エアロゾル研究
Online ISSN : 1881-543X
Print ISSN : 0912-2834
ISSN-L : 0912-2834
最新号
選択された号の論文の8件中1~8を表示しています
特集「フィールドエアロゾル観測のプラットフォーム」
研究論文
  • 熊谷 貴美代, 齊藤 由倫, 田子 博, 飯島 明宏, 渡邊 雅子, 佐藤 圭, 森野 悠
    2022 年 37 巻 2 号 p. 117-126
    発行日: 2022/06/20
    公開日: 2022/06/24
    ジャーナル フリー

    Understanding various source contributions of secondary organic aerosols (SOAs) is important for devising strategies to alleviate PM2.5 pollution. We measured anthropogenic and biogenic secondary organic markers and dicarboxylic acids, all of which are photooxidation products in PM2.5, both during the day and at night in Maebashi, Gunma, a suburban site in the Kanto region, in the summer of 2018. The results showed that concentrations of organic carbon and water-soluble organic carbon in PM2.5 increased during the daytime. Concentrations of 2,3-dihydroxy-4-oxopentanoic acid (DHOPA), a toluene-derived marker, and phthalic acid (PhA), a naphthalene-derived marker, were higher during the day than at night on days with high O3 levels. As for α-pinene-derived markers, 3-methylbutane-1,2,3-tricarboxlic acid (MBTCA), 3-hydroxy glutaric acid, and pinic acid concentrations also increased during the daytime. However, pinonic acid concentrations did not show a clear difference between day and night. Levoglucosan, the molecular marker for biomass burning, was observed at a low concentration. Concentrations of DHOPA, PhA, and MBTCA were positively correlated with average O3 concentrations. These results indicated that photochemical reactions increased the concentrations of anthropogenic and biogenic SOAs. This study confirmed that anthropogenic and biogenic SOAs contributed to increased PM2.5 level in the summer in Maebashi.

  • Muhammad Aiman Mohd Nor, Yoshihide Suwa
    2022 年 37 巻 2 号 p. 127-135
    発行日: 2022/06/20
    公開日: 2022/06/24
    ジャーナル フリー

    The LPT (Lagrangian particle tracking) is a fluid simulation technique that monitors particle movement in a flow field. Numerical errors such as truncation and rounding off can affect trajectory time integrations. Particle tracking is crucial for studying aerosol behavior near a surface, such as filter fibers, where airflow has steep spatial velocity gradients and noticeable temporal velocity fluctuations. In this research, the accuracy of six different numerical methods for solving the Lagrangian particle motion equation were compared. The impact of floating-point and flow curvature on particle capture by a circular cylinder collector were also studied. As the result, it was found that the accuracy of the methods was significantly influenced by floating-point precision. However, a smaller time step did not always imply greater calculation accuracy. The accuracy of numerical methods was also greatly affected by a flow curvature. A low-order method sometimes can be a better choice for lower numerical precision computations.

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