How to quantify the adsorption affinity of gases?
The term you are looking for is "adsorption enthalpy". However calculating that value will depend on a variety of factors mainly the absorbate and substrate, but it is not that simple. The surface structure of substrates matters and a $[111]$ oriented crystallographic face will have a different adsorption enthalpy with a given absorbate that say a $[001]$ crystallographic face. 

I suggest you study this more, namely the Langmuir adsorption model and Brunauer–Emmett–Teller Theory (BET). Especially since BET is a popular technique to measure adsorption.