Atmosphere (unit) for the purposes of specifying the physical properties of substances, “"standard pressure"” should be precisely . A pressure of 1 atm can also be stated as: Scuba divers and others use the word "atmosphere" and "atm" in relation to pressures that are relative to mean atmospheric pressure at sea level (1.013 bar). For example, a partial pressure of oxygen is calibrated typically using air at sea level, so is expressed in units of atm. The old European unit technical atmosphere (at) is equal to 1 kilogram-force per square centimetre (kgf/cm), Pa. Atmosphere (unit) The standard atmosphere (symbol: atm) is a
Pressure Pressure is distributed to solid boundaries or across arbitrary sections of fluid "normal to" these boundaries or sections at every point. It is a fundamental parameter in thermodynamics, and it is conjugate to volume. The SI unit for pressure is the pascal (Pa), equal to one newton per square metre (N/m, or kg·m·s). This name for the unit was added in 1971; before that, pressure in SI was expressed simply in newtons per square metre. Other units of pressure, such as pounds per square inch and bar, are also in common use. The CGS unit of pressure is the barye