The term Polycyclic Aromatic Hydrocarbons (PAH) refers to a group of several hundred individual substances. Benzo[a]pyrene (BaP) is the best-known pollutant and is used as an indicator substance.

PAHs form during incomplete combustion involving fossil fuels or other organic materials. Indoors, PAHs can occur particularly in tar products. Black coatings and adhesives do not necessarily contain tar; they often consist of bitumen.

In residential construction, PAHs were mostly used in tar adhesives for parquet floors, roofing and waterproofing membranes, and tar-asphalt coatings. Production of tar adhesives in Germany ended in the mid-1970s, although tar-containing adhesives continued to be used until around 1981. Since then, mainly synthetic adhesives have been used.

PAHs can enter the body through food, direct skin contact or breathing, and can cause illness, particularly following long-term exposure. Numerous PAHs, including the indicator substance BaP, are classified as carcinogenic. BaP can also impair fertility and harm unborn children.

Parquet and other floor coverings were often laid with tar-containing adhesives. Harmful emissions may have long since dissipated, only to become exposed again during renovation work.

Analysis is needed to determine whether tar-containing construction products contain PAHs and at what concentration. Smell or appearance alone is insufficient. The risk posed by a PAH-containing product depends on its PAH content, installation location and condition.

Different solutions are available for removing contamination. The appropriate solution must therefore be decided case by case. Removal should always be carried out by specialists, even where private individuals are not prohibited from doing so.