High-Precision Measurements of [superscript 33]S and [superscript 34]S Fractionation during SO[subscript 2] Oxidation Reveal Causes of Seasonality in SO[subscript 2] and Sulfate Isotopic Composition
This study presents high-precision isotope ratio-mass spectrometric measurements of isotopic fractionation during oxidation of SO[subscript 2] by OH radicals in the gas phase and H[subscript 2]O[subscript 2] and transition metal ion catalysis (TMI-catalysis) in the aqueous phase. Although temperatur...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | en_US |
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American Chemical Society (ACS)
2014
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| Online Access: | http://hdl.handle.net/1721.1/90584 https://orcid.org/0000-0002-1348-9584 |
| _version_ | 1826189333518876672 |
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| author | Harris, Eliza Sinha, Barbel Hoppe, Peter Ono, Shuhei |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Harris, Eliza Sinha, Barbel Hoppe, Peter Ono, Shuhei |
| author_sort | Harris, Eliza |
| collection | MIT |
| description | This study presents high-precision isotope ratio-mass spectrometric measurements of isotopic fractionation during oxidation of SO[subscript 2] by OH radicals in the gas phase and H[subscript 2]O[subscript 2] and transition metal ion catalysis (TMI-catalysis) in the aqueous phase. Although temperature dependence of fractionation factors was found to be significant for H[subscript 2]O[subscript 2] and TMI-catalyzed pathways, results from a simple 1D model revealed that changing partitioning between oxidation pathways was the dominant cause of seasonality in the isotopic composition of sulfate relative to SO[subscript 2]. Comparison of modeled seasonality with observations shows the TMI-catalyzed oxidation pathway is underestimated by more than an order of magnitude in all current atmospheric chemistry models. The three reactions showed an approximately mass-dependent relationship between [superscript 33]S and [superscript 34]S. However, the slope of the mass-dependent line was significantly different to 0.515 for the OH and TMI-catalyzed pathways, reflecting kinetic versus equilibrium control of isotopic fractionation. For the TMI-catalyzed pathway, both temperature dependence and [superscript 33]S/[superscript 34]S relationship revealed a shift in the rate-limiting reaction step from dissolution at lower temperatures to TMI-sulfite complex formation at higher temperatures. 1D model results showed that although individual reactions could produce Δ[superscript 33]S values between −0.15 and +0.2‰, seasonal changes in partitioning between oxidation pathways caused average sulfate Δ[superscript 33]S values of 0‰ throughout the year. |
| first_indexed | 2024-09-23T08:13:07Z |
| format | Article |
| id | mit-1721.1/90584 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:13:07Z |
| publishDate | 2014 |
| publisher | American Chemical Society (ACS) |
| record_format | dspace |
| spelling | mit-1721.1/905842022-09-23T11:40:30Z High-Precision Measurements of [superscript 33]S and [superscript 34]S Fractionation during SO[subscript 2] Oxidation Reveal Causes of Seasonality in SO[subscript 2] and Sulfate Isotopic Composition Harris, Eliza Sinha, Barbel Hoppe, Peter Ono, Shuhei Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Ono, Shuhei Harris, Eliza Ono, Shuhei This study presents high-precision isotope ratio-mass spectrometric measurements of isotopic fractionation during oxidation of SO[subscript 2] by OH radicals in the gas phase and H[subscript 2]O[subscript 2] and transition metal ion catalysis (TMI-catalysis) in the aqueous phase. Although temperature dependence of fractionation factors was found to be significant for H[subscript 2]O[subscript 2] and TMI-catalyzed pathways, results from a simple 1D model revealed that changing partitioning between oxidation pathways was the dominant cause of seasonality in the isotopic composition of sulfate relative to SO[subscript 2]. Comparison of modeled seasonality with observations shows the TMI-catalyzed oxidation pathway is underestimated by more than an order of magnitude in all current atmospheric chemistry models. The three reactions showed an approximately mass-dependent relationship between [superscript 33]S and [superscript 34]S. However, the slope of the mass-dependent line was significantly different to 0.515 for the OH and TMI-catalyzed pathways, reflecting kinetic versus equilibrium control of isotopic fractionation. For the TMI-catalyzed pathway, both temperature dependence and [superscript 33]S/[superscript 34]S relationship revealed a shift in the rate-limiting reaction step from dissolution at lower temperatures to TMI-sulfite complex formation at higher temperatures. 1D model results showed that although individual reactions could produce Δ[superscript 33]S values between −0.15 and +0.2‰, seasonal changes in partitioning between oxidation pathways caused average sulfate Δ[superscript 33]S values of 0‰ throughout the year. 2014-10-07T17:18:47Z 2014-10-07T17:18:47Z 2013-09 2013-09 Article http://purl.org/eprint/type/JournalArticle 0013-936X 1520-5851 http://hdl.handle.net/1721.1/90584 Harris, Eliza, Barbel Sinha, Peter Hoppe, and Shuhei Ono. “High-Precision Measurements of [superscript 33]S and [superscript 34]S Fractionation during SO[subscript 2] Oxidation Reveal Causes of Seasonality in SO[subscript 2] and Sulfate Isotopic Composition.” Environ. Sci. Technol. 47, no. 21 (November 5, 2013): 12174–12183. https://orcid.org/0000-0002-1348-9584 en_US http://dx.doi.org/10.1021/es402824c Environmental Science & Technology Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Chemical Society (ACS) Ono |
| spellingShingle | Harris, Eliza Sinha, Barbel Hoppe, Peter Ono, Shuhei High-Precision Measurements of [superscript 33]S and [superscript 34]S Fractionation during SO[subscript 2] Oxidation Reveal Causes of Seasonality in SO[subscript 2] and Sulfate Isotopic Composition |
| title | High-Precision Measurements of [superscript 33]S and [superscript 34]S Fractionation during SO[subscript 2] Oxidation Reveal Causes of Seasonality in SO[subscript 2] and Sulfate Isotopic Composition |
| title_full | High-Precision Measurements of [superscript 33]S and [superscript 34]S Fractionation during SO[subscript 2] Oxidation Reveal Causes of Seasonality in SO[subscript 2] and Sulfate Isotopic Composition |
| title_fullStr | High-Precision Measurements of [superscript 33]S and [superscript 34]S Fractionation during SO[subscript 2] Oxidation Reveal Causes of Seasonality in SO[subscript 2] and Sulfate Isotopic Composition |
| title_full_unstemmed | High-Precision Measurements of [superscript 33]S and [superscript 34]S Fractionation during SO[subscript 2] Oxidation Reveal Causes of Seasonality in SO[subscript 2] and Sulfate Isotopic Composition |
| title_short | High-Precision Measurements of [superscript 33]S and [superscript 34]S Fractionation during SO[subscript 2] Oxidation Reveal Causes of Seasonality in SO[subscript 2] and Sulfate Isotopic Composition |
| title_sort | high precision measurements of superscript 33 s and superscript 34 s fractionation during so subscript 2 oxidation reveal causes of seasonality in so subscript 2 and sulfate isotopic composition |
| url | http://hdl.handle.net/1721.1/90584 https://orcid.org/0000-0002-1348-9584 |
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