Ground based in situ observations of dicho at Birkenes (NO0001R). These measurements are gathered as a part of the following projects EMEP, NILU and they are stored in the EBAS database (http://ebas.nilu.no/). Parameters measured are: pm10_pm25_mass in pm10_pm25 (mass_concentration_of_pm10_pm25_mass_in_pm10_minus_pm2p5_in_air), pm25_mass in pm25 (mass_concentration_of_pm2p5_ambient_aerosol_particles_in_air)