ABSTRACT
The chemical class of polycyclic aromatic hydrocarbons (PAH) comprises a group of several hundred compounds including noxious substances which are strongly suspected of inducing cancer in man. Consequently limitation of the PAH air quality to the level of less polluted areas would reduce the lung cancer frequency correspondingly. A risk assessment of the carcinogenic hazards evoked by air-polluting PAH in man must rely on experimental animal investigations, as well as epidemiological findings. The PAH are taken in by inhalation and by ingestion of food. Since the resorption of PAH via the mucosa of stomach and intestinal tract seems to be rather low, the intake by respiration plays a decisive role for man. However, the PAH content of air is caused only to a minor extent by automobile exhaust gases, it seems doubtful whether an improved additional combustion of exhaust gases of Otto engines would considerably reduce the PAH content in the atmosphere.
