Large contribution of water-insoluble secondary organic aerosols in the region of Paris (France) during wintertime

Jean Sciare (1, 2) , Odile d'Argouges (1) , Roland Sarda-Esteve (1, 2) , Cécile Gaimoz (1) , Cristina Dolgorouky (1) , Nicolas Bonnaire (1, 2) , Olivier Favez (3) , Bernard Bonsang (1, 2) , Valérie Gros (1, 2)

1 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
2 CAE - Chimie Atmosphérique Expérimentale
3 INERIS - Institut National de l'Environnement Industriel et des Risques

Near real-time measurements of carbonaceous aerosols were performed in fine aerosols for a 10-day period during winter at a suburban site of Paris (France). These measurements were performed using an OCEC Sunset Field instrument for elemental carbon (EC) and organic carbon (OC); a Particle-Into-Liquid-Sampler coupled with a Total Organic Carbon (PILS-TOC) instrument for water-soluble OC (WSOC); and a 7-lambda aethalometer for absorption. A successful comparison was performed with filter sampling performed in parallel for EC, OC, and WSOC, providing further confidence on the results obtained by the online analyzers. A modified version of the aethalometer model was used to derive hourly concentrations of 3 organic aerosol (OA) sources: fossil fuel, wood burning, and secondary. This source apportionment was validated for primary OA (fossil fuel, wood burning) using time-resolved measurements of specific tracers (including levoglucosan, water-soluble potassium and methanol for wood burning) and showed that secondary organic aerosols (SOA) were the most abundant OA species during our study. Water-soluble properties of these different OA sources were investigated from the reconstruction of experimentally determined water-soluble/insoluble OC. About 23% of WSOC was found to be of a secondary (photochemical) origin. A large fraction of SOA was assigned as water-insoluble and could originate from semi-volatile primary OA from wood burning and/or anthropogenic emissions. These results have been obtained at a typical suburban site in France and may be then representative of a larger European area. They bring new light on the commonly accepted idea that SOA is mainly water-soluble.

Keywords: AEROSOLS ORGANIQUES SECONDAIRES<br />---<br />B

Domains: Environmental Sciences

Jean Sciare, Odile d'Argouges, Roland Sarda-Esteve, Cécile Gaimoz, Cristina Dolgorouky, et al.. Large contribution of water-insoluble secondary organic aerosols in the region of Paris (France) during wintertime. Journal of Geophysical Research: Atmospheres, 2011, 116, pp.D22203. ⟨10.1029/2011JD015756⟩. ⟨ineris-00963327⟩