What happens to atmospheric pressure as altitude increases?

As altitude increases, the total atmospheric pressure decreases due to the thinning of the air layer above a given altitude. This reduction occurs because the majority of the Earth’s atmospheric mass is concentrated closer to the surface. At higher altitudes, there are fewer air molecules exerting pressure, leading to a decrease in the total atmospheric pressure experienced by individuals. This phenomenon is fundamental in aeromedical understanding, as it impacts various physiological processes, including oxygen availability for respiration.

While it is true that the partial pressures of gases like oxygen and nitrogen also change with altitude, the key focus here is on total atmospheric pressure, which clearly indicates that with increased elevation, there is less pressure exerted by the atmosphere overall.