Atmospheric Pressure

Atmospheric pressure can be thought of as the weight of all of the air above the height of an observation. The average pressure at sea level is 29.92 in. Hg (inches of mercury), 1013 mb, or 1 atmos. Pressure is not uniform everywhere.

Atmospheric Pressure

Source: WeatherSTEM

Air Density and Pressure

Like air density, air pressure decreases rapidly with height (~ 1mb/10 m). Source: WeatherSTEM