On the presence of high nitrite (NO 2 − ) in coarse particles at Mt. Qomolangma

作者：Zhongyi Zhang, Chunxiang Ye, Yichao Wu, Tao Zhou, Pengfei Chen, Shichang Kang, Chong Zhang, Zhuang Jiang, Lei Geng · 发表于：Atmospheric chemistry and physics · 年份：2025 · DOI：10.5194/acp-25-10625-2025 · 被引用次数：3 · 研究领域：Methane Hydrates and Related Phenomena、Coal and Its By-products、Geology and Paleoclimatology Research

Abstract. Atmospheric reactive nitrogen cycling, with nitrous acid (HONO) and particulate nitrite (NO2-) as important intermediates, is crucial for maintaining the atmospheric oxidation capacity of background atmosphere on the Tibetan Plateau. During an 11 d field campaign at the Base Camp of Mt. Qomolangma in spring of 2022, we observed significant enrichments of NO2- in total suspended particulate (TSP) with a mean concentration of 375±386 ng m−3, while NO2- was absent in fine particles (PM2.5). The comparison revealed that NO2- predominately exists in coarse particles. Local surface soil at the sampling site also exhibited high levels of NO2-, with δ15N value similar to NO2- in TSP. This isotopic similarity suggests that wind-blown soil is probably the primary source of NO2- in TSP, accounting for the background levels. While concentration changes of water-soluble inorganic ions in TSP and PM2.5 in response to shifts in air mass back-trajectories imply that atmospheric pollutants transported from South Asia may further elevate the NO2-, the specific mechanisms of long-range transport resulting in NO2- accumulation in TSP rather than PM2.5 remain unknown and need to be investigated. The elevated levels of TSP NO2- may readily participate in atmospheric reactive nitrogen cycling through gas-particle partitioning or photolysis, leading to the production of HONO, OH and NO and thereby influencing oxidation chemistry. Further efforts on the sources and atmospheric chemistry of ...