Source Characterization of Polycyclic Aromatic Hydrocarbons by Using Their Molecular Indices: An Overview of Possibilities - Reviews of Environmental Contamination and Toxicology - page 107

5.7.2 Ratios of Four- to Five-Ringed PAHs

The benz[ a ]anthracene/benzo[ a ]pyrene (BaA/BaP) ratio is little influenced by pho-
todegradation and has been used (sometimes together with the FL0/PY0 ratio) to
identify enhanced industrial emissions or to distinguish diesel or wood emissions
from gasoline emissions (Lehndorff and Schwark 2004 ; Zhu et al. 2011 ). The BaA/
BaP ratio may be adequate to distinguish coal tar and creosote residues from urban
background PAHs (Costa and Sauer 2005 ; Costa et al. 2004 ). Wood combustion has
a BaA/BaP ratio of about 1 (Lai et al. 2011 and references therein).
Low pyrene/benzo[ a ]pyrene (PY0/BaP) ratios indicated a negligible contribution
of terrigenous flows into the aquatic system, whereas PY0/BaP > 10 indicated petro-
genic sources (De Luca et al. 2004 ). The PY0/BaP ratio may be used to discriminate
coal from wood combustion, but may not be applied to discriminate between com-
bustion products of different wood species (Guillon et al. 2013 ). PY0/BaP values
have been reported for diesel (≈10), gasoline emissions (≈1) and wood combustion
(≈0.7) (Lai et al. 2011 ; Ravindra et al. 2008 and articles cited by these authors).

5.8 Assignment of PAHs to Sources

One way to estimate the different source contributions to a sample is to empirically
classify PAHs into pyrolytic, petrogenic or natural, even if some PAHs could have
more than one origin (Page et al. 2006 ; Stout et al. 2004 ; Table 3 ). For instance, a
typical urban background sediment containing approximately 74% of pyrogenic
and 26% of petrogenic PAHs is distinctly different from some pyrogenic finger-
prints (Battelle Memorial Institute et al. 2003 ). Assignment of PAHs to sources
depends on the specific region examined (local sources) and on the analytical meth-
ods applied (number of PAH analytes), which is why the lists of PAHs assigned to
sources differ between different studies (Jeanneau et al. 2008 ).

5.8.1 PCA/PMF Classification

PAH classification schemes occasionally emerge from a successful discriminant
analysis application for a certain contamination case. The resulting compilation of
PAH indices may have a local or wider applicability, and offers adequate resolution,

Table 3 PAH apportionment to sources according to Stout et al. ( 2004 )
Pyrogenic Petrogenic Mixed Biogenic

A0, FL0, PY0, FP1, BaA,
C0,C1, BbF, BkF, BeP,
BaP, IP, DA, ghi

N0, N1, N2, N3, N4, B, F0, F1, F2, F3, AE,
AY, DF, PA2, PA3, PA4, D0, D1, D2, D3,
D4, FP2, FP3, C2, C3, C4

C0, PA1 PER

See Table 1 for PAH abbreviations