"Carbon dioxide has been vilified for decades as a driver of global warming. A new study finds signs that CO2, exhaled in every breath, can exert an equally worrisome threat -- impaired cognition -- in nearly every energy-efficient classroom, meeting hall or office space."
"The work assessed decision-making in 22 healthy young adults. Their performance on six of nine tests dropped notably when researchers raised indoor carbon dioxide levels to 1,000 parts per million from a baseline of 600 ppm. On seven tests, performance fell substantially more when the room’s CO2 was boosted to 2,500 ppm, scientists report in a paper to be published in Environmental Health Perspectives.
These data are surprising, says Roger Hedrick of Architectural Energy Corp. in Boulder, Colo., because '1,000 ppm of CO2 used to be considered a benchmark of good ventilation.' Hedrick, an environmental engineer, chairs the committee that drafts commercial ventilation standards through the American Society of Heating, Refrigerating, & Air-Conditioning Engineers."