Effect on health of man-made mineral fibres in kindergarten ceilings.

The relation between the presence of readily visible man-made mineral fibre (MMMF) products in the ceilings and the presence/frequency of symptoms and diseases, and the correlation between the presence/frequency of symptoms and diseases and the concentration of MMMF in the indoor environment was investigated in 24 kindergartens. A combination of traditional epidemiological techniques and a technical analysis of a number of indoor air parameters did not support the hypothesis that release of MMMF from readily visible MMMF products in the ceilings was mainly responsible for the occurrence of symptoms or diseases related to indoor exposure in kindergartens.

Correlating health effect with indoor air quality in kindergartens.

In 24 kindergartens the relation between the presence of readily visible, man-made mineral-fiber products in the ceilings and the presence/frequency of symptoms or diseases and the correlations between complaints of symptoms or disease and the concentration of man-made mineral-fibres in the indoor environment was investigated. A combination of traditional epidemiological technique and a technical analysis of a number of indoor-air parameters did not support the hypothesis that the presence of readily visible man-made mineral-fiber products in the ceiling should be mainly responsible for the occurrence of symptoms and/or disease related to indoor exposure in kindergartens.

Indoor air pollution with smoke constituents--an experimental investigation.

In a sealed room of approximately 60 m3, sidestream cigarette smoke was maintained at a constant level of approximately 20 ppm during a 3-hr experimental period. Air concentrations of carbon monoxide, nitrogen dioxide, hydrogen cyanide, acrolein, and other aldehydes were measured in situations with and without persons present. It was demonstrated that these smoke constituents were encountered in lower concentrations with than without persons present. It was further demonstrated that measurement of carboxyhemoglobin concentrations was not a good general indicator for exposure to various tobacco smoke constituents because of the vast differences in cigarette equivalent time values between the different smoke constituents. Subjective discomfort was estimated by means of questionnaires distributed every 30 min during the experimental period and was found to be almost identical irrespective of exposure to whole sidestream smoke or to only its gas phase. Exposure of volunteers to acrolein caused considerably less discomfort than exposure to sidestream smoke or to the gas phase alone.

Myocardial morphology in rabbits exposed to various gas-phase constituents of tobacco smoke--an ultrastructural study.

Rabbits were continuously exposed to 200 ppm carbon monoxide. Using the same criteria as applied by earlier investigators for morphological myocardial damage, no histotoxic effect on myocardial morphology could be demonstrated when electron-microscopic investigations were performed blindly. Similarly, exposure to 0.5 ppm hydrogen cyanide, 0.5 ppm hydrogen cyanide + 200 ppm carbon monoxide, 0.5 ppm hydrogen cyanide + 200 ppm carbon monoxide + 5 ppm nitric oxide and to 50 ppm carbonyl sulphide for 1-7 weeks had no significant effect on myocardial ultrastructure.

The effect of carbon monoxide exposure on morphology of lungs and pulmonary arteries in rabbits. A light- and electron-microscopic study.

Rabbits were continuously exposed either to 200 parts per million carbon monoxide for 3, 4, and 6 weeks or to 1,900 parts per million carbon monoxide for 5 h. Blind light and transmission electron microscopic investigations showed no morphological changes in the lung parenchyma, lung vasculature or in pulmonary arteries of the exposed animals when compared with controls. The discrepancies with findings previously reported by other authors are discussed.

Exposure of rabbits to carbon monoxide and other gas phase constituents of tobacco smoke.

Non cholesterol-fed rabbits were exposed to carbon monoxide at concentrations in air of either 200, 2000, or 4000 ppm (= 0.02, 0.2, or 0.4% vol/vol). Further, exposure was performed to 0.5 ppm hydrogen cyanide alone or in combination with 200 ppm carbon monoxide or with 200 ppm carbon monoxide and 5 ppm nitric oxide and eventually to 50 ppm carbonyl sulphide. Duration of the continuous exposures were between 1/2 week and 12 weeks. Using the same criteria for intimal damage as in earlier morphological studies, no histotoxic effect on intimal/subintimal morphology of coronary arteries or the aorta could be demonstrated, when light-microscopic evaluation was performed blindly.

Ultrastructural changes of the rabbit lung after a 5 ppm nitric oxide exposure.

Four male rabbits were continuously exposed to 5 ppm nitric oxide for 14 days. Four rabbits served as controls. Specimens from pulmonary arterioles and alveolar tissue were examined by light and transmission electron microscopy. The most conspicuous findings were fluid-containing vacuoles inside the arteriolar endothelial cells and/or in the intercellular junctions. Thickening of the alveolo-capillary membrane due to accumulation of edema fluid in the interstitial space was also observed.