Many different factors affect the density of air. Most measurably, as altitude increases, air becomes less dense, decreasing atmospheric pressure. Standard altitude-pressure tables allow ...

the air pressure is only around 33,700 Pa approximately one third of the atmospheric pressure at sea level. Altitude sickness is a set of symptoms caused by rapidly ascending to areas high above ...

Inside the spacecraft, the atmosphere can be controlled so ... to keep body fluids in the liquid state. At this altitude the total air pressure is no longer sufficient to keep body fluids from ...