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

• Published in: Science Advances
• Main Authors: Hattori, Shohei, Iizuka, Yoshinori, Alexander, Becky, Ishino, Sakiko, Fujita, Koji, Zhai, Shuting, Sherwen, Tomás, Oshima, Naga, Uemura, Ryu, Yamada, Akinori, Suzuki, Nozomi, Matoba, Sumito, Tsuruta, Asuka, Savarino, Joel, Yoshida, Naohiro
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Greenland; Greenland ice core; ice core
• Online Access: https://eprints.whiterose.ac.uk/173794/; https://eprints.whiterose.ac.uk/173794/1/Hattori_2021.pdf; https://doi.org/10.1126/sciadv.abd4610

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 (Δ17OSO42-) 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 Δ17OSO42- with a 10 to 15 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.