Ground based in situ observations of filter_3pack at Nausta (NO0655R). These measurements are gathered as a part of the following projects CAMP, NILU and they are stored in the EBAS database (http://ebas.nilu.no/). Parameters measured are: sulphur_dioxide in air (mass_concentration_of_sulphur_dioxide_expressed_as_sulphur_in_air), sum_ammonia_and_ammonium in air+aerosol (mass_concentration_of_sum_ammonia_and_ammonium_in_aerosol)