Anthropogenic Impacts on Tropospheric Reactive Chlorine Since the Preindustrial

• Published in: Geophysical Research Letters
• Main Authors: Zhai, Shuting, Wang, Xuan, Mcconnell, Joseph, R, Geng, Lei, Cole‐dai, Jihong, Sigl, Michael, Chellman, Nathan, Sherwen, Tomás, Pound, Ryan, Fujita, Koji, Hattori, Shohei, Moch, Jonathan, M, Zhu, Lei, Evans, Mat, Legrand, Michel, Liu, Pengfei, Pasteris, Daniel, Chan, Yuk‐chun, Murray, Lee, T, Alexander, Becky
• Other Authors: University of Washington Seattle, School of Energy and Environment Hong Kong, City University of Hong Kong Hong Kong (CUHK), Desert Research Institute (DRI), School of Earth and Space Sciences Hefei, University of Science and Technology of China Hefei (USTC), South Dakota State University (SDSTATE), Universität Bern / University of Bern (UNIBE), University of York York, UK, Graduate School of Environmental Studies Nagoya, Nagoya University, Tokyo Institute of Technology Tokyo (TITECH), Harvard University, Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Georgia Institute of Technology Atlanta, University of Rochester USA
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [CHIM.OTHE]Chemical Sciences/Other; Greenland; Greenland ice core; ice core
• Online Access: https://hal.science/hal-04264411; https://hal.science/hal-04264411/document; https://hal.science/hal-04264411/file/Zhai_et_al_2021GL093808.pdf; https://doi.org/10.1029/2021GL093808

International audience Abstract Tropospheric reactive gaseous chlorine (Cl y ) impacts the atmosphere's oxidation capacity with implications for chemically reduced gases such as methane. Here we use Greenland ice‐core records of chlorine, sodium, and acidity, and global model simulations to show how tropospheric Cl y has been impacted by anthropogenic emissions since the 1940s. We show that anthropogenic contribution of nonsea‐salt chlorine significantly influenced total chlorine and its trends after the 1940s. The modeled regional 170% Cl y increase from preindustrial to the 1970s was driven by acid displacement from sea‐salt‐aerosol, direct emission of hydrochloric acid (HCl) from combustion, and chemical reactions driven by anthropogenic nitrogen oxide (NO x ) emissions. Since the 1970s, the modeled 6% Cl y decrease was caused mainly by reduced anthropogenic HCl emissions from air pollution mitigation policies. Our findings suggest that anthropogenic emissions of acidic gases and their emission control strategies have substantial impacts on Cl y with implications for tropospheric oxidants, methane, and mercury.