If more air is added to a column, what happens to the density and surface pressure?

When more air is added to a column, the density of the air within that column increases because density is defined as mass per unit volume. As more air (mass) is introduced into the same volume, the overall density rises.

Additionally, this increase in air mass directly contributes to an increase in surface pressure. Surface pressure is a result of the weight of the air above a certain point; thus, as you add more air to the column, the total weight above the surface increases, which in turn raises the pressure exerted at that surface.

Therefore, both density and surface pressure increase when more air is added to a column, reflecting the fundamental relationships in atmospheric science regarding mass, weight, and pressure dynamics.