What does 1 ata represent?

1 ata, or one atmosphere of absolute pressure, represents the standard atmospheric pressure at sea level. This is generally defined as being equivalent to 101.3 kilopascals (kPa) or 14.7 pounds per square inch (psi). Under these conditions, the pressure exerted by the atmosphere on the surface of the Earth is at its baseline level.

Understanding this concept is critical for divers and anyone involved in underwater activities, as the pressure increases with depth. At greater depths, the pressure exerted by the water column adds to the atmospheric pressure, which is why divers often refer to specific atmospheric pressures at various depths. For instance, at 33 feet underwater, the total pressure is approximately 2 ata due to the additional pressure from the water. However, 1 ata specifically designates the pressure at sea level under standard conditions.