Investigations of some aspects of atmospheric pollution by anaesthetic gases. I: Diffusion of halothane across plastic and rubber tubes.
Plastic and rubber tubing, of the types used frequently to convey anaesthetic gases to and from the patient, or anaesthetic waste gases out of the operating theatre, were assessed for their capacity to allow diffusion of halothane through the tube wall. The magnitude of this effect has been calculated in relation to pollution of the operating theatre atmosphere under different circumstances.
Leakage and absorption of isoflurane by different types of anaesthetic circuit and monitoring tubing
Summary Conductive rubber anaesthetic circuit tubing both absorbs volatile agents and leaks these agents through its walls. We quantified the leakage and absorption properties of the most commonly used plastic materials used to make breathing circuit tubing, relative to conductive rubber. We then compared two different types of plastic tubes used to carry gas to volatile agent monitors; one made of polyvinyl chloride, the other made of polyvinyl chloride lined internally with a thin layer of polyethylene. We found that the three commonly used plastic types used to make anaesthetic circuit tubing all leak less volatile anaesthetic through their walls than conductive rubber. Polyethylene and polypropylene tubing absorb significantly less volatile anaesthetic than conductive rubber; however, this is not the case with polyvinyl chloride tubing. Differences in the leakage and absorption properties of polyvinyl chloride monitoring tubing are not significantly changed by the addition of a thin internal layer of polyethylene. It is therefore not worthwhile incorporating this feature into production.
Study on the gaseous emissions from a landfill
Abstract Emissions from landfills contain a variety of compounds, organic and inorganic, which can create problems with human health. Here we examine the pollutants methane, hydrogen sulphite, mercaptans, sulphur dioxide, nitrogen dioxide and certain volatile organic compounds (VOCs) that are expected to be found in landfill emissions, in order to assess the environmental impact on the surrounding area. Results indicate that the concentrations in the landfill itself are quite high and in most cases above the ambient air quality limits, while for the surrounding area they are low. The problem is created by H 2 S and the mercaptans which, although in low content, have a distinct odour and cause problems to the neighbouring dwellings.