Atmospheric Pressure

The pressure exerted by the atmosphere because of the attraction of gravity exerted on the air directly above the measuring instrument. Under standard conditions, at sea level, the atmospheric pressure is 14.69 pounds per square inch, 29.92 inches of mercury, 1013.2 millibars and 1.01325 newtons per square meter. This is called one atmosphere of pressure (one atm). Atmospheric pressure is also called barometric pressure.