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Subject: Oxidation × WGL Institute: TROPOS ×

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    Highly Oxygenated Organic Molecules (HOM) from Gas-Phase Autoxidation Involving Peroxy Radicals: A Key Contributor to Atmospheric Aerosol
    (Washington, DC : ACS Publ., 2019) Bianchi, Federico; Kurtén, Theo; Riva, Matthieu; Mohr, Claudia; Rissanen, Matti P.; Roldin, Pontus; Berndt, Torsten; Crounse, John D.; Wennberg, Paul O.; Mentel, Thomas F.; Wildt, Jürgen; Junninen, Heikki; Jokinen, Tuija; Kulmala, Markku; Worsnop, Douglas R.; Thornton, Joel A.; Donahue, Neil; Kjaergaard, Henrik G.; Ehn, Mikael
    Highly oxygenated organic molecules (HOM) are formed in the atmosphere via autoxidation involving peroxy radicals arising from volatile organic compounds (VOC). HOM condense on pre-existing particles and can be involved in new particle formation. HOM thus contribute to the formation of secondary organic aerosol (SOA), a significant and ubiquitous component of atmospheric aerosol known to affect the Earth's radiation balance. HOM were discovered only very recently, but the interest in these compounds has grown rapidly. In this Review, we define HOM and describe the currently available techniques for their identification/quantification, followed by a summary of the current knowledge on their formation mechanisms and physicochemical properties. A main aim is to provide a common frame for the currently quite fragmented literature on HOM studies. Finally, we highlight the existing gaps in our understanding and suggest directions for future HOM research. © 2019 American Chemical Society.
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    The Importance of the Representation of DMS Oxidation in Global Chemistry‐Climate Simulations
    (Hoboken, NJ : Wiley, 2021) Hoffmann, Erik Hans; Heinold, Bernd; Kubin, Anne; Tegen, Ina; Herrmann, Hartmut
    The oxidation of dimethyl sulfide (DMS) is key for the natural sulfate aerosol formation and its climate impact. Multiphase chemistry is an important oxidation pathway but neglected in current chemistry-climate models. Here, the DMS chemistry in the aerosol-chemistry-climate model ECHAM-HAMMOZ is extended to include multiphase methane sulfonic acid (MSA) formation in deliquesced aerosol particles, parameterized by reactive uptake. First simulations agree well with observed gas-phase MSA concentrations. The implemented formation pathways are quantified to contribute up to 60% to the sulfate aerosol burden over the Southern Ocean and Arctic/Antarctic regions. While globally the impact on the aerosol radiative forcing almost levels off, a significantly more positive solar radiative forcing of up to +0.1 W m−2 is computed in the Arctic (>60°N). The findings imply the need of both further laboratory and model studies on the atmospheric multiphase oxidation of DMS.