Scientists in South Korea have developed a high-efficiency particulate air filter (HEPA) that can stop 99.9% of influenza and COVID-19 viruses.
Researchers from the institute improved upon the HEPA filter by coating it with plasmonic metal nanoparticles to produce photothermal effects – the mechanism that results in a substance’s production of heat energy.
In the tests conducted, the photothermal HEPA filters killed viral and bacterial cells after they were radiated with light-emitting diodes in the visible light band and heated up to 60 degrees Celsius or higher within 10 to 15 seconds.
According to the researchers, current HEPA filters installed in air purifying systems are at risk of accumulating a build-up of pollutants that may result in secondary infections. To prevent this, the HEPA filters use ultraviolet rays, which can also cause corrosion that may shorten the filters’ lifespan.
Yoo Seung-hwan, the lead author of the research, explained: “By applying the photothermal HEPA filter technology, up to 99.9 percent of viruses collected in the filter can be removed, so any secondary contamination can be prevented because bacteria and viruses cannot proliferate in the filter.”
The photothermal-effect-based HEPA air filters can be installed into existing air purifying systems or incorporated into new products.
Local air filter developer Cleantech, which has secured the license for the technology, is already building facilities for the production of photothermal HEPA filters, which may be available on the market later this year.