Carbon nanotubes were produced by plasma discharging of graphite electrodes in air at 1 atm. The combined yield of CNTs and carbon nanoparticles is ∼20 wt % relative to the mass of cathode deposits or 14 wt% of graphite electrode consumed. The yields of CNTs and carbon nanoparticles under different inert gas atmospheres, such as He, Ar, N2, and air were compared.