Effects of low-level inhalation exposure to carbon dioxide in indoor environments: A short review on human health and psychomotor performance

Scientific literature and documents pertaining to the effects of inhalation exposure to carbon dioxide (CO₂) on human health and psychomotor performance were reviewed. Linear physiological changes in circulatory, cardiovascular, and autonomic systems on exposure to CO₂ at concentrations ranging from 500 to 5000 ppm were evident. Human experimental studies have suggested that short-term CO₂ exposure beginning at 1000 ppm affects cognitive performances including decision making and problem resolution. Changes in autonomic systems due to low-level exposure to CO₂ may involve these effects. Further research on the long-term effects of low-level CO₂ exposure on the autonomic system is required. Numerous epidemiological studies indicate an association between low-level exposure to CO₂ beginning at 700 ppm and building-related symptoms. Respiratory symptoms have been indicated in children exposed to indoor CO₂ concentrations higher than 1000 ppm. However, other indoor comorbid pollutants are possibly involved in such effects. In the context of significant linear increase of globally ambient CO₂ concentration caused by anthropogenic activities and sources, reducing indoor CO₂ levels by ventilation with ambient air represents an increase in energy consumption in an air-conditioned building. For the efficient energy control of CO₂ intruding a building from ambient air, the rise of atmospheric CO₂ concentration needs to be urgently suppressed.