The lung surfactant is a mixture of lipids with small fraction of proteins that covers the air-water interface of alveoli. It experiences significant oxidative stress due to a variety of oxidizing agents to which it is exposed. Oxidation of lipids not only leads to reduction of the unsaturated lipids fraction but may also cause accumulation of oxidation products in the monolayer. The proposed research project is aimed at explaining molecular-level consequences of oxidative stress experienced by the lung surfactant. We plan to employ state-of-the-art atomistic-level molecular dynamic simulations together with experimental Langmuir balance measurements of monolayers that model the human lung surfactant. We will examine the role of oxidation products, oxidizing agents, and natural lungs antioxidants on biophysical properties of the pulmonary surfactant.