The efficient sputtering and decomposition of Europa's regolith by energetic charged particles produces an atmosphere representative of its surface composition. In addition to O2 and H2 from the decomposition of ice, we show that molecules representative of organics and salts will be present in ionic form at levels detectable using an ion mass spectrometer on an orbiting spacecraft. Such an instrument can also measure isotope ratios to determine surface age. ¿ 1998 American Geophysical Union