Thesis summary: Secondary Organic Aerosols (SOA) have an obvious but misunderstood impact on the climate balance and on air quality. They are produced in the atmosphere by oxidation of volatils organic compounds (VOCs) and semi-volatils organic compounds (SVOCs) emitted of which 90% are biogenic. Within the WP1 of Labex CaPPA, the PhLAM and LPCA laboratories worked independently to characterize the physicochemical properties of these precursors and their hydrated complexes on the one hand by rotational spectrosocopy as part of micro-solvation studies and on the other hand by studies of their reactivity and their ability to produce SOAs in the simulation chamber CHARME including the study of their hygroscopic properties. This PhD thesis project aims for the first time to combine these different approaches in order to make the link between the physicochemical properties at the molecular scale of hydrated complexes (with the compounds identified in the SOAs) and the hygroscopicity properties of the SOAs at the particle scale. This original, ambitious and unifying project proposes three complementary studies: (i) the reactivity of precursors and the ability to form SOA in CHARME; (ii) the micro-solvation of VOCs and SVOCs identified in AOS, studied by chirped-pulse spectroscopy in jet-cooled conditions; (iii) the hygroscopic properties of the AOS studied by complementary approaches (measurements of condensation cloud nuclei, IR spectroscopy in hydration cells).

Supervisors: A. Cuisset (LPCA/ULCO) - M. Goubet (PhLAM/UdL)