Ground based in situ observations of filter_3pack at Ulborg (DK0031R). 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: arsenic in aerosol (mass_concentration_of_arsenic_in_dry_aerosol_particles_in _air), nickel in aerosol (mass_concentration_of_nickel_in_dry_aerosol_particles_in _air), zinc in aerosol (mass_concentration_of_zinc_in_dry_aerosol_particles_in _air)