Inert gas asphyxiation are more uncomfortable in low-oxygen environments that result from inert gas exposure; however, the experience is still less aversive than CO exposure. A typical human breathes between 12 and 20 times per minute at a rate primarily influenced by carbon dioxide concentration, and thus pH, in the blood. With each breath, a volume of about 0.6 litres is exchanged from an active lung volume (tidal volume + functional residual capacity) of about 3 litres. Normal Earth atmosphere is about 78% nitrogen, 21% oxygen, and 1% argon, carbon dioxide, and other gases. After just two or three breaths of nitrogen, the
Atmosphere of Venus surface is 67 kg/m, which is 6.5% that of liquid water on Earth. The pressure found on Venus's surface is high enough that the carbon dioxide is technically no longer a gas, but a supercritical fluid. This supercritical carbon dioxide forms a kind of sea that covers the entire surface of Venus. This sea of supercritical carbon dioxide transfers heat very efficiently, buffering the temperature changes between night and day (which last 56 terrestrial days). The large amount of CO in the atmosphere together with water vapour and sulfur dioxide create a strong greenhouse effect, trapping solar energy and raising