The ambient air is entrained intensively into atmospheric pressure thermal plasma jets causing reduction of the jet temperature and velocity and resulting in oxidation of the injected particles. A system for shielding plasma jet has been used to improve jet characteristics and reduce oxygen content. Two gases have been applied as a shroud gas argon and acetylene. Both gases showed benefits of the plasma jet shrouding. Particles of Al(2)O(3) sized in the range of tens of microns were injected into the jet. Effect of the shroud gas on distribution of the velocity and radiation intensity of the particles was studied.