“…The importance of ventilation in maintaining people's health was recognized scientifically in the early urbanization phase in Europe (Li 2020) by pioneering researchers of hygiene, such as von Pettenkofer (1858), who believed in the traditional filth theory of disease. However, following the 1850 cholera outbreak in London, the old miasma theory of disease (from which the filth theory was derived) was abandoned.…”