Characterization of black carbon in fine aerosol particles using high lateral resolution TOF-SIMS.

Fine aerosol particles were analyzed by time-of-flight secondary ion mass spectrometry with high lateral resolution. After sulfate particles with a diameter of about 1 μm were sputtered by gallium primary ions (a gallium focused ion beam), solid materials with a diameter of about 100 nm were occasionally found inside the particles. Since the mass spectrum for the solid material was almost the same as that of graphite, we concluded that the solids were black carbon. It was also found that the black carbon located at the surface of the sulfate core, and they were usually surrounded by organic matter.