Ground based in situ observations of nitrate at Westerland (DE0001R) using high_vol_sampler. These measurements are gathered as a part of the following projects CAMP and they are stored in the EBAS database (http://ebas.nilu.no/). Parameters measured are: nitrate in aerosol (mass_concentration_of_nitrate_expressed_as_nitrogen_in_dry_aerosol_particles_in _air)