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Biomedical subjects

H U Wanner

Publications and source records attributed to H U Wanner.

At least 55 records · Page 3Linked to original sources
PubMed1978

[Disturbance due to traffic noise at night].

In order to obtain bases for the establishment of threshold values in the new environmental law, a random sample survey with 1600 persons in urban and rural areas has been made on the degree of disturbance by street traffic noice in the night.

Circadian Rhythm↗
PubMed1976

[Measurement of exhaust gases of cars in the neighbourhood of roads (author's transl)].

Air samples were collected in plastic bags simultaneously at various measuring points in the close range of streets. When examining the various bag materials, Teflon bags showed the smallest deviations in direct analyses and in analyses of up to two hours after the drawing of samples. The following methods were used for the analysis of the air samples collected in the bags: coulometry for CO and SO2, chemiluminescence for NO/NO2, chromotropic acid for CH2O and flame ionization for hydrocarbon. The various components were measured close to a highway and near streets in residential and business areas.

Air Pollution↗
PubMed1975

[Microbial contamination of air by activated sludge units (author's transl)].

Measurements of the germ emissions in various activated sludge units with different ventilations systems have shown that the lowest density occurs with small bubble ventilation; with medium bubble and brush ventilation rather high values were measured; the spray devices used for foam elimination had a particularly unfavorable influence. In great germ densities above the pools (50-100 000 germs/m3) - depending on the weather - between 500 and 1500 germs/m3 were measured at a distance of 50 and 100 meters. At distances of 200 and 400 m the number of germs was about the same as normally measured in the outside air (100-500 germs/m3). In a closed pool altogether considerably higher values were measured: In the immediate neighbourhood of the activated sludge unit they amounted to abt. 10 000-25 000 germs/m3; in the hall 3000-4000 germs/m3 were measured, whereby the part of coliform bacteria amounted to 1-2% and that of enterococci to 2-4%. It has to be taken into account that besides the measured intestinal flora further pathogenous agents are present in the aerosols. In closed units, therefore, a greater risk of aerogenous infections exists, whereas in open-air pools this danger can be judged as very small.

Aerosols↗
PubMed1975

[Emissions from combustion of indoor dust (author's transl)].

Combustion of dust is an old problem which has gained a new importance since the introduction of electric storage heaters for space heating. Physico-chemical changes caused by heating indoor dust in a model apparatus were investigated. Four dust samples of different origins were heated at three temperatures (200, 400, 600 degrees C) for three residence times (5, 15, 30 min). The higher the temperature, the higher the weight loss expressed as percentage (15 to 75%). The residence time had no effect on the loss. Three dust samples showed pH of about 7 before heated, while the fourth showed pH of about 10. After heating to 200 degrees C, the pH of one of the samples rose from 7 to 10. When heated to 400 and 600 degrees C, all the samples showed pH values between 10 and 11. The residence time had no effect. The pH of the gaseous reaction products did not show uniform pattern at 200 degrees C. At 400 degrees C, the measured pH was between 7.5 and 8.5, while at 600 degrees C no further change was observed. Changes in pH took place during the first fifteen minutes. Chemical analysis of the reaction products with help of detector tubes indicated that dust samples when heated emit carbon monoxide, carbon dioxide, oxides of nitrogen and ammonia.

Air↗