I have a CO2 monitor in my home office. 800-1100 ppm are pretty normal readings. If I open a window, I can get it down to ~400 ppm, but I don't notice any difference between the two.
I've heard that ~4000 ppm is noticeable and can impair, but it's impossible to get the level that high, even in a closed room with no ventilation.
I've heard that ~4000 ppm is noticeable and can impair, but it's impossible to get the level that high, even in a closed room with no ventilation.