Multiphase Chemistry Group

The Multiphase Chemistry group performs laboratory studies related to the chemistry, photochemistry and kinetics of atmospheric multiphase processes involving organic, halogen, nitrogen oxide and odd oxygen species on substrates relevant for aerosol particles, cirrus ice, ocean surface, soil surfaces, snow and sea ice. Understanding these processes is relevant for the assessment of the human impact on atmospheric composition, climate, human and ecosystem health.
We use a combination of in-situ spectroscopy, flow tube and chamber techniques to cover scales from molecular level world of interfaces to the microstructure in aerosol particles and to the mesosopic medium of snow.
We educate young scientists in laboratory atmospheric chemistry within the frame of the Institute of Atmospheric and Climate Sciences (IAC) at ETH Zürich (Department of Environmental Systems Sciences, D-USYS).

overview ReClean

ReCLEAN - Reactive nitrogen at the CLimate, Energy, Agriculture, water, and health Nexus

ETH Domain Joint Initiative: Reactive nitrogen at the CLimate, Energy, Agriculture, water, and health Nexus (ReCLEAN)

Aerosol Multiphase Photochemistry

Multiphase Photochemistry

The interplay between reactive oxygen species and the multiphase chemistry of nitrogen, halogen and secondary organic species in aerosol particles. Reactive oxygen species are at the origin of redox processes within the aqueous phase of aerosol particles containing secondary organic and inorganic species. The consequences are halogen and nitrogen oxides recycling, formation and loss of organics, which are all implicated in atmospheric oxidation capacity as well as the burden and health impact of aerosol particles. 

ice

Interfacial Ice Chemistry

We seek to develop a deeper understanding of acid-base chemistry and interplay with hydrogen bonds and solvation at the ice- and water-air interface.

SnowChem

Multiphase Snow Chemistry

We examine transport and chemistry in snowpacks, with a focus on the dynamics of snow and how microphysics affect chemistry. 

teaser for STXM

Scanning Transmission Microscopy for Environmental and Energy Research

We develop Scanning Transmission X-ray Microspectroscopy for environmental and energy research at the Swiss Light Source.

Napp

X-ray excited photoelectron spectroscopy for environmental science

We develop and use X-ray excited electron spectroscopy for atmospheric research at the SIM & Phoenix & ISS endstations at the Swiss Light Source (SLS) and the ALS at the Lawrence Berkeley National Laboratory.

A complete publication list is available at the institutional repository (DORA PSI).

  • Alam MK, Qian B, Davis GB, Donn M, Kumar A, Trinchi A, et al.
    Fluorinated pesticides are a growing source of PFAS contamination in the environment: an Australian perspective on use, fate and ecotoxicity
    Ecotoxicology and Environmental Safety. 2026; 314: 120038 (20 pp.). https://doi.org/10.1016/j.ecoenv.2026.120038
    DORA PSI
  • Ishino S, Willis MD, Angot H, Bartels-Rausch T, Crabeck O, Delille B, et al.
    The biogenic sulfur cycle in the coupled ocean–sea ice–atmosphere system
    Elementa: Science of the Anthropocene. 2026; 14(1): 1-60. https://doi.org/10.1525/elementa.2025.00067
    DORA PSI
  • Kolozsvari KRA, Garner NM, Bell DM, Top J, Ammann M, Ault AP
    Pre-existing particle composition controls the initial viscosity and aging of α-pinene-derived secondary organic aerosol
    Environmental Science: Atmospheres. 2026; 6: 676-686. https://doi.org/10.1039/d6ea00006a
    DORA PSI
  • Man R, Zhu Y, Wu Z, Alpert PA, Wang B, Dou J, et al.
    Direct observation of core-shell structure and water uptake of individual submicron urban aerosol particles
    Atmospheric Chemistry and Physics. 2026; 26(1): 349-363. https://doi.org/10.5194/acp-26-349-2026
    DORA PSI
  • Tinorua S, Brem BT, Decker ZCJ, Slowik JG, Alpert PA, Ammann M, et al.
    Ubiquity of aviation ultrafine particles and lubrication oil compounds near Zurich Airport
    Environmental Science and Technology. 2026; 60(17): 13051-13062. https://doi.org/10.1021/acs.est.5c18458
    DORA PSI
  • Wallington TJ, Ammann M, Crowley JN, Herrmann H, Jenkin ME, McNeill VF, et al.
    Evaluated kinetic and photochemical data for atmospheric chemistry: volume IX- gas-phase reactions of halogenated alkanes, alkenes, and oxygenated compounds
    Atmospheric Chemistry and Physics. 2026; 26(10): 6579-6592. https://doi.org/10.5194/acp-26-6579-2026
    DORA PSI
  • Ammann M
    Concluding remarks: atmospheric chemistry in cold environments
    Faraday Discussions. 2025; 258: 597-613. https://doi.org/10.1039/d5fd00042d
    DORA PSI
  • Bartels-Rausch T, Creamean J, Thomas JL, Willis M, Zieger P
    Ten crucial unknowns in atmospheric chemistry in the cold
    Faraday Discussions. 2025; 258: 10-22. https://doi.org/10.1039/d5fd00056d
    DORA PSI
  • Chen S, Abouhaidar R, Artiglia L, Yang H, Boucly A, Iezzi L, et al.
    Influence of surfactants with differently charged headgroups on the surface propensity of bromide
    Journal of Physical Chemistry A. 2025; 129(13): 3085-3097. https://doi.org/10.1021/acs.jpca.4c07539
    DORA PSI
  • Garner NM, Mahrt F, Top J, Tadei V, Kilchhofer K, Takahama S, et al.
    Photochemistry of iron-containing secondary organic aerosol is impacted by relative humidity during formation
    npj Climate and Atmospheric Science. 2025; 8(1): 246 (9 pp.). https://doi.org/10.1038/s41612-025-01109-6
    DORA PSI
  • Giorio C, Borca CN, Zherebker A, D’Aronco S, Saidikova M, Sheikh HA, et al.
    Iron speciation in urban atmospheric aerosols: comparison between thermodynamic modeling and direct measurements
    ACS Earth and Space Chemistry. 2025; 9(3): 649-661. https://doi.org/10.1021/acsearthspacechem.4c00359
    DORA PSI
  • Kilchhofer K, Ammann M, Torrent L, Cheung RKY, Alpert PA
    Copper accelerates photochemically induced radical chemistry of iron-containing secondary organic aerosol (SOA)
    Atmospheric Chemistry and Physics. 2025; 25(14): 8061-8086. https://doi.org/10.5194/acp-25-8061-2025
    DORA PSI
  • Kilchhofer K, Barth A, Utinger B, Kalberer M, Ammann M
    Reactive oxygen species buildup in photochemically aged iron- and copper-doped secondary organic aerosol proxy
    Aerosol Research. 2025; 3(1): 337-349. https://doi.org/10.5194/ar-3-337-2025
    DORA PSI
  • Kong X, Ammann M, George C, Knopf D
    Atomic and molecular ions in atmospheric chemistry: interfacial reactivity, emerging mechanisms, and future perspectives
    Journal of Geophysical Research: Atmospheres. 2025; 130(20): e2025JD044379 (24 pp.). https://doi.org/10.1029/2025JD044379
    DORA PSI
  • Kuhn J, Stutz J, Bartels-Rausch T, Thomas JL, Cesler-Maloney M, Simpson WR, et al.
    The interplay between snow and polluted air masses in cold urban environments
    Faraday Discussions. 2025; 258: 502-520. https://doi.org/10.1039/d4fd00176a
    DORA PSI
  • Mahrt F, Nikkho S, Zaks J, Uppal G, Lam A, Ammann M, et al.
    Surprising crystallinity of biomass burning secondary organic aerosol from catechol and nitrate radical reactions: evidence and possible implications
    Environmental Science and Technology. 2025; 59(32): 16923-16932. https://doi.org/10.1021/acs.est.5c06834
    DORA PSI
  • Mishra A, Kilchhofer K, Iezzi L, Pöschl U, Alpert PA, Ammann M, et al.
    Photochemical degradation of iron citrate in anoxic viscous films enhanced by redox cascades
    ACS Earth and Space Chemistry. 2025; 9(3): 689-698. https://doi.org/10.1021/acsearthspacechem.4c00364
    DORA PSI
  • Pohl MO, Violaki K, Liu L, Gaggioli E, Glas I, von Kempis J, et al.
    Comparative characterization of bronchial and nasal mucus reveals key determinants of influenza A virus inhibition
    mSphere. 2025; 10(9): e0036525 (26 pp.). https://doi.org/10.1128/msphere.00365-25
    DORA PSI
  • Richter C, Gholami S, Manoharan Y, Buttersack T, Longetti L, Artiglia L, et al.
    Uptake of ammonia by ice surfaces at atmospheric temperatures
    Faraday Discussions. 2025; 258: 532-545. https://doi.org/10.1039/d4fd00169a
    DORA PSI
  • Top J, Garner NM, Sari Doré F, Zhang Y, Carstens C, Dubois C, et al.
    Influence of relative humidity and seed particles on molecular composition of α-pinene ds secondary organic aerosol
    ACS ES&T Air. 2025; 2(8): 1565-1574. https://doi.org/10.1021/acsestair.5c00064
    DORA PSI
  • Vattioni S, Peter T, Weber R, Dykema JA, Luo B, Stenke A, et al.
    Injecting solid particles into the stratosphere could mitigate global warming but currently entails great uncertainties
    Communications Earth & Environment. 2025; 6(1): 132 (10 pp.). https://doi.org/10.1038/s43247-025-02038-1
    DORA PSI
  • Alpert PA, Corral Arroyo P, Ammann M
    Microanalytical studies of multiphase reactions and particle aging
    In: Conny JM, Buseck PR, eds. Microanalysis of Atmospheric Particles Microanalysis of atmospheric particles: techniques and applications. Geophysical monograph series. Hoboken: Wiley; 2024:201-222. https://doi.org/10.1002/9781119554318.ch10
    DORA PSI
  • Ammann M, Alpert PA, Artiglia L, Bao F, Bartels-Rausch T, Ospina JFF, et al.
    Multiphase chemistry in the atmosphere
    Chimia. 2024; 78(11): 754-761. https://doi.org/10.2533/chimia.2024.754
    DORA PSI
  • Buttersack T, Gladich I, Gholami S, Richter C, Dupuy R, Nicolas C, et al.
    Direct observation of the complex S(IV) equilibria at the liquid-vapor interface
    Nature Communications. 2024; 15(1): 8987 (8 pp.). https://doi.org/10.1038/s41467-024-53186-5
    DORA PSI
  • De Angelis D, Longetti L, Bonano G, Cresi JSP, Foglia L, Pancaldi M, et al.
    A sub-100 nm thickness flat jet for extreme ultraviolet to soft X-ray absorption spectroscopy
    Journal of Synchrotron Radiation. 2024; 31(Part 3): 605-612. https://doi.org/10.1107/S1600577524001875
    DORA PSI
  • Decker ZCJ, Alpert PA, Ammann M, Anet JG, Bauer M, Cui T, et al.
    Emission and formation of aircraft engine oil ultrafine particles
    ACS ES&T Air. 2024; 1(12): 1662-1672. https://doi.org/10.1021/acsestair.4c00184
    DORA PSI
  • Fauré N, Chen J, Artiglia L, Ammann M, Bartels-Rausch T, Kanji ZA, et al.
    Formation of sodium chloride on the surface of sulfate-rich gobi desert salt in response to water adsorption
    ACS ES&T Air. 2024; 1(11): 1373-1382. https://doi.org/10.1021/acsestair.4c00092
    DORA PSI
  • Garner NM, Osthoff HD
    Conversion of a senior instrumental analysis laboratory course to online delivery and remote learning
    Journal of Chemical Education. 2024; 101(2): 448-455. https://doi.org/10.1021/acs.jchemed.3c00805
    DORA PSI
  • Garner NM, Top J, Mahrt F, El Haddad I, Ammann M, Bell DM
    Iron-containing seed particles enhance α-pinene secondary organic aerosol mass concentration and dimer formation
    Environmental Science and Technology. 2024; 58(38): 16984-16993. https://doi.org/10.1021/acs.est.4c07626
    DORA PSI
  • Knopf DA, Ammann M, Berkemeier T, Pöschl U, Shiraiwa M
    Desorption lifetimes and activation energies influencing gas-surface interactions and multiphase chemical kinetics
    Atmospheric Chemistry and Physics. 2024; 24(6): 3445-3528. https://doi.org/10.5194/acp-24-3445-2024
    DORA PSI
  • Nikkho S, Bai B, Mahrt F, Zaks J, Peng L, Kiland KJ, et al.
    Secondary organic aerosol from biomass burning phenolic compounds and nitrate radicals can be highly viscous over a wide relative humidity range
    Environmental Science and Technology. 2024; 58(49): 21702-21715. https://doi.org/10.1021/acs.est.4c06235
    DORA PSI
  • Reza M, Iezzi L, Finkenzeller H, Roose A, Ammann M, Volkamer R
    Iodine activation from iodate reduction in aqueous films via photocatalyzed and dark reactions
    ACS Earth and Space Chemistry. 2024; 8(12): 2495-2508. https://doi.org/10.1021/acsearthspacechem.4c00224
    DORA PSI
  • Sellegri K, Simó R, Wang B, Alpert PA, Altieri K, Burrows S, et al.
    Influence of open ocean biogeochemistry on aerosol and clouds: recent findings and perspectives
    Elementa: Science of the Anthropocene. 2024; 12(1): 00058 (35 pp.). https://doi.org/10.1525/elementa.2023.00058
    DORA PSI
  • Testa B, Durdina L, Alpert PA, Mahrt F, Dreimol CH, Edebeli J, et al.
    Soot aerosols from commercial aviation engines are poor ice-nucleating particles at cirrus cloud temperatures
    Atmospheric Chemistry and Physics. 2024; 24(7): 4537-4567. https://doi.org/10.5194/acp-24-4537-2024
    DORA PSI