At what altitude is air density typically at its lowest?

Air density decreases with increasing altitude due to the thinning of the atmosphere. At higher altitudes, the atmospheric pressure drops, leading to a lower concentration of air molecules. This results in reduced air density, meaning that the air becomes less dense as one ascends.

At ground level, air density is at its highest because the weight of the air above compresses the layers below it, increasing the density. As altitude increases, the weight of the air above decreases, resulting in lower atmospheric pressure and air density.

Mid altitude regions still contain a significant amount of weight from the air above, and are therefore relatively denser compared to high altitudes. Hence, it is at high altitudes where air density reaches its minimum value. This phenomenon is important in various applications, including aviation and meteorology, as it affects lift, engine performance, and weather patterns.