A large atomic chlorine source inferred from mid-continental reactive nitrogen chemistry
A large atomic chlorine source inferred from mid-continental reactive nitrogen chemistry
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DOI：
10.1038/nature08905
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发表时间：
2010-03-11
期刊：
影响因子：
64.8
通讯作者：
Brown, Steven S.
中科院分区：
文献类型：
--
作者：
Thornton, Joel A.;Kercher, James P.;Brown, Steven S.
卤素原子和氧化物具有高活性，能深刻地影响大气成分。氯原子可以缩短气态单质汞(1)和碳氢化合物（如温室气体甲烷(2)）的寿命。氯原子还影响催化破坏或产生对流层臭氧的循环(3)，这是一种对植物和动物生命有潜在毒性的温室气体。对流层内无机氯转化为气态氯原子前体通常被认为是一种沿海或海洋空气现象(4)。在这里，我们报告在离最近的海岸线1,400公里处对氯原子前体硝基氯的中大陆观测。我们观察到相对于其氮氧化物前体的消耗，持续和显著的硝基氯生产。将这些发现与基于长期监测网络的气溶胶和降水组成数据的模式预测进行比较，表明仅美国邻近地区的硝基氯化物产量就与以前对沿海和海洋地区的全球估计相似(5)。我们还认为，相当一部分对流层氯原子(6)可能直接来自人为污染物。
Halogen atoms and oxides are highly reactive and can profoundly affect atmospheric composition. Chlorine atoms can decrease the lifetimes of gaseous elemental mercury(1) and hydrocarbons such as the greenhouse gas methane(2). Chlorine atoms also influence cycles that catalytically destroy or produce tropospheric ozone(3), a greenhouse gas potentially toxic to plant and animal life. Conversion of inorganic chloride into gaseous chlorine atom precursors within the troposphere is generally considered a coastal or marine air phenomenon(4). Here we report mid-continental observations of the chlorine atom precursor nitryl chloride at a distance of 1,400km from the nearest coastline. We observe persistent and significant nitryl chloride production relative to the consumption of its nitrogen oxide precursors. Comparison of these findings to model predictions based on aerosol and precipitation composition data from long-term monitoring networks suggests nitryl chloride production in the contiguous USA alone is at a level similar to previous global estimates for coastal and marine regions(5). We also suggest that a significant fraction of tropospheric chlorine atoms(6) may arise directly from anthropogenic pollutants.