Elevated Levels of CO2 May Impair Cognitive Abilities, Study Says

Elevated levels of carbon dioxide in indoor settings can have a detrimental effect on decision-making abilities and work performance, according to a new study. In a series of tests, U.S. researchers exposed 22 healthy adults to different levels of carbon dioxide concentrations (600 parts-per-million, 1,000 ppm, and 2,500 ppm) in an office-like room. Under each condition, the participants were asked to take a computer-based test that measured their decision-making abilities. According to the findings, published in the journal Environmental Health Perspectives , the participants’ performance declined notably on six of nine tests when CO2 levels were increased to 1,000 ppm; performance declined substantially on seven of the tests when levels were bumped to 2,500 ppm. Earlier research has associated increased student absences and poorer performance with higher CO2 levels, said William Fisk, a researcher at the Lawrence Berkeley National Laboratory and co-author of the study. “But we never thought CO2 was actually responsible,” he said. “We assumed it was a proxy for other [pollutants].”