Oxidative potential (OP) of aerosols is apportioned to the main PM sources found in 15 sites over France. The sources present clear distinct intrinsic OPs at a large geographic scale, and a drastic redistribution between the mass concentration and OP measured by both ascorbic acid and dithiothreitol is highlighted. Moreover, the high discrepancy between the mean and median contributions of the sources to the given metrics raises some important questions when dealing with health endpoints.