西藏拉萨大气颗粒物理化特征与源解析

拉萨地处青藏高原的中心，市区海拔为3650m、含氧量只有海平面的 30-60%，是世界上海拔最高、环境最敏感、生态最脆弱的首府城市。位于拉萨河谷的冲积扇上,四周被相对高度 1000 米左右的大山包围形成了大“Y”字形地形，逆温天气时有发生，极不利于大气污染物的输送扩散，大气污染隐患非常大。但是由于受观测条件限制，拉萨地区大气颗粒物理化特性及其源解析研究很少，是尚未能公布大气污染物源解析的极少数首府城市之一。.通过长期观测研究拉萨地区大气颗粒物以及相关气象参数的时空变化，不仅可以加深拉萨地区大气颗粒物的分布规律、来源、传输机制的认识，获得人类活动对青藏高原的影响提供背景资料；通过对拉萨地区大气颗粒物理化特性的研究，不仅可以加深西藏高原地区低温低压、强紫外线、高臭氧等特殊环境条件下大气颗粒物的形成机制的认识，获得高寒区域大气化学变化的信息，为研究极地及高山地区大气化学问题提供参考。

With its high altitude at 3,650 meters and the oxygen level only about 30-60% of that at sea level, Lhasa, the capital city of Tibet Autonomous Region, is located around the center of the Tibet Plateau and has the highest altitude and most vulnerable environmental and ecological conditions among the capital cities in China. Surrounded by mountains about 1000 meters higher, Lhasa is located on the alluvial fan of Lhasa River Valley, the bottom part of a Y-shaped area. Because of its location and the frequent occurrence of inversion, Lhasa is subject to potential air pollution, as the transport and dispersion of air pollutants can be difficult. Due to the difficulties in monitoring air pollution, there are few studies dealing with physicochemical characteristics and source apportionment of atmospheric particulate matter in Lhasa area. As a result, Lhasa is one of the few capital cities in China that have not reported on the source apportionment of atmospheric particulate matter yet. .Through long-term monitoring the temporal and spatial changes in atmospheric particulate matter and related meteorological conditions, an improved understanding can be obtained toward the distribution, sources, and transport mechanisms of atmospheric particulate matter in Lhasa area, which will provide fundamental information on the impacts of anthropogenic activities on the Tibet Plateau. Studying the physicochemical characteristics of atmospheric matter in Lhasa area can expand the knowledge base on the formation mechanisms of atmospheric particulate matter under the specific conditions of Tibet Plateau, such as low temperature and low atmospheric pressure, high UV radiation, and high levels of ozone. This study will obtain information on atmospheric chemical processes in high-cold regions, which will provide a sound basis for studying atmospheric chemistry in polar and high mountain areas.