athmosperic pressure is?

Atmospheric pressure is the force exerted by the weight of the air above a given point on Earth's surface. It is commonly measured in units of pressure such as millibars or inches of mercury. Atmospheric pressure decreases with increasing altitude, as there is less air above a given point to exert pressure.

Atmospheric pressure is the force per unit area exerted against a surface by the weight of the air above that surface in a gravitational field. It is commonly measured in units of pascals (Pa), atmospheres (atm), or inches of mercury (inHg).