Expanding urbanization and agricultural intensification across neighboring South Asia and East Asia have substantially threatened atmospheric condition over the Third Pole (TP) during the past few decades. Whether the atmospheric condition over the TP is still as clean as a representative of the regional background draws great concern. In this work, great differences in levoglucosan concentration within/above the atmospheric boundary layer height are revealed. Levoglucosan results support the hypothesis that atmospheric pollutants in the mid-troposphere over the TP are mainly affected by long-range transport, although there are some local biomass burning emissions in residential areas. In addition, levoglucosan concentration in the mid-troposphere over the TP is at the same magnitude as marine and polar regions, but about 2–3 magnitudes lower than neighboring densely-populated Asian regions. With insights of levoglucosan records, this work therefore proves that the high-altitude TP still has largely pristine atmospheric conditions, and is one of the cleanest remote regions on the Earth.

在过去的几十年中，邻近的南亚和东亚地区不断扩大的城市化进程和农业集约化已经严重威胁了第三极的大气条件。TP上的大气条件是否仍然像区域背景的代表一样干净，这引起了极大的关注。在这项工作中，揭示了在大气边界层高度之内/之上的左旋葡聚糖浓度的巨大差异。左旋葡聚糖的结果支持以下假设：尽管在居住区中有一些局部生物质燃烧排放物，但对流层中部对流层中的大气污染物主要受远程运输影响。此外，TP上对流层中层的左旋葡聚糖浓度与海洋和极地地区的幅度相同，但是比邻近的人口稠密的亚洲地区低大约2-3个数量级。因此，利用左旋葡聚糖记录的见解，这项工作证明了高海拔TP在很大程度上仍处于原始的大气条件，并且是地球上最干净的偏远地区之一。