Removal of biological aerosols by oil coated filters

An elevated risk associated with exposure to bioaerosols calls for the development and implementation of new, efficient and cost effective methods of airborne biological particle control. While filtration remains the most efficient method of removal of airborne particles, some issues related to possible re-entrainment of captured particles from the rear face of the filter back into the air carrier have to be addressed. Obviously, viable biological particles blown off from the filter surface could still cause substantial damage to human and animal health and contaminate the ambient air environment. A new technology utilizing coating of filter fibres by biologically active tea tree oil (TTO) is considered in this paper. It was found that precoating of filter fibres with TTO and following usage of such filters for bioaerosol control could provide significant benefits in terms of rapidly inactivating captured microorganisms and, minimizing the number of live/viable particles possibly blown off from the filter by the air. Three bacterial strains with a range of biological stress sensitivity were used in this research. It was found that 99% of stress sensitive Eschericliia coli and Pseudomons fluorescens are inactivated on the surface of the TTO coated filter within 8 and 2 min of exposure, respectively. A robust strain of Bacillus subtilis demonstrated inactivation in the order of one logarithm per 30 min of process operation. These results look very promising for the implementation of this new technology for the control of air quality in domestic and industrial applications.