Ground based in situ observations of nitrate at Jungfraujoch (CH0001G) using filter_2pack. These measurements are gathered as a part of the following projects ACTRIS, EMEP, GAW-WDCA and they are stored in the EBAS database (http://ebas.nilu.no/). Parameters measured are: nitrate in pm1 (mass_concentration_of_nitrate_in_pm1_in_air)