A team of researchers at the Fritz Haber Institute of the Max Planck Society in Berlin, the Qatar Environment and Energy Research Institute/Hamad Bin Khalifa University, the synchrotrons PETRA III in Hamburg and SOLEIL in Gif-sur-Yvette (France), the Sorbonne University in Paris, the ETH Zurich, and the PSI Center for Energy and Environmental Science (Switzerland) have made a groundbreaking discovery in understanding how air pollution forms at the molecular level. Their investigation, published in the journal Nature Communications, sheds light on the complex chemical processes occurring at the boundary between liquid, in particular aqueous solutions, and vapor in our atmosphere.