Inter-comparison of source apportionment models for the estimation of wood burning aerosols during wintertime in an Alpine city (Grenoble, France)
1Université Lyon 1, Lyon 69626, France; CNRS, UMR 5256, IRCELYON, Institut de Recherches sur la Catalyse et l'Environnement de Lyon, Villeurbanne, 69626, France
2Universités d'Aix-Marseille-CNRS, UMR 6264: Laboratoire Chimie Provence, Equipe Instrumentation et Réactivité Atmosphérique, Marseille, 13331, France
3Université Joseph Fourier-Grenoble 1-CNRS, UMR 5183, Laboratoire de Glaciologie et Géophysique de l'Environnement, Saint Martin d'Hères, 38402, France
4Université Savoie-Polytech'Savoie, Laboratoire de Chimie Moléculaire et Environnement, Le Bourget du lac, 73376, France
5Association pour le contrôle et la préservation de l'air en région grenobloise (ASCOPARG), Grenoble, 38100, France
6Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ-IPSL, 91191 Gif sur Yvette, France
Abstract. The emission of organic aerosols (OA) in the ambient air by residential wood burning is nowadays a subject of great scientific concern and a growing number of studies aim at apportioning the influence of such emissions on urban air quality. In the present study, results obtained using two commonly-used source apportionment models, i.e., Chemical Mass Balance (CMB, performed with off-line filter measurements) and Positive Matrix Factorization (PMF, applied to aerosol mass spectrometer measurements), as well as using the recently-proposed aethalometer model (based on the measurement of the aerosol light absorption at different wavelengths) are inter-compared. This work is performed using field data obtained during the winter season (14 to 30 January 2009) at an urban background site of a French Alpine city (Grenoble). Converging results from the different models indicate a major contribution of wood burning organic aerosols (OMwb) to the organic fraction, with mean OMwb contributions to total OA of about 67%, 60% and 38% for the CMB, the aethalometer and the AMS-PMF models, respectively. Quantitative discrepancies might notably be due to the overestimation of OMwb calculated by the CMB due to the loss of semi-volatile compounds from sources to receptor site, as well as to the accounting of oxidized primary wood burning organic (OPOAwb) aerosols within the Oxygenated Organic Aerosol (OOA) PMF-factor. This OOA factor accounts on average for about 50% of total OM, while non-combustion sources contribute to about 25% and 28% of total OM according to the CMB and aethalometer models, respectively. Each model suggests a mean contribution of fossil fuel emissions to total OM of about 10%. A good agreement is also obtained for the source apportionment of elemental carbon (EC) by both the CMB and aethalometer models, with fossil fuel emissions representing on average more than 80% of total EC.