ABSTRACT
Polycyclic aromatic hydrocarbons (PAH) are especially formed by the incomplete combustion or pyrolysis of organic material containing carbon and hydrogen. Metallurgical coke or polytetrafluoroethylene (PTFE) produce only small or nondetectable amounts of PAH. The concentration of PAH emitted depends largely on the type of fuel. In comparison with domestic heating, the emitted amounts of PAH are small and can probably be neglected when assessing the total hazard arising from PAH emitted by different groups of emitters. The PAH detected in exhaust gas are formed exclusively during combustion. Investigations carried out in the US with trucks produced PAH emissions similar to those of comparable automobiles with gasoline engines. In the atmosphere, however, PAH are hardly present as gases. The concentration of individual PAH in the sewage sludge of the 25 purification plants varied within a decimal power. Foodstuffs may be contaminated with PAH via airborne particulate matter, by direct drying with smoke, or by absorbtion during the smoking process.
