Flash infrared radiation disinfection of fibrous filters contaminated with bioaerosols

Aims: To investigate the effectiveness of infrared (IR) radiation heating in disinfecting air filters loaded with bioaerosols. Methods and Results: An irradiation device was constructed considering the unique characteristics of IR and the physical dimensions and radiative properties of air filters. Filters loaded with test bioaerosols were irradiated with the device and flash heated to an ultra-high temperature (UHT). A maximum of 3 center dot 77-, 4 center dot 38- and 5 center dot 32-log inactivation of B. subtilis spores, E. coli, and MS2 virus respectively was achieved within 5 s of irradiation. Inactivation efficiency could be increased by using a higher IR power. Microscopic analysis showed no visible damage from the heat treatment that would affect filtration efficiency. Conclusions: Because the disinfection was a dry heat process, a temperature greater than 200 degrees C was found necessary to successfully inactivate the test micro-organisms. The results demonstrate that IR is able to quickly disinfect filters given sufficient incident power. Compared to existing filter disinfection technologies, it offers a faster and more effective solution. Significance and Impact of the Study: It has been shown that IR heating is a feasible option for filter disinfection; possibly reducing fomite transmission of collected micro-organisms and preventing bioaerosol reaerosolization.