Title : High resolution caracterization of (ultra)fine secondary pollution in the Paris
Atmospheric pollution is associated with demonstrated health and climate issues. Our
understanding of the sources and transformation processes are confronted with the
chemical complexity of the particulate phase, and more particularly of its organic
fraction. The metrological limits of the instruments commonly used in the various
observatories therefore deprive us of a complete vision of the mechanisms involved.
Indeed, it has been recently underlined that in Paris, for instance, around 80% of
organic matter is secondary, without being able to link it to natural or anthropogenic
sources. As part of the in-situ observations at the SIRTA station (located at LSCE)
within the European ACTRIS infrastructure, the CAE team acquires a high-resolution
aerosol mass spectrometer (ACSM-X, manufactured by Aerodyne) to better
characterize, in real time, the primary and secondary chemical composition and its
sources. Based on this new instrumentation, this thesis will focus on three different
– the thorough metrological evaluation of the instrument’s performance towards its
implementation for continuous measurements;
– the annual caracterization of the sources of the organic fraction, with a dedicated
interest in the role of wood burning (in a context of energetic upheaval),
– and the contribution of biogenic and marine biogenic sources; and the evaluation
of the chemical composition of ultrafine particles (<200nm), as well as their
representations in chemistry-transport models.
This thesis is complementary to the instrumentation deployed at SIRTA, within the
framework of the European ACTRIS infrastructure, and also in the near real time
source apportionment work of the EU-Greendeal RI-URBANS project.