A new form of nanosized SrTiO3 semiconducting oxide material with an average crystal grain size of 27 nm has been synthesized using the physical high-energy ball milling technique. The unique presence of the singly charged "O-" ions in the lattice oxygen sites of the nano-range crystal grain material has been observed in the XPS study. This unprecedented and interesting discovery has expounded on the new oxygen sensing mechanism for the near 1/2 slope gradient (the best value ever reported) in the logarithmic relationship of the electrical conductance with the oxygen partial pressure. The derived SrTiO3 oxygen gas sensors were found to operate at 40degreesC (the lowest temperature ever reported for an SrTiO3-based sensor) that is near to the human body temperature.