摘要：a c k g r o u n d: Associations of higher indoor carbon dioxide (CO2) concentrations with impaired work performance, increased health symptoms, and poorer perceived air quality have been attrib-uted to correlation of indoor CO2with concentrations of other indoor air pollutants that are also influenced by rates of outdoor-air ventilation.oB j e c t i v e s: We assessed direct effects of increased CO2, within the range of indoor concentrations, on decision making.Me t h o d s: Twenty-two participants were exposed to CO2at 600, 1,000, and 2,500 ppm in an office-like chamber, in six groups. Each group was exposed to these conditions in three 2.5-hr ses-sions, all on 1 day, with exposure order balanced across groups. At 600 ppm, CO2came from out-door air and participants' respiration. Higher concentrations were achieved by injecting ultrapure CO2. Ventilation rate and temperature were constant. Under each condition, participants com-pleted a computer-based test of decision-making performance as well as questionnaires on health symptoms and perceived air quality. Participants and the person administering the decision-making test were blinded to CO2level. Data were analyzed with analysis of variance models.re s u l t s: Relative to 600 ppm, at 1,000 ppm CO2, moderate and statistically significant decrements occurred in six of nine scales of decision-making performance. At 2,500 ppm, large and statistically significant reductions occurred in seven scales of decision-making performance (raw score ratios, 0.06–0.56), but performance on the focused activity scale increased.co n c l u s i o n s: Direct adverse effects of CO2on human performance may be economically impor-tant and may limit energy-saving reductions in outdoor air ventilation per person in buildings. Confirmation of these findings is needed
