The Pressure RMS in Micropascal refers to the root mean square value, it is the local pressure deviation from the ambient atmospheric pressure, caused by a sound wave. And is denoted by Pm. Pressure RMS in Micropascal is usually measured using the Micropascal for Pressure. Note that the value of Pressure RMS in Micropascal is always positive. Typically, the value of Pressure RMS in Micropascal is greater than 0.