A comparison of pulsed vs. continuous ultraviolet light sources for the de-contamination of surfaces

The experimental results in the development of a decontamination process that uses ultraviolet (UV) light and chemical photosensitizer for disinfecting surfaces and solutions are reported. Reduction in the microbial viability as a function of applied UV fluence is presented for the inactivation of Bacillus subtilis niger spores. Preliminary results obtained with both aqueous solutions and surfaces indicate that pulsed UV light is more effective than continuous UV light. Nearly two logs of enhanced inactivation have been achieved with the photosensitized UV process.