10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Analysis of Gas-phase and Particulate Reaction Products from High-NOx Photooxidation of n-dodecane: Influence of Temperature and Relative Humidity on Secondary Organic Aerosol Formation
HOUSSNI LAMKADDAM, Aline Gratien, Edouard Pangui, Mathieu Cazaunau, Marc David, Jean-Michel Polienor, Murielle Jerome, Cécile Gaimoz, Bénédicte Picquet-Varrault, Jean-François Doussin, LISA, Universités Paris-Est-Créteil et Paris Diderot
Abstract Number: 1205 Working Group: Aerosol Chemistry
Abstract Organic aerosol (OA) plays an important role on atmospheric chemistry, climate change and public health. While OA particles can be directly emitted into the atmosphere, they can also be introduced in the atmosphere by secondary organic aerosol (SOA) formation. However our current knowledge of oxidation pathways and chemical composition of the SOA is limited and poorly understood considering the difficulty of the chemical transport model (CTM) to predict the OA mass in the atmosphere (Heald et al., 2011). It results to large uncertainties in the estimation of the impact on climate and air quality of the atmospheric aerosols.
In this context, the aim of this work is to study SOA formation from oxidation of precursors such as long chain alkanes which represent a substantial fraction of the unresolved complex mixture in diesel fuel (Gentner et al, 2012). Beside the fact that it represents a relevant class of compound for the urban atmosphere, long chain alkanes are also very interesting model-molecule to investigate the sensitivity to different reaction pathways of the organic matter, i.e. fragmentation, functionalization or oligomerization, during its atmospheric oxidation.
The experiments were carried out in the CESAM chamber (http://cesam.cnrs.fr) (Wang et al., 2011). It is a 4,2 m3 stainless steel chamber which allows to conduct experiments at different temperature and relative humidity, constant pressure and under a very realistic actinic flux. It is also equipped with a large range of analytical instruments to characterize the gas-phase and particulate reaction products.
In particular, the present work assesses the effect of temperature (from 10 to 30°C) and relative humidity (from <1 to 70%) on the high-NOx photooxidation of n-dodecane. Aside aerosol mass production, the mechanism was also investigated by measuring SOA composition. Mechanistic pathways of the gaseous and particulate products will be proposed.
This work was supported by the European Community within the 7th Framework Program, section “Support for Research Infrastructure – Integrated Infrastructure Initiative”: EUROCHAMP-2 and also by the French National Programme of Atmospheric Chemistry (PN-LEFE CHAT). CNRS-INSU is acknowledged for supporting the CESAM chamber as national instrument.
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