The coronavirus is at the lower end of a HEPA filter’s range, so it might not be 100% effective on a single pass. But if a HEPA system is run over a period of time, it can take out a big chunk of viruses — somewhere in the high ninetieth percentile (99.94 to 99.97%). And long enough exposure to the UV light in an air purifying device can disable some viruses, including COVID-19.