Why Crowded Meetings And Conference Rooms Make You So, So Tired
But carbon dioxide levels rise rapidly in poorly ventilated rooms, because exhaled air is about 4 percent carbon dioxide by volume. In the lecture hall in Helsinki, the monitor showed the concentration quickly reaching 1,000 ppm — the threshold at which a room starts feeling stuffy for most people, according to the American Society of Heating, Refrigeration and Air-Conditioning Engineers. The fresh air combined with the departure of dozens of CO2-exhaling humans sent carbon dioxide levels plunging, all the way down below 600 ppm within minutes.
Source: www.washingtonpost.com