Ground based in situ observations of NOx at Kosetice (NOAK) (CZ0003R) using chemiluminescence_photolytic. 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)