This article is a review of data published in Russian and foreign studies that reflect current problems concerning content of carbon dioxide in spaces of residential and public buildings, including children's educational organizations. We consider: mechanisms of action of high concentrations of carbon dioxide on the human body, which manifests as acute and delayed disruptions of metabolic processes in circulatory, central and respiratory systems; existing carbon dioxide content measurement methods used for indoor spaces; principles of setting microclimate and air quality standards for temporarily and constantly occupied indoor spaces and the respective parameter control principles. This analytical review revealed the need for standard-setting efforts, development and approval of a methodology enabling measurement of the actual carbon dioxide concentration in children's educational institutions, since routine measures adopted for the purpose lack in effectiveness or realization, which prevents normalization and stabilization of all qualitative and quantitative air parameters at the levels making the environment of a classroom safe and optimal for education-related activities given high occupancy of the space.