Ps = 1013.5 mb(毫巴)
此處毫巴=1000 巴 = 1000 dyne/cm2，這是以前氣象學上使用的單位。
Pa = pascal (帕) = 1 N/m2，hPa (百帕) = 102 N/m2 (hPa = mb)，這是現在氣象學上使用的單位。
1 atm
= 76 cm-Hg = 760 mm-Hg = 760 torr
= 29.9 in-Hg = 10.336 m-H2O
= 1033.6 gw/cm2 = 1.0336 kgw/cm2 = 1.0336 × 104 kgw/m2
= 14.7 lb/in2 = 14.7 psi = 1.013 × 106 dyne/cm2
= 1.013 bar = 1013 mb = 1.013 × 105 N/m2
= 1.013 × 105 Pa = 1013 hPa