Molecular Absorption and Evolution Mechanisms of PM2.5 Brown Carbon Revealed by Electrospray Ionization Fourier Transform-Ion Cyclotron Resonance Mass Spectrometry During a Severe Winter Pollution Episode in Xi'an, China
Molecular Absorption and Evolution Mechanisms of PM2.5 Brown Carbon Revealed by Electrospray Ionization Fourier Transform-Ion Cyclotron Resonance Mass Spectrometry During a Severe Winter Pollution Episode in Xi'an, China
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中国西安冬季严重污染期间电喷雾电离傅里叶变换离子回旋共振质谱揭示 PM 2.5 棕碳的分子吸收和演化机制
DOI：
10.1029/2020gl087977
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发表时间：
2020
影响因子：
5.2
通讯作者：
Rudolf Hohn
中科院分区：
文献类型：
--
作者：
Zeng Yaling;Shen Zhenxing;Takahama Satoshi;Zhang Leiming;Zhang Tian;Lei Yali;Zhang Qian;Xu Hongmei;Ning Yanli;Huang Yu;Cao Junji;Rudolf Hohn
了解棕碳（BrC）的分子水平化学对于减少气溶胶辐射强迫的不确定性非常重要。时间分辨环境 PM2.5 样本是在 2017 年 1 月中国西安严重污染期间收集的，利用电喷雾电离傅里叶变换离子回旋共振质谱结合偏最小二乘回归分析，对 BrC 分子及其吸收特性进行了全面的非目标和全扫描，将整体紫外线吸收分配给各个分子。 CHNO和CHNOS分子的估计吸收呈现夜间流行，而CHOS、CHNS、CHN、CHO、CHS和CH分子呈现动态趋势。碳共轭与 CHO 和 CHNO 分子的估计吸收呈正相关，而与 CHNOS 则表现出混合关系。较高的氮含量与 BrC 分子的光吸收性能增强有关，而较高的氧和硫含量似乎与二次转化过程中的光漂白有关。
Knowledge of the molecular‐level chemistry of brown carbon (BrC) is important in reducing the uncertainties in aerosol radiative forcing. Time‐resolved ambient PM2.5samples were collected during a severe pollution episode in January 2017 over Xi'an, China for a comprehensive nontarget and full scanning of BrC molecules and their absorption properties using electrospray ionization Fourier transform–ion cyclotron resonance mass spectrometry combined with partial least squares regression analysis, which apportioned the overall ultraviolet absorption to individual molecules. The estimated absorption of CHNO and CHNOS molecules exhibited nighttime prevalence, whereas CHOS, CHNS, CHN, CHO, CHS, and CH molecules presented a dynamic trend. Carbon conjugation was positively correlated with estimated absorption by CHO and CHNO molecules, while exhibiting a mixed relationship with CHNOS. Higher nitrogen content was associated with enhanced light‐absorption properties of BrC molecules, while higher oxygen and sulfur content appeared to be associated with photobleaching during secondary transformation.