What is atmospheric pressure?

Atmospheric pressure is the static pressure exerted by the weight of Earth's atmosphere, also known as barometric or air pressure. It decreases as elevation increases because there is less overlying atmospheric mass above the measurement point. The standard atmosphere is defined as 101,325 pascals, which roughly equals the mean sea-level pressure.

What we know

• Atmospheric pressure is the static pressure exerted by the weight of the atmosphere. [1, 2]
• As elevation increases, atmospheric pressure decreases because there is less overlying atmospheric mass. [2]
• The standard atmosphere is a unit of pressure defined as 101,325 pascals. [2, 3]
• A standard atmosphere is approximately equivalent to the mean sea-level atmospheric pressure on Earth. [2, 3]

Where to go next

• what followedHow does elevation affect boiling points?
• how it workedWhat is a barometer used for?
• compared withWhat are standard conditions for temperature and pressure?
• the bigger pictureWhat is ambient pressure?
• how we knowHow is pressure measured in pascals?
• an unexpected connectionWhy does water boil at lower temperatures at high altitudes?Lower atmospheric pressure at higher elevations reduces the surrounding environmental pressure required for a liquid's vapor pressure to cause boiling.

Sources

• [1]atmospheric pressure (Wikidata Q81809) · CC0 1.0
• [2]Atmospheric pressure · CC BY-SA 4.0
• [3]Standard atmosphere (unit) · CC BY-SA 4.0
• [4]Boiling point · CC BY-SA 4.0
• [5]Standard temperature and pressure · CC BY-SA 4.0