Yeah, I had a year of school in a very elderly school building with limited ventilation. When it was raining and all the windows were shut, I remember it being really hard to stay awake and focused. Didn’t learn until many years later to recognize that and that those are the symptoms of excessively high carbon dioxide levels (at the time, I thought maybe it was “low oxygen”, that everyone’s breathing had used up the oxygen, since I knew that fresh air would wake me up).

I’ve been in some office buildings with poor ventilation that do the same thing, though not as severely as that school.