ANR-DFG - Appel à projets générique 2018 - DFG

PARAMOUNT: Production of Aerosol paRticle orgAnic Matter in ClOUds: chamber and laboratory studies, mechanisms, modelling and iNTegration – PARAMOUNT

PARAMOUNT : Production of Aerosol paRticle orgAnic Matter in ClOUds: chamber and laboratory studies, mechanisms, modelling and iNTegration

Demonstrate how and quatify how much the cloud processes contributes to the atmospheric organic aerosol burden.

Well identified precursors

Chemical processes in clouds have been suggested to contribute substantially to organic aerosol particle mass since a long time. Recent evidence from the HCCT-2010 field study and the CUMULUS chamber study suggest that this organic mass production can be substantial and depends on the concentration of available organic precursor compounds in the gas phase. However, considerable uncertainties exist, e.g. with regards to the nature of the resulting aerosol particles which might be metastable and loose at least part of their OM content during the cloud droplet evaporation. Hence, PARAMOUNT is aimed at the investigation of cloud processes which are able to process organic constituents and produce organic aerosol particle mass<br />The project focus on the multiphase chemistry of very relevant polyfunctional precursors such as polyfunctional carbonyls and acids. With these precursors, a combination of aqueous-phase laboratory and CESAM chamber studies are undertaken to examine the multiphase cloud processing. The planned aqueous-phase laboratory studies are laying the groundwork with regard to kinetics and mechanism of the multiphase processing of the mentioned compounds.

The CESAM chamber experiments, which are central in PARAMOUNT mainly focus on studying the organic mass production by the chemical in-cloud processing of these compounds one by one, grouped or with mixtures with all of them. The chamber studies use different seeds and oxidant precursors to examine the organic mass production under different environmental and diurnal conditions. The organic mass increases during the cloud episodes will be investigated. Besides the organic mass formation, the partitioning of organic compounds under cloud conditions should be studied to evaluate possible enrichments of organic carbonyl compounds observed during the cloud field campaign HCCT-2010. The organic aerosol fraction will be analysed on-line by two Aerosol Mass Spectrometer instruments and the processing of the interstitial gas phase and the phase partitioning will be investigated by PTR-MS and the use of a mini CVI (counter virtual impactor) followed by offline analysis.

Finally, the performed CESAM experiments are being modelled with the complex multiphase chemistry mechanism MCM/CAPRAM. The multiphase modelling will be performed to both validate the mechanism and support the interpretation of the chamber experiments.

Overall, the proposed project PARAMOUNT will be a scientific breakthrough for understanding of in-cloud processes clarifying the role of clouds for atmospheric organic aerosol mass production.

The next steps will includes the set-up and the animation of a international debates among scientists interested in clouds chemical processes to establish the importance of those processes in atmospheric chemistry

Wu J., Monod A., Cazaunau M., Mertes S., Temime-Roussel B., Pangui E., Poulain L., Berge A., Wen L., Gratien A., Otto T., Brun N., Tilgner A., Herrmann H., Doussin J.F. Direct observation of secondary organic aerosol formation from the photooxidation of glyoxal during cloud condensation-vaporization cycles. European Aerosol Conference. 31
August-4 September 2020 (Oral - virtual conference)

González-Sánchez, J. M., Brun, N., Wu, J., Morin, J., Temime-Rousell, B., Ravier, S., Mouchel-Vallon, C., Clément, J.-L. and Monod, A.: On the importance of atmospheric loss of organic nitrates by aqueous-phase OH-oxidation, Atmos. Chem. Phys., 21, 4915–4937, 2021

Wu J., Brun N., González-Sánchez J.M., R’Mili B.*, Temime Roussel B., Ravier S., Clément J.L., Monod A. Substantial organic impurities at the surface of synthetic ammonium sulfate particles. Atmos. Meas. Tech., 15, 3859–3874, 2022

Brun N., González-Sánchez J.M, Demelas C., Clément J.L., Monod A. A fast and efficient method for the analysis of a-dicarbonyl compounds in aqueous solutions: development and application. Chemosphere, submitted

Barth, M. C., Ervens, B., Herrmann, H., Tilgner, A., McNeill, V. F., Tsui, W. G., et al. (2021). Box model intercomparison of cloud chemistry. Journal of Geophysical Research: Atmospheres, 126, e2021JD035486. doi.org/10.1029/2021JD035486

Tilgner, A., Schaefer, T., Alexander, B., Barth, M., Collett Jr., J. L., Fahey, K. M., Nenes, A., Pye, H. O. T., Herrmann, H., and McNeill, V. F.: Acidity and the multiphase chemistry of atmospheric aqueous particles and clouds, Atmos. Chem. Phys., 21, 13483–13536, 2021

Tilgner et al. SPACCIM modelling of the non-radical aqueous-phase chemistry of organic compounds in clouds and deliquesced aerosols.

Chemical processes in clouds have been suggested to contribute substantially to organic aerosol particle mass since a long time. Recent evidence from the HCCT-2010 field study and the CUMULUS chamber study suggest that this organic mass production can be substantial and depends on the concentration of available organic precursor compounds in the gas phase. However, considerable uncertainties exist, e.g. with regards to the nature of the resulting aerosol particles which might be metastable and loose at least part of their OM content during the cloud droplet evaporation. Hence, PARAMOUNT is aimed at the investigation of cloud processes which are able to process organic constituents and produce organic aerosol particle mass. The project will focus on the multiphase chemistry of very relevant polyfunctional precursors such as polyfunctional carbonyls and acids. With these precursors, a combination of aqueous-phase laboratory and CESAM chamber studies will be undertaken to examine the multiphase cloud processing. The planned aqueous-phase laboratory studies will lay the groundwork with regard to kinetics and mechanism of the multiphase processing of the mentioned compounds. The suggested CESAM chamber experiments, which are central in PARAMOUNT will mainly focus on studying the organic mass production by the chemical in-cloud processing of these compounds one by one, grouped or with mixtures with all of them. The planned chamber studies will use different seeds and oxidant precursors to examine the organic mass production under different environmental and diurnal conditions. The organic mass increases during the cloud episodes will be investigated. Besides the organic mass formation, the partitioning of organic compounds under cloud conditions should be studied to evaluate possible enrichments of organic carbonyl compounds observed during the cloud field campaign HCCT-2010. The organic aerosol fraction will be analysed on-line by two Aerosol Mass Spectrometer instruments and the processing of the interstitial gas phase and the phase partitioning will be investigated by PTR-MS and the use of a mini CVI (counter virtual impactor) followed by offline analysis. Finally, the performed CESAM experiments are being modelled with the complex multiphase chemistry mechanism MCM/CAPRAM. The multiphase modelling will be performed to both validate the mechanism and support the interpretation of the chamber experiments. Overall, the proposed project PARAMOUNT will be a scientific breakthrough for understanding of in-cloud processes clarifying the role of clouds for atmospheric organic aerosol mass production.

Project coordination

Jean François Doussin (Laboratoire inter-universitaire des systèmes atmosphériques)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

LISA Laboratoire inter-universitaire des systèmes atmosphériques
TROPOS Leibniz-Institut für Troposphärenforschung
LCE Laboratoire de Chimie de l'Environnement

Help of the ANR 275,108 euros
Beginning and duration of the scientific project: April 2019 - 36 Months

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