Pressure measures force per unit area, with SI units of pascals (1 Pa = 1 N/m2). As elevation increases, there is less overlying atmospheric mass, so that atmospheric pressure decreases with increasing elevation.

In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Atmospheric pressure, atm Definition:ĭefinition of Atmospheric pressure, atm provided by WikiPedia:Ītmospheric pressure, sometimes also called barometric pressure, is the pressure within the atmosphere of Earth (or that of another planet). One millimeter of mercury is approximately 1 torr, which is 1/760 of standard atmospheric pressure (101325760 =133.322368421 pascals). Although not an SI unit, the millimeter of mercury is still routinely used in medicine, meteorology, aviation, and many other scientific fields. Millimeter of mercury, mmhg Definition:ĭefinition of Millimeter of mercury provided by wikipedia: Conversion formulas Kilopound per square inch , Pounds per square inch (ksi, psi):

600 mmhg to atm