What is the total atmospheric pressure at sea level typically expressed as?

The total atmospheric pressure at sea level is typically expressed as 1 atmosphere. This unit is a standard measurement that reflects the weight of the air above the Earth's surface pressing down. At sea level, this pressure is approximately equal to 101.3 kilopascals or 760 millimeters of mercury in other units. The concept of 1 atmosphere is foundational in many fields, including scuba diving, as it serves as a baseline for understanding how pressure changes with depth in water. As divers descend, the pressure increases by 1 atmosphere for every 10 meters (33 feet) of seawater, which is crucial to calculate when planning dives and ensuring safety. The other options reflect pressures that are markedly higher than what is experienced at sea level, which would not be applicable in this context.