まとめ
1,1-ジクロロ-2,2,2-トリフルオロエタン (CFC-123) は,CFC-11の潜在的な代替品です. 主な大気沈殿地はOHラジカルとの反応であり,CFC-11と比較して寿命が大幅に短縮され,平流層の塩素注入が減少しています.
科学分野:
- 大気化学 大気化学
- 環境科学 環境科学
- 化学工学化学工学とは
背景:
- トリクロフルオロメタン (CFC-11) の使用は,オゾン層と気候への影響のために制限されています.
- 1,1-ジクロロ-2,2,2-トリフッロエタン (CFC-123) は,CFC-11の産業用代替品として提案されています.
- CFC-123は赤外線を吸収する化合物で,CFC-11よりも大気中で安定性が低いと予想されます.
研究 の 目的:
- 大気中のCFC-123の化学破壊率を計算する.
- CFC-123.3の主な大気沈殿点と寿命を決定する.
- CFC-123とCFC-11の大気中の振る舞いを比較する.
主な方法:
- 3次元の世界大気モデルを使用した.
- CFC-123の化学破壊速度を,様々な大気中のプロセスで計算した.
- OHの急性反応速度定数に基づいて,安定状態の寿命を推定した.
主要な成果:
- CFC-123の主な吸収源は,熱帯圏 (12km以下) でOHラジカルによる破壊であり,その損失の88%を占めています.
- 最も高い破壊率は2km以下の赤道地帯で発生しています.
- CFC-123の計算された安定状態の寿命は1.5年です.
結論:
- CFC-123は,CFC-11よりもはるかに短い大気中の寿命を持っています.
- CFC-11は,同じ排出量で,CFC-123よりも,大気中のモラ含量と平流層の塩素注入量がかなり高くなります.
- CFC-123のトロポスフィアのOHラジカル反応は,ストラトスフィアの影響を制限する主要な除去経路です.
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