To understand effects of aerosol aging processes and establish relationships between aerosol chemical composition, morphology and optical properties. Multi-scale approaches (theoretical, laboratories and remote sensing) are used.
Illustration : Aerosol microphysical, chemical and optical properties from fundamental heterogeneous processes to remote sensing.
Introduction
Complexity of atmospheric aerosol particles composition, morphology and aging processes, which affect their light scattering and hygroscopic properties, leads to significant uncertainty in prediction of climate radiative forcing, cloud formation and precipitation. Deriving aerosol composition on the global scale is essential for improving climate prediction, however is an extremely challenging task for space or ground-based remote sensing used for the global aerosol measurements. Establishing relationships between aerosol chemistry, morphology and optics suggests important implementations in remote sensing observations of aerosol composition and assimilation of measurements in global aerosol modeling (see also WP-4).
Materials and methods
Laboratory equipement :
Reactors and Simulation Chamber.
Micro-Raman spectrometer HR Evolution (Horiba Ltd.) and development of coupled particle-levitation devices
Ozonolysis of organic particles (fatty acids) in an Aerosol Flow Tube
X-microanalyses, Raman and atomic force microscopy
IRTF and UV-vis spectrometers, photoacoustic spectroscopy
Theoretical approach :
Classical and quantum molecular dynamics
Forward and inverse numerical codes for linking physical and optical properties and for calculating radiative budget.
Field experiment :
Participation in the SHADOW campaign in Sénégal.
Optical obervations and aerosol sampling : urban and desert sites in France, Senegal and Negev desert.
Ongoing studies and Results
Heterogeneous reactivity of mineral dust particles with volatile organic compounds (VOCs) : characterization of the chemical composition and adsorption properties for different natural samples with two selected VOCs (limonene and toluene). Monitoring of the gas and adsorbed phases shows very different behaviors in terms of adsorbed quantities and nature of the adsorbed fraction (mostly irreversible for limonene and reversible for toluene).
Photoreactivity and hygroscopicity of single particles : study of photo-degradation of solid inorganic particles and mixed inorganic / organic particles – Influence of particle coating by organic compound.
Detection of trace elements bioaccessibility in fine and ultrafine atmospheric particles in an industrial environment.
Classical molecular dynamics simulations : characterization of Palmitic Acid (PA) adsorbed on salt (NaCl) at different temperatures (235K, 300K), with different coverage and various humidity. Water induces well structured PA islands at the salt surface as observed experimentally.
Classical molecular dynamics simulations: study of the interaction of HO2 with organic aerosols.
Atmospheric fate of organic particulate matter : combination of offline (GC-MS, TEM, AFM) and online analysis (SMPS/IRTF) to describe fine changes on chemical, physical and optical properties of particles during ageing by ozone.
Remote optical observations and aerosol sampling : evidence of dust/sea salt internal mixture, liquid coating of dust and soot. Optical observations distinctly responded to change in the aerosol composition.
Optical properties of dust particles in the IR and the UV-vis spectral range : laboratory measurements of extinction spectra for aerosols using IRTF and UV-vis spectrometers. Retrieve of complex refractive indexes over the whole spectral range (300 nm to 15 mm) using Kramers-Kroenig equations. The method will be applied for volcanic ashes. Collaboration with the LPCA has started to complete this study by using photoacoustic spectroscopy, coupled to the PC2A set-up used in order to measure absorption spectra of black carbon aerosols.
Illustrations : (1) Extinction spectra of silica particles from UV to IR spectral range. (2) Adsorption of limonene on mineral dust (Bordj desert). (3) Photo-reactivity and hygroscopicity of single particles by using an environmental acoustic levitation cell. (4) Evolution of aerosol optical properties and chemical composition in a desert setting caused by penetration of sea breeze (Derimian et al., 2016, ACPD).
Key publications (2015)
L. Hormain, M. Monnerville, C. Toubin, D. Duflot, B. Pouilly, S. Briquez, M. I. Bernal-Uruchurtu, R. Hernández-Lamoneda, « Ground state analytical ab initio intermolecular potential for the Cl2-water system », J. Chem. Phys. 142 (2015) 144310.
Habartová, A., Hormain, L., Pluharová, E., Briquez, S., Monnerville, M., Toubin, C., and Roeselová, M., Molecular Simulations of Halomethanes at the Air/Ice Interface, J. Phys. Chem. A 119, 10052, 2015
Ourrad, H., Thévenet, F., Gaudion, V., Riffault,V.: Limonene photocatalytic oxidation at ppb levels: assessment of gas phase reaction intermediates and secondary organic aerosol heterogeneous formation, Applied Catalysis B-Environmental, 168-169, 183-194,doi: 10.1016/j.apcatb.2014.11.048, 2015.
X. Xu, W. Zhao, Q. Zhang, S. Wang, B. Fang, W. Chen, D. S. Venables, X. Wang, W. Pu, X. Wang, X. Gao, and W. Zhang, « Optical properties of atmospheric fine particles near Beijing during the HOPE-J3A Campaign », Atmos. Chem. Phys. Discuss. 15 (2015) 33675–33730
Sobanska, S., Barbillat, J., Moreau, M., Nuns, N., De Waele, I., Tobon, Y. A., Petitprez D., and Bremard, C. Influence of stearic acid coating of NaCl surface on the reactivity with NO2 under humidity. Phys. Chem. Chem. Phys. 2015, 17, 10963-10977. doi: 10.1039/C4CP05655H
A. Navel, G. Uzu, L. Spadini, S. Sobanska, J. Martins. Combining microscopy with spectroscopic and chemical methods for tracing the origin of atmospheric fallouts from mining sites. J. Hazard. Mater. 300 (2015) 538 – 545, doi: 10.1016/j.jhazmat.2015.07.035
Visez, N, Chassard, G., Azarkan, N., Naas, O., Sénéchal, H., Sutra, J-P., Poncet, P.and Choël, M.: Wind-Induced Mechanical Rupture of Birch Pollen: Potential Implications for Allergen Dispersal, Journal of Aerosol Science, 89, 77–84, doi:10.1016/j.jaerosci.2015.07.005, 2015
Chassard G., Choël M., Gosselin S., Vorng H., Petitprez D., Shahali Y., Tsicopoulos A., Visez N., « Kinetic of NO2 uptake by Phleum pratense pollen: Chemical and allergenic implications”.
Environmental Pollution, 196, 107-113, 2015.
Mbengue, S., Alleman, L. and Flament, P.: Trace elements bioaccessibility in fine and ultrafine atmospheric particles in an industrial environment, Environmental Geochemistry and Health,37(5), 875-889, 2015.
Riffault, V., Arndt, J., Marris, H., Mbengue, S., Setyan, A., Alleman,L.Y., Deboudt, K., Flament, P., Augustin, P., Delbarre H., and Wenger, J.: Fine and ultrafine particles in the vicinity of industrial activities: A review, Critical Reviews in Environmental Science and Technology, 45:21, 2305-2356, 2015.
