The CaPPA laboratory of excellence – Physics and Chemistry of the Atmospheric Environment draws on the multidisciplinary expertise of 7 research teams (LOA, PC2A, PhLAM, SAGE, LPCA, ICARE, LASIR) to promote metrological innovation in the field of the atmospheric environment. Its first area of interest is in the “aerosol” system and its precursors to better understand their role on climate forcing and the hydrological cycle, and its second is the evolution of air quality at global, regional and local scales, with specific studies devoted to radionuclides.