Li Chaoliu, Zhang Chao, Kang Shichang, Xu Yinbo, Yan Fangping, Liu Yixi, Rai Mukesh, Zhang Hongbo, Chen Pengfei, Wang Pengling, He Cenlin, Gao Shaopeng, Wang Shuxiao
State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2024 Apr 20;922:171321. doi: 10.1016/j.scitotenv.2024.171321. Epub 2024 Feb 28.
Carbonaceous particles play a crucial role in atmospheric radiative forcing. However, our understanding of the behavior and sources of carbonaceous particles in remote regions remains limited. The Tibetan Plateau (TP) is a typical remote region that receives long-range transport of carbonaceous particles from severely polluted areas such as South Asia. Based on carbon isotopic compositions (ΔC/δC) of water-insoluble particulate carbon (IPC) in total suspended particle (TSP), PM, and precipitation samples collected during 2020-22 at the Nam Co Station, a remote site in the inner TP, the following results were achieved: First, fossil fuel contributions (f) to IPC in TSP samples (28.60 ± 9.52 %) were higher than that of precipitation samples (23.11 ± 8.60 %), and it is estimated that the scavenging ratio of IPC from non-fossil fuel sources was around 2 times that from fossil fuel combustion during the monsoon season. The f of IPC in both TSP and PM samples peaked during the monsoon season. Because heavy precipitation during the monsoon season scavenges large amounts of long-range transported carbonaceous particles, the contribution of local emissions from the TP largely outweighs that from South Asia during this season. The results of the IPC source apportionment based on ΔC and δC in PM samples showed that the highest contribution of liquid fossil fuel combustion also occurred in the monsoon season, reflecting increased human activities (e.g., tourism) on the TP during this period. The results of this study highlight the longer lifetime of fossil fuel-sourced IPC in the atmosphere than that of non-fossil fuel sources in the inner TP and the importance of local emissions from the TP during the monsoon season. The findings provide new knowledge for model improvement and mitigation of carbonaceous particles.
碳质颗粒在大气辐射强迫中起着关键作用。然而，我们对偏远地区碳质颗粒的行为和来源的了解仍然有限。青藏高原（TP）是一个典型的偏远地区，接收来自南亚等严重污染地区的碳质颗粒的远距离传输。基于2020 - 2022年在TP内部偏远站点纳木错站采集的总悬浮颗粒物（TSP）、PM和降水样品中水溶性颗粒碳（IPC）的碳同位素组成（ΔC/δC），取得了以下结果：首先，TSP样品中IPC的化石燃料贡献（f）（28.60±9.52%）高于降水样品（23.11±8.60%），据估计，季风季节非化石燃料源的IPC清除率约为化石燃料燃烧源的2倍。TSP和PM样品中IPC的f在季风季节达到峰值。由于季风季节的强降水清除了大量远距离传输的碳质颗粒，TP本地排放的贡献在这个季节大大超过了南亚的贡献。基于PM样品中ΔC和δC的IPC源解析结果表明，液体化石燃料燃烧的最高贡献也出现在季风季节，反映了这一时期TP上人类活动（如旅游业）的增加。本研究结果突出了TP内部大气中化石燃料源IPC的寿命比非化石燃料源的更长，以及季风季节TP本地排放的重要性。这些发现为碳质颗粒的模型改进和减排提供了新知识。
