Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Impact of sulfur dioxide oxidation by Stabilized Criegee Intermediate on sulfate
Abstract We revise the Carbon Bond chemical mechanism to explicitly represent three Stabilized Criegee Intermediates (SCIs) and their subsequent reactions with sulfur dioxide, water monomer, and water dimer, and incorporate the reactions into the Community Multiscale Air Quality model. The reaction of sulfur dioxide with SCI produces sulfuric acid which partitions into sulfate. We examine the impact of sulfur dioxide oxidation by SCI on sulfate using two different measured rate constants for the reaction of sulfur dioxide and SCI. When we use the higher rate constant and emissions estimates from the Biogenic Emissions Inventory System, it enhances monthly mean sulfate in summer by ∼20% in biogenically active areas. Enhancements are driven primarily by SCI produced from the reactions of biogenically derived alkenes and ozone. The use of the lower rate constant only marginally enhances sulfate since it is 65 times lower than the higher rate constant. We performed several sensitivity analyses to investigate the impacts of uncertain biogenic emissions and SCI loss rates. When we use the higher rate constant and emissions estimates from the Model of Emissions of Gases and Aerosols from Nature, it enhances monthly mean sulfate by ∼75%. A simulation using the lowest reported rate constant for the reaction of SCI and water indicated the maximum enhancement of sulfate from this chemistry was up to 4 μg/m3 over a 24-h period in some locations in the Southeastern U.S. Predictions without the SCI reaction are lower than observed sulfate while predictions with the SCI reaction improve the agreements with observations.
Highlights Examine the impact of SO2 oxidation by SCI on sulfate. SO2 oxidation by SCI can substantially enhance summertime sulfate. Impact of SO2 oxidation by SCI on wintertime sulfate is small. Use of MEGAN emissions produces more sulfate than BEIS emissions. Reaction of SCI and H2O strongly influences the production of sulfate by SCI.
Impact of sulfur dioxide oxidation by Stabilized Criegee Intermediate on sulfate
Abstract We revise the Carbon Bond chemical mechanism to explicitly represent three Stabilized Criegee Intermediates (SCIs) and their subsequent reactions with sulfur dioxide, water monomer, and water dimer, and incorporate the reactions into the Community Multiscale Air Quality model. The reaction of sulfur dioxide with SCI produces sulfuric acid which partitions into sulfate. We examine the impact of sulfur dioxide oxidation by SCI on sulfate using two different measured rate constants for the reaction of sulfur dioxide and SCI. When we use the higher rate constant and emissions estimates from the Biogenic Emissions Inventory System, it enhances monthly mean sulfate in summer by ∼20% in biogenically active areas. Enhancements are driven primarily by SCI produced from the reactions of biogenically derived alkenes and ozone. The use of the lower rate constant only marginally enhances sulfate since it is 65 times lower than the higher rate constant. We performed several sensitivity analyses to investigate the impacts of uncertain biogenic emissions and SCI loss rates. When we use the higher rate constant and emissions estimates from the Model of Emissions of Gases and Aerosols from Nature, it enhances monthly mean sulfate by ∼75%. A simulation using the lowest reported rate constant for the reaction of SCI and water indicated the maximum enhancement of sulfate from this chemistry was up to 4 μg/m3 over a 24-h period in some locations in the Southeastern U.S. Predictions without the SCI reaction are lower than observed sulfate while predictions with the SCI reaction improve the agreements with observations.
Highlights Examine the impact of SO2 oxidation by SCI on sulfate. SO2 oxidation by SCI can substantially enhance summertime sulfate. Impact of SO2 oxidation by SCI on wintertime sulfate is small. Use of MEGAN emissions produces more sulfate than BEIS emissions. Reaction of SCI and H2O strongly influences the production of sulfate by SCI.
Impact of sulfur dioxide oxidation by Stabilized Criegee Intermediate on sulfate
Sarwar, Golam (Autor:in) / Simon, Heather (Autor:in) / Fahey, Kathleen (Autor:in) / Mathur, Rohit (Autor:in) / Goliff, Wendy S. (Autor:in) / Stockwell, William R. (Autor:in)
Atmospheric Environment ; 85 ; 204-214
10.12.2013
11 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch