In the atmosphere, everything has to do with everything else – and all of it has to do with chemistry. Scientists at the Max Planck Institute for Chemistry in Mainz therefore study topics such as how ozone or organic substances produced by plants affect the climate. Or the role played by aerosols, tiny airborne particles, in the formation of clouds and rainfall. Generally, the scientists focus on the study of the chemical – and physical – processes in the Earth system, and particularly in the interplay between the atmosphere, oceans, land and biosphere. In so doing, they measure data across the globe, conduct lab tests and construct models of the systems under examination. Another topic of interest is geochemistry: using the chemical characteristics in rocks and sea water, the scientists study the past and present-day processes in the Earth system, for instance, from a climate perspective.