Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 5851-5864, 2017
https://doi.org/10.5194/acp-17-5851-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
12 May 2017
Alteration of the size distributions and mixing states of black carbon through transport in the boundary layer in east Asia
Takuma Miyakawa1,2, Naga Oshima3, Fumikazu Taketani1,2, Yuichi Komazaki1, Ayako Yoshino4, Akinori Takami4, Yutaka Kondo5, and Yugo Kanaya1,2 1Department of Environmental Geochemical Cycle Research, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa, 236-0001, Japan
2Institute for Arctic Climate and Environment Research, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa, 236-0001, Japan
3Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, 305-0052, Japan
4Center for Regional Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
5National Institute for Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo, 190-8518, Japan
Abstract. Ground-based measurements of black carbon (BC) were performed near an industrial source region in the early summer of 2014 and at a remote island in Japan in the spring of 2015. Here, we report the temporal variations in the transport, size distributions, and mixing states of the BC-containing particles. These particles were characterized using a continuous soot monitoring system, a single particle soot photometer, and an aerosol chemical speciation monitor. The effects of aging on the growth of BC-containing particles were examined by comparing the ground-based observations between the near-source and remote island sites. Secondary formation of sulfate and organic aerosols strongly affected the increases in BC coating (i.e., enhancement of cloud condensation nuclei activity) with air mass aging from the source to the outflow regions. The effects of wet removal on BC microphysics were elucidated by classifying the continental outflow air masses depending on the enhancement ratios of BC to CO (ΔBC ∕ ΔCO), which were used as an indicator of the transport efficiency of BC. It was found that ΔBC ∕ ΔCO ratios were controlled mainly by the wet removal during transport in the planetary boundary layer (PBL) on the timescale of 1–2 days. The meteorological conditions and backward trajectory analyses suggested that air masses strongly affected by wet removal originated mainly from a region in southern China (20–35° N) in the spring of 2015. Removal of large and thickly coated BC-containing particles was detected in the air masses that were substantially affected by the wet removal in the PBL, as predicted by Köhler theory. The size and water solubility of BC-containing particles in the PBL can be altered by the wet removal as well as the condensation of non-BC materials.

Citation: Miyakawa, T., Oshima, N., Taketani, F., Komazaki, Y., Yoshino, A., Takami, A., Kondo, Y., and Kanaya, Y.: Alteration of the size distributions and mixing states of black carbon through transport in the boundary layer in east Asia, Atmos. Chem. Phys., 17, 5851-5864, https://doi.org/10.5194/acp-17-5851-2017, 2017.
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Short summary
We have deployed a single particle soot photometer (SP2) to characterize black carbon (BC) aerosols near industrial sources in Japan in the early summer of 2014 and at a remote island in the spring of 2015. The observed changes in the SP2-derived size distributions and mixing state of BC-containing particles with air mass transport are connected to meteorological variability (transport pathways and air mass histories) in spring in east Asia.
We have deployed a single particle soot photometer (SP2) to characterize black carbon (BC)...
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