ACPD Atmospheric Chemistry and Physics Discussions ACPD Atmos. Chem. Phys. Discuss. 1680-7375 Göttingen, Germany 10.5194/acp-2019-410 Molecular Characterization of Organosulfates in Arctic Ocean and Antarctic atmospheric aerosols Ye Yuqing 1 Xie Zhouqing 1 2 Zhu Ming 3 Wang Xinming https://orcid.org/0000-0002-1982-0928 3 Institute of Polar Environment & Anhui Key Laboratory of Polar Environment and Global Change, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, Fujian 361021, China State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou, 510640, China 06 05 2019 2019 1 24 Copyright: © 2019 Yuqing Ye et al. 2019 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://acp.copernicus.org/preprints/acp-2019-410/ The full text article is available as a PDF file from https://acp.copernicus.org/preprints/acp-2019-410/acp-2019-410.pdf

<p>Organic aerosols are ubiquitous components of atmospheric aerosols. Organosulfate aerosols have been detected in the Arctic Ocean atmosphere and may play an important role in the radiative balance in Polar Regions. Aerosol samples from the Arctic Ocean and Antarctic atmosphere during 2014/2015 CHINARE were analysed by ultrahigh resolution mass spectrometry coupled with negative ion mode electrospray ionization (ESI(-)-UHRMS). Hundreds of organic compounds were detected and tentatively determined by their formulas, including organosulfates (OSs), nitrooxy-organosulfates (NOSs), organonitrates (ONs) and oxygenated hydrocarbons (OxyCs). The number of OSs/NOSs accounted for 28&ndash;32&thinsp;% of the total number of detected molecules at polar sites and ONs were 28&ndash;40&thinsp;%. Organic compounds of Arctic Ocean and Antarctic aerosols had high oxidation states for carbon and a large percentage of high molecular weight formulas; this indicated that <q>aged</q> organic aerosols likely comprise a significant part of the polar atmosphere. We hypothesized that highly oxidized HMW compounds tend to be transported to the polar area from stratospheric reservoirs. Dramatic differences of the molecular characteristics were observed when we compared aerosol samples between polar sites and Guangzhou sites, reflecting the different oxidation mechanisms and atmospheric transmission. The polar sites contained higher fractions of OSs/NOSs and lower fractions of ONs than the Guangzhou sites did; this indicated that the oxidation of NO<sub><i>x</i></sub> was weaker in the polar region. Observing that the fraction and oxidation states of polycyclic aromatic OSs/NOSs polar regions were similar to the Guangzhou urban area but not the rural area implied an anthropogenic influence on OSs/NOSs in remote polar areas. In addition, the contribution of potential precursors (anthropogenic and biogenic volatile organic compounds) to OS and NOS formation as well as the effects of nss-SO<sub>4</sub> aerosols, pH and RH on OS formation in polar areas were discussed. Our study presents the first overview of OSs and ONs in the Arctic Ocean and Antarctic atmosphere and promotes the understanding of their characteristics and sources.</p>

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