The CESAM chamber home page

 

It is now well established that heterogeneous chemistry has a drastic impact on the tropospheric composition. The complex physicochemical processes involved in this chemistry include : phase exchange, surface reactions, reactions in condensed phase followed by transfer to the gas phase have to be quantified in order to be able to develop reliable atmospheric models, and thus have a better understanding of the tropospheric chemistry.

Integrating heterogeneous physicochemical parameters (kinetics constants, accommodation coefficients, complexe refractive indexes, hygroscopicity parameter etc…) requires new tools allowing to perform experiments in conditions as close as possible to natural ones. This is the goal of the simulation chamber called CESAM (which means Multiphase Atmospheric Experimental Simulation Chamber).

This simulation chamber has been designed specifically to perform in realistic conditions experiments involving several phases like organic particule, water droplets, mineral dust, soot, salts and gas phase.

CESAM is an atmospheric simulation chamber dedicated to the study of multiphase atmospheric processes such as the formation of secondary aerosol or gaseous compounds in cloud-phase reactivity. This is a stainless steel reactor with a volume of 4.2 m3, equipped of pumping devices allowing to make a secondary vacuum, particularly to limit the potential memory effects which may persist to another experience.

The particular design of this chamber allows :

  • to work at low enough levels of concentration to ensure that the studied processes are representative of those occurring in the natural atmospheres
  • to ensure a lifetime of aerosol consistent with the study of its aging process. The body of the reactor is double-walled allowing the circulation of heat transfer fluids to regulate the temperature of the reaction mixture. This system is modular since it has twelve side plates supporting various equipment (optical spectrometry, lines of transfer, pump tubing, ports of introduction and sampling). The chamber is equipped with the most modern tools for metrology of aerosols and their precursors.

Being awarded "National Instrument of CNRS-INSU", CESAM is widely open to the international community. CESAM is part of the facilities of the European consortium Eurochamp

------------------ News ------------------

Sept, 2016
Le projet REDDUST récompensé à l'EAC 2016

Lors de la dernière European Aerosol Conference tenue à Tours (France) le 4-9 Septembre 2016, le Best Poster Award à été decerné au travail intitulé «Global scale variability of the mineral dust longwave refractive index from new in situ chamber measurements » par C. Di Biagio et al..
Le poster propose de nouvelles déterminations d’indice de réfraction infrarouge des poussières désertiques obtenues à partir de mesures in situ dans la chambre de simulation CESAM.

January, 1, 2016
Experimental determination and theoretical framework of kinetic fractionation at the water vapour – ice interface at low temperature

Climate reconstruction from ice cores rely on good knowledge of equilibrium and kinetic isotopic fractionation at each step of the water cycle. One of the strongest limitations when interpreting water isotopes in remote Antarctic ice cores is the formulation of the isotopic fractionation at solid condensation (vapour to ice). The uncertainties associated with the coefficients for equilibrium fractionation and water vapour diffusion in air make the formulation of isotopic fractionation at solid condensation only empirical.
Here, using (1) recent development in the measurements of water isotopes in the water vapour through infra-red spectroscopy and (2) the possibility to measure accurately 17O-excess of water, we test the classical formulation and parameterization of isotopic fractionation at solid condensation. The spatial variability of water vapour isotopic composition differs from classical formulation from Jouzel and Merlivat (1984, figure b) but can be relatively well reproduced by the resolution of diffusion toward a cold plate. In addition, our experiments highlight the impact of kinetic fractionation at condensation on 17O-excess for the first time. This preliminary study opens new perspectives to revisit the classical formulation of water isotopic fractionation during solid condensation at very low temperature. Ref : http://dx.doi.org/10.1016/j.gca.2015.11.009

November, 10, 2015
"Irrespirable - Comment échapper à l’asphyxie" vient de paraître

Le livre sur la pollution de l'air "Irrespirable - Comment échapper à l’asphyxie" vient de paraître aux éditions Taillandier/Arte édition. Écrit par Delphine Prunault et Alice Bomboy. Décrivant, entre autre, la stratégie que nous mettons en oeuvre avec CESAM, cet ouvrage vient appuyer un long métrage documentaire prochainement diffusé (février 2016) dans le cadre des soirées thématiques d'ARTE.
Fruit d’une longue investigation, cet ouvrage fait l’état des lieux précis de l’ampleur de la menace, détaille les conséquences de la pollution sur la santé et tord le cou aux idées reçues. Cette enquête vous donne les clés pour vous protéger, le mieux possible, de ce fléau. Un document choc.
http://boutique.arte.tv/f10615-irrespirable_livre