It is formed by the type I pneumocytes of the alveolar wall, the endothelial cells of the capillaries and the basement membrane between.

This strength comes from the type IV collagen in between the endothelial and epithelial cells.

Damage can occur to this barrier at a pressure difference of around 40 millimetres of mercury (0.053 bar).

This can be a result of several possible causes, including blast injury, swimming-induced pulmonary edema, and breathing gas entrapment or retention in the lung during depressurization, which can occur during ascent from underwater diving or loss of pressure from a pressurized vehicle, habitat or pressure suit.

Possible consequences of rupture of the blood–air barrier include arterial gas embolism and hemoptysis.