Dear Student ,
The standard atmosphere is a unit of pressure defined as 101,325 Pa, which is equivalent to 760 mm Hg, 29.9212 inches Hg, or 14.696 psi. i.e. atm. is the standard atmosphere unit of atmospheric pressure .
1 atm = 101,325Pa = 760 mm of Hg = 140696 psi
REGARDS