Isotopic evidence for acidity-driven enhancement of sulfate formation after SO2 emission control

Shohei Hattori; Yoshinori Iizuka; Becky Alexander; Sakiko Ishino; Koji Fujita; Shuting Zhai; Tomás Sherwen; Naga Oshima; Ryu Uemura; Akinori Yamada; Nozomi Suzuki; Sumito Matoba; Asuka Tsuruta; Joel Savarino; Naohiro Yoshida

doi:10.1126/sciadv.abd4610

Isotopic evidence for acidity-driven enhancement of sulfate formation after SO₂ emission control

Sci Adv. 2021 May 5;7(19):eabd4610. doi: 10.1126/sciadv.abd4610. Print 2021 May.

Authors

Shohei Hattori¹, Yoshinori Iizuka², Becky Alexander³, Sakiko Ishino^{4

5}, Koji Fujita⁶, Shuting Zhai³, Tomás Sherwen^{7

8}, Naga Oshima⁹, Ryu Uemura⁶, Akinori Yamada¹⁰, Nozomi Suzuki⁴, Sumito Matoba², Asuka Tsuruta⁴, Joel Savarino¹¹, Naohiro Yoshida^{4

12

13}

Affiliations

¹ Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Yokohama 226-8502, Japan. [email protected] [email protected].
² Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
³ Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195-1640, USA.
⁴ Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Yokohama 226-8502, Japan.
⁵ National Institute of Polar Research, Research Organization of Information and Systems, Tokyo 190-8518, Japan.
⁶ Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8601, Japan.
⁷ National Centre for Atmospheric Science, University of York, York YO10 5DD, UK.
⁸ Wolfson Atmospheric Chemistry Laboratories, University of York, York YO10 5DD, UK.
⁹ Meteorological Research Institute, Tsukuba 305-0052, Japan.
¹⁰ Toshima Electric Ltd., Tokyo 170-0005, Japan.
¹¹ University of Grenoble Alpes, CNRS, IRD, Grenoble INP, IGE, F-38000, Grenoble, France.
¹² Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8551, Japan.
¹³ National Institute of Information and Communications Technology, Tokyo 184-8795, Japan.

Abstract

After the 1980s, atmospheric sulfate reduction is slower than the dramatic reductions in sulfur dioxide (SO₂) emissions. However, a lack of observational evidence has hindered the identification of causal feedback mechanisms. Here, we report an increase in the oxygen isotopic composition of sulfate ([Formula: see text]) in a Greenland ice core, implying an enhanced role of acidity-dependent in-cloud oxidation by ozone (up to 17 to 27%) in sulfate production since the 1960s. A global chemical transport model reproduces the magnitude of the increase in observed [Formula: see text] with a 10 to 15% enhancement in the conversion efficiency from SO₂ to sulfate in Eastern North America and Western Europe. With an expected continued decrease in atmospheric acidity, this feedback will continue in the future and partially hinder air quality improvements.

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