> 420/800/1200 ppm has no meaningful difference That claim contradicts the results of the NIEHS study "Is CO2 an Indoor Pollutant?"[1], which has found that "R

> 420/800/1200 ppm has no meaningful difference That claim contradicts the results of the NIEHS study "Is CO2 an Indoor Pollutant?"[1], which has found that "Relative to 600 ppm, at 1,000 ppm CO2, moderate and statistically significant decrements occurred in six of nine scales of decision-making performance." [1] https://web.archive.org/web/20160305212909/http://ehp.niehs.nih.gov/wp-content/uploads/2012/09/ehp.1104789.pdf https://web.archive.org/web/20160305212909/http://ehp.niehs....