Presentation Information
[AAS08-P09]Size Segregated Characterizations of Iron in Aerosols in the East Asian Outflow in Winter-
Spring Seasons: Source Apportionment and Evolutions of Water-Soluble Fraction
*Takuma Miyakawa1, Chunmao Zhu1, Morihisa Yokokawa2, Mitsunobu Mukawa3, Yugo Kanaya1 (1.Japan Agency for Marine-Earth Science and Technology, 2.Sibata Scientific Technologies, 3.Murata Keisokuki Service)
Keywords:
Asian Dust,Iron source apportionment,Iron Water solubility,East Asian winter monsoon
Trace metals in aerosol particles impact Earth’s radiative budget, human health, and ocean
biogeochemistry. Semi-continuous measurements of the elemental composition of fine-mode
(PM2.5) and total (PM10) aerosols and high-volume air sampling (5-d)/offline chemical analyses
were conducted on a remote island of Japan in the winter–spring of 2023–2024 to characterize
the source apportionment and water-soluble fraction of geochemically important elements such
as Fe in the East Asian outflow region. PM2.5 and PM10 total aerosol (Fe) concentrations reached
to 85 and 205 (2.7 and 7.4) µg m−3, respectively (April 17–20, 2024), during the observation
period, suggesting the strong influence of Asian dust transport to the outflow region causing the
violence of short-term air quality standard in Japan. Water-soluble fraction of Fe (FsolFe) greatly
varied from 3% to 40% for PM2.5 aerosols and were less than 1.5% for coarse mode aerosols
(>2.5 µm), indicating that mineral dust dominated coarse mode and that mineral dust
contributions temporally varied for PM2.5 aerosols. Temporal variations in PM2.5 and PM10 Fe
concentrations were analyzed with concentrations of tracer species (Si and black carbon) by
following our previous study (Miyakawa et al., 2023) and were classified into dust and non-dust
Fe contributions for PM2.5 and coarse mode aerosols. Size segregated FsolFe were investigated
using dust contributions and aging processes (transport time and impacts of acidic components).
The source apportionment (dust vs. non-dust) was essential to account for the FsolFe variations for
PM2.5 aerosols, whereas coarse mode aerosols were affected largely by aging processes because
they were mainly apportioned to be dust. Our observations provided the combined data sets of
size segregated Fe concentrations and the evolutions of FsolFe through aging processes as useful
constraints to develop, validate, and refine numerical models simulating the detailed behavior of
Fe in aerosols over the regions under East Asian winter monsoon influences.
Miyakawa, T., Ito, A., Zhu, C., Shimizu, A., Matsumoto, E., Mizuno, Y., and Kanaya, Y.: Trace elements in PM2.5 aerosols in East Asian outflow in the spring of 2018: emission, transport, and source apportionment, Atmos. Chem. Phys., 23, 14609–14626, https://doi.org/10.5194/acp-23-14609-2023, 2023.
biogeochemistry. Semi-continuous measurements of the elemental composition of fine-mode
(PM2.5) and total (PM10) aerosols and high-volume air sampling (5-d)/offline chemical analyses
were conducted on a remote island of Japan in the winter–spring of 2023–2024 to characterize
the source apportionment and water-soluble fraction of geochemically important elements such
as Fe in the East Asian outflow region. PM2.5 and PM10 total aerosol (Fe) concentrations reached
to 85 and 205 (2.7 and 7.4) µg m−3, respectively (April 17–20, 2024), during the observation
period, suggesting the strong influence of Asian dust transport to the outflow region causing the
violence of short-term air quality standard in Japan. Water-soluble fraction of Fe (FsolFe) greatly
varied from 3% to 40% for PM2.5 aerosols and were less than 1.5% for coarse mode aerosols
(>2.5 µm), indicating that mineral dust dominated coarse mode and that mineral dust
contributions temporally varied for PM2.5 aerosols. Temporal variations in PM2.5 and PM10 Fe
concentrations were analyzed with concentrations of tracer species (Si and black carbon) by
following our previous study (Miyakawa et al., 2023) and were classified into dust and non-dust
Fe contributions for PM2.5 and coarse mode aerosols. Size segregated FsolFe were investigated
using dust contributions and aging processes (transport time and impacts of acidic components).
The source apportionment (dust vs. non-dust) was essential to account for the FsolFe variations for
PM2.5 aerosols, whereas coarse mode aerosols were affected largely by aging processes because
they were mainly apportioned to be dust. Our observations provided the combined data sets of
size segregated Fe concentrations and the evolutions of FsolFe through aging processes as useful
constraints to develop, validate, and refine numerical models simulating the detailed behavior of
Fe in aerosols over the regions under East Asian winter monsoon influences.
Miyakawa, T., Ito, A., Zhu, C., Shimizu, A., Matsumoto, E., Mizuno, Y., and Kanaya, Y.: Trace elements in PM2.5 aerosols in East Asian outflow in the spring of 2018: emission, transport, and source apportionment, Atmos. Chem. Phys., 23, 14609–14626, https://doi.org/10.5194/acp-23-14609-2023, 2023.