OH 在大气水相中的有机硫酸盐的激进氧化
Daniel T Gweme1, Sarah A Styler1
1Department of Chemistry & Chemical Biology, McMaster University, Hamilton, Ontario L8S 4L8, Canada.
The journal of physical chemistry. A
|October 21, 2024
概括
有机硫酸盐 (OS) 被大气中的基 (OH) 氧化,寿命从几分钟到几天不等. 它们的反应性受到碳链长度,芳香度和离子强度的影响,因此需要将它们纳入大气模型.
科学领域:
- 大气化学 大气化学
- 环境科学 环境科学
- 化学动力学 化学动力学
背景情况:
- 有机硫酸盐 (OS) 在大气颗粒物 (PM) 中很常见,影响其性能.
- 虽然研究了OS的形成,但对它们在大气中的降解的理解较少.
研究的目的:
- 确定五个关键有机硫酸盐的反应速率常数和基 (OH) 氧化产物.
- 研究pH值和离子强度如何影响大气条件下的OS反应.
主要方法:
- 对OS+OH反应的双分子速率常数 (kOS+OHII) 的实验测量.
- 在不同的pH值和离子强度下,从OS形成的氧化产品的分析.
主要成果:
- OS与OH以10^8 - 10^9 M^-1 s^-1的速度反应,导致大气中寿命短.
- 随着碳链长度和芳香度的增加,反应性会增加,而不依赖于pH值.
- 离子强度显著降低了OS的反应性,特别是对于硫酸.
结论:
- OS易受OH氧化,形成有机过氧化物和基化芳化合物.
- 大气模型需要纳入这些OS降解途径.
- 仅仅环境OS度可能无法准确反映生产率.
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