ヒドロキシル基と二酸化窒素のガス相結合率
Andrew K Mollner1, Sivakumaran Valluvadasan, Lin Feng
1Arthur Amos Noyes Laboratory of Chemical Physics, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Science (New York, N.Y.)
|October 30, 2010
まとめ
窒素酸 (HONO(2) を形成する反応は,大気化学にとって極めて重要です. 新しい測定により,より正確な速度定数が得られ,ロサンゼルスなどの汚染地域におけるオゾン予測に影響を与えています.
科学分野:
- 大気化学 大気化学
- 環境科学 環境科学
背景:
- ヒドロキシルラジカル (OH) と二酸化窒素 (NO2) の反応により,ガス状窒酸 (HONO2) が形成されるのは,大気化学における重要なプロセスである.
- HONO2形成の速度係数の以前の測定は,特に熱帯圏条件 (760 torr) とペロキシニートル酸 (HOONO) を生成する二次チャネルによる不確実性があります.
研究 の 目的:
- 関連する大気条件下でのHONO2形成の速度係数を正確に決定する.
- HONO2形成チャネルとHOONO形成チャネルの分割を定量化するために.
主な方法:
- 2つの繊細なレーザースペクトロスコピーの技術を使用して,全体的な反応速度と分岐比率を同時に測定しました.
- トロポスフィアの条件をシミュレートするために,25°Cと760 torrの空気で実験を行った.
主要な成果:
- HONO2形成の速度定数は,より正確で,9.2 (±0.4) × 10^-12 cm^3 molecule^-1 s^-1 が 760 torr.で得られた.
- 新しいレート定数は,以前に報告された値よりも低いため,このチャネルからの貢献は,いくつかの推定値よりも低いことを示唆しています.
- この研究では,2つの反応チャネル間の分割を定量化しました.
結論:
- 改訂されたHONO2形成の速度定数は,大気モデルのためのより正確なパラメータを提供します.
- この発見は,この改善された運動データの光化学モデル予測,特にロサンゼルスのような都市空域のオゾン濃度に対する影響を示しています.
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