The pressure exerted by the air is said to be the atmospheric pressure and it acts as force over the surface of the earth. As pulls exerted by the gravity of the earth.
Commonly measured by the barometer, a device used to measure that atmosphere when values are measured or taken from the average mean sea levels.
Thus its defined be as force per unit area as air has weight. The development of high and low pressure is measured at the sea level which is 1013 pascal.
This is an endocrine basin in the death valley of California and is noted as the lowest point in the north America and is has a depth of 282 feet below the sea level. This site itself consists of a pool of bad water and is next to the road in the sink and has accumulated slats that surround the basin and is thus is undrinkable and thus has got this name.