Shouwen ZHANG
PhD in Sciences de la Matière, du Rayonnement et de l'Environnement
THesis defended on 14th October 2016
SAGE Department - IMT Lille-Douai
and Laboratoire de Physico- Chimie de l’Atmosphère (LPCA)


Title and thesis summary

Dynamic analysis, in near field and with a finer temporal resolution, of a sub-micron aerosol in urban situation under industrial influence

The chemical composition of submicron particles (PM₁) was monitored for over one year (July 2013-September 2014), at high temporal resolution (< 30 min), using an Aerosol Chemical Speciation Monitor (ACSM) for the non-refractory fraction (NR-PM₁ : organic, sulfate, nitrate, ammonium and chloride) and an aethalometer for black carbon (BC), together with micrometeorology parameters. An intensive campaign (July 2014) completed the data set including the monitoring of volatile organic compounds by PTR-TOFMS. The chosen site has an urban background typology, under the influence of a large area with industrial and harbor activities. The chemical composition of aerosols was analyzed globally, seasonally and using four wind sectors. A study of the SO₂-to-SO₄ conversion in the industrial sector has shown that this process is favored at high relative humidity (> 70%), low vertical turbulence (σw : 0-0.5 m sˉ¹) and low wind speed (0-2 m sˉ¹). Using PMF (Positive Matrix factorization) source receptor modeling, three primary sources of organic species, relatied to traffic, combustion of biomass and domestic cooking, have been identified, as well as a secondary source. The seasonal and sector PMF analyses, with and without constraints, helped to identify two additional factors in the marine and industrial sectors. Some specific events (sea breezes, high pollution events and nearby ship movements) were studied, allowing to extract an average mass spectrum associated with ship emissions for the latter, ShOA (Ship-like organic aerosol). This factor only contributes to 0.5% of the particulate organic fraction on average but up to more than 90% over short periods.

Referees :
Valérie GROS, CR (HDR), CNRS-LSCE, Gif-sur-Yvette
Anne MONOD, PR, LCE, Aix-Marseille Université

Members of jury :
Sébastien DUSANTER, MA, SAGE, Mines Douai

Supervisor :
Véronique RIFFAULT, PR, SAGE, Mines Douai

Hervé DELBARRE, PR, LPCA, ULCO, Dunkerque

Work with: 
S. DUSANTER (Mines Douai)

Financing : 50% Région Nord-Pas de Calais – 50% Mines Douai

Laboratories : SAGE and LPCA