What is Barometirc Pressure?

Barometric pressure is the pressure on Earth’s atmosphere at any point of time. Mostly it is strictly approximated by the hydrostatic pressure which is caused by the weight of air above the measure point. There is an inverse relation between the altitude and atmospheric pressure.  As the height or the altitude increases, the pressure decreases and vice versa. Barometric pressure is an instrument used for measuring the height of an object above a fixed level.

The standard atmospheric (atm) is a unit of pressure. It accurately equals to 101.325 kPa.
This value represents the main sea level pressure at the latitude of Paris and precisely denotes the mean sea level for various industrial nations, which are at the same altitude of various industrial nations.

In United States of America, compressed air flow is usually measured in ‘standard cubic feet’ per unit of time, where ‘standard’ stands for the equivalent quantity of air at set temperature and pressure. There are slight differences in the value of standard atmosphere. Here temperature equals 68 °F (20 °C), air density equals to 0.0765 lb/ft³ (1.225 kg/m³), altitude and sea level are one and the same, and relative humidity equals 0%. Similarly, there are variations in atmospheric pressure in different industries.

They are several factors which determine the variation of barometric pressure from day to day and in various regions. Some of them are rotation of the earth, uneven heating of the earth’s surface, different altitudes and variations in the locale.