Observation of N 2 O 5 Deposition and ClNO 2 Production on the Saline Snowpack
Observation of N 2 O 5 Deposition and ClNO 2 Production on the Saline Snowpack
复制标题
盐水积雪上 N 2 O 5 沉积和 ClNO 2 生成的观测
DOI：
10.1021/acsearthspacechem.0c00317
复制
发表时间：
2021
影响因子：
3.4
通讯作者：
Pratt, Kerri A.
中科院分区：
文献类型：
--
作者：
McNamara, Stephen M.;Chen, Qianjie;Edebeli, Jacinta;Kulju, Kathryn D.;Mumpfield, Jasmine;Fuentes, Jose D.;Bertman, Steven B.;Pratt, Kerri A.
硝酰氯（ClNO2）是高活性氯自由基的前体，也是二氧化氮（NO2）的储存库，由氯化物与N2O5反应形成，在冬季具有较长的大气寿命。以前的实地观察，建模，和实验室冰流管的结果导致的假设，盐雪是一个来源的ClNO2沉积后的五氧化二氮（N2O5）。由于广泛使用的道路盐（主要是岩盐）和沉积的积雪，盐积雪在密歇根州卡拉马祖，进行了调查的潜力，直接ClNO2生产N2O5沉积。垂直气体剖面和雪室实验在2018年1月至2月期间进行，化学电离质谱测量ClNO2和N2O5。垂直气体剖面测量表明，N2O5和ClNO2沉积在裸露和积雪覆盖的地面。然而，积极的（向上）ClNO2通量只观察到在积雪覆盖的地面，表明盐积雪可以作为ClNO2的来源。一小部分的ClNO2配置文件在积雪覆盖的地面没有表现出梯度，指示ClNO2生产和损失之间的平衡，包括通过水解。暴露于当地的雪合成N2O5室实验过程中导致ClNO2生产，这取决于积雪的物理结构。总之，这些结果表明，盐积雪源的ClNO2，与预期的相关性，冬季内陆和沿海地区的雪。
Nitryl chloride (ClNO2), a precursor to highly reactive chlorine radicals and a reservoir for nitrogen dioxide (NO2), is formed from the reaction of chloride with N2O5, which has a longer atmospheric lifetime during the winter. Previous field observations, modeling, and laboratory ice flow tube results led to the hypothesis that saline snow is a source of ClNO2following the deposition of dinitrogen pentoxide (N2O5). Due to the widespread use of road salt (primarily halite) and its deposition to the snowpack, the saline snowpack in Kalamazoo, Michigan, was investigated for the potential for direct ClNO2production following N2O5deposition. Vertical gas profile and snow chamber experiments were conducted during January–February 2018 with chemical ionization mass spectrometry measurements of ClNO2and N2O5. The vertical gas profile measurements showed N2O5and ClNO2deposition over both bare and snow-covered ground. However, positive (upward) ClNO2fluxes were only observed over the snow-covered ground, showing that the saline snowpack can serve as a source of ClNO2. A fraction of the ClNO2profiles over the snow-covered ground did not exhibit gradients, indicative of a balance between ClNO2production and loss, including through hydrolysis. Exposure of local snow to synthesized N2O5during chamber experiments resulted in ClNO2production that depended on the snowpack physical structure. Together, these results demonstrate a saline snowpack source of ClNO2, with expected relevance to both wintertime inland and coastal regions with snow.