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Backgroud and Objective: Many methods were used for air purification to prevent the spreading or to control microorganisms. Ion generator is a new technology to split the airborne molecules of water into positively (H+) and negatively (O2-) charges. In this study, the bacterial and fungal killing efficacy of ion generator (IG) was evaluated against 5 bacteria and 5 fungi including Streptococcus pneumoniae, Bacillus subtilis, Escherichia coli, Pseudomanas aeruginosa, Burkholderia pseudomallei, Candida albicans, Aspergillus fumigatus, Rhizopus sp, Pennicillium sp and Microsporum sp.
Methods: The experiments were done in a plexi glass chamber (size of 100 x 50 x 50 cm). Plates containing approximately 102 CFU of each bacteria or fungal strains were left opened in the chamber or five milliliters of 104-108 CFU/ml of the bacteria or 103-104 CFU/ml of fungi, one at a time, were sprayed into the chamber and evaluated the killing efficiency of IG after 30, 60 and 120 min operation time. The efficacy of IG was also evaluated in the atmosphere of two microbiology rooms with the size of 22-24 m2 high 3 m.
Results: The percentages of bacterial killing were varied from 73.1 to 99.3. The killing efficacy was demonstrated to be varied from one type of microorganisms to the others. The maximum killing efficacy of IG were 99.3%, 91.3%, 90.1%, 87.96%, and 83.1% for E. coli, P. aeruginosa, B. pseudomallei, B. subtilis and S. pneumoniae, respectively. For fungi, the rate of killing was ranged from 42.6 to 93.9%. Rhizopus sp. was found to be the most susceptible (91.9 to 93.9%) whereas A. fumigatus was the most tolerance (42.6 to 53.9%). In contrast, the operation of IG for 1 hour in 2 microbiology laboratories could reduce the microorganisms in the air at around 10-14%.
Conclusion: The IG was found to have no effect on bacteria or fungi that grown on agar plates but it can be used efficiently to kill bacteria and fungi in the air within 30 min of operation but the fungi were found to be less susceptible.
Keywords: Ion generator, bacterial killing, fungal killing, Plasmacluster Ion.