Reactions on mineral dust.

Tropospheric aqueous-phase chemistry: kinetics, mechanisms, and its coupling to a changing gas phase.

Atmosphere: State of the Art and Challenges Barbara Nozier̀e,*,† Markus Kalberer,*,‡ Magda Claeys,* James Allan, Barbara D’Anna,† Stefano Decesari, Emanuela Finessi, Marianne Glasius, Irena Grgic,́ Jacqueline F. Hamilton, Thorsten Hoffmann, Yoshiteru Iinuma, Mohammed Jaoui, Ariane Kahnt, Christopher J. Kampf, Ivan Kourtchev,‡ Willy Maenhaut, Nicholas Marsden, Sanna Saarikoski, Jürgen Schnelle-Kreis, Jason D. Surratt, Sönke Szidat, Rafal Szmigielski, and Armin Wisthaler †Ircelyon/CNRS and Universite ́ Lyon 1, 69626 Villeurbanne Cedex, France ‡University of Cambridge, Cambridge CB2 1EW, United Kingdom University of Antwerp, 2000 Antwerp, Belgium The University of Manchester & National Centre for Atmospheric Science, Manchester M13 9PL, United Kingdom Istituto ISAC C.N.R., I-40129 Bologna, Italy University of York, York YO10 5DD, United Kingdom University of Aarhus, 8000 Aarhus C, Denmark National Institute of Chemistry, 1000 Ljubljana, Slovenia Johannes Gutenberg-Universitaẗ, 55122 Mainz, Germany Leibniz-Institut für Troposphar̈enforschung, 04318 Leipzig, Germany Alion Science & Technology, McLean, Virginia 22102, United States Max Planck Institute for Chemistry, 55128 Mainz, Germany Ghent University, 9000 Gent, Belgium Finnish Meteorological Institute, FI-00101 Helsinki, Finland Helmholtz Zentrum München, D-85764 Neuherberg, Germany University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States University of Bern, 3012 Bern, Switzerland Institute of Physical Chemistry PAS, Warsaw 01-224, Poland University of Oslo, 0316 Oslo, Norway

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The molecular identification of organic compounds in the atmosphere : state of the art and challenges

[1] Water-soluble macromolecular substances with spectral properties of “humic-like substances” (HULIS) were recently found to form the major identified fraction of the organic aerosol at urban and rural sites in Europe. With primary sources identified so far (e.g., biomass combustion) it is not possible to explain the observed HULIS levels in Europe, therefore there is an ongoing search for other sources - which form HULIS in situ in the atmosphere. Here we show that secondary aerosol formation of atmospheric polymers occurs by heterogeneous reaction of isoprenoid or terpenoid emissions in the presence of a sulfuric acid aerosol catalyst. Competing oxidants such as ozone or the presence of humidity decreased the reaction yield, but the formation of humic–like substances was not disabled. Calculations indicate that the presented reaction pathway could be an additional source for HULIS in the continental aerosol.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2003GL017738

Secondary organic aerosol formation in the atmosphere via heterogeneous reaction of gaseous isoprene on acidic particles

Recent experimental evidence indicates that heterogeneous chemical reactions play an important role in the gas-particle partitioning of organic compounds, contributing to the formation and growth of secondary organic aerosol in the atmosphere. Here we present laboratory chamber studies of the reactive uptake of simple carbonyl species (formaldehyde, octanal, trans,trans-2,4-hexadienal, glyoxal, methylglyoxal, 2,3-butanedione, 2,4-pentanedione, glutaraldehyde, and hydroxyacetone) onto inorganic aerosol. Gas-phase organic compounds and aqueous seed particles (ammonium sulfate or mixed ammonium sulfate/sulfuric acid) are introduced into the chamber, and particle growth and composition are monitored using a differential mobility analyzer and an Aerodyne Aerosol Mass Spectrometer. No growth is observed for most carbonyls studied, even at high concentrations (500 ppb to 5 ppm), in contrast with the results from previous studies. The single exception is glyoxal (CHOCHO), which partitions into the aqueous aerosol much more efficiently than its Henry's law constant would predict. No major enhancement in particle growth is observed for the acidic seed, suggesting that the large glyoxal uptake is not a result of particle acidity but rather of ionic strength of the seed. This increased partitioning into the particle phase still cannot explain the high levels of glyoxal measured in ambient aerosol, indicating that additional (possibly irreversible) pathways of glyoxal uptake may be important in the atmosphere.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2005JD006004

Chamber studies of secondary organic aerosol growth by reactive uptake of simple carbonyl compounds

The interactions of gas-phase acetone with liquid sulfuric acid solutions are described. The solutions were prepared as 0.05−0.10 μm thick films deposited on single-crystal metal substrates. Experiments were carried out over broad ranges of acid composition (70 − >96 wt % H2SO4), temperature (180−220 K), and acetone pressure (10-7−10-3 Pa). Two types of measurements are reported:  the time-dependent acetone uptake probability, and the infrared spectra of absorbed acetone and its reaction products. From the infrared measurements, a reaction scheme is identified in which gas-phase acetone is taken up by sulfuric acid to form protonated acetone. In solutions containing more than 70 wt % H2SO4, protonated acetone undergoes a self-condensation/dehydration reaction to form mesityl oxide. In films that contain 85 wt % or more H2SO4, a second reaction sequence occurs, ultimately resulting in the formation of trimethylbenzene. The uptake probability measurements are consistent with the infrared data. In 70 wt % H2...

Chemistry at and near the Surface of Liquid Sulfuric Acid: A Kinetic, Thermodynamic, and Mechanistic Analysis of Heterogeneous Reactions of Acetone

A new heterogeneous reaction, namely the sulfate-mediated conversion of acetone to 4-methyl-3-penten-2-one and trimethylbenzene, is reported. The reaction products were observed in their absorbed states by Fourier transform infrared spectroscopy and in the gas phase by mass spectrometry. In addition, protonated, absorbed acetone was observed under certain conditions. The reaction exhibits a strong concentration and / or temperature dependence, with non-reactive uptake as protonated acetone dominating at low temperatures and sulfate concentrations and reactive uptake occurring above 200 K and 75 wt. % H2SO4. Under conditions where reactive uptake occurs, the steady-state acetone loss probability is roughly 40%. It was not possible in this study to assess the relative effects of temperature and concentration on the reactivity of sulfate toward acetone.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/98GL00250

Joanna L. Duncan

Papers

Chemistry at and near the Surface of Liquid Sulfuric Acid: A Kinetic, Thermodynamic, and Mechanistic Analysis of Heterogeneous Reactions of Acetone

A new sulfate‐mediated reaction: Conversion of acetone to trimethylbenzene in the presence of liquid sulfuric acid