High-efficiency particulate air filters, better known as HEPA filters, have been around since the 1940s. According to a recent Inquirer.net article, scientists in Seoul, South Korea have developed an updated version that kills 99.9% of influenza and COVID-19 viruses. This is thanks to the application of new photothermal technology that absorbs light energy and converts it into heat energy. It’s been used for drug delivery, cell death, and solar batteries.
Researchers at the Korea Institute of Energy Research devised a way to manufacture photothermal HEPA filters by coating standard filters with plasmonic metal nanoparticles that produce photothermal effects. When radiated with benign light-emitting diodes, and heated up higher than 140 degrees Fahrenheit within 10-15 seconds, the filters kill viral and bacterial cells. The technology has been licensed to Cleantech, an air filter manufacturer in Busan that is currently building facilities to produce the photothermal HEPA filters. They should be available for purchase later this year.