Berkeley Lab scientists surprised to find significant adverse effects of CO2 on human decision-making performance.
Overturning decades of conventional wisdom, researchers at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have found that moderately high indoor concentrations of carbon dioxide (CO2) can significantly impair people’s decision-making performance. The results were unexpected and may have particular implications for schools and other spaces with high occupant density.
“In our field we have always had a dogma that CO2 itself, at the levels we find in buildings, is just not important and doesn’t have any direct impacts on people,” said Berkeley Lab scientist William Fisk, a co-author of the study, which was published in Environmental Health Perspectives online last month. “So these results, which were quite unambiguous, were surprising.” The study was conducted with researchers from State University of New York (SUNY) Upstate Medical University.
On nine scales of decision-making performance, test subjects showed significant reductions on six of the scales at CO2 levels of 1,000 parts per million (ppm) and large reductions on seven of the scales at 2,500 ppm. The most dramatic declines in performance, in which subjects were rated as “dysfunctional,” were for taking initiative and thinking strategically. “Previous studies have looked at 10,000 ppm, 20,000 ppm; that’s the level at which scientists thought effects started,” said Berkeley Lab scientist Mark Mendell, also a co-author of the study. “That’s why these findings are so startling.”