PhD in Sciences de la terre et de l'univers
Thesis defended on 11th December 2017
Département Sciences de l’Atmosphère et Génie de l’Environnement (SAGE) de l’IMT Lille Douai


Title and thesis summary

Identification of determinants of gaseous organic pollutant concentration in the eastern mediterranean basin

Volatile organic compounds (VOCs) play a key role within the atmospheric system acting as precursors of ozone and secondary organic aerosols (OA). In the Mediterranean region, particulate and gaseous concentrations are usually higher than in most continental European regions especially during summertime. However, air pollution in this region remains difficult to characterize because of a lack of atmospheric measurements. This thesis provides a better understanding of the sources and fate of VOCs in the Eastern Mediterranean region. During the intensive field campaign held in March 2015 at a background site of Cyprus, real-time measurements of a large number of VOCs have been performed, allowing the evaluation of their concentration levels in ambient air, improving the understanding of their major sources in the area, and describing their variabilities and their potential origins. A factorial analysis (PMF) showed that the local biogenic sources and the regional background were found to be the largest contributors to the VOC concentrations observed at this site. Benefiting from real-time OA measurements, a parallel between organic aerosol and gas phase composition was conducted. Biogenic VOC interactions with anthropogenic compounds can influence formation and growth of newly particles, inducing a reinforcement of secondary OA fraction. Finally, on-line measurements of primary VOCs were performed from January 2015 to February 2016 to provide a better characterization of the seasonal variation in VOCs and their sources impacting the Eastern Mediterranean region.

President of jury :
M. Jean SCIARE, Professeur, The Cyprus Institute – Chypre

Referees :
M. Nikolaos MIHALOPOULOS, Professeur, University of Crete – Grèce
M. Eric VILLENAVE, Professeur, Université de Bordeaux

Examiner :
Mme Aurélie COLOMB, Maître de conférences, Université Clermont-Auvergne

Responsible :
M. Stéphane SAUVAGE, Maître assistant, IMT Lille Douai

Thesis co-supervisor :
Mme Valérie GROS, Directrice de recherche CNRS, LSCE

Thesis supervisor :
Mme Nadine LOCOGE, Professeure, IMT Lille Douai

Laboratory : Département Sciences de l’Atmosphère et Génie de l’Environnement (SAGE) de l’IMT Lille Douai

Financing : Mines Douai