窒素二酸化物の光感受性還元は,窒素酸の源であるヒュミック酸に,窒素酸の源として作用する

Konrad Stemmler¹, Markus Ammann, Chantal Donders

¹Paul Scherrer Institut, Laboratory of Radio- and Environmental Chemistry, CH-5232 Villigen, Switzerland. konrad.stemmler@psi.ch

Nature

|March 10, 2006

まとめ

日光に含まれるヒュミック酸は,二酸化窒素を減少させ,窒素酸を生成します. この発見は,日中の高い窒素酸レベルと大気中酸化におけるその役割を説明する.

科学分野:

大気化学大気化学
環境科学環境科学
フォトケミストリーフォトケミストリー

背景:

窒素酸は,大気汚染物質の分解に不可欠なヒドロキシルラジカルの主要な前駆体です.
トロポスフィアの窒素酸の源は,昼間の改善が観察されているにもかかわらず,まだ十分に理解されていません.

研究の目的:

日中の濃縮された窒素酸の形成の背後にある未知のメカニズムを調査する.
地球の大気中の窒素酸の新たな源を特定する.

主な方法:

放射性管状ガス流動炉における窒素二酸化物に対するヒュミック酸フィルムの暴露.
放射線照射下にあるヒュミック酸の表面で発生する光化学反応を分析する.

主要な成果:

光活性化ヒュミック酸による二酸化窒素の減少は,ガス状窒素酸の重要な源として特定されました.
この表面の光化学は,二酸化窒素と反応し,窒素酸を形成する還元性種を生成します.
形成の速度は,日中の高い窒素酸濃度と一致しています.

結論:

ヒューミック酸の表面は,光誘発反応を通じて昼間窒素酸の生成に重要な役割を果たします.
このプロセスは,下層トロポスフィアのヒドロキシルラジカル形成に大きく貢献します.
この発見は,境界層における大気化学の潜在的影響のある経路を強調している.

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