Polycyclic Aromatic Hydrocarbons
Polycyclic Aromatic Hydrocarbons (PAH) are members of a large group of organic compounds widely distributed in the atmosphere. Their molecular structure comprises of carbon and hydrogen atoms only, within two or more fused aromatic rings. The best known PAH is benzo[a]pyrene (B[a]P).
Sources
The main sources of PAH in the UK are domestic coal and wood burning (39%), industrial emissions (19%), and road transport (8%).
Health Effects
There is clear evidence that PAH mixtures are carcinogenic in humans and several individual PAHs are carcinogenic in experimental studies. The toxicity of PAH mixtures vary depending upon their composition. Increased risks of lung cancer, in particular, have been associated with increased concentrations of PAHs.
