A different approach to estimate air moisture

When comparing dry and humid air densities and trying to understand which one is denser, the right answer not necessarily follows our intuition. This happens in the Environmental Engineering lectures when students are asked: Is dry or humid air denser? To understand the role of water vapor in air, a method to compute the mass mixing ratio, specific humidity and average molecular weight is presented. This set of equations is more precise than the traditional method and clarifies how water vapor influences physical properties such as air density and bulk molecular weight.