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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/acp-2017-288
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
05 Apr 2017
Review status
This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).
Long-term (2001–2012) trends of carbonaceous aerosols from remote island in the western North Pacific: an outflow region of Asian pollutants and dust
Suresh K. R. Boreddy1, Md. Mozammel Haque1,a, and Kimitaka Kawamura1,a 1Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
anow at: Chubu Institute of Advanced Studies, Chubu University, Kasugai 487-8501, Japan
Abstract. The present study reports on long-term trends of carbonaceous aerosols in total suspended particulate (TSP) samples collected at Chichijima Island in the western North Pacific during 2001–2012. Seasonal variations of elemental, organic, and water-soluble organic carbon (EC, OC and WSOC) concentrations showed maxima in winter to spring and minima in summer. These seasonal differences in the concentrations of carbonaceous aerosols are associated with the outflows of polluted air masses from East Asia, which are clearly distinguishable from pristine air masses from the central Pacific. The higher concentrations of carbonaceous aerosols during winter to spring are associated with long-range atmospheric transport of East Asian polluted air masses, whereas lower concentrations may be due to pristine air masses from the central Pacific in summer. The annual trends of OC/EC, WSOC and WSOC/OC showed significant (p<0.05) increases during the period of 2001–2012, suggesting that an enhanced secondary formation of organic aerosols (SOA) via photochemical oxidation of anthropogenic and biogenic volatile organic compounds (VOCs) during long-range atmospheric transport. We found a significant increase in nss-K+/EC ratios, demonstrating that biomass burning-derived organic aerosols are increased, while combustion-derived anthropogenic sources are decreased over the western North Pacific. Further, secondary biogenic emissions are also important over the western North Pacific as inferred from a significant increase in the concentrations of methanesulfonate (MSA, a tracer for biogenic source). We also found significant increases in OC/TC and WSOC/TC ratio, suggesting that contribution of SOA to total carbon (TC) are significantly increased over the western North Pacific followed by long-range atmospheric transport.

Citation: Boreddy, S. K. R., Haque, Md. M., and Kawamura, K.: Long-term (2001–2012) trends of carbonaceous aerosols from remote island in the western North Pacific: an outflow region of Asian pollutants and dust, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2017-288, in review, 2017.
Suresh K. R. Boreddy et al.
Suresh K. R. Boreddy et al.
Suresh K. R. Boreddy et al.

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Short summary
East Asian emissions of pollutants have a serious impact on aerosols over the North Pacific and occasionally North America during winter and spring. To better understand these impacts, we conducted a long-term study on carbonaceous aerosols (CA) over the western North Pacific. The present study demonstrates that CA strictly follow the seasonal wind patterns and contributions of photochemical oxidation of biomass and biogenic VOCs to SOA have increased whereas combustion sources have decreased.
East Asian emissions of pollutants have a serious impact on aerosols over the North Pacific and...
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