[Further microbiological studies of the air in a newly built (under the pavement) section of the underground railway in Budapest]. / Weitere mikrobiologische Untersuchungen der Luft eines neugebauten (Unterpflasters-) Teils der U-Bahn in Budapest.

In three subway stations, which are "sub-pavement" stations (Budapest), microbiological air analyses were simultaneously carried out by means of sedimentation and by the use of Krotow's impactor. In the course of the examinations, which lasted eight months, the following max. values were obtained on the agar plates: 78 colonies/dm2/h and 239 colonies/m3; the rates of incidence for pathogenic and indicator bacteria were 2.7 and 1.7 per 10 plates. The strongest airflow was 0.7 m/sec. These values were obtained at the "Nagy-várad tér" station, which forms a transition to the subway stations. The "stopper effect" was found to exist here as well, although not to such an extent as in the deep subway stations, but still more pronounced than in the other two "subpavement" stations "Esceri ut" and "Határ ut". The microbiological values are at any rate more favourable than in the subway stations dealt with in an earlier paper.

[Contributions to the vertical development of the airborne microflora above a junction in the Hungarian capital of Budapest (author's transl)]. / Beiträge zur vertikalen Entwicklund der Luftmikroflora oberhalb eines Verkehrskontenpunktes in der Hauptstadt Budapest.

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.

[Airborne microflora found in some stations of the metro in the Hungarian capital of Budapest (author's transl)]. / Luftmikroflora-Untersuchungen in einigen Haltestellen der Untergrundbahn (Metro) der Hauptstadt Budapest.

Both the microflora and some physical parameters of the air in three underground railway (metro) stations were analysed. The air samples taken in the first two stations contained considerably more microbes, namely three times as many, than the sample from station No. 3. In the samples from the first two stations both the pathogenic and anthropogenic germs occured more frequently than in the samples from the third station. The normal flora consisted of gram-positive cocci/Streptococci, Micrococci, Sarcina. Roughly 10 per cent of the microbes proved to be spore-formers. Selective investigations led to the detection of Staph. aureus, Enterococci, Haemophilus influenzae, Escherichiae, Klebsiella and Proteus bacteria. The reason why the stations of line 2 were found to be contaminated to a greater degree is probably because of the higher passenger traffic, the smaller space, as well as the stronger airflow due to the artificial ventilation and the piston effect of the trains. The effect of the artificial environmental conditions on the staff of the metro company still needs further investigation. The effect on the passengers is considered to be less pronounced.

[Analysis of the germ content of the air in university lecture rooms (author's transl)]. / Untersuchung der Keimbelastung der Luft von Universitäts-Unterrichsträumen.

The microflora of the air in university lecture rooms was examined with the sedimentation method. For this purpose blood agar (20 degrees C and 37 degrees C), saline agar and Endo plates were used. The germ counts identified correlate to the size and utilization of the rooms. The lowest germ count was determined in the room used for practical work, which was followed by the lecture room. The newly built lecture room contained the highest colony count. The floor ventilation furnishes an explanation for this. Most of the colonies were Gram-positive cocci (micrococci, indifferent streptococci, sarcins). Aerobic spore-forming organisms were found to be present in smaller quantities than cocci. Fungi, mainly, moulds grew better at a temperature of 20 centigrade. The microbiological monitoring of air forms an important part of environmental protection. Great importance can be attached to a stardization of the air germ count in the prevention of airborne infections.