Ground based in situ observations of nitrogen_dioxide at Birkenes (NO0001R) using glass_sinter. These measurements are gathered as a part of the following projects CAMP, sel_GEOmon2.1, EMEP, NILU and they are stored in the EBAS database (http://ebas.nilu.no/). Parameters measured are: nitrogen_dioxide in air (mass_concentration_of_nitrogen_dioxide_expressed_as_nitrogen_in_air)