Polynuclear Aromatic Hydrocarbons (NPAH) and environment.
Nitrated polynuclear aromatic hydrocarbons (NPAH) have been recognised as
belonging to long-term toxic compounds and, on the other hand, were
identified in several anthropogenic emissions and among by-products of
photochemical smog: Therefore, in seventies and eighties they began subject
of investigation in ambient air and emission products, although any
regulation limited they release in the environment. Our institute, IIA-CNR,
belongs to the restricted number of scientific laboratories which
investigate NPAH since long time. Most studies were addressed to
standardise analytical methods and sampling procedures for NPAH present in
the atmosphere as well in emissions, while the remaining ones allowed to
set up a consistent data base of concentration levels reached by NPAH in
the air of Italian cities and other locations worldwide (Himalaya,
Antarctica, Arctic Region, Japan, Algeria, Amazon). These studies also
provided information about the relative importance of direct emission and
in situ generation (started by photochemical oxidants) with respect to the
occurrence of NPAH in the environment. In fact, the identification of
individual congeners revealed that in many cases the exact nature of NPAH
was source-dependent. In particular, between MW=247 isomers
2-nitrofluoranthene and 2-nitropyrene are of photochemical origin, whilst
1-nitropyrene, 3-nitrofluoranthene and 8-nitrofluoranthene are associated
to direct emissions; similarly, 2-nitrofluorene and 3-nitrophenanthrene are
related to diesel car exhausts, whilst in the atmosphere 3-nitrofluorene
and 2-nitrophenanthrene are present at higher extents.
Despite the scarce concern given to NPAH by Scientific Agencies as well as
Health and Government Institutions, the investigations focussed onto these
pollutants were continued by IIA-CNR and nowadays they experience a renewed
concern, provoked by the recent studies on long-term toxicity for man and
mammals. NPAH are nowadays subject of investigations conducted by well
trained laboratories belonging to Monitoring Networks of Pollution of
Italian Regions paying more attention to environmental issues.
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