富士山体を用いた夏季自由対流圏における雲水中揮発性有機化合物の観測  [in Japanese] Controlling Factors of Volatile Organic Compounds in Cloud Water at the Summit of Mt. Fuji in the Free Troposphere during the Summer  [in Japanese]

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Abstract

<p>2010年から2018年までの7月と8月に富士山頂(標高3,776 m)で大気および雲水を採取して、27種類の人為起源揮発性有機化合物 (AVOCs) (塩素化炭化水素16種、単環芳香族炭化水素8種、二環芳香族炭化水素3種)と6種類の生物起源揮発性有機化合物を分析した。雲水中VOCs (体積加重平均VOCs濃度:2.07 nM、<i>n</i>=159)の約9割はAVOCsであり、主成分はトルエンであった。これは富士山頂における大気中トルエン濃度が高いことを反映していた。雲水中AVOCs濃度は空気塊が大陸南部から輸送されたときに高く、最低濃度を示した海洋由来時の約1.5倍であった。雲水中トルエン濃度は総無機イオンの低下とともに指数関数的に減少した。雲水中クロロホルム、<i>o</i>-キシレン、リモネン濃度は大気中濃度とヘンリー定数から求めた計算値に比べて実測値は数倍高く、ヘンリー則からの予測値以上に濃縮されていた。疎水性が高いVOCsほど雲水に高濃縮されており、自由対流圏における雲水でもHULIS (フミン様物質)のような界面活性物質がVOCsの高濃縮に関与していることが示唆された。</p>

<p>At the summit of Mt. Fuji in July and August from 2012 to 2018, 27 kinds of anthropogenic volatile organic compounds (AVOCs) and 6 types of biogenic volatile organic compounds (BVOCs) in the air and in cloud water were determined. AVOCs occupied about 90% of the VOCs in the cloud water (volume-weighted mean VOCs concentration: 2.07 nM, <i>n</i>=159) and the main component was toluene, reflecting its high concentration in the ambient air. The concentration of the AVOCs in the cloud water was high when the airmass was transported from the southern continent and was about 1.5 times higher than that when it came from the ocean. The concentration of toluene in the cloud water decreased exponentially with the increase in the total ion concentration. The concentrations of some VOCs such as chloroform, <i>o</i>-xylene, and limonen in the cloud water were several times higher than their Henry's law predicted values. Among the chlorinated hydrocarbons, highly hydrophobic chloroform was more concentrated than dichloromethane in the cloud water. Atmospheric surfactants such as HULIS (Humic-like Substances) could affect the enrichment of the VOCs in the cloud water even in the free troposphere.</p>

Journal

  • Journal of Japan Society for Atmospheric Environment / Taiki Kankyo Gakkaishi

    Journal of Japan Society for Atmospheric Environment / Taiki Kankyo Gakkaishi 55(5), 191-203, 2020

    Japan Society for Atmospheric Environment

Codes

  • NII Article ID (NAID)
    130007890702
  • Text Lang
    JPN
  • ISSN
    1341-4178
  • Data Source
    J-STAGE 
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