Carbon monoxide: the invisible killer.

Carbon monoxide (CO) is a colourless, odourless and tasteless gas. It is emitted when carbon containing compounds are incompletely combusted. This paper reports on concentrations of CO in the environment in relation to anthropogenic emission sources and assesses the extent of the health hazard from this common air pollutant. It includes the results of CO monitoring in a variety of locations in south west London. The conclusion is that indoor emission sources present a greater and more insidious health risk than do outdoor emission sources. Methods for reducing the dangers it poses are briefly summarised.