Ground based in situ observations of chemiluminescence_photolytic at Oulanka (FI0022R). These measurements are gathered as a part of the following projects EMEP and they are stored in the EBAS database (http://ebas.nilu.no/). Parameters measured are: NOx in air (mass_concentration_of_nox_expressed_as_nitrogen_in_air), nitrogen_dioxide in air (mole_fraction_of_nitrogen_dioxide_in_air), nitrogen_dioxide in air (mass_concentration_of_nitrogen_dioxide_expressed_as_nitrogen_in_air), nitrogen_monoxide in air (mass_concentration_of_nitrogen_monoxide_expressed_as_nitrogen_in_air)