Pressure and thickness The average atmospheric pressure , at sea level , is about NUMBER@1 atmosphere -LRB- atm -RRB- = NUMBER@2 kPa -LRB- kilopascals -RRB- = NUMBER@3 psi -LRB- pounds per square inch -RRB- = NUMBER@4 torr = NUMBER@5 inches of mercury -LRB- symbol Hg -RRB- .

The average pressure of the atmosphere at sea level is about NUMBER@6 kilopascals -LRB- about NUMBER@3 pounds per square inch -RRB- .
