How does atmospheric pressure vary with altitude?

At sea level the atmospheric pressure is 1013-1023 hPa at 15 degree. Every ~ 8 meter 1 hPa will reduce. read more

Thanks for the A2A. The other answerers have covered the fine points pretty well. Inversely proportional, less mass of air atop you, etc. From a chemical engineering standpoint, compare it to hydrostatic pressure. read more

Atmospheric pressure reduces with altitude for two reasons - both related to gravity. The gravitational attraction(*) between the earth and air molecules is greater for those molecules nearer to earth than those further away - they have more weight - dragging them closer together and increasing the pressure (force per unit area) between them. read more

Atmospheric pressure is around 1,014 millibars (14.7 pounds/inch 2) at sea level. At an elevation of 10 km (6 miles or about 30,000 feet), roughly the height of Mt. Everest, pressure drops to 265 millibars. That's less than 30% of the pressure at sea level! Both atmospheric pressure and the density of air decrease with altitude. read more

pressure decreases with increasing altitude The pressure at any level in the atmosphere may be interpreted as the total weight of the air above a unit area at any elevation. At higher elevations, there are fewer air molecules above a given surface than a similar surface at lower levels. read more