A compact high-current nanosecond accelerator has been designed and tested for experiments concerned with removal of toxic organic impurities from air. This accelerator provides the electron energy up to 400 keV, the beam current of 0.25 to 1.1 kA, the pulse length from 30 to 40 ns, the pulse repetition rate of 200 Hz continuously and up to 1 kHz in 30-second burst mode. The accelerator is based on a SM-3N nanosecond generator that has an all-solid-state switching system with an inductive storage and a semiconductor opening switch (SOS). The vacuum chamber houses an extended metal-ceramic explosion- emission cathode 5-mm wide and 750-mm long. The outlet window is 80 mm wide and 850 mm long.