In this video, MTM researcher Christian Stråhlman presents his research idea for which he has applied for a research grant to further understand the photo-chemistry of the atmosphere through measuring negative ions. The video is produced by Christian himself in the MAX IV laboratory in Lund during some current research experiments that he is doing there together with an international team of researchers. Please let yourself be fascinated and impressed by the research facilities available, learn more about how using synchrotron light can separate the atoms in a molecule into positive and negative ions, which can be led into a positive and a negative spectrometer, and see what components Christian finds in a box.