Chemical characterization of SOA from diesel and gasoline vehicles with untargeted approaches

Abstract : Recent studies have shown that the PM emissions of modern cars equipped with the newest after-treatment technologies are mainly related to the production of secondary organic aerosols (SOA) especially in the case of gasoline vehicles. The objective of this work is to identify specific molecular markers or chemical patterns that can be further used in PM source apportionment studies to discriminate SOA from diesel and gasoline vehicles. Experiments were performed on a chassis dynamometer with a gasoline and diesel Euro 5 vehicles. Exhaust emissions were diluted before introduction into a potential aerosol mass (PAM) oxidation flow reactor (OFR) for aging and SOA formation. About 50 filter samples were collected upstream and downstream the PAM-OFR and analyzed using innovative non-targeted approaches with high-resolution mass spectrometry coupled to gas or liquid chromatography. The data treatment and statistical analysis will allow to highlight features or chemical patterns specific of gasoline and diesel SOA.