How is the weight of air quantified at sea level?

The weight of air at sea level is quantified by pressure because atmospheric pressure is a direct representation of the weight of the air above a given point. At sea level, atmospheric pressure is commonly measured in inches of mercury (inHg) or pascals (Pa). This pressure results from the gravitational pull on the air molecules present in the atmosphere. Since air has weight, the force exerted by this weight creates pressure, which can be measured to understand how much air is present in a given volume above sea level.

Additionally, pressure correlates closely with the concept of weight because it reflects the cumulative effect of all the air molecules stacked above a specific point. Temperature and density also play roles in understanding air characteristics, but they do not directly measure the weight of air in the same way that pressure does. Therefore, pressure is the most accurate and commonly used metric for quantifying the weight of air at sea level.