Organic aerosol source apportionment by offline-AMS over a full year in Marseille
Carlo Bozzetti1, Imad El Haddad1, Dalia Salameh2,7, Kaspar Rudolf Daellenbach1, Paola Fermo3, Raquel Gonzalez3, Maria Cruz Minguillón4, Yoshiteru Iinuma5, Laurent Poulain5, Emanuel Müller6, Jay Gates Slowik1, Jean-Luc Jaffrezo7, Urs Baltensperger1, Nicolas Marchand2, and André Stephan Henry Prévôt11Paul Scherrer Institute (PSI), 5232 Villigen-PSI, Switzerland 2Aix Marseille Univ., CNRS, LCE, 13331 Marseille, France 3Università degli Studi di Milano, 20133 Milano, Italy 4Institute of Environmental Assessment and Water Research (IDAEA), CSIC, 08034 Barcelona, Spain 5Leibniz Institute für Troposphärenforschung, 04318 Leipzig, Germany 6Eawag, 8600 Dübendorf, Switzerland 7Université Grenoble Alpes, CNRS, LGGE, 38000 Grenoble, France
Received: 20 Jan 2017 – Accepted for review: 30 Jan 2017 – Discussion started: 01 Feb 2017
Abstract. We investigated the seasonal trends of OA sources affecting the air quality of Marseille (France) which is the largest harbor of the Mediterranean Sea. This was achieved by measurements of nebulized filter extracts using an aerosol mass spectrometer (offline-AMS). PM2.5 (particulate matter with an aerodynamic diameter < 2.5 micrometers) filter samples were collected over 1 year from August 2011 to July 2012. The same samples were also analyzed for major water-soluble ions, metals, elemental and organic carbon (EC/OC), and organic markers, including n-alkanes, hopanes, polyaromatic hydrocarbons (PAHs), lignin and cellulose pyrolysis products and nitrocatechols. The application of positive matrix factorization (PMF) to the water-soluble AMS spectra enabled the extraction of five factors, related to hydrocarbon-like OA (HOA), cooking OA (COA), biomass burning OA (BBOA), oxygenated OA (OOA), and an industry-related OA (INDOA). Seasonal trends and relative contributions of OA sources were compared with the source apportionment of OA spectra collected from the AMS field deployment at the same station but in different years and for shorter monitoring periods (February 2011 and July 2008). Online- and offline-AMS source apportionment revealed comparable seasonal contribution of the different OA sources. Results revealed that BBOA was the dominant source during winter representing on average 48 % of the OA, while during summer the main OA component was OOA (63 % of OA mass on average). HOA related to traffic emissions contributed on a yearly average 17 % to the OA mass, while COA was a minor source contributing 4 %. The contribution of INDOA was enhanced during winter (17 % during winter and 11 % during summer), consistent with an increased contribution from light alkanes, light PAHs (fluoranthene, pyrene, phenantrene) and selenium, which is commonly considered as an unique coal combustion and coke production marker. Online- and offline-AMS source apportionments revealed evolving levoglucosan:BBOA ratios, being higher during late autumn and March. A similar seasonality was observed in the ratios of cellulose combustion markers to lignin combustion markers, highlighting the contribution from cellulose rich biomass combustion, possibly related to agricultural activities.
Bozzetti, C., El Haddad, I., Salameh, D., Daellenbach, K. R., Fermo, P., Gonzalez, R., Minguillón, M. C., Iinuma, Y., Poulain, L., Müller, E., Slowik, J. G., Jaffrezo, J.-L., Baltensperger, U., Marchand, N., and Prévôt, A. S. H.: Organic aerosol source apportionment by offline-AMS over a full year in Marseille, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2017-54, in review, 2017.