This volume is the 3rd in a series of comprehensive publications devoted
to the molecular spectra and environmentally important properties of
polycyclic aromatic compounds which constitute one of the most
interesting classes of environmental carcinogens. Since the first
identification of dibenz(a, h)anthracene and later benzo(a)pyrene as
chemical carcinogens in the 1930's, the number of publications devoted
to this ubiquitously occurring group of compounds has increased
constantly. Therefore, this reference source for the spectral,
physicochemical and en- vironmentaJ properties of polycyclic aromatic
compounds should be a welcome addition to the previous volumes for
scientists engaged in the investigation, characterisation and control of
this hazardous class of pollutants. As was the case with the preceding
volume, this publication is the fruit of a close collaboration within
the General Directorate for SCience, Research and Development of the
Commission of the European Communities between the Environment Institute
of the Joint Research Centre Ispra, the Community Bureau of Reference
and expert laboratories in the member states. F. Geiss Director of the
Environment Institute JRC Ispra 1. Introduction Polycyclic Aromatic
Compounds (PAC) are an important class of carcinogenic environmental
pollutants, which occur in air, water, soils, sediments, in food and in
the work area. Because many hundreds of closely related isomers are
being formed and released in the environment from combustion processes
of fossil fuels and other organic materials, their environmental and
health con- trol presents a difficult task.
