Biomass burning is considered as the second largest source of Volatile Organic Compounds (VOCs) emissions into the atmosphere. It is also a large source of nitrogen oxides. These emissions are still poorly characterized with variable VOCs/NOx ratios depending on the fuel type and burn conditions. While using modern analytical techniques to fire emissions measurements, a significant fraction of VOCs and semi-VOCs (SVOCs) remains unidentified. Recent field studies have shown that the VOC emissions from wildfires could include highly reactive alkenes, aromatics and photolabile oxygenated VOCs. An investigation of the physicochemical transformation of biomass burning plumes in the atmosphere is required to predict impact of wildfires on air quality and climate. The nighttime biomass burning plumes evolution and their impacts on air quality and climate change represent a challenge in atmospheric chemistry where nighttime processing involves NO3 and N2O5.
The overall objective of the proposed PhD thesis is to bring a comprehensive research effort on the nighttime chemistry of biomass burning emissions and its implications for air quality through laboratory studies. Experiments will be conducted mostly in HELIOS atmospheric simulation chamber (https://helios-cnrs.org/). The obtained results will be incorporated and tested in air quality and global models including fire emissions and chemistry, in the framework of collaborations with modelling groups. Indeed, laboratory evaluation of chemical transformation of VOCs produced from biomass burning during the nighttime processing aims at reducing uncertainties associated with the NO3-VOCs reaction mechanisms. Comprehensive research will be conducted to better describe how the nighttime chemistry influences the composition and evolution of smoke plumes. This research will form the student’s PhD thesis and is expected to lead to several scientific publications
Profile:
We seek a highly motivated individual trained in one or more aspects of atmospheric chemistry or physics to perform fundamental research.
The candidate will be supervised by Wahid Mellouki and co-supervised by Prof A.R. Ravishankara from the Colorado State University (Fort-Collins, USA). He/She will have to visit CSU to complete part of the work. The candidate will be part of the Atmospheric Reactivity Group and will be supported by the members of the group as well as by the technical/administrative services of ICARE-CNRS (Orléans, France).
The deadline for applications is 30 June 2020, they must be sent to mellouki@cnrs-orleans.fr, and selection will be made by the end of July 2020.
