The University of Helsinki (Federico Bianchi in the picture) in collaboration with the Paul Scherrer Institute installed a Neutral Cluster & Air Ion Spectrometer (NAIS) on the Jungfrau East Ridge. With this instrument the number concentration of both ions and not neutral clusters in the atmosphere according to their electrical mobility distribution will be measured for the next two years. Hopefully retrieving as much information as possible regarding new particle formation in the free troposphere. Photo by Erik Herrmann, PSI.