The best is a combination of hepa and activated carbon filters Combination filters. Flu viruses are about 0.08 µm to 0.12 µm in size, and in the case of the corona virus, science also assumes a size of 0.08 µm to 0.14 µm. This is where our H14 filter comes into its own. For germs with a test particle size of 0.1 to 0.2 µm, it achieves a separation efficiency of 99.995 %. The downstream activated carbon filter uses chemical adsorbents to neutralize the protective shell of the last viral outliers, thus making a significant contribution to reducing the amount of germs in the air to zero and containing the risk of infection. Translated with www.DeepL.com/Translator (free version)