The present invention relates to oxygen gas sensors. Oxygen gas sensor comprising a housing (5) which encompasses an active media in the form of AlN pellet (7); a light source (1) located outside the housing (5) for generating an exciting light (3); a luminescence recorder (10) located outside the housing (5) and configured to receive a luminescent light (8) from pellet (7) when it is excited by the light source (1). The light source (1) is configured to generate a light with an emission wavelength of 300 to 330 nm. The AlN pellet (7) consists of AlN nanopowder with a grain size in the range from 40 to 80 nm, preferably 60, nm and is configured to luminescent with a light of 420 nm when excited by the exciting light (3) from the light source (1).