Zhou Binhuang, Huang Yu, Feng Liangyu, Zhang Zihao, Li Haiwei, Wu Yun, Ye Jianhuai, Ge Xinlei
Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
Toxics. 2025 May 27;13(6):443. doi: 10.3390/toxics13060443.
Optical properties and chemical composition of atmospheric fine particles (PM) are critical to their environmental and health effects. In this study, we analyzed the organic aerosols (OA) in PM samples in Nanjing, China, collected during the summer and winter of 2019 and 2023. Results show a decline in both concentrations and light-absorbing abilities of methanol-soluble organic carbon (MSOC) and water-soluble OC (WSOC) in OA from 2019 to 2023. Due to increased combustion activities, MSOC and WSOC concentrations, and their corresponding mass absorption efficiencies were all higher in winter than in summer. Furthermore, fluorescence indices suggest that OA in Nanjing was influenced by a mix of microbial/biogenic sources. Fluorescent properties of both WSOC and MSOC were dominated by humic-like components but the remaining contribution from protein-like components was more significant in MSOC. The molecular composition of OA did not show a remarkable difference between 2019 and 2023. Overall, CHON compounds were the most abundant species, followed by CHO and CHN compounds, and aliphatic compounds dominated all molecular types except for CHN (in positive mode) and CHON, CHOS (in negative mode). Regarding the OA sources, the numbers of molecules from fossil fuel combustion and biomass burning (BB) were a bit more in 2023 than in 2019, and signal intensities of BB-related molecules were also higher in winter than in summer; the presence of organosulfates indicate the contribution of aqueous-phase oxidation to OA, especially during high relative humidity conditions. At last, correlations between OA molecules and light absorption efficiencies indicate that the key light-absorbing species in winter and summer were likely quite different despite similar chemical compositions, and in summer, CH and CHN compounds were important to light absorption, whereas CHNS compounds became more important in winter.
大气细颗粒物（PM）的光学性质和化学成分对其环境和健康影响至关重要。在本研究中，我们分析了2019年和2023年夏季及冬季在中国南京采集的PM样本中的有机气溶胶（OA）。结果显示，2019年至2023年期间，OA中甲醇可溶性有机碳（MSOC）和水溶性有机碳（WSOC）的浓度及其吸光能力均有所下降。由于燃烧活动增加，MSOC和WSOC浓度及其相应的质量吸收效率在冬季均高于夏季。此外，荧光指数表明，南京的OA受微生物/生物源混合影响。WSOC和MSOC的荧光特性均以类腐殖质成分为主，但MSOC中类蛋白质成分的剩余贡献更为显著。2019年和2023年之间，OA的分子组成没有显著差异。总体而言，CHON化合物是最丰富的物种，其次是CHO和CHN化合物，除CHN（正模式）和CHON、CHOS（负模式）外，脂肪族化合物在所有分子类型中占主导地位。关于OA来源，2023年化石燃料燃烧和生物质燃烧（BB）产生的分子数量比2019年略多，与BB相关分子的信号强度在冬季也高于夏季；有机硫酸盐的存在表明水相氧化对OA有贡献，特别是在高相对湿度条件下。最后，OA分子与吸光效率之间的相关性表明，尽管化学成分相似，但冬季和夏季的关键吸光物种可能有很大不同，在夏季，CH和CHN化合物对光吸收很重要，而CHNS化合物在冬季变得更为重要。
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