If 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.
The difference between Satish-involved studies and other studies is extreme, too. Their first 2012 study tested levels at 600, 1000, and 2500ppm. In many categories they observed the 2500ppm group receiving "dysfunctional" ratings in their tests. Even their 1000ppm group saw significant drops.
This sparked the panic about CO2 levels that led to people buying CO2 sensors and thinking that not unusual CO2 levels were actually destroying their ability to think. Many conclude that this has been happening all of their lives and to everyone around them who is unaware.
It triggered a lot of follow-up studies. Confusing, some of those (like the Harvard one everyone cites) included Satish, meaning they weren't independent despite coming from different organizations.
The really interesting thing is that many of the follow-up studies that don't include Satish have even used CO2 levels much higher than the 2012 study that caused the panic. Here is one I grabbed at random that went all the way up to 15,000ppm and failed to find any significant changes: https://pubmed.ncbi.nlm.nih.gov/29789085/
There was also a lot of CO2 research before Satish come along that failed to find significant effects at these relatively low levels. It has been researched in the contexts of air quality for submarines and space shuttles by militaries and NASA because keeping the crew of those operating optimally is important, clearly.
CO2 on the ISS routinely gets up to 5 mmHg = 6,500 ppm, because the CO2 scrubber is more effective at that concentration. According to NASA it's "not practical from a hardware standpoint" to set the operational CO2 limit at 4,000 ppm.
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?
In these studies, are the people told that they have less CO2 in the air?
My experience is more like being slightly drunk. If you know you need to be sharp (client meeting in a meeting room with shitty air), of course you can do it.
But when you have a relaxed team meeting in the same room, the jokes start getting really bad _really_ fast after the CO2 levels start going up.
I've only seen legitimate CO2 concentration studies with small impact on sleep quality (>1000ppm ie unventilated rooms can cause 1-5% decline in sleep efficiency, observable as more nighttime wake ups or longer sleep).
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.