August Gärtner and building, housing and communal hygiene 100 years of housing hygiene in Jena.

August Gärtner who had been called to the first Chair of Hygiene in Jena in 1886 has provided impulses decisive for the development of hygiene in the fields of construction, housing and communities. He has formulated important requirements for indoor climate, e.g. for heating, ventilation, indoor air temperature, indoor air humidity, avoidance of temperature asymmetry and thermal insulation of houses. His requirements to ensure adequate insulation, e.g. a ratio between window area and floor area of 1:8-1:10, have remained valid until today. Missing attention to his findings with regard to sewage disposal gained on the occasions of two typhoid outbreaks in Jena as early as in 1901 and 1915 resulted in the last water-borne typhoid outbreak in Germany in 1980, in the same place.