Survival of Microorganisms on Antimicrobial Filters and the Removal Efficiency of Bioaerosols in an Environmental Chamber

Abstract

Exposure to bioaerosols causes various adverse health effects including infectious and respiratory diseases, and hypersensitivity. Controlling exposure to bioaerosols is important for disease control and prevention. In this study, we evaluated the efficacies of various functional filters coated with antimicrobial chemicals in deactivating representative microorganisms on filters or as bioaerosols. Tested functional filters were coated with different chemicals that included (i) Ginkgo and sumac, (ii) Ag-apatite and guanidine phosphate, (iii) SiO 2 , ZnO, and Al 2 O 3 , and (iv) zeolite. To evaluate the filters, we used a model ventilation system (1) to evaluate the removal efficiency of bacteria (Escherichia coli and Legionella pneumophila), bacterial spores (Bacillus subtilis spore), and viruses (MS2 bacteriophage) on various functional filters, and (2) to characterize the removal efficiency of these bioaerosols. All experiments were performed at a constant temperature of 25ºC and humidity of 50%. Most bacteria (excluding B. subtilis) rapidly decreased on the functional filter. Therefore, we confirmed that functional filters have antimicrobial effects. Additionally, we evaluated the removal efficiency of various bioaerosols by these filters. We used a six-jet collision nebulizer to generate microbial aerosols and introduced it into the environmental chamber. We then measured the removal efficiency of functional filters with and without a medium-efficiency filter. Most bioaerosol concentrations did not significantly decrease by the functional filter only but decreased by a combination of functional and medium-efficiency filter. In conclusion, functional filters could facilitate biological removal of various bioaerosols, but physical removal of these by functional was minimal. Proper use of chemical-coated filter materials could reduce exposure to these agents.

Development of antibacterial and antifungal silver-coated polyurethane foams as air filtration units for the prevention of respiratory diseases

“…; Kim et al . ). The inactivation of airborne micro‐organisms by functionalized filters is primarily caused by contact rather than removal by filtration; therefore, filters coated with appropriate antimicrobial agents have been proposed to reduce the growth of pathogenic micro‐organisms (Kim et al .…”

“…The inactivation of airborne micro‐organisms by functionalized filters is primarily caused by contact rather than removal by filtration; therefore, filters coated with appropriate antimicrobial agents have been proposed to reduce the growth of pathogenic micro‐organisms (Kim et al . ). Various functionalized filters coated with antimicrobial chemicals have been demonstrated to be effective in reducing microbial colonization on filters (Kim et al .…”

“…Various functionalized filters coated with antimicrobial chemicals have been demonstrated to be effective in reducing microbial colonization on filters (Kim et al . ), and airborne silver nanoparticles have also been demonstrated as having the potential to reduce the bioaerosol generation from filters (Lee et al . ).…”

Mixed Matrix Poly(Vinyl Alcohol)-Copper Nanofibrous Anti-Microbial Air-Microfilters

“…In order to ally anti-bacterial activity with separation performance, functionalization of nanofibers post-electrospinning with biocide agents, such as bronopol, thiocyanic acid, or selected metal nanoparticles has been investigated [9,10,11,12,13,14]. However, the use of solvents during functionalization and the potential biocide agent leaching are limitations preventing an industrial-scale application.…”

Bench-Scale Aerosol Filtration Test System and Evaluation of an Acoustic Bioaerosol Removal Device for Indoor Air Streams

“…2009a;Kim et al 2012; Miaskiewicz-Peska and Lebkowska 2012) as described below. Kim et al (2012) describe the use of an environmental chamber utilizing a nebulizer to generate a Bacillus subtilis bioaerosol challenge to investigate PRE of medium efficiency filters. An SKC biosampler is used for sampling of the viable bioaerosol.…”