Sources and atmospheric processes determining airborne concentrations of polycyclic aromatic hydrocarbons and their degradation products

The polycyclic aromatic hydrocarbons are a group of chemical substances present in the atmosphere which are known to be a cause of lung cancer. They are formed when carbon-containing fuels such as coal, oil or gas are burned, as well as being emitted from some industrial processes such as aluminium smelting. Whilst road vehicles and home heating are known to be significant sources, the relative amounts coming from different sources are not well known and this research intends to use measurements of these compounds in the atmosphere to infer which sources are mainly responsible. It is also known that polycyclic aromatic hydrocarbons are changed by chemical reactions in the atmosphere but the rates of these reactions are not well known and these are also to be studied. These reactions cause the formation of other chemicals known as PAH-derivatives for which measurement methods will be developed. The outcome will be a much improved understanding of the sources and processes affecting these compounds in the atmosphere leading ultimately to the possibility of more cost-effective control measures being taken.