Polycyclic Aromatic Hydrocarbons (PAHs)
Polycyclic Aromatic Hydrocarbons (PAHs), also known as polyaromatic hydrocarbons, are organic compounds containing only carbon and hydrogen and composed of multiple aromatic rings (Figure 1). These compounds are formed when oxygen is limited, and incomplete combustion of organic matter such as wood, tobacco products, or fossil fuels occurs. These pollutants do not break down and are very persistent in the environment. PAHs are known carcinogens and have been linked to skin, lung, bladder, liver, and stomach cancers.
Figure 1: Chemical structure of selected PAHs (source image for PAH structures)