Ineris
Location
Verneuil en Halatte, Oise | France
Job description
The knowledge of aerosols (particulate matter, PM) in ambient air is essential to assess health and climate impacts of air pollution. Their sources, formation processes and chemical composition are still poorly known. Biomass burning accounts for a significant part of the primary emissions of fine PM in the ambient air notably in winter period due to wood combustion used for residential heating purposes. This source also emits large quantities of volatile and semi-volatile organic species leading to the formation, via (photo-)chemical processes, of secondary organic aerosols (SOA) accounting for a substantial part of fine PM concentrations. However, SOA formation yields from this source, or from the corresponding SOA precursors emitted, are still poorly documented in the literature especially for night-time processes (involving nitrate radical). Moreover, the toxicological potential of primary and aged biomass burning emissions, or related SOA, is also poorly understood and notably the links between biological responses and particle physicochemical properties.
In this context, the main objectives of this post-doctoral work are to study and understand the SOA formation processes from residential wood-burning appliance emissions (logwood stove) and from typically emitted SOA precursors (e.g., polycyclic aromatic hydrocarbons (PAHs) and phenolic compounds or mixture of them). To do so, logwood stove emissions, or pure precursors, will be aged using an oxidant flow reactor (OFR) under different oxidation conditions (OH or NO3 radicals), simulating the diurnal and nocturnal atmospheric processes. A detailed physicochemical characterization of the gaseous and particulate phases will be carried out. The implementation of advanced instrumentation such as a CI-ToF-MS (Chemical Ionization - Time of Flight-Mass Spectrometry), combining several ionization modes (H3O+, NH4+, O2+, I-) and aerosol analysis modules (e.g., Extractive ElectroSpray Ionization or CHARON, CHemical analysis of AeRosol ON-line) will permit to determine and measure, at a molecular level, volatile and semi-volatile organic substances in real time. This will allow the study of the primary particle emission and secondary formation dynamics from the wood log stove emissions, obtained under conditions as representative as possible of a common use. Finally, analysis of potential links between the detailed physicochemical characterization of the gaseous and particulate phases and the biological responses obtained through exposure of pulmonary cells at the air-liquid interface (ALI) during a complementary work (PhD project WOODTOX), will be performed.
Your mission will focus on the following priorities:
- Operate the oxidation flow reactor (PAM-OFR) and the state of art of on-line instrumentation (SMPS, CPMA, AAC, ACSM/AMS, CI-ToF-MS + EESI and PTR-MS + CHARON) to perform the aging experiments and measure the chemical and physical properties of the gaseous and particulate phases together with related QA/QC procedures.
- Independently operate these instruments, and other instruments (e.g., gas analyzers) in the laboratory and on the INERIS biomass burning facility.
- Validate and analyze the data by these instruments and interpret the results obtained.
- Link physicochemical characterization with toxicological responses.
- Present results at scientific meetings and during international scientific conferences. Valorize the results through research project reports and publish them in peer-reviewed literature.
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