4 ms·

It should be noted though, that the effects of low oxygen are already very well known and well understood, thanks to decades of research funded by air and space

It should be noted though, that the effects of low oxygen are already very well known and well understood, thanks to decades of research funded by air and space agencies. It should therefore be pretty easy for CO2 researchers to control the outcomes of their experiments against the known physiological effects of hypoxia, to determine what effects are actually caused by CO2. And aside from that, the dosages being discussed here are far, far lower than would be a noticeable dent in the amount of oxygen in the atmosphere. 1000 ppm CO2, the lower bound of observed cognitive effects, is 0.1% CO2, way less than the point where hypoxia is known to cause problems. The atmosphere is 20.9% oxygen at sea level and while I am not an expert in the math of partial pressure, a decrease of atmospheric oxygen to 20.8% doesn't strike me as sufficient to explain the observed effects. That's a 0.4% decrease in the partial pressure of oxygen, or about the equivalent of a 300 foot increase in altitude, or taking an elevator to the 20th floor of a building, nowhere near enough increase in altitude to make you light-headed.

greenleaf2 8y ago
The symptoms of slight sub-clinical hypoxia are in line with the observed effects of people in high CO2 office rooms: headaches, concentration problems, tiredness, etc. In a closed small room, the oxygen is mostly used up after a couple of days. One person in a small tightly closed room will lower the oxygen level significantly, by 5-10% (consumption is around 20 cubic feet, and a small room has about 200 cubic feet oxygen in volume in total) CO2 and oxygen work in tandem in the human body, and studies in the medical field have shown that an increase in carbon dioxide increases breathing rate, breathing volume, heart rate and metabolic rate. The result is an increased need for oxygen, which will not be met in a closed room. Thus I speculate that an increase in CO2 with an accompanying increase in oxygen (or at least a stable flow) will mostly negate the observed symptoms. My preliminary working theory would be that the previously observed effects from high CO2 in rooms (office rooms for example) are due to the interaction of both high CO2 and low O2.
cordonbleu 8y ago
there is a complication, this is not all about solution chemistry, this is a biological system that uses molecular affinities to transport O2 and CO2. A propertiy of any transport chain is lowest affinity at source of substance, highest affinity at destination. the overall efect is that small variences in atmospheric O2 have a large effect at the lung surface where the lowest O2 affinity occurs. This also is sensative to the promiscuity of haemoglobin, having affinity for BOTH O2 and CO2 kneejerk link below V http://bio1520.biology.gatech.edu/nutrition-transport-and-homeostasis/gas-exchange-in-animals/ http://bio1520.biology.gatech.edu/nutrition-transport-and-ho... https://en.wikipedia.org/wiki/Oxygen%E2%80%93hemoglobin_dissociation_curve https://en.wikipedia.org/wiki/Oxygen%E2%80%93hemoglobin_diss... www2.hawaii.edu/~moeng/Web_Zoo142/Lecture Notes/Zoo142ch23.pdf [PDF]

greenleaf2 8y ago

The symptoms of slight sub-clinical hypoxia are in line with the observed effects of people in high CO2 office rooms: headaches, concentration problems, tiredness, etc. In a closed small room, the oxygen is mostly used up after a couple of days. One person in a small tightly closed room will lower the oxygen level significantly, by 5-10% (consumption is around 20 cubic feet, and a small room has about 200 cubic feet oxygen in volume in total) CO2 and oxygen work in tandem in the human body, and studies in the medical field have shown that an increase in carbon dioxide increases breathing rate, breathing volume, heart rate and metabolic rate. The result is an increased need for oxygen, which will not be met in a closed room. Thus I speculate that an increase in CO2 with an accompanying increase in oxygen (or at least a stable flow) will mostly negate the observed symptoms. My preliminary working theory would be that the previously observed effects from high CO2 in rooms (office rooms for example) are due to the interaction of both high CO2 and low O2.

cordonbleu 8y ago

there is a complication, this is not all about solution chemistry, this is a biological system that uses molecular affinities to transport O2 and CO2. A propertiy of any transport chain is lowest affinity at source of substance, highest affinity at destination. the overall efect is that small variences in atmospheric O2 have a large effect at the lung surface where the lowest O2 affinity occurs. This also is sensative to the promiscuity of haemoglobin, having affinity for BOTH O2 and CO2 kneejerk link below V http://bio1520.biology.gatech.edu/nutrition-transport-and-homeostasis/gas-exchange-in-animals/ http://bio1520.biology.gatech.edu/nutrition-transport-and-ho... https://en.wikipedia.org/wiki/Oxygen%E2%80%93hemoglobin_dissociation_curve https://en.wikipedia.org/wiki/Oxygen%E2%80%93hemoglobin_diss... www2.hawaii.edu/~moeng/Web_Zoo142/Lecture Notes/Zoo142ch23.pdf [PDF]