[supercat]

There, fixed it.

From what I've read the body uses blood CO2 concentrations to regulate breathing. If all CO2 were removed, things would go totally out of whack. I'm not sure whether breathing CO2-free air, even for an extended period of time, would cause such an effect, however. The normal partial pressure of CO2 in the air is so much lower than the amount that people can tolerate, that I'm not sure it greatly affects the amount of CO2 exhaled.

[expatpat]

If all CO2 were removed, the least of your problems would be blood levels -- you would starve to death. No CO2 means no vegetation and nothing to eat. Everything we eat is either vegetation, or something that ate something that ate vegetation......