Ground based in situ observations of dmps at Zeppelin mountain (Ny-Ålesund) (NO0042G). These measurements are gathered as a part of the following projects ACTRIS, EMEP, GAW-WDCA, NILU and they are stored in the EBAS database (http://ebas.nilu.no/). Parameters measured are: particle_number_size_distribution in aerosol (number_concentration_of_positive_ions_in_dry_aerosol_particles_in_air), particle_number_size_distribution in aerosol (number_concentration_of_positive_ions_in_dry_aerosol_particles_in_air), particle_number_size_distribution in aerosol (number_concentration_of_positive_ions_in_dry_aerosol_particles_in_air)