A novel photocatalytic mop fan air cleaning system has been developed. The novel mop fan system is optimized in terms of the pollutant degradation efficiency, energy consumption, appearance and cost reduction based on previous research. The fluid dynamic characteristic and energy consumption of the novel mop fan system has been identified by experimental testing. Pollutant degradation effect of the mop fan on a typical industry pollutant, diesel fume, has also been tested. It was found that the system has very low energy consumption and is very effective to destroy the diesel fume, a microparticulate pollutant. The system is suitable for any indoor environment to clean the air by removing the particulates, odors, virus, bacteria and volatile organic pollutants. Copyright © 2012 John Wiley & Sons, Ltd.