This paper describes a model for the calculation of radiation from small particles injected into the wake of a hypersonic vehicle. The analysis extends the calculation of such radiation from the free molecular regime, previously modeled, to the full range of flow regimes appropriate to altitudes from 150 to 10 km. The model is based on the particle dynamics and heating from free molecule flow to continuum flow, and the thermal and radiative properties of the particle material. Calculations have been performed for particles of carbon, SiC and WC, from 150 to 10 km. Results show that under certain conditions the particle radiation may be enhanced by the higher density gas at lower altitudes.