My local library displays CO2 level on an inconspicuous wall fixture as part of the HVAC system. If the level gets too high large shutters (near the ceiling) open directly to the outside, supposedly as a failsafe. The head librarian said he's never seen them open in the past dozen years. After 20 years of patronizing this facility I now know a little bit more on its operation.
The bottleneck might be the air in the room
391–400 of 499 posts
Re: The bottleneck might be the air in the room
#392I 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…
[dead]
Re: The bottleneck might be the air in the room
#393I noticed this when comparing my experience in open offices with lots of airflow to the cramped spaces of our WeWork co-working space. I could feel the difference. Also one time I slept in a small basement room with no ventilation. I woke up at 3am feeling like I couldn't breathe. I opened the door and felt better.
Re: The bottleneck might be the air in the room
#394If you want citations search my post history, but CO2 cognitive impact studies have a replication issue.
We’ve been studying the impact of CO2 for decades, at much higher levels than you see in office buildings and have never recorded any cognitive impact (until many thousands of PPM) until the Satish study in 2012 and a handful of other studies that Satish was involved in.
If you think about it for a second these studies can’t be accurate. If they were, you’d see differences on SAT scores of hundreds of points depending on building ventilation. You’d see huge variations between taking the SAT in the springtime when the windows are more likely to be open or in the winter.
You’d expect to see massive performance differences across nearly every metric between regions that use AC vs those that depend on opening windows.
And we do not see anything like that.
Re: The bottleneck might be the air in the room
#395Earlier quoted context omitted.
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 differentiat…
>Pulse oximeters have some limitations. They can only employ light at two wavelengths Why only 2?
I think that might be a descriptive statement based on what's in the market, vs hypothetical implementations.
Re: The bottleneck might be the air in the room
#396I do free diving recreationally and I think the opposite is true. Air in the room is not the bottleneck, ever. Finding the right goal with the right people is. Even with very very little air a lot can be done, in fact constraints, even as fundamental as air, can help.
Re: The bottleneck might be the air in the room
#397If you want citations search my post history, but CO2 cognitive impact studies have a replication issue. We’ve been studying the impact of CO2 for decades, at much higher levels than you see in office buildings and have never recorded any cognitive impact (until many thousands of PPM) until the Satish study in 2012 and a handful of other studies that Satish was involved in. If you think about it for a second these st…
Yes, I'm a little skeptical as well. My apartment generally runs between 1000 and 1500 ppm, and I sometimes work outside, but I haven't noticed large differences in ability to work and concentrate between the two. (What does help is moving back and forth.)
I tried keeping my room well-ventilated (500-700 ppm) for a few weeks and didn't notice much impact on sleep and work. There was a burst of positive effects a few days into the experiment but it didn't last and was likely unrelated.
The air definitely starts feeling stale and gross around 2000 to 3000, so I try to keep it below 2000.
That's all personal anecdote, but it similarly drives me to ask: Where's the replication?
Re: The bottleneck might be the air in the room
#398Earlier quoted context omitted.
Because the thresholds everyone gets from the studies were not measured in that location. It would be like the weather station telling you it was 160 degrees outside because they put their thermal sensor on the asphalt, but you wanted to know the air temperature.
Or your watch telling you the room is 98 degrees because it's only ever measuring your body temperature
98F = 36.6C
Re: The bottleneck might be the air in the room
#399"Opening a window or a door costs nothing."
Central ventilation system at my job can handle open windows. So that is prohibited :-(
Re: The bottleneck might be the air in the room
#400As a high school teacher, I first noticed this effect when I started using a CO2 monitor in my classroom as a proxy for air freshness during COVID. The CO2 levels in our supposedly "no problem with the air" classrooms shot up to 2000 ppm within minutes of the start of school and stayed there all day. Kids weren't checked out ONLY because I teach mathematics. They were breathing bad air, too. Worse, when I brought the…
>The good news is that I stopped worrying about making my house "tight" for the sake of energy efficiency. I keep some windows cracked all year and don't worry about how tight the door seals are. You could also install an energy recovery ventilation (ERV) system.
Houses where I live were fitted with those. People turned them down to the lowest settings because they were loud. Then people developed health issues due to high CO2 and they had to refit the systems.