I got a CO2 meter out of curiosity. They are, indeed, about US$150. I get a little under 500ppm indoors.<p>Incidentally, humans can tolerate much higher CO2 levels with accommodation, but, as with altitude, it takes days. The US Navy submarine people have done considerable work on this. So this is not a global warming issue.<p>Real CO2 sensors are still about US$60 as a part. The standard sensor has a heating element, and uses about 75mA, so this isn't suitable for battery operation. 1mA sensors are now available, but for US$160 or so. This cost problem is holding back widespread use in HVAC systems. HVAC systems for rooms where the people load varies widely (classrooms, offices, hotel function rooms, restaurants) should have a CO2 sensor to tell how much outside air you should be pulling in. But outside of hotels, they're rare.<p>Cheap "air quality sensors" measure volatile organics, which is something else entirely.
Every meeting room in our office building has a little meter in it which rotates through displaying three different measurements: temperature, relative humidity and CO2 ppm. Most of my colleagues are surprised when I point this out to them.<p>The floors of our office that I sit in has two sizes of meeting rooms: one for eight/nine people and one for three people. Free meeting rooms are scarce during regular hours, so sometimes we cram in to three-person room.<p>It's fun watching the CO2 measurement climb from 800 to 1400. Supposedly 400 ppm is outdoors, 800 ppm is indoors and anything higher is a little unusual. I have fun pointing out the reason why we are all feeling sleepy and docile towards the end of a meeting is because of the CO2!<p>See also: <a href="https://www.nytimes.com/2019/05/06/health/conference-room-air.html" rel="nofollow">https://www.nytimes.com/2019/05/06/health/conference-room-ai...</a>
The effect mentioned in this article is certainly not suffocation. 2000 ppm of CO2 is about 0.2% of the air, and doesn't signficantly reduce oxygen levels. It's a real problem, but calling it suffocation is pretty dumb.<p>This is possibly even a more serious problem in tightly weatherized bedrooms. I was in a rehabbed house tightly weatherized by the contractor (to meet a typical building code). It had radiant heat. When my wife and I sat in the bedroom for 1 hour, a calibrated CO2 sensor showed levels rising to 1600 ppm. (Humans put out lots of CO2). Sleeping 6 - 8 hours in that environment is very likely to cause cognitive impairment the next day. So if you're in a "tight" house, make sure to sleep with the windows open!<p>Raising the question of course, of why then tightly weatherize the house? Well, so we can say, we're being environmentally responsible, of course!
RevK (who runs a UK ISP) has been looking at this since March:<p><a href="https://www.revk.uk/2019/03/air-quality-and-co-levels.html" rel="nofollow">https://www.revk.uk/2019/03/air-quality-and-co-levels.html</a><p><a href="https://www.revk.uk/2019/03/understanding-co2-air-quality-better.html" rel="nofollow">https://www.revk.uk/2019/03/understanding-co2-air-quality-be...</a><p>He’s very much an old-school Hacker; it’s worth reading the posts he’s made since those two.
In high school I remember being consistently very tired in certain classes. One of them was health class, which replaced phys. ed. for one quarter, meaning that an entire gymnasium worth of students was crammed into a classroom. Others such classes were internal classrooms with no outside walls, and hence no windows. I suspected CO2 was an issue at the time but obviously had no way to prove it.
But if the air is so much charged with CO2 we feel it and we end up opening the windows it seems? At least at my job meeting rooms windows are systematically opened between meetings.
I suspect this may be why I'm so tired after meetings, but I'm not sure. It would be nice to test the air in the meeting room. There are dozens of different sensors on sale on Amazon, but if I buy one, how do I know if it's correct?
I hope we'll have those kind of sensors in our phones someday. Also you have to be lucky enough to be working with people who care about this stuff
Air-conditioning, CO2 monitoring, etc.. Vs opening a window and have a few trees and plants around<p>Isn't the latter (when possible) better for cognitive capacities and well-being? and most importantly for the global environment
I always suspected this. I recall several times in crowded lecture halls feeling drowsy and uncomfortable. My theory was co2 but I didn't know enough about how it works.<p>Interesting to think though about the whole co2 thing, if we keep burning fossil fuels we won't be able to think properly anymore?
This reminded me of <a href="https://slatestarcodex.com/2018/08/23/carbon-dioxide-an-open-door-policy/" rel="nofollow">https://slatestarcodex.com/2018/08/23/carbon-dioxide-an-open...</a>.<p>After reading it I started leaving either a window or a door cracked, but honestly did not notice a difference.