Deactivation of clumped and dirty spores of Bacillus globigii

Issues associated with deactivating clumped spores of a biological pathogen are discussed within the context of decontaminating a civil facility using reactive gases. It is argued that gases will prove necessary to fully complete a decontamination and restoration operation following contamination with a biological pathogen. This is simply due to the fact that pathogenic agents may have found their way into hidden and otherwise inaccessible spaces, such as air ducts and cracks, where liquid-based reagents may prove impractical to employ. Results are given for ozone de-activating both clumped and dirty spores of the pathogen surrogate B. globigii. Re-hydration of dry spores is found to greatly enhance the effectiveness of ozone. The re-hydration process is found to require hours if moist air is employed as the source of water. At high relative humidity, capillary condensation of water within spore clumps is found to adversely effect the global deactivation rate in clumped spores. The cleanliness of the spores did not significantly affect the global kinetics. Using selected electronic materials, estimates of collateral damage induced by the reactive gas are also reported.