[Contributions to the vertical development of the airborne microflora above a junction in the Hungarian capital of Budapest (author's transl)].

Over a period of one and a half years aerohygienic microbiological analyses by means of sedimentation were carried out in the highest building of Budapest, the tower block which houses the theoretical institutions of the Semmelweis University. While it was possible to culture quite frequently pathogenic and indicator bacteria (microbes of human origin) in the floors close to the ground, their occurrence decreased more and more in the upper stories. The number of colony-forming units (CFU) also diminished from the bottom to the top. In addition, the microbiological parameters depended to a considerable extent on the direction of the sampling points. Most pathogens were borne on the coarse dust of the north-easterly wind which usually prevails in the capital. The expected summer maximum was only found in blood dishes and at observation points on a lower level. The seasonal influence, however, became apparent as expected. A detailed analysis of our results points to the microbiological air contamination caused by the ventilation systems in the largest buildings.