Viruses like COVID-19 cannot spread themselves. For this they need a carrier such as an aerosol, which is emitted by people who talk, cough and breathe. The diameter of a COVID-19 virus particle, which is transported by an aerosol, depends on the air humidity, but can never be less than 0.12 µm. The VisionAir Blue Line MicrobeFree air purifier captures more than 99% of all particles larger than 1 µm. The report even mentions that “the worst case efficiency with which particles are filtered is above 97% for particles of 0.1 µm”. However, the efficiency has been tested with particles that are even smaller. This concludes that the VisionAir Blue Line MicrobeFree filters aerosols-transported COVID-19 particles in its filter.