High temperature air chemistry is a crucial issue concerning next reusable space vehicle thermal protection system. The aim of this paper is to measure N2 and O2 densities and characteristic temperatures thanks to spontaneous Raman scattering within the boundary layer of a stainless steel flat plate cooled down at 300 K. This shear-flow test configuration is considered as a nonequilibrium air plasma test case. Vibrational and rotational temperatures are determined by comparing experimental spectra with computed ones. The density calculation is performed using the ratio of first vibrational transition intensities for both cases with and without plasma at 38 hPa. Several sections were investigated between 15 and 40 mm from the leading edge. All these sections exhibit a classical boundary layer pattern. The rotational temperature is completely in equilibrium with the plate and reaches 2500 K at the outer edge of the boundary layer. On the contrary, the vibrational temperature drops to 1500 K near of the plate and is about 5000 K in the freestream. Molecular densities are smaller than expected at equilibrium, about 60% of the equilibrium value in the freestream for N2.