State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Environ Pollut. 2020 Jun;261:114144. doi: 10.1016/j.envpol.2020.114144. Epub 2020 Feb 7.
With the recent rapid development of urbanization, atmospheric pollutants such as polycyclic aromatic hydrocarbons (PAHs) have attracted wide attention, particularly in remote regions. The Tibetan Plateau (TP), known as the third pole is adjacent to areas with heavy atmospheric pollution, such as South and East Asia. However, the spatial distribution and sources of PAHs on the TP remain unclear. Thus, we investigated the sources and spatio-temporal distributions of PAHs on the TP by combining aerosol sample data from six sites, including Ngari (NG), Laohugou (LHG), Beiluhe (BLH), Nam Co (NMC), Everest (EV), and Yulong (YL), in 2014 and 2016. The average concentrations of 15 PAHs at the six sites ranged from 3.4 to 15.2 ng m, with a decreasing trend from the marginal to inner areas of the plateau. The highest concentration was that in YL in the southeastern part of the TP, with an average of 15.2 ng m. The PAH concentrations in NG, NMC, and YL were higher in autumn and winter and lower in summer. High molecular weight PAHs usually exists in the particulate phase whereas tricyclic PAHs can change from particulate to gaseous phase, therefore it can indicate long-range transport. Tricyclic PAHs were the dominant PAHs on the TP (44%-58%), indicating long-range atmospheric transport as the major source of PAHs. Principal component analysis (PCA) and diagnostic ratio analysis showed that biomass and coal combustion were the major sources of PAHs in inland areas of the TP; however, marginal plateau areas were affected by fossil fuel emissions. Compared with levels in Beijing and other urban sites, the toxic equivalent quantity (TEQ) was low (0.36-1.06 ng m), suggesting a low risk to human and ecosystem health.
随着城市化进程的快速发展，大气污染物如多环芳烃（PAHs）受到了广泛关注，尤其是在偏远地区。青藏高原（TP）作为第三极，与南亚和东亚等大气污染严重的地区相邻。然而，TP 上 PAHs 的空间分布和来源仍不清楚。因此，我们结合了 2014 年和 2016 年在纳木错（NMC）、那曲（NG）、老河沟（LHG）、白河（BLH）、珠峰（EV）和玉龙雪山（YL）六个站点采集的气溶胶样本数据，研究了 TP 上 PAHs 的来源和时空分布。六个站点的 15 种 PAHs 的平均浓度范围为 3.4-15.2ng/m，呈从高原边缘到内部逐渐降低的趋势。TP 东南部的 YL 站点的浓度最高，平均浓度为 15.2ng/m。NG、NMC 和 YL 站点的 PAH 浓度在秋季和冬季较高，夏季较低。高分子量的 PAHs 通常存在于颗粒物相中，而三环 PAHs 可以从颗粒物相转变为气相，因此可以指示远距离传输。三环 PAHs 是 TP 上的主要 PAHs（44%-58%），表明远距离大气传输是 PAHs 的主要来源。主成分分析（PCA）和诊断比分析表明，内陆地区 PAHs 的主要来源是生物质和煤炭燃烧；然而，高原边缘地区则受到化石燃料排放的影响。与北京和其他城市站点的水平相比，毒性等效量（TEQ）较低（0.36-1.06ng/m），表明对人类和生态系统健康的风险较低。
