Abstract:
Particulate organic nitrates, among the major components of secondary organic aerosols and fine particles, play important roles in regional nitrogen cycle, ozone budget, and cloud condensation nuclei formation. However, the pollution characteristics of particulate organic nitrates at mountain areas and the effects of anthropogenic pollutant transport remain poorly understood. In this study, field sampling and measurements were conducted at a high-elevation mountain site over North China Plain in winter and spring. Total five kinds of particulate organic nitrates in fine particles were determined by ultra-high performance liquid chromatography-electrospray mass spectrometry. The average total concentrations of particulate organic nitrates were 330 ± 121 ng m-3 and 247 ± 63 ng m-3 in winter and spring. The monoterpene-derived organic nitrates were the dominant components in both seasons with their contribution higher than 70%, accounting for 1.2 ± 0.8% and 2.0 ± 1.0% in organic aerosols in winter and spring, respectively. The significantly higher levels of particulate organic nitrates in winter than spring was ascribed to the strong effects of mountain-valley breezes and coal combustion plumes. The increasing concentrations of NOx and particulate matters brought by the valley breeze at daytime facilitated the formation of MHN215, OAKN359, and OAHN361, while the rising SO2 abundance and the sulfate aerosols transported by elevated emission sources affected the formation of MDCN247 at nighttime.
摘要:
有机硝酸盐,在次级有机气溶胶和细颗粒的主要成分中,在区域氮循环中发挥重要作用,臭氧预算,和云凝结核形成。然而,山区颗粒有机硝酸盐的污染特征和人为污染物迁移的影响仍然知之甚少。在这项研究中,冬季和春季在华北平原的高海拔山区进行了现场采样和测量。采用超高效液相色谱-电喷雾质谱法测定细颗粒中5种颗粒有机硝酸盐的含量。冬季和春季颗粒有机硝酸盐的平均总浓度为330±121ngm-3和247±63ngm-3。单萜衍生的有机硝酸盐是两个季节的主要成分,其贡献高于70%,冬季和春季有机气溶胶分别占1.2±0.8%和2.0±1.0%,分别。冬季的有机硝酸盐含量明显高于春季,这归因于山谷微风和煤燃烧羽流的强烈影响。白天山谷微风带来的NOx和颗粒物浓度的增加促进了MHN215,OAKN359和OAHN361的形成,而SO2丰度的增加和由高排放源运输的硫酸盐气溶胶在夜间影响了MDCN247的形成。