Zünd, Andreas (Andi), Dr.

ETH Zürich Dr. Andreas (Andi) Zünd Institut f. Atmosphäre und Klima CHN O17.2 Universitaetstr. 16 8092 Zürich Switzerland Phone: +41-44-633-4063 E-Mail:

Research Focus and Current Interests

• Formation, chemical, and physical processing of atmospheric aerosols and their role in the atmospheric life cycle of volatile organic compounds.
• Secondary organic aerosol (SOA): sources, chemical properties and effects on regional air quality and the global climate system.
• Gas-particle partitioning and equilibrium thermodynamics of non-ideal mixtures characterizing aerosol particles.
• Physical Chemistry of phase transitions, phase separation, and physical states of complex organic-inorganic mixtures.
• Liquid-liquid phase separation in aerosol particles containing water, organic compounds and dissolved inorganic electrolytes.
• Understanding the interplay of chemical composition, mixing thermodynamics, viscosity, mass transfer kinetics, and morphology of atmospheric and laboratory aerosol.
• Development and applications of an advanced thermodynamic group-contribution model to compute activity coefficients and chemical potentials: AIOMFAC model.
• Efficient and reliable algorithms for the calculation of liquid-liquid phase separation and phase stabilities in organic-inorganic systems.
• Development of detailed physicochemical process models for the improvement of parametrizations in atmospheric large-scale models.

Peer-reviewed Publications

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• Zuend, A., and Seinfeld, J. H.: A practical method for the calculation of liquid-liquid equilibria in multicomponent organic-water-electrolyte systems using physicochemical constraints, Fluid Phase Equilib., 337, 201–213, doi:10.1016/j.fluid.2012.09.034, 2013.
• Song, M., Marcolli, C., Krieger, U. K., Zuend, A., and Peter, T.: Liquid-liquid phase separation in aerosol particles: dependence on O:C, organic functionalities, and compositional complexity, Geophys. Res. Lett., 39, L19801, doi:10.1029/2012GL052807, 2012.
• Lienhard, D. M., Bones, D. L., Zuend, A., Krieger, U. K., Reid, J. P., and Peter, T.: Measurements of thermodynamic and optical properties of selected aqueous organic and organic-inorganic mixtures of atmospheric relevance, J. Phys. Chem. A, 116, 9954–9968, doi:10.1021/jp3055872, 2012.
• Zuend, A. and Seinfeld, J. H.: Modeling the gas-particle partitioning of secondary organic aerosol: the im-portance of liquid-liquid phase separation, Atmos. Chem. Phys., 12, 3857–3882, doi:10.5194/acp-12-3857-2012, 2012.
• Song, M., Marcolli, C., Krieger, U. K., Zuend, A., and Peter, T.: Liquid-liquid phase separation and morphology of internally mixed dicarboxylic acids/ammonium sulfate/water particles, Atmos. Chem. Phys., 12, 2691–2712, doi:10.5194/acp-12-2691-2012, 2012.
• Lienhard, D. M., Zobrist, B., Zuend, A., Krieger, U. K., and Peter, T.: Experimental evidence for excess entropy discontinuities in glass-forming solutions, J. Chem. Phys., 136, 074515, doi:10.1063/1.3685902, 2012.
• Zuend, A., Marcolli, C., Booth, A. M., Lienhard, D. M., Soonsin, V., Krieger, U. K., Topping, D. O., McFiggans, G., Peter, T., and Seinfeld, J. H.: New and extended parameterization of the thermodynamic model AIOMFAC: calculation of activity coefficients for organic-inorganic mixtures containing carboxyl, hydroxyl, carbonyl, ether, ester, alkenyl, alkyl, and aromatic functional groups, Atmos. Chem. Phys., 11, 9155–9206, doi:10.5194/acp-11-9155-2011, 2011.
• Soonsin, V., Zardini, A. A., Marcolli, C., Zuend, A., and Krieger, U. K.: The vapor pressures and activities of dicarboxylic acids reconsidered: the impact of the physical state of the aerosol, Atmos. Chem. Phys., 10, 11753–11767, doi:10.5194/acp-10-11753-2010, 2010.
• Zuend, A., Marcolli, C., Peter, T., and Seinfeld, J. H.: Computation of liquid-liquid equilibria and phase stabilities: implications for RH-dependent gas/particle partitioning of organic-inorganic aerosols, Atmos. Chem. Phys., 10, 7795–7820, doi:10.5194/acp-10-7795-2010, 2010.
• Ciobanu, V. G., Marcolli, C., Krieger, U. K., Zuend, A., and Peter, T.: Efflorescence of ammonium sulfate and coated ammonium sulfate particles: evidence for surface nucleation, J. Phys. Chem. A, 114, 9486–9495, doi:10.1021/jp103541w, 2010.
• Zuend, A., Marcolli, C., Luo, B. P., and Peter, T.: A thermodynamic model of mixed organic-inorganic aerosols to predict activity coefficients, Atmos. Chem. Phys., 8, 4559–4593, doi:10.5194/acp-8-4559-2008, 2008.

Theses

• Zuend, A.: Modelling the Thermodynamics of Mixed Organic-Inorganic Aerosols to Predict Water Activities and Phase Separations, PhD thesis, ETH Zurich, Zurich, Switzerland, doi:10.3929/ethz-a-005582922, 2007.
• Zuend, A.: Entwicklung eines Kinetischen Monte Carlo Modells der Dynamik von Eisoberflächen, Diploma thesis, ETH Zurich, Zurich, Switzerland, zuend_dipl_2004.pdf (in German), 2004.

Other Publications

• Competence Center Environment and Sustainability (CCES), project IMBALANCE (IMpact of Biomass burning AerosoL on Air quality aNd ClimatE); Co-author of annual progress reports (2009 – 2012): http://www.cces.ethz.ch/projects/clench/imbalance.
• AIOMFAC model website, http://www.aiomfac.caltech.edu, launched in January 2012. The website provides information and access to the AIOMFAC model for the calculation of activity coefficients of organic compounds, water, and inorganic ions in homogeneous mixtures.