Lung diseases are among the leading causes of death worldwide. Besides clinical and laboratory investigations on which rely advancements in the cure of various lung diseases, computational models can be significantly supportive in these investigations. The lung is an extremely complex organ composed of connective tissue, and a network of airways, branching from larger to smaller diameters (classified by 24 generations) ending with the alveolated microstructure and alveolar sacs. The lung experiences large geometrical changes and deformation over breathing cycles, hence, regarding mechanics, it is a challenge to formulate an adequate computational model. Also, modeling airflow within the lung parenchyma is very demanding due to the complexity of the microstructure. Many computer models, with various degrees of simplification and sophistication, have been introduced for lung simulation, but a robust and generally applicable model is still lacking. We here present a formulation of a 3D multiscale-multiphysics finite element which includes mechanics, airflow, and mass transport. The mechanics relies on the Wilson-Bachofen model for the lung supporting structure, while the gradient-driven physical fields are modeled according to the smeared concept (Kojic Transport Model). Numerical examples illustrate the generality and applicability of our finite element model.