Health and safety are about short- and long-term effects. There is a debate about how CO2 affects our health, but there appears to be a consensus that levels above 2,000 ppm disturb our wellbeing and efficiency, levels above 5,000 ppm are hazardous, and 10,000 ppm is life-threatening.
The latest research is conducted at NASA, where there has been a thorough health control of the astronauts working on the International Space Station (ISS).
Another clinical study, done on Earth, shows that on nine scales of decision-making performance, test subjects showed significant reductions on six of the scales at CO2 levels of 1,000 ppm and large reductions on seven of the scales at 2,500 ppm.
The most dramatic decline in performance, in which subjects were rated as “dysfunctional”, was when 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,” says Berkeley lab scientist Mark Mendell, co-author of the study, “that’s why these findings are so startling.”
Read the full study here: http://newscenter.lbl.gov/2012/10/17/elevated-indoor-carbon-dioxide-impairs-decision-making-performance/