PON-PC, an oxidized phospholipid with a 9-carbon fatty acyl chain ending in an aldehyde at the sn-2 position, arises from the oxidation of palmitoyl oleoyl phosphatidylcholine (POPC) or through interaction with ozone in pulmonary surfactant. It is found in oxidized LDL. At a 40 microM concentration, PON-PC diminishes the production of TNF-alpha, nitric oxide (NO), and NADP+ in primary mouse alveolar macrophages and lowers the bactericidal capability of RAW 264.7 cells. Additionally, levels of PON-PC increase in the bronchoalveolar lavage fluid (BALF) of mice exposed to cigarette smoke or in older mice.