Evaluating the efficiency of UVC radiation on HEPA filters to remove airborne microorganisms

Nowadays, HEPA filters is used in hospitals, clean rooms, microbiology hoods, ventilation of surgery rooms, and Pharmacy for removing microorganisms and reduce health hazard. The aim of this study is to increase the efficiency of HEPA filters with UVC radiation to reduce the density of airborne microorganisms.
Material and The closed–loop chamber was made to evaluate Staphylococcus epidermidis, Bacillus subtilis bacteria and Aspergillus Niger, Penicillium fungi. The concentration of fungi and bacteria suspension Respectively was 106, 107 CFU/ml. After the suspension was prepared, it was sprayed into the closed loop chamber by nebulizer. Sampling was done with UVC radiation (1.8 mW/cm2 Illuminance) and no radiation (dark) that included time periods 60, 90 and 120 minutes. Microorganisms density was determined in term of CFU/m3.
The result showed that there was a significant difference between UVC radiation and dark section for all the microorganisms (epidermidis, subtilis, Niger and Penicillium) at each time periods (P value UVC radiation is effectiveness to decrease concentration of four microorganisms. because UVC radiation could remove both bacteria and fungi. While the other studies in other countries, UVA radiation is only effective in reducing bacteria. Therefore, achieved greater efficiencies of HEPA filters, using HEPA filters with UVC will have a significant effect on reducing the density of microorganisms.