Air pressure is the force of air pressing down on Earth’s surface. It is present everywhere in the atmosphere. Air pressure changes depending on location and conditions.

At sea level, air pressure is higher because more air is above. In mountains, pressure is lower because there is less air overhead. Barometers are tools used to measure air pressure. Changes in pressure are used in weather forecasting.

Air pressure is measured in units such as pascals or millibars. It is part of atmospheric and weather systems.