Fractionation of Stable Isotopes in Atmospheric Aerosol Reactions

• Main Author: Meusinger, Carl
• Format: Book
• Language: English
• Published: Department of Chemistry, Faculty of Science, University of Copenhagen 2013
• Subjects: ice core
• Online Access: https://curis.ku.dk/portal/da/publications/fractionation-of-stable-isotopes-in-atmospheric-aerosol-reactions(0204206b-936e-42a2-bd49-592ec17ac23a).html; https://soeg.kb.dk/permalink/45KBDK_KGL/fbp0ps/alma99122251461205763

Aerosols - particles suspended in air - are the single largest uncertainty in our current understanding of Earth's climate. They also affect human health, infrastructure and ecosystems. Aerosols are emitted either directly into the atmosphere or are formed there for instance in response to chemical reactions and undergo complex chemical and physical changes during their lifetimes. In order to assess processes that form and alter aerosols, information provided by stable isotopes can be used to help constrain estimates on the strength of aerosol sources and sinks. This thesis studies (mass-independent) fractionation processes of stable isotopes of C, N, O and S in order to investigate three different systems related to aerosols: 1. Post-depositional processes of nitrate in snow that obscure nitrate ice core records 2. Formation and aging of secondary organic aerosol generated by ozonolysis of X-pinene - an abundant precursor to biogenic aerosol 3. Oxidation of SO2 to sulfuric acid - one of the key species in aerosol formation Laboratory experiments were designed and conducted as part of this thesis to investigate these processes. In addition, advanced data treatment and chemical modeling were performed as required. The kndings provide important results for the studies' respective felds, including a description of the isotopic fractionation and quantum yield of nitrate photolysis in snow, equilibrium fractionation in secondary organic aerosol and fractionation constants of different oxidation pathways of SO2.