Mitigation of airborne transmission of respiratory viruses by ventilation – past, present and future

The importance of ventilation of spaces for occupants’ health has been known for many years. Ancient Egyptians used natural ventilation to remove dust and thus to reduce respiratory diseases of stone carvers working indoors (Janssen 1999). In the past ventilation has been used to reduce airborne transmission of respiratory generated infectious agents in buildings. In the book “Natural and Artificial Methods of Ventilation” (Robert Byle & Son, London 1899), chapter X it is stated “The report on the influenza epidemic presented to Parliament by the Local Government Board indicates the extreme importance of proper ventilation – especially in schools – which is pronounced to be the only real safeguard against that disease.”. Several ventilation solutions in classroom and hospital patient rooms are suggested in the book with focus on the clean air distribution. Thus, already two centuries ago the importance of clean air distribution for fulfilling the main goal of ventilation, namely to provide occupants with clean air for breathing has been considered...