Fig. 13.

Validation of the CO₂ monitoring network through a field test in a school. Shown is the measured course of CO₂ concentration over 6 school hours (07:45–12:15). A gray shading corresponds to no ventilation, during a blue one there is ventilation and in the dashed areas the classroom was empty. A ventilation-dependent decrease in CO₂ concentration with an expected delay after opening the windows can be clearly seen. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)