-insulated place, I often leave some windows cracked to help with this.
Over periods of centuries, presumably evolution would ameliorate most or all of the problem with global changes.
"evolution would ameliorate most or all of the problem" is a funny way of saying that "a lot of people are going to die younger (or have fewer children) because of this". That's the only way evolution works.
It doesn't need to be a lot younger or a lot fewer. The effect will almost certainly be virtually undetectable, especially when compared to many other evolutionary forces (e.g., diet, particulates in air, lack of exercise, social policies, etc.).
If you want to improve global quality of life, CO2 levels are almost certainly not the right place to start.
I feel like my cognitive ability has dwindles the past few years and while there are for sure much bigger factors playing into that, I wonder how much these environmental factors are a part of it.
Rising atmospheric CO2 is a very real concern, and I am very concerned about the long-term mental effects of atmospheric CO2 rising into the 900+ range.
But short-term, the effects of any rise from 350 to 400ppm outdoors is going to be vastly dwarfed by indoor factors (in some poorly ventilated buildings like old schools, PPM can rise to 2000+). It's far more likely that what you encountered was due to poor ventilation than due to overall global CO2 rise.
given the current demonstration of half the population's response to a worldwide-pandemic, there is going to be zero done about CO2 levels or climate-change in general, people are just going to watch the atmosphere boil off over centuries while the 1% move higher into their penthouses and crank the a/c
I see a lot of people wanting to monitor CO2 levels. But what's the cheapest remediation option for an individual if the outside air is also pretty bad whether other pollution or just high CO2?
The questions I have are: is it more effective to scrub the CO2 or just to increase the partial oxygen pressure? What are the options for each.
Given that oxygen tanks are existing medical device, I would assume that just supplementing oxygen is the easiest way to offset the CO2. Or is the CO2 harmful even in high oxygen environments?
The study does mention "[Studies] like Satish et al. (2012) and Allen et al. (2016) are part of a growing body of scientific evidence pointing to CO2 as a pollutant—not just a proxy for ventilation rate—with direct detrimental impacts on the cognitive function of humans in schools and offices."
>is it more effective to scrub the CO2 or just to increase the partial oxygen pressure?
In all nuclear submarines (which stay submerged for months at a time) and spacecraft I know about, designers have chosen to scrub CO2.
I think they have no choice but to scrub CO2 because CO2 has important effects on the body (e.g., increasing acidity of the blood) that cannot be counteracted by any concentration of O2.
On subs, I think they react the CO2 with calcium hydroxide. On spacecraft, NASA has used lithium hydroxide (because lithium weighs less than calcium). The hydroxide gets used up during the mission. then NASA switched to some complicated system that does not use up a reagent.
CO2 is such a small proportion of the atmosphere that I have a hard time imagining its active mechanism for cognitive impairment is the displacement of oxygen. It seems you would have to scrub the CO2. Luckily, the easiest way to do this even in a big city is just to open a window.
Our best option in a high pollution area is to live in a building that has made a good internal filtering system. I think it’s extremely difficult to setup in an individual house.
However, the outside air will not be high co2. That’s equal enough worldwide. I’m in a city and it’s about 450 ppm outside. Higher than global average but still fine for ventilation.
If you also measure particulates, you can get a sense of whether simply opening a window is sufficient.
You can get an ERV (energy-recovering ventilator) with a good filter and install in your exterior wall/window. Just be careful not to block a window that serves as a fire exit.
The navy has extensively studied performance in high CO2 environments on submarines, and found that it has no impact under levels much higher than you're likely to get indoors.
It's not a good random sample, but they were exposed to C02 levels 10x higher than what you'd be exposed to even in a poorly ventilated conference room.
Possibly "tolerance" to high levels of CO2, and/or a baseline level of cognitive performance that's already impacted by chronic exposure to high levels of CO2?
Studies that raised the alarm on C02 levels showed a severe impact on cognitive function at 1,500ppm. Submariners routinely live and work in levels at 5,000ppm.
>baseline level of cognitive performance that's already impacted by chronic exposure to high levels of CO2
If that explanation is true submariners would barley be capable of operating their boats.
>Possibly "tolerance" to high levels of CO2,
And if that explanation is true new submariners would be barely functional.
The most likely explanation is that the study that showed severe impairment at relatively low levels is wrong.
I think the poster has a good point. It's not just the one submariner study he's referencing that's relevant, it's the decades of experience navies of various nations have operating submarine fleets - the armed forces are not shy about collecting physiological data in the service of operational readiness. If the headline article is correct, we should be very concerned that a significant fraction of the world's nuclear weapons are immediately operated by officers experiencing extraordinary CO2 exposure. Every submariner is green at some point (and there are female submariners as well) - how is acclimation handled?
I agree it's worth investigating. I just found it peculiar how unreceptive they were to the suggestion that the population was unrepresentative, yet how aware they were that the population was, in fact, unrepresentative.
The original suggestion, way up thread, was not to overgeneralize studies. This is a huge problem in our society.
I'm not unreceptive . It's entirely possible that fit militarily aged men under a certain height aren't as impacted by high C02 levels.
However I find it unlikely that they are completely immune to the effect at a dose 10x higher than what the people in the original Harvard study were exposed to.
As to whether long term exposure has a mitigating effect. That's possible, but if the effect is as great as the Harvard study shows, then the navy almost certainly would have noticed the impact on new submariners in the last 80 years.
Btw the original Harvard study was mostly college students, so it's hardly representative either.
All the studies I've seen that do show an impact, aren't using just C02, they are more broadly studying poor ventilation--C02 is just one factor. Every study that isolates C02 level shows nothing. The most likely explanation is that if there is an impact on cognition from poor building ventilation, it's not the C02 doing it.
I researched this topic pretty thoroughly a while back. I was worried enough by the hype that I bought a C02 monitor, but after I researched it, I'm not concerned.
These studies back up your claims. Thanks for sharing them. They were both done by the same people. Do you know if anyone else has tried to reproduce their results?
I would like to know the specific substances in exhalation that negatively affect humans. CO2 not being one of them would be good news.
>Those are prospective astronauts. I would expect them to be even more tolerant of CO2 and claustrophobia than submariners.
They weren't prospective astronauts, they were "astronaut like individuals". Men and women in their 30s and 40s with bachelor degrees and technical skills who can pass a modified flight physical (that from the description in the paper doesn't include any kind of C02 exposure).
Unlike submariners they aren't regularly exposed to 5,000ppm of C02, the height limit is much higher, and almost half of the participants were women.
They might be in better shape than the people in the Harvard experiment, because they screened out many medical conditions. But they are also lot older on average, and the exclusion criteria weren't particularly selective (140/90 bp for example).
Assuming good health has a protective effect you'd still expect so see some effect at 5x (5,000ppm) the level that showed an impact on the Harvard students.
The unrepresentativeness is irrelevant. It's quite conceivable that young fit men can take 20% more CO2 than the typical person before showing symptoms. 1000% is not, because it would have been noticed before and publicised as incredible. People have been on submarines for decades. You're telling me that, not only is there a hitherto unknown biological mechanism that renders young fit men practically immune to a toxic gas that debilitates the typical person at 0.1 times the dose and 0.01 times the exposure period, which is in itself a fantastic claim, but you're also telling me that this has not been noticed by any submariner in any country in decades! That nobody brought a fat politician aboard and noticed them keel over! That no old rich guy (perhaps... a famed movie director?) wanted to see the depths of the ocean! If you have priors on anything, it should be that this study is almost certainly wrong at a fundamental level. Quibbling about sample representativeness is a rounding error, which is why many people in this thread are well aware but completely uninterested in it.
They were exposed to C02 levels 10x higher than what you'd be exposed to even in a poorly ventilated conference room. It's likely that this mitigates any biological differences.
Nothing is certain, but that study combined with the fact that submariners have been operating for months at at time with C02 levels up to 5,000ppm and no one has ever noticed a problem says that studies showing a severe impact at 1,500ppm are probably wrong.
Well, what was the 02 concentration? Did they just change the CO2 and N2 relative concentrations while keeping the O2 normal?
Not that I have detailed knowledge the implications of N2 vs CO2 on O2 uptake.
I could be wrong, but I would think the CO2 increase comes at an O2 loss. While there is about 20% of O2 in the atmosphere, and <1% CO2, but it only takes .2% of O2 --> CO2 to drop the relative concentration of oxygen by 1 percent, which should be noticeable, especially the more out of shape you are.
Naval seamen are also in a lot better shape, so they aren't on the borderline of O2 uptake (like a lot of the most vulnerable COVID-19 people).
The effects people are worried about are at 1k to 2k ppm. Even assuming CO2 is displacing O2 only, the drop in O2 levels is less than the change in about 100ft of elevation. Since oxygen only accounts for about 1/5 of the displaced gasses, you're talking about a difference in about 20 ft of elevation.
Not enough to notice even for horribly out of shape people, and definitely not enough to cause the kind of effects reported.
Have you been to Denver? Changing altitude has a greater than 1% change in O2 available. You feel it initially but quickly adapt and don’t tell them they are cognitively impaired. :)
I believe many of those people quit because they experience anxiety or other negative effects from moderate CO2 levels. Many others never apply to the submarine service in the first place because they have experienced CO2-triggered anxiety which they believe is claustrophobia.
Submariners get several CO2 tolerance exams, as reported on Quora:
> At Basic Enlisted SubSchool (BESS) you are tasked with quite a few things that test you for claustrophobia. The old Ascent tank (to practice submarine emergency escapes I understand that is is no longer used) had air locks where you would crowd and entire class into the chamber (in Navy terms 'nut to butt'), and pressurize it so you could open the hatch into the tank and then free ascent (in a Stankehood) to the surface. Lots of fun, washed out a few who couldn't deal with the air lock.
> Later in the training they piled us all into a decompression tank and took us to atmospheric pressure equaling some depth or other (it's been a while... almost 40 years) and then they keep an eye on you.
> In theory, it's to see if you can handle the air pressure... during the long wait (more than three hours,) due to having the Midnight to 6 AM watch in one of the admin buildings the night before I dozed off. The instructors woke me up when they cracked the hatch and let people out. I thought I was in trouble, but they laughed at me and told me that it was really a 'final exam' in detecting claustrophobics... and my falling asleep proved I didn't have it.
It's very unlikely that there's enough variability that some people can tolerate 10x the amount of C02 with zero effects.
But if I'm wrong, you can look to the 3 other studies I linked that weren't submariners. The studies that test C02 in isolation show no effect at common indoor levels (and levels several times higher).
Poor ventilation might have an impact on cognition, but it doesn't look like C02 is the cause.
I now believe you are right. Thanks for explaining carefully and kindly. :)
Now I'm curious about which exhalations are the culprit.
"The major VOCs in the breath of healthy individuals are isoprene (12–580 ppb), acetone (1.2–1,880 ppb), ethanol (13–1,000 ppb), methanol (160– 2,000 ppb), and other alcohols."
This does not appear to be a new study on the effects of CO2. It only mentions there will be more indoor co2 as a result of combustion?
Scihub didn’t work for this one so I can’t be sure. I’m quite interested in this topic, and there are a small number of studies indicating the issue may be real. However, it is unclear this adds to them.
IF the issue is real it is nonetheless useful to know what this study measures.
Icons for the left are now saying boycott tesla and other anti climate change statements. The right i highly doubt will ever support a quick transition to clean energy. Hope this doesn't turn into a fringe political issue now
I'm really sensitive to high CO2 levels, so ever since I was young I had a habit of opening all the windows in my classrooms when I arrived. I feel stuffy and uncomfortable until I get fresh air. It always bugged me that nobody else seemed to notice or care.
After it was recommended here on HN, I bought this CO2 meter [0] and I've been very satisfied with my purchase. It reminds me to open the window and that has had a tremendous impact on my health. I've gotten to the point where I now keep the window slightly open at all times.
I'll share an anecdote which would appear to support the hypothesis that higher CO2 levels affect cognition. I play Heroes of the Storm and my performance in the game becomes notably worse as CO2 levels rise. It's not a huge thing, but I start to make more mistakes and my decision-making gets worse. This is important because at my skill-level (top 100 to top 250 globally, depending on my activity levels) it only takes one mistake in the late-game to throw the match. I've had the CO2 meter start beeping in the middle of a match, and after opening the window I've managed to turn things around because I can think with greater clarity.
Could it be (to the op) that your body has some different oxygen/co2 processing ability? I encourage you to get and oxygen sensor (the kind you put on your finger) that measures your bodies o2. Your description sounds like what I've been reading about people who have covid-19 and their bodies don't detect that don't have enough oxygen.
This response worried me so I went out to purchase a pulse oximeter yesterday. I've tried it a couple times, before and after various activities, and the number is usually at 99 or 100. The lowest number I've measured is a 97, but that was after wearing an N95 mask for an extended period of time; and I was able to quickly get that back up to 100 after taking a few deep breaths. But these measurements have all been taken while my CO2 meter showed a value of less than ~600ppm, so I'll have to run a few experiments with closed doors and windows to check if higher CO2 levels have an impact.
I've also made a note to discuss this topic with my doctors, just as a precaution.
Air filters do not remove CO2. They remove only dust.
Some so-called "air purifiers" produce ozone, which burns the lungs, nose, and eyes. I hope you're not using one of those.
"Consider a high-quality air purifier that can capture and destroy harmful particles. Make sure the device does not produce ozone, another harmful air pollutant." -- American Lung Association
https://www.lung.org/blog/air-in-your-home
I wonder if that's why people seem to have gotten less intelligent over the past few years (IQ scores seem to confirm this). I thought it was because of social media but maybe high CO2 is to blame.
I would never have thought that the movie Idiocracy would become reality; it seemed so ridiculously far-fetched at the time... Even with its 500 year timeframe... Now it looks like it may actually happen for real in only a few hundred years.
I wonder if I watched that movie again today if it would come across more as a drama than a comedy.
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[ 2.5 ms ] story [ 123 ms ] threadTom Scott did a great video on it a while back
https://youtu.be/1Nh_vxpycEA
Do yourself a favor and get an air quality monitor like an awair
https://getawair.com/
and monitor the levels.
Making sure they are good in whatever indoor areas you spend a good amount of time in is a night and day difference cognitively.
That said, I'm not sure I buy the thesis as a whole. As far as I am aware, last time this came up, the Navy has done pretty detailed tests on CO2 concentration as a result of submarine warfare and found no significant impairments up to 1200ppm.
I use a RAD-0301, which works fine as a monitor and an alarm by itself, but which I connect to a Raspberry Pi for dashboard purposes using the code shared here: https://news.ycombinator.com/item?id=22764488
There are plenty of fully dumb plain monitors too, but since you picked a smart IOT one I'd personally really want to make sure it'd work LAN-only and supported a wide array of integrations. From a quick glance it's not clear the Awair does that, and it does not have HomeKit support for example.
----
1: https://www.epa.gov/air-sensor-toolbox/evaluation-emerging-a...
2: https://www.epa.gov/research-states/low-cost-air-quality-sen...
Because they're called eCO2 sensors while being cheaper and lower power than real CO2 sensors, many air quality monitors have been using them and then surfacing their readings as "CO2 levels" under the mistaken belief that they can use the sensor to measure CO2. But it won't measure environmental CO2 at all, just predict the amount of CO2 the humans in a room would typically generate. Which is all you need for air quality monitoring, but just be aware you're not actually measuring CO2 if that's what you're curious about.
There are monitors with real CO2 sensors, but you'll want to look for a teardown to see what sensor is actually being used before you purchase. The Awair 2 seems to have a real NDIR CO2 sensor (Telaire T6703), for example: https://wiki.liutyi.info/display/CO2/Awair+2+inside#Awair2in...
Full cost should be ~$70, I'd expect assembly and flashing to take ~1h the first time. The most complicated thing you'll have to do from an electronics standpoint is solder on the pin header to the sensor, other than that it's just jumper wires and flashing over USB. No need for adding resistors or capacitors or anything like that.
If you're not comfortable with soldering, I _think_ the evaluation kit for the SCD30 [3] comes with pre-assembled headers. There's also a third-party variant [4] that comes with a cable header you can break out [5].
I strongly recommend that you use the SCD30. I've tested a variety of sensor components from a variety of manufacturers and the SCD30 was by far the best performing. Other sensors have problems with auto-calibration in a residential environment so either give nonsense readings or drift without periodic manual calibration.
However if you want something _really_ cheap, you can replace the SCD30 with the ~$20 MH-Z19 and the total price will be ~$30. The auto-calibration on these is utterly terrible however, so you'll need to manually calibrate it with fresh air every couple of months to compensate for drift.
And as others have warned, beware of retail products. A lot of them have fake "CO2" or "eCO2" sensors that don't measure CO2 but try to guess it based on other measurements. These are completely useless and are not at all indicative of actual CO2 levels.
[0]: Purchase: https://octopart.com/esp32-devkitc-32d-espressif+systems-924..., info: https://www.espressif.com/en/products/devkits/esp32-devkitc/...
[1]: Purchase: https://octopart.com/scd30-sensirion-89692236?r=sp, info: https://www.sensirion.com/en/environmental-sensors/carbon-di...
[2]: https://esphome.io/
[3]: https://octopart.com/sek-scd30-sensor-sensirion-101025983?r=...
[4]: https://www.seeedstudio.com/Grove-CO2-Temperature-Humidity-S...
[5]: https://www.seeedstudio.com/Grove-4-pin-Female-Jumper-to-Gro...
On a realistic note, this is a cause for concern for astronauts on the ISS. They experience chronic, significantly elevated ppCO2 levels (4 torr, vs 0.3 torr at sea level), which cases headaches and fatigue, and possibly what's known as the "space stupids," where very high-key, detail oriented people start messing up checklist items and don't perform nearly as well as they should.
Turns out I needed to let in some fresh air more often.
Getting to 1000ppm of CO2 is remarkably easy in a room with 25 cubic metres of volume.
Or just buy a finished product for this somewhere I guess.
https://jamanetwork.com/journals/jama/fullarticle/2764955
Quote:
> Oxygen concentration inhaled by healthy subjects wearing a surgical mask covering an N95 respirator decreases to about 17%, and the concentration of carbon dioxide increases to about 1.2% - 3% in a short period of light work (2-3). Although participants did not show any obvious changes in physical function and did not have any discomfort ratings, the average carbon dioxide concentration inhaled was far higher than the limit of 0.1% of indoor carbon dioxide concentration in many countries. With prolonged mask wearing, untoward reactions may gradually appear. In another long-term study, after wearing an N95 mask for 12 hours the CO2 concentration of subjects increased to 41.0 mmHg, far higher than the baseline value of 32.4mm Hg at the beginning of the test (4). The subjects mainly reported headache, dizziness, feeling tired and communication obstacles. In real life, the situations and time of wearing masks are much longer than the above experimental research settings.
(If they did, I'd be very worried about surgeons!)
The solution is not rooms with air-filtration-conditioning or whatever, there are natural processes for that, the long term solution I see is just a reduced economic activity like during lockdowns, focused on essential sectors (so not luxury, entertainment, ..)
But the backlog of CO2 to be removed to reach reasonable post-industrial levels (to say nothing of preindustrial) is tens of trillions of dollars if done artificially.
The solution is EVs + alt energy, and to stop industrializing every possible arable acre for agriculture and switch to vertical farming.
If rising CO2 levels trigger cognitive impairment, you should be wary of everything else you think is triggered by rising CO2 levels. Because you, and all scientists, and all politicians, and Greta: You're cognitively impaired.
Probably good to be thinking about the latter, and in my well-insulated place, I often leave some windows cracked to help with this.
Over periods of centuries, presumably evolution would ameliorate most or all of the problem with global changes.
If you want to improve global quality of life, CO2 levels are almost certainly not the right place to start.
But short-term, the effects of any rise from 350 to 400ppm outdoors is going to be vastly dwarfed by indoor factors (in some poorly ventilated buildings like old schools, PPM can rise to 2000+). It's far more likely that what you encountered was due to poor ventilation than due to overall global CO2 rise.
The questions I have are: is it more effective to scrub the CO2 or just to increase the partial oxygen pressure? What are the options for each.
Given that oxygen tanks are existing medical device, I would assume that just supplementing oxygen is the easiest way to offset the CO2. Or is the CO2 harmful even in high oxygen environments?
The study does mention "[Studies] like Satish et al. (2012) and Allen et al. (2016) are part of a growing body of scientific evidence pointing to CO2 as a pollutant—not just a proxy for ventilation rate—with direct detrimental impacts on the cognitive function of humans in schools and offices."
In all nuclear submarines (which stay submerged for months at a time) and spacecraft I know about, designers have chosen to scrub CO2.
I think they have no choice but to scrub CO2 because CO2 has important effects on the body (e.g., increasing acidity of the blood) that cannot be counteracted by any concentration of O2.
On subs, I think they react the CO2 with calcium hydroxide. On spacecraft, NASA has used lithium hydroxide (because lithium weighs less than calcium). The hydroxide gets used up during the mission. then NASA switched to some complicated system that does not use up a reagent.
However, the outside air will not be high co2. That’s equal enough worldwide. I’m in a city and it’s about 450 ppm outside. Higher than global average but still fine for ventilation.
If you also measure particulates, you can get a sense of whether simply opening a window is sufficient.
This study found no impact on decision making at 15000 ppm https://pubmed.ncbi.nlm.nih.gov/29789085/
That's 10x higher than you're likely to be exposed to in a poorly ventilated conference room.
> we were unable to replicate this effect in a submariner population
Please don't over-generalize paper results.
It's not exactly a good random sampling, they filter candidates very aggressively.
>baseline level of cognitive performance that's already impacted by chronic exposure to high levels of CO2
If that explanation is true submariners would barley be capable of operating their boats.
>Possibly "tolerance" to high levels of CO2,
And if that explanation is true new submariners would be barely functional.
The most likely explanation is that the study that showed severe impairment at relatively low levels is wrong.
People are telling you that this study may not be reflective of the general population, and you are only demonstrating their point.
It seems like you are really invested in a particular outcome for this research. Maybe you should take a step back and try to let go of your biases.
Dying on the hill of one particular study is the definition of cherrypicking.
The original suggestion, way up thread, was not to overgeneralize studies. This is a huge problem in our society.
However I find it unlikely that they are completely immune to the effect at a dose 10x higher than what the people in the original Harvard study were exposed to.
As to whether long term exposure has a mitigating effect. That's possible, but if the effect is as great as the Harvard study shows, then the navy almost certainly would have noticed the impact on new submariners in the last 80 years.
Btw the original Harvard study was mostly college students, so it's hardly representative either.
Here's another study that shows no impact on military aged people who aren't submariners https://www.ncbi.nlm.nih.gov/pubmed/31240239.
And here's a study that showed no impact from an introduction of pure C02 (these weren't submariners either) https://onlinelibrary.wiley.com/doi/full/10.1111/ina.12284?c...
And here's another one that shows no cognitive impact at 5,000ppm https://www.sciencedirect.com/science/article/abs/pii/S03601...
All the studies I've seen that do show an impact, aren't using just C02, they are more broadly studying poor ventilation--C02 is just one factor. Every study that isolates C02 level shows nothing. The most likely explanation is that if there is an impact on cognition from poor building ventilation, it's not the C02 doing it.
I researched this topic pretty thoroughly a while back. I was worried enough by the hype that I bought a C02 monitor, but after I researched it, I'm not concerned.
Those are prospective astronauts. I would expect them to be even more tolerant of CO2 and claustrophobia than submariners.
> And here's a study that showed no impact from an introduction of pure C02 (these weren't submariners either) https://onlinelibrary.wiley.com/doi/full/10.1111/ina.12284?c....
> And here's another one that shows no cognitive impact at 5,000ppm https://www.sciencedirect.com/science/article/abs/pii/S03601....
These studies back up your claims. Thanks for sharing them. They were both done by the same people. Do you know if anyone else has tried to reproduce their results?
I would like to know the specific substances in exhalation that negatively affect humans. CO2 not being one of them would be good news.
They weren't prospective astronauts, they were "astronaut like individuals". Men and women in their 30s and 40s with bachelor degrees and technical skills who can pass a modified flight physical (that from the description in the paper doesn't include any kind of C02 exposure).
Unlike submariners they aren't regularly exposed to 5,000ppm of C02, the height limit is much higher, and almost half of the participants were women.
They might be in better shape than the people in the Harvard experiment, because they screened out many medical conditions. But they are also lot older on average, and the exclusion criteria weren't particularly selective (140/90 bp for example).
Assuming good health has a protective effect you'd still expect so see some effect at 5x (5,000ppm) the level that showed an impact on the Harvard students.
Nothing is certain, but that study combined with the fact that submariners have been operating for months at at time with C02 levels up to 5,000ppm and no one has ever noticed a problem says that studies showing a severe impact at 1,500ppm are probably wrong.
Not that I have detailed knowledge the implications of N2 vs CO2 on O2 uptake.
I could be wrong, but I would think the CO2 increase comes at an O2 loss. While there is about 20% of O2 in the atmosphere, and <1% CO2, but it only takes .2% of O2 --> CO2 to drop the relative concentration of oxygen by 1 percent, which should be noticeable, especially the more out of shape you are.
Naval seamen are also in a lot better shape, so they aren't on the borderline of O2 uptake (like a lot of the most vulnerable COVID-19 people).
The general population is much more out of shape.
Not enough to notice even for horribly out of shape people, and definitely not enough to cause the kind of effects reported.
Is a submarine’s ratio of O2 to CO2 maintained at a normal fresh air ratio at its higher absolute CO2 level?
etc.
That study, of CO2 effects on submariners, suffers from selection bias.
Here's a US Navy presentation from 2003 that indicates that 10% of submariners quit during their first assignment for psychological reasons: http://annex.ipacweb.org/library/conf/03/bing.pdf
I believe many of those people quit because they experience anxiety or other negative effects from moderate CO2 levels. Many others never apply to the submarine service in the first place because they have experienced CO2-triggered anxiety which they believe is claustrophobia.
Some anecdata: https://www.reddit.com/r/newtothenavy/comments/439j6f/for_pr...
Apparently prospective astronauts must pass a CO2 tolerance test: https://www.forbes.com/sites/quora/2016/02/05/could-you-pass...
EDIT:
Submariners get several CO2 tolerance exams, as reported on Quora:
> At Basic Enlisted SubSchool (BESS) you are tasked with quite a few things that test you for claustrophobia. The old Ascent tank (to practice submarine emergency escapes I understand that is is no longer used) had air locks where you would crowd and entire class into the chamber (in Navy terms 'nut to butt'), and pressurize it so you could open the hatch into the tank and then free ascent (in a Stankehood) to the surface. Lots of fun, washed out a few who couldn't deal with the air lock.
> Later in the training they piled us all into a decompression tank and took us to atmospheric pressure equaling some depth or other (it's been a while... almost 40 years) and then they keep an eye on you.
> In theory, it's to see if you can handle the air pressure... during the long wait (more than three hours,) due to having the Midnight to 6 AM watch in one of the admin buildings the night before I dozed off. The instructors woke me up when they cracked the hatch and let people out. I thought I was in trouble, but they laughed at me and told me that it was really a 'final exam' in detecting claustrophobics... and my falling asleep proved I didn't have it.
https://www.quora.com/How-claustrophobic-is-it-to-be-in-a-nu...
But if I'm wrong, you can look to the 3 other studies I linked that weren't submariners. The studies that test C02 in isolation show no effect at common indoor levels (and levels several times higher).
Poor ventilation might have an impact on cognition, but it doesn't look like C02 is the cause.
Now I'm curious about which exhalations are the culprit.
"The major VOCs in the breath of healthy individuals are isoprene (12–580 ppb), acetone (1.2–1,880 ppb), ethanol (13–1,000 ppb), methanol (160– 2,000 ppb), and other alcohols."
https://doi.org/10.1080/10473289.1999.10463831
Scihub didn’t work for this one so I can’t be sure. I’m quite interested in this topic, and there are a small number of studies indicating the issue may be real. However, it is unclear this adds to them.
IF the issue is real it is nonetheless useful to know what this study measures.
It doesn't seem to be a trial, it's more like a deduction (basically model fitting) from available data.
https://twitter.com/RBReich/status/1260255145310339073
That is not an anti-climate-change statement.
After it was recommended here on HN, I bought this CO2 meter [0] and I've been very satisfied with my purchase. It reminds me to open the window and that has had a tremendous impact on my health. I've gotten to the point where I now keep the window slightly open at all times.
I'll share an anecdote which would appear to support the hypothesis that higher CO2 levels affect cognition. I play Heroes of the Storm and my performance in the game becomes notably worse as CO2 levels rise. It's not a huge thing, but I start to make more mistakes and my decision-making gets worse. This is important because at my skill-level (top 100 to top 250 globally, depending on my activity levels) it only takes one mistake in the late-game to throw the match. I've had the CO2 meter start beeping in the middle of a match, and after opening the window I've managed to turn things around because I can think with greater clarity.
[0] https://www.amazon.com/gp/product/B001PDGFR8/
I've also made a note to discuss this topic with my doctors, just as a precaution.
Which makes you contribute more to CO2 levels than people who don't do that. You literally let the heat escape in the cold months.
Some so-called "air purifiers" produce ozone, which burns the lungs, nose, and eyes. I hope you're not using one of those.
"Consider a high-quality air purifier that can capture and destroy harmful particles. Make sure the device does not produce ozone, another harmful air pollutant." -- American Lung Association https://www.lung.org/blog/air-in-your-home
https://www.lung.org/clean-air/outdoors/what-makes-air-unhea...
I would never have thought that the movie Idiocracy would become reality; it seemed so ridiculously far-fetched at the time... Even with its 500 year timeframe... Now it looks like it may actually happen for real in only a few hundred years.
I wonder if I watched that movie again today if it would come across more as a drama than a comedy.