I keep seeing these studies showing that tiny increases in CO2 impair cognition, but I have trouble believing them. The US navy runs their submarines with CO2 levels that vary from 300-11,300ppm.[1] Their own studies show that CO2 levels of 4% (40,000ppm) do not affect cognition[2]:
> Thus, CO2 at 40,000 ppm for 2 weeks did not affect performance on multiple tests of cognitive function in physically fit young airmen, a population probably not unlike submariners.
CO2 tended to cause poor sleep, headache, and hand tremor before it caused cognitive issues.
Another bit of evidence that makes me doubt these recent studies is that the levels of CO2 in your lungs are much higher than what is in the atmosphere. Exhaled air is around 5% CO2. Each breath doesn't replace 100% of the air in your lungs. If you have a container that is 5% CO2 and you replace 80% of it with air containing 400ppm CO2, you're down to 10,320ppm. Inhale 1,000ppm CO2 and your lungs will be at 10,800ppm CO2. In other words: a 250% increase in atmospheric CO2 levels only causes a 4% increase in lung CO2 levels at the beginning of a breath. If such tiny changes significantly affected cognition, we would see impairment happen in many more circumstances (such as when walking or smoking).
If something's impairing cognition in stuffy rooms, I don't think it's CO2.
Their measures of focused activity were nearly unchanged, while measures like initiative and strategy declined somewhat at 1,000ppm and sharply at 2,500ppm.
"Within the limitations of this experiment, (1) breathing 4%
CO2 for one hour slows information processing by impairing the response selection stage of processing and not the stimulus encoding stage and (2) with increasing time-on-task information processing is increasingly impaired and the magnitude of this effect is similar for each processing stage. These findings help define a useful model of
human information processing and identify the locus of CO2 impairment."
That could explain the null results found by the Navy.
I don't think its the co2 itself that make you dizzy. Co2 is just a trace gas to measure air exchange. There are probably other gases, particles, and fumes that impair your cognition which accumulate with poor ventilation.
I've often complained that flying is the most exhausting thing you can do that involves not doing anything at all. Long meetings are number two on the list...
That's from hypoxia. Being in an airliner is equal to being at about 5,000'. The reduced air density means less oxygen and you get fatigued (also reduces cognition, coordination, vigilance and night vision).
Closer to 8000' in commercial airliners. While it's technically hypoxia, insofar as it's less oxygen than at sea level, I don't know if 8000' is enough to cause the effects you're describing. Anecdotally, I'm a fat smoker, and I don't seem to notice any of those negative effects at 8000', but I certainly notice them at around 12000' or so.
I didn't realize it was that high. I guess I was remembering from the Cessna 421 I flew, but we were cruising at more like FL250. Looks like the 787 brings it down to like 6k though.
Getting exhausted from flying is not due to CO2, because a plane has more ventilation (measured in air changes per hour) than the majority of buildings.
I thought it was also due to micro movements of your body trying to remain stable. Kind of like driving a truck on a rocky road but at a much smaller scale for much longer.
I've not seen that claim before but it certainly seems plausible. It does seem less tiring if you're sitting next to an empty seat rather than a person.
Many residential buildings have horrible ventilation as they commonly rely on the random forces of wind and thermal gradient to force fresh air through cracks around windows and doors and through other holes in the building envelope. This can lead to long periods of time with ventilation far below ASHRAE standards. Conversely, if you are getting enough ventilation through leakage, the quality of the air may be poor due to pollen or other pollutants. One way to address this is to set up a positive pressure situation with a high quality air purifier pulling fresh outside air through a ducting system like https://www.iqair.com/sites/default/files/documents/InFlowW1.... If you don't own your home or just don't want to run a duct through your wall, you can add a window kit such as the LG COV31735301 Room Air Conditioner Exhaust Duct.
David Heinemeier Hansson (DHH of Ruby on Rails fame) gave a great talk recently on air quality: https://youtu.be/MRqh8oLY7Ik
Apparently his wife was showing signs of Formaldehyde poisoning after they moved into a newly constructed home. This motivated him to investigate the air quality in their house and he bought industrial-level air testing equipment to figure out what was going on (since many of the consumer-grade devices were wildly inaccurate). He also did a deep dive into the research on how air quality impacts cognitive and creative performance. Fascinating talk, worth watching.
Just reached 4:30 sec and he has mentioned lack of ventilation in their house, which I know to be a common problem with new build housing through dealing with condensation problems.
UK: most of the bog standard double glazed windows have a little vent up at the top so you can open a fairly small slat and get a small air gap.
35min: his risk priorities are mould, particulate matter, volatile organic chemicals, co2, on the grounds that CO2 is easier to manage
The problem is that if it’s cold enough outside that you need double glazing, then opening the slats would negate the benefit. Heat exchangers really are the only solution here, but of course the UK seems to be at least a century behind on residential building standards compared to anywhere else I’ve lived in Europe.
The idea is to minimize heat loss from conductivity through the windows, but accept the heat loss that comes with venting air.
Old single-pane windows were missing the vent probably because a) old building codes let you have less ventilation or b) the old windows were leaking air around the frames in addition to conductively leaking heat through the single-pane glass.
Acoustic isolation is a motivator for double glazing in some locations. And the vents are small (6mm by 30cm full open).
Most Victorian era houses have 'air bricks' in various locations (terracotta bricks with a small grid of holes in them) and the houses were pretty leaky.
UK government is moving to remove *
cooking on open gas from the building regulations for new homes in a few years (big methane/burning fume generator). Eventually as post above parent says we will move to more rational ways of heating the houses. Piping an inflammable gas to millions of houses has always struck me as a bit strange.
I really hope they don’t. One, electric cooking is shit however you wrap it up. I have found a large correlation between people being okay with electric cooking in places I’ve lived and also not cooking/not knowing how to cook. That’s probably the only way electric cooking has become so prevalent in the UK. Who would want to anyway if stuck with electric?
Two, I do not want to have to wait hours for the tank to heat up again after someone takes half a minute too long in the shower.
The power just isn’t there when it comes to electric water heating. I am very glad to live in a house with a combi gas boiler right now where the whole house can have a shower on demand, straight after each other if need be.
Until we all have massive heat pumps or some other way of getting high-power heat from domestic electric, it makes complete sense to me for us to pipe gas around while most of our domestic energy usage in the UK goes to heat.
Yes, induction does have higher max power in comparison to the terrible resistance hobs and the slightly less terrible ceramics. The problem with induction is that it doesn't work when you don't have a completely even bottom (on your cookware). Cookware warps over time. You can get induction wok stoves, but that misses the point. You can also get a nice gas stove with a massive centre hob for your wok needs.
Even forgetting the evenness issues, which ceramic stoves share too, the modulation just isn't there. Lower power on induction and ceramic means alternating the same power on and off. This does average out over the long term to a lower power, but what if you need a constant lower power? The power settings also tend to be discrete and far apart, which is again completely useless for a lot of fine applications. It's completely useless for instance you want your pilau rice to steam properly at the end of cooking at a low power in a shallow, broad stainless steel pan (as it should be), rather than sticking to the bottom of the pan.
Unless you mean the idea is "how do we make it look like we're doing something about building performance without hurting volume house builders' feelings?".
The 'proper' solution all homes should be built with is low air permeability (no trickle vents) and a whole house ventilation system, ideally with a heat exchanger.
Not just CO2, but heat lowers performance. Every time I go into an office and the AC is set to like 75 or higher, I just feel groggy. Set it to like 72, or lower, and it's a lot easier to stay awake. 65 or so in the winter is perfect, I love it when it's brisk in the office -- I get in early intentionally and before 8 AM it's nice and cool.
"Despite this minimal deviation in temperature, the researchers found remarkable differences in cognitive functioning. In one lab study, participants were asked to proofread an article while they were in either a warm (77°) or a cool (67°) room. Participants in warm rooms performed significantly worse than those in cool rooms, failing to identify almost half of the spelling and grammatical errors (those in cool rooms, on the hand, only missed a quarter of the mistakes). These results suggest that even simple cognitive tasks can be adversely affected by excessive ambient warmth."
When it is cold enough, body starts to shake, each muscle is convulsing, consuming glucose and making it into heat.
Brains use a lot of power that comes from methabolism. Could it be that human body tries to warm itself using brains to utilize glucose by doing cognitive tasks?
Anecdotally, every degree above 70F drastically reduces my ability to function. 76F in an office is bordering on hopeless for me. Way too hot to think.
Has this paper from 2015 been replicated or otherwise followed up since? I tried a quick google search but all I found seemed to be referencing this one study.
So, add some people that you know will agree with you.
That has all the smell of a con artist, and some people are good on sensing this. Others aren't, and if the population of the meeting is random enough, many people will fall over it. It is also not a new discovery.
I've only read the abstract but it seemed to imply that the well ventilated office with artificially high levels of CO2 (labelled Green+ ?) resulted in higher scores than the well ventilated environment with low CO2.
In real life this is a non-issue since all commercial buildings that have undergone any sort of renovation in the last 25 years have CO2 monitoring integrated into their HVAC control system.
In which country and under which building standard? Because I can tell you, I’ve been in plenty of modern buildings all over the world where there was clearly not enough oxygen in several of the rooms.
That's not a minor nitpick. It's important to note the difference. If you double the amount of CO2 in a room, that's still not a lot of CO2, and if you displace oxygen to double it, you've still got tons of oxygen. Humans are hyper-sensitive to higher CO2 levels, even while still getting a lot of oxygen.
Certainly in any developed country, though I can't speak for the developing world. HVAC controls have been around basically for as long as we have been making large inhabited structures (nearly 100 years).
Both in the UK and HK I’ve been in rooms where there is a clear lack of anything approximating clean and fresh air, be it faulty installation or poor adherence to code, I don’t know.
Either way, at least on a personal level, increased awareness of the risks is not a non-issue :-)
Business happens in a wide range of buildings around the world. I think the research is pretty important still.
It also depends on office layout, every floor could be completely unique and built by different people. Perhaps your skyscrapers HVAC takes it into account but the office you are in is laid out with an enclosed conference room. The vents are not enough and the HVAC isn't sensing per room just an average sensor somewhere so it doesn't compensate.
The takeaway for me is just to keep it in mind, not cause a big fuss. I think that's a sane thing to do.
It's per-zone monitoring integrated into each wall-mounted space sensor. That communicates with the terminal unit supplying ventilation to each room on an individual basis. Your office building is actually a very large robot controlled by quite a bit of software.
I guess my point is that's just not true for every building. I've never worked in a building with fancy HVAC. So dismissing the issue as solved doesn't work for me.
My last office was a skyscraper and it's AC was just domestic wall mounted conditioners. There was ventilation, but it was only in the central area.
The office before that was a two floor building with the same thing, except no ventilation in the door and solid roofing. Ventilation came from wall vents to outside. The conference room got stuffy and we would have to leave the door open. In our offices we would just open the windows. The office before that was a three story narrow building with openable windows and domestic AC units again.
All very professional commercial buildings, but definitely no fancy HVAC.
But isn't the building targeting 'under 1000ppm?' That is the standard, and it's well over the point at which these new studies are noticing mental decline.
I work in a leed platinum building, and I've been testing the air with 2 different brands of CO2 monitors, and I see them stick to around 850 ppm once everyone is in for the day.
You need to heat the air in winter and cool it in summer. Some office building operators simply minimize the air exchange to show saving to their superiors.
Same goes for buses in my city in summer. Drivers get a bonus for savings on gas so the aircon is turned down to bare minimum and it is suffocating inside especially as bus gets crowded. And opening windows is prohibited.
Electric trams on the other hand have aircon to the max so it is freezer temperatures.
I agree. It sounds innocuous, but 2 hour meetings basically end up eating half a day. You do some work when you come in at 9, by 10 everyone's there and the meeting starts, by the time it's done, it's lunch, and you get back to work at like 1 until the end of the workday. Sitting down at 9 only to get up at 10 is almost a waste of productive hour.
Submarine anecdote: we'd bump up oxygen levels a little bit to make the crew more alert. Oxygen had a max spec that we worried about because high oxygen could cause fires.
Anecdotally a submarine crew is too exhausted to feel effects from CO2 when it's in spec. If atmospheric controls were down and CO2 shot up, headaches were normal. Far from a controlled experimental environment.
I'm going to guess no, based on the fact that in Apollo 13 they had plenty of oxygen, but they needed to stop the buildup of CO2 or they would die, no amount of oxygen would help them, since CO2 is poisonous.
No. Building Codes typically refer to a standard like ASHRAE 62, which basically prescribes a fresh-air rate for a space by size and occupancy. Demand based ventilation is not common in my experience (small commercial buildings).
Probably right. Many clients view it only as an added expense for equipment. Beyond that, there is a certain type of client/owner who is skeptical of any automation beyond a bi-metallic thermostat.
Healthy Workers combines people data (with their explicit consent) and sensor data.
It is also not only about CO2 and O2. I wouldn’t know what they are tracking now but the idea is that they track everything environmental-building related.
At the very least, I'd track at least 3-4 factors beyond simple CO2, so it makes sense to integrate that all at once at HVAC level rather than carry around 5 sensors.
At the PPM required for cognitive impairment, how long does someone need to be in the area for this to measurably affect them?
I know at my workplace, we tend to have short meetings (thankfully!). However we inhabit the upper sections of old downtown square, which was 7 different buildings architecturally "glued" together. But when we do have meetings, they're back to back with other meetings given the shared meeting space.
But this is even more sinister if what I'm thinking is correct: the toxins accumulate even if it doesn't impair the first meeting (or 3), and effects worsen through the day for anyone in there.
All that extra CO2 could also raise temperature locally inside the meeting room, at least if it's got sunlight shining into it somehow. And the increased temperature will probably make the people involved feel even less comfortable and thus less able to think clearly! We'll need to develop radically new technology to scrub all this CO2 out of the planet's meeting rooms and save the world from its detrimental effects.
> Thus, CO2 at 40,000 ppm for 2 weeks did not affect performance on multiple tests of cognitive function in physically fit young airmen, a population probably not unlike submariners.
CO2 tended to cause poor sleep, headache, and hand tremor before it caused cognitive issues.
Another bit of evidence that makes me doubt these recent studies is that the levels of CO2 in your lungs are much higher than what is in the atmosphere. Exhaled air is around 5% CO2. Each breath doesn't replace 100% of the air in your lungs. If you have a container that is 5% CO2 and you replace 80% of it with air containing 400ppm CO2, you're down to 10,320ppm. Inhale 1,000ppm CO2 and your lungs will be at 10,800ppm CO2. In other words: a 250% increase in atmospheric CO2 levels only causes a 4% increase in lung CO2 levels at the beginning of a breath. If such tiny changes significantly affected cognition, we would see impairment happen in many more circumstances (such as when walking or smoking).
If something's impairing cognition in stuffy rooms, I don't think it's CO2.
1. https://www.nap.edu/read/11170/chapter/5#47
2. https://www.nap.edu/read/11170/chapter/5#54