• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Sustainable Humanosphere >Photochemical Aging Mechanism of Aqueous Organic Aerosols
【24h】

Photochemical Aging Mechanism of Aqueous Organic Aerosols

机译：水性有机气溶胶的光化学老化机理

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

A major source of uncertainty in predicting the climate and health effects of organic aerosol is how its composition changes over their atmospheric lifetimes. Here, products and intermediates of the oxidation of atmospherically relevant aqueous di-carboxylic acids (DCAs) initiated by gas-phase hydroxyl radicals, OH(g), at the air-water interface were detected by mass spectrometry in a novel setup under various experimental conditions. Exposure of sub-millimolar reactant aqueous microjets to ~ 10 ns OH(g) pulses from the 266 nm laser flash photolysis of 0_3(g)/0_2(g)/H_2O(g) mixtures yielded an array of interfacial intermediates/products, including peroxyl radicals and peroxides, that were unambiguously and simultaneously identified in situ by mass spectrometry[l,2]. An important finding is that the oxidation of DCAs initiated by gas-phase OH radicals leads not only to their stepwise degradation but also to the formation of more reactive species, such as hydroperoxides, which can propagate radical chain reactions in the condensed aerosol phase. We demonstrate that the reactivities of shorter-chain DCAs homologues (oxalic acid and malonic acid) toward OH(g) decrease dramatically, in line with the higher hydrophilicity of the shorter chain mono-anions that inhibits their partitioning to the air-water interface. The present results would explain why and how shorter-chain DCAs naturally accumulate in aged organic aerosol. Our results suggest that interface-specific OH oxidation of DCAs would play a far more significant role in photochemical aging process of atmospheric aerosols than previously assumed.
机译：预测有机气溶胶对气候和健康的影响时，不确定性的主要来源是其组成在整个大气寿命中如何变化。在这里，通过质谱在各种实验下通过新颖的方法检测了在空气-水界面处由气相羟基自由基OH（g）引发的大气相关含水二羧酸（DCA）氧化的产物和中间体条件。亚毫摩尔级反应物水溶液微喷嘴暴露于266 nm激光闪光灯对0_3（g）/ 0_2（g）/ H_2O（g）混合物的266 nm激光光解产生的〜10 ns OH（g）脉冲，产生了一系列界面中间体/产物，包括过氧自由基和过氧化物，它们可以通过质谱法原位明确地同时鉴定[1,2]。一个重要发现是，气相OH自由基引发的DCA氧化不仅导致其逐步降解，而且还导致形成更多的反应性物种（例如氢过氧化物），后者可以在冷凝的气溶胶相中传播自由基链反应。我们证明，短链DCA同源物（草酸和丙二酸）对OH（g）的反应性急剧降低，这与较短链单阴离子的较高亲水性相一致，后者抑制了它们向空气-水界面的分配。目前的结果将解释为什么短链DCA以及如何在老化的有机气溶胶中自然积累。我们的结果表明，DCA的特定于界面的OH氧化在大气气溶胶的光化学老化过程中将发挥比以前设想的重要得多的作用。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号