To the Editor
New Zealand Herald
That much-maligned but oh-so-vital gas, carbon dioxide
In reference to the article in Monday 7th March Herald: Air we breathe may befuddle us. The article reports on a study claiming that carbon dioxide in indoor environments may be making us sick
Carbon dioxide (CO2) is certainly soporific (sleep inducing) and levels as high as 13.5% CO2 measured in some hibernating mammals burrows is believed to be a factor in their ability to hibernate for months. However, the levels of CO2 measured by these researchers could not be responsible for making office workers drowsy. Furthermore these levels are unlikely to influence cognitive ability or health.
This is because the very small increases in ambient CO2 levels from .04 % (4000ppm) to .05% (5,000 ppm) as documented in this study are unlikely to have any influence on body CO2 levels in humans which are maintained at orders of magnitude higher. The lungs of an average healthy person contain a whopping 6.5% CO2 by volume. Similar levels are found in all mammals. So if these researchers were correct in blaming CO2, the entire mammalian kingdom would be in a permanent soporific haze.
Using CO2 as a measure to compare air quality in green buildings vs normal buildings is valid. Blaming CO2 for the measured cognitive impairment is probably not. So perhaps these researchers might be willing to reconsider their conclusions relating to CO2. For it seems likely that other “pollutants” in stale air are responsible for their findings.
Just like every other mammal we thrive best in an environment as close as possible to nature. And while they may have gotten their science slightly off, I think their conclusion is correct: the more green the building environment is, the better for us.
Glenn White
Director Buteyko Breathing Clinic
Freemans Bay, Auckland
