The present invention provides an ultraviolet radiation system which generates UVC radiation with maximal radiation output and little or no degradation in radiation output during operation of the lamps. The system provides UVC radiation at a wavelength of 253.7 nm, which is effective to kill or deactivate pathogens on surfaces irradiated by the emitted UVC radiation and is simultaneously effective to decontaminate air which passes uniformly over the entire length of the UVC lamps. Uniformly flowing air cools the lamps to maximize the conversion efficiency of power input to the lamps to UVC radiation from the lamps, and at the same time decontaminates the flowing air such that air in the room is also decontaminated.