Photocatalytic Disinfection of Indoor Air

The present study demonstrated the antibacterial effect of photocatalytic oxidation in indoor air using titanium dioxide as the catalyst. Through a series of experiments, it was determined that titanium dioxide did enhance the inactivation rate of the microorganisms under certain conditions. In these experiments the air velocity, relative humidity, UV intensity were varied. It was found that higher velocities retarded destruction rate, due to the low retention time in the reactor. It was also determined that TiO{sub 2} did not accelerate the reaction at low humidities (30%). At a relative humidity of 50%, there was complete inactivation of the organisms, but at higher humidities (85%), 10% of the organisms were still viable. The experiments showed that at higher UV intensities, most of the inactivation was being done by the UV photons. However, the photons were not able to completely inactivate the microorganisms. In the photocatalysis experiments, there was complete inactivation of the bacteria.