Efficacy of iodine-treated biocidal filter media against bacterial spore aerosols

Abstract

Aims: To assess the effectiveness of iodine‐treated biocidal filter media against bacterial spore aerosols. Methods and Results: Bacillus subtilis spores were aerosolized and introduced into a filtration system. Both treated and untreated filters exhibited high viable removal efficiency (>99·996%) with negligible variation in pressure drop during the entire experiment. The viability of collected spores on the filter was investigated by enumeration of spores extracted from the filter by vortexing. At room temperature and low relative humidity (RH), the survival fraction of the treated filter was significantly lower than that of the untreated filter (P‐value < 0·05). Meanwhile, at room temperature and high RH and at high temperature and high RH, the survival fractions on the treated medium were statistically the same as the untreated control at room temperature and low RH. Conclusions: Both treated and untreated filters achieved excellent viable removal efficiency for spores. The pressure drop of the treated filter was not affected by the iodine treatment. The viability of collected bacterial spores was decreased because of the exertion of iodine disinfectant. Significance and Impact of the Study: The evaluation demonstrates that the iodine‐treated filter is a viable medium for respiratory protection against infectious spore aerosols. The results warrant further evaluation of smaller biological agents, which exhibit higher penetration.

Investigation of Antimicrobial Activity of Grapefruit Seed Extract and Its Application to Air Filters with Comparison to Propolis and Shiitake

“…One promising method is an antimicrobial filtration system that physically captures bioaerosols on air filters and then inactivates the airborne microorganisms on the surface of the filters by treatment with antimicrobial materials such as silver or titanium-based nanoparticles (Li et al, 2006;Jin et al, 2007,), iodine powders (Lee et al, 2008), and carbon nanotubes (Brady-Estévez et al, 2008;Jung et al, 2011a).…”

Bioaerosol Science, Technology, and Engineering: Past, Present, and Future

“…The filter inside the system often fails to collect smaller biological agents, and those collected may still grow and propagate when the humidity level is adequate. In recent years, antimicrobial materials are also incorporated into air filter to inhibit the growth of collected microorganisms (Foarde et al 2000;Cecchini et al 2004;Lee et al 2008a). The filtration technologies developed using nanoscale materials for water treatments (Brady-Estevez et al 2010;Schoen et al 2010) can certainly be adapted for airborne microbial aerosol control.…”

Life Comes from the Air: A Short Review on Bioaerosol Control

“…Therefore, there is a demand for the development of new filter materials that are capable of addressing these problems regarding deposited bioaerosols. Filters treated with anti-microbial components such as iodine (Lee et al, 2008b;Eninger et al, 2008) and membrane-breaking enzymes have been developed and tested as anti-microbial filters. However, when non-biological dust is deposited on the surfaces of filters during operation, the attached antimicrobial materials will be instantly covered by dust and their effects nullified.…”