Chemical characterization and stable carbon isotopic composition of particulate Polycyclic Aromatic Hydrocarbons issued from combustion of 10 Mediterranean woods

A Guillon,N Marchand,K Le Ménach,H Budzinski,E Villenave,P.-M Flaud

doi:10.5194/acp-13-2703-2013

Abstract

Abstract. The objectives of this study were to characterize polycyclic aromatic hydrocarbons from particulate matter emitted during wood combustion and to determine, for the first time, the isotopic signature of PAHs from nine wood species and Moroccan coal from the Mediterranean Basin. In order to differentiate sources of particulate-PAHs, molecular and isotopic measurements of PAHs were performed on the set of wood samples for a large panel of compounds. Molecular profiles and diagnostic ratios were measured by gas chromatography/mass spectrometry (GC/MS) and molecular isotopic compositions (δ13C) of particulate-PAHs were determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Wood species present similar molecular profiles with benz(a)anthracene and chrysene as dominant PAHs, whereas levels of concentrations range from 1.8 to 11.4 mg g−1 OC (sum of PAHs). Diagnostic ratios are consistent with reference ratios from literature but are not sufficient to differentiate the species of woods. Concerning isotopic methodology, PAH molecular isotopic compositions are specific for each species and contrary to molecular fingerprints, significant variations of δ13C are observed for the panel of PAHs. This work allows differentiating wood combustion (with δ13CPAH = −28.7 to −26.6‰) from others origins of particulate matter (like vehicular exhaust) using isotopic measurements but also confirms the necessity to investigate source characterisation at the emission in order to help and complete source assessment models. These first results on woodburnings will be useful for the isotopic approach to source tracking.

Highlights

M chromatography/mass spectrometry (GC/MS) and molecular isotopic compositions (δ13C) of particulate-PAHs were ments such as water (Latimer and Zheng, 2003; Amoako et al, 2011), sediments (Latimer and Zheng, 2003; Srogi, determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS)
We show that the use of a single molecular fingerprint based on PAH concentrations could traduce the origin of Mediterranean wood burnings regardless of the wood species because of the similarities of molecular fingerprints of the eleven woods, as expected
Combustion of woods was performed under controlled conditions in a burning chamber in order to compare the nature of the woods, wood species and conditions of burning

Summary

Introduction

M chromatography/mass spectrometry (GC/MS) and molecular isotopic compositions (δ13C) of particulate-PAHs were ments such as water (Latimer and Zheng, 2003; Amoako et al, 2011), sediments (Latimer and Zheng, 2003; Srogi, determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Most of PAHs tic ratios are consistent with reference ratios from literature come from the incomplete combustion of organic materibut are not sufficient to differentiate the species of woods. Concerning isotopic methodology, PAH molecular isotopic compositions are specific for each species and contrary to molecular fingerprints, significant variations of δ13C are obmIAaRnCb,ei2n0g1s1)(.AItnkinthsoenOatamncdoesApahrneeyre,S,1t9ch9ie4ey;naKrceaendgisettribalu.t,e2d01b1e-; tween gaseous phase and particles (Eiguren-Fernandez et al, served for the panel of PAHs. This work allows differentiating wood combustion (with δ13CPAH = −28.7 to −26.6 ‰). Guillon et al.: Chemical characterization and stable carbon isotopic composition burning such as building heating, cooking (Lee et al, 2005) or swidden, slash-and-burn farming, and because of natural wood combustions (forest fires)

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Conclusion