Antimicrobial Filter Developed to Reduce Microorganisms in Subway Air Purifiers by Up to 85%

[Financial News] The Korea Railroad Research Institute (KRRI) announced on the 16th that it had developed technology adding antimicrobial functionality to the prefilter, the primary filter in air purifiers. The technology was applied to an air purifier at an actual subway platform—Suwon City Hall station on the Suin–Bundang Line—and its performance was verified on site.
According to KRRI, air purifiers generally use both a 'prefilter,' which first removes large particles such as dust, and a 'HEPA filter,' which removes smaller particles such as fine dust. KRRI applied an antimicrobial coating to the 'prefilter,' whose structure is simple and easy to replace, so that it could reduce not only dust but also microorganisms.
KRRI coated the surface of a Polyolefin prefilter with a functional composite material to give it antimicrobial performance. The institute also verified its high antimicrobial effectiveness at an actual subway station, increasing the technology's potential for commercialization.
Treating only the prefilter in an air purifier on a subway station platform reduced microorganisms captured by the entire filter system by 41.02–43.41%. This was similar to the 47.44–50.62% reduction achieved when the existing HEPA filter was treated for antimicrobial performance.
When both the prefilter and HEPA filter received antimicrobial treatment, microorganisms decreased by 82.03% to 85.88%, demonstrating excellent reduction performance. In laboratory tests of the prefilter's antimicrobial effectiveness, Escherichia coli decreased by 99.2%, while Staphylococcus aureus decreased by more than 99.9%.
KRRI expects its antimicrobial prefilter to be installed in front of standard HEPA filters in air-quality improvement devices in subway cars and air purifiers installed in concourses and on platforms. It can also be expanded for use in air purifiers and ventilation and air-conditioning systems at multi-use facilities where air-quality improvement is needed.
Koh Sang-won, a principal researcher at KRRI, said, "The antimicrobial prefilter can provide antimicrobial functionality more easily and economically than existing HEPA filters. When used with a HEPA filter, it is a technology capable of removing most of the microorganisms captured by the filters." He added, "We plan to commercialize the technology so that it can be applied not only in subways and underground stations with high passenger density, but also in a variety of multi-use facilities."

[email protected] Yeon Ji-an Reporter