在OH和光驱加工后,catechol及其产品的多相臭氧氧化
Sithumi M Liyanage1, Meredith Schervish2, Habeeb H Al-Mashala1
1Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States.
概括
野火排放的排放,如甲基醇,形成云中的二级有机气溶 (SOA). 这种SOA的随后的臭氧氧化,特别是暴露在紫外线后,显著减缓了反应性物种,增加了它们在大气中的寿命.
科学领域:
- 大气化学 大气化学
- 环境科学 环境科学
- 生物质燃烧排放的排放量
背景情况:
- 化合物,特别是甲基醇,在生物质燃烧排放中很丰富.
- 云中的甲基醇氧化形成二次有机气溶 (SOA),有助于棕色碳 (BrC) 染色体.
- 在云蒸发后,亚微米SOA颗粒通过氧化剂和光进行进一步处理.
研究的目的:
- 研究由甲基醇衍生SOA的多相臭氧氧化.
- 模拟云处理 (OH启动的氧化) 和后云处理 (臭氧和光驱氧化).
- 确定相对湿度 (RH) 和紫外线辐射对臭氧吸收和SOA特性的影响.
主要方法:
- 使用涂层壁流管装置研究臭氧反应动力学.
- 采用动态多层建模来分析实验数据并推断扩散性.
- 进行了显微镜实验,以定性评估材料特性.
主要成果:
- 用OH处理的甲醇膜的臭氧吸收系数为2 × 10-6 (0%RH) 和9 × 10-6 (50%RH).
- OH-和光处理片的吸收系数较低: 2 × 10-7 (0% RH) 和 4 × 10-6 (50% RH).
- 用水蒸气塑化但在紫外线照射下变玻璃化的Catechol SOA,影响臭氧扩散.
结论:
- 在玻璃化SOA (紫外线照射后) 和低RH下,臭氧扩散速度明显较慢.
- 较慢的扩散可以将反应性物种的大气寿命从几个小时延长到一天以上.
- 了解这些过程对于模拟燃烧气溶的生物质大气衰老至关重要.
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