[PeterPrinciple]

and then there is this:

Folks, the air is only .033% co2, there isn’t much there! Of course 78% is nitrogen and that alone may kill us./sarc

http://mistupid.com/chemistry/aircomp.htm

Human Respiration
The air that leaves a person’s lungs during exhalation contains 14% oxygen and 4.4% carbon dioxide.
Atmospheres with oxygen concentrations below 19.5 percent can have adverse physiological effects, and atmospheres with less than 16 percent oxygen can become life threatening.

Folks, look at that. we need at least 19.5 presence o2 in the atmosphere and we only have 20.94% The real danger is potential lack of oxygen. lets build a model of what happens when that happens.

[Moseley]

Again, I smell a great future in lots of research grants.