How does outdoor air pressure change when altitude increases?

How does outdoor air pressure change when altitude increases?

• A. Increases
• B. Decreases
• C. Stays the same
• D. Not defined

Answer: (B)

Air pressure decreases as altitude increases. The pressure at a location is the weight of the air that sits above it per unit area, so as you climb higher there is less air above you pressing down. Because air is compressible, its density also drops with height, which makes the pressure fall even more quickly in the upper atmosphere. This relationship is described by the hydrostatic balance, roughly dP/dh = -rho*g. In practical terms, sea-level pressure is about 1013 hPa, and at higher elevations it becomes much lower, so the air feels thinner. Therefore outdoor air pressure goes down when you go up, not up or stay the same.

Air pressure decreases as altitude increases. The pressure at a location is the weight of the air that sits above it per unit area, so as you climb higher there is less air above you pressing down. Because air is compressible, its density also drops with height, which makes the pressure fall even more quickly in the upper atmosphere. This relationship is described by the hydrostatic balance, roughly dP/dh = -rho*g. In practical terms, sea-level pressure is about 1013 hPa, and at higher elevations it becomes much lower, so the air feels thinner. Therefore outdoor air pressure goes down when you go up, not up or stay the same.