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 ClNO₂ following 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 ClNO₂ production following N₂O₅ deposition. Vertical gas profile and snow chamber experiments were conducted during January–February 2018 with chemical ionization mass spectrometry measurements of ClNO₂ and N₂O₅. The vertical gas profile measurements showed N₂O₅ and ClNO₂ deposition over both bare and snow-covered ground. However, positive (upward) ClNO₂ fluxes were only observed over the snow-covered ground, showing that the saline snowpack can serve as a source of ClNO₂. A fraction of the ClNO₂ profiles over the snow-covered ground did not exhibit gradients, indicative of a balance between ClNO₂ production and loss, including through hydrolysis. Exposure of local snow to synthesized N₂O₅ during chamber experiments resulted in ClNO₂ production 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.

中文翻译：

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盐雪堆上N ₂ O ₅沉积和ClNO _2产生的观察

氯化镍（ClNO ₂）是高反应性氯自由基的前体，也是二氧化氮（NO ₂）的储存器，是由氯化物与N ₂ O ₅的反应形成的，该气体在冬季的大气寿命更长。先前的现场观察，建模和实验室冰流管结果得出这样的假设：盐水盐是五氧化二氮（N ₂ O ₅）沉积后的ClNO ₂来源。由于道路盐（主要是岩盐）的广泛使用及其在雪堆中的沉积，我们调查了密歇根州卡拉马祖市的盐雪堆，研究了氮污染后直接生产ClNO ₂的潜力。₂ O ₅沉积。在2018年1月至2月进行了垂直气体剖面和雪室实验，并使用化学电离质谱法测量了ClNO ₂和N ₂ O ₅。垂直气体剖面测量表明，N ₂ O ₅和ClNO ₂沉积在裸露和积雪的地面上。但是，仅在积雪覆盖的地面上观察到了正的（向上）ClNO ₂通量，这表明盐水积雪可以作为ClNO ₂的来源。少量的ClNO ₂在积雪覆盖的地面上的剖面没有显示出梯度，表明ClNO _2的产生和损失（包括通过水解）之间的平衡。在室内实验期间，局部雪暴露于合成的N ₂ O ₅导致ClNO _2的产生取决于雪堆的物理结构。这些结果共同证明了ClNO ₂的盐积雪源，与冬季有雪的内陆和沿海地区均具有预期的相关性。