Primary Sulfate Is the Dominant Source of Particulate Sulfate during Winter in Fairbanks, Alaska

• Published in: ACS ES&T Air
• Main Authors: Moon, Allison, Jongebloed, Ursula, Dingilian, Kayane, K, Schauer, Andrew, J, Chan, Yuk-Chun, Cesler-Maloney, Meeta, Simpson, William, R, Weber, Rodney, J, Tsiang, Ling, Yazbeck, Fouad, Zhai, Shuting, Wedum, Alanna, Turner, Alexander, J, Albertin, Sarah, Bekki, Slimane, Savarino, Joël, Gribanov, Konstantin, Pratt, Kerri, A, Costa, Emily, J, Anastasio, Cort, Sunday, Michael, O, Heinlein, Laura, M D, Mao, Jingqiu, Alexander, Becky
• Other Authors: Department of Atmospheric Sciences Seattle, University of Washington Seattle, School of Earth and Atmospheric Sciences Atlanta, Georgia Institute of Technology Atlanta, Department of Chemistry and Biochemistry Fairbanks, University of Alaska Fairbanks (UAF), 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), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Climate and Environmental Physics Laboratory Russia, Ural Federal University Ekaterinburg (UrFU), Department of Chemistry Ann Arbor, University of Michigan Ann Arbor, University of Michigan System-University of Michigan System, Department of Earth and Environmental Sciences Ann Arbor, Department of Land, Air and Water Resources, University of California Davis (UC Davis), University of California (UC)-University of California (UC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: air quality; aerosols; stable isotopes; sulfate; particulate matter; sulfur oxidation; [SDE]Environmental Sciences; Arctic; Fairbanks; North Star; Human health; Alaska
• Online Access: https://insu.hal.science/insu-04322354; https://insu.hal.science/insu-04322354/document; https://insu.hal.science/insu-04322354/file/moon-et-al-2023-primary-sulfate-is-the-dominant-source-of-particulate-sulfate-during-winter-in-fairbanks-alaska.pdf; https://doi.org/10.1021/acsestair.3c00023

International audience Within and surrounding high-latitude cities, poor air quality disturbs Arctic ecosystems, influences the climate, and harms human health. The Fairbanks North Star Borough has wintertime particulate matter (PM) concentrations that exceed the Environmental Protection Agency's (EPA) threshold for public health. Particulate sulfate (SO 4 2−) is the most abundant inorganic species and contributes approximately 20% of the total PM mass in Fairbanks, but air quality models underestimate observed sulfate concentrations. Here we quantify sulfate sources using sizeresolved δ 34 S(SO 4 2−), δ 18 O(SO 4 2−), and Δ 17 O(SO 4 2−) of particulate sulfate in Fairbanks from January 18th to February 25th, 2022 using a Bayesian isotope mixing model. Primary sulfate contributes 62 ± 12% of the total sulfate mass on average. Most primary sulfate is found in the size bin with a particle diameter < 0.7 μm, which contains 90 ±5% of total sulfate mass and poses the greatest risk to human health. Oxidation by all secondary formation pathways combined contributes 38 ± 12% of total sulfate mass on average, indicating that secondary sulfate formation is inefficient in this cold, dark environment. On average, the dominant secondary sulfate formation pathways are oxidation by H 2 O 2 (13 ± 6%), O 3 (8 ± 4%), and NO 2 (8 ± 3%). These findings will inform mitigation strategies to improve air quality and public health in Fairbanks and possibly other high-latitude urban areas during winter.