title: Short-term effect of humid airflow on antimicrobial air filters using Sophora flavescens nanoparticles.
abstract: Bioaerosols have received social and scientific attention because they can be hazardous to human health. Recently, antimicrobial treatments using natural products have been used to improve indoor air quality (IAQ) since they are typically less toxic to humans compared to other antimicrobial substances such as silver, carbon nanotubes, and metal oxides. Few studies, however, have examined how environmental conditions such as the relative humidity (RH), surrounding temperature, and retention time of bacteria on filters affect the filtration and antimicrobial characteristics of a filter treated with such natural products. In this study, we investigated changes in the morphology of the natural nanoparticles, pressure drop, filtration efficiency, and the inactivation rate caused by the short-term effect of humid airflow on antimicrobial fiber filters. Nanoparticles of Sophora flavescens were deposited on the filter media surface using an aerosol process. We observed coalescence and morphological changes of the nanoparticles on fiber filters under humid conditions of an RH >50%. The level of coalescence in these nanoparticles increased with increasing RH. Filters exposed to an RH of 25% have a higher pressure drop than those exposed to an RH >50%. In an inactivation test against Staphylococcus epidermidis bacterial aerosol, the inactivation efficiency at an RH of 25% was higher than that at an RH of 57% or 82%. To effectively apply antimicrobial filters using natural products in the environment, one must characterize the filters under various environmental conditions. Thus, this study provides important information on the use of antimicrobial filters made of natural products.
authors.affiliation: Environmental Sensor System Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea.
authors.forename: Gi Byoung
authors.initials: GB
authors.lastname: Hwang
authors.forename: Jung Eun
authors.initials: JE
authors.lastname: Lee
authors.forename: Chu Won
authors.initials: CW
authors.lastname: Nho
authors.forename: Byung Uk
authors.initials: BU
authors.lastname: Lee
authors.forename: Seung Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Jae Hee
authors.initials: JH
authors.lastname: Jung
authors.forename: Gwi-Nam
authors.initials: GN
authors.lastname: Bae
mesh_terms: D000336:Aerosols; D000391:Air Microbiology; D000393:Air Pollutants / Q000302:isolation & purification; D016902:Air Pollution, Indoor / Q000517:prevention & control*; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology; D004867:Equipment Design; D005374:Filtration / Q000295:instrumentation / Q000379:methods*; D006813:Humidity; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D028321:Plant Preparations / Q000737:chemistry* / Q000494:pharmacology; D029909:Sophora / Q000737:chemistry*; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000302:isolation & purification; D013499:Surface Properties; D013997:Time Factors
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D000890:Anti-Infective Agents; D028321:Plant Preparations