People in a conference room can create enough CO2 to impair cognitive function

Best reply on the thread was: Now show us what 20-30 students in a single classroom does to air quality. I went to a brand new high school in 1992. There was a phenomenon of a few students passing out here and there. It was discovered after the first quarter that no one had opened the vents to the outdoors and the building was circulating the inside air around.

There are several comments about personal AQI sensors. Can anyone recommend an affordable one? Mostly for scientific curiosity.

I discovered the importance of fresh air last year because I have downstairs room in my apartment with no operable windows. I wondered why I always felt tired when I worked from there. Anectodal, but it turns out it was just a matter of air quality. Now I keep my windows open as much as possible. It was above 32 degrees recently and so I opened my windows and keep them open. I now prefer to be cold with fresh air than warm with bad air. This is really an unfortunate consequence of modern building systems, that all buildings are more or less isolated ecosystems circulating HVAC air.

I have the privilege of working from home and always wondered why I would feel like death when visiting the office. I strongly suspect this is the answer.

Would be interesting to see what CO2 levels look like in office buildings throughout the year. In the middle of summer and winter, more makeup air coming in from outside raises HVAC costs. I don’t know what industry practices are for large scale HVAC but if there’s a way to save money I’m guessing there are cases where building managers will cut the margins thin.