<Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (September 2017) (Learn how and when to remove this template message) </Td> </Tr> <P> Atmospheric pressure is caused by the gravitational attraction of the planet on the atmospheric gases above the surface, and is a function of the mass of the planet, the radius of the surface, and the amount of gas and its vertical distribution in the atmosphere . It is modified by the planetary rotation and local effects such as wind velocity, density variations due to temperature and variations in composition . </P> <P> The standard atmosphere (symbol: atm) is a unit of pressure defined as 101 325 Pa (1.013 25 bar), equivalent to 760 mmHg (torr), 29.92 inches Hg and 14.696 psi . </P> <P> The mean sea - level pressure (MSLP) is the average atmospheric pressure at sea level . This is the atmospheric pressure normally given in weather reports on radio, television, and newspapers or on the Internet . When barometers in the home are set to match the local weather reports, they measure pressure adjusted to sea level, not the actual local atmospheric pressure . </P>

What is the standard value of atmospheric pressure