Ground based in situ observations of filter_3pack at Ulborg (DK0031R). These measurements are gathered as a part of the following projects CAMP, EMEP and they are stored in the EBAS database (http://ebas.nilu.no/). Parameters measured are: ammonia in air (mass_concentration_of_ammonia_expressed_as_nitrogen_in_air), arsenic in aerosol (mass_concentration_of_arsenic_in_dry_aerosol_particles_in _air), chromium in aerosol (mass_concentration_of_chromium_in_dry_aerosol_particles_in _air), copper in aerosol (mass_concentration_of_copper_in_dry_aerosol_particles_in _air), iron in aerosol (mass_concentration_of_iron_in_dry_aerosol_particles_in _air), lead in aerosol (mass_concentration_of_lead_in_dry_aerosol_particles_in _air), manganese in aerosol (mass_concentration_of_manganese_in_dry_aerosol_particles_in _air), zinc in aerosol (mass_concentration_of_zinc_in_dry_aerosol_particles_in _air)