You protect your surroundings and yourself
To catch and to deactivate. What is caught by the nanofiber membrane in both directions, is being deactivated by accelerated copper oxide. The VK series respirators contains a layer with accelerated copper oxide both from inner and outer side and so they provide excellent protection in both directions. They deactivate viruses coming from external environment or from user himself if he is infected. Only if you are safe, you will not endanger others.