Xue Guo-Yan, Wang Ge-Hui, Wu Can, Xie Yu-Ning, Chen Yu-Bao, Li Xing-Ru, Wang Xin-Pei, Li Da-Peng, Zhang Si, Ge Shuang-Shuang, Ding Zhi-Jian
Key Laboratory of Geographic Information Science, Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China.
Institute of Eco-Chongming, Shanghai 200062, China.
Huan Jing Ke Xue. 2020 Feb 8;41(2):554-563. doi: 10.13227/j.hjkx.201908019.
To investigate the pollution characteristics and sources of organic aerosols at a background site of the Yangtze River Delta, day- and night- PM samples were collected from May 30 to August 15, 2018 in Chongming Island, China and measured for their normal alkanes (-alkanes) and polycyclic aromatic hydrocarbons (PAHs) content employing a GC-MS technique. Concentrations of PM, -alkanes, and PAHs during the entire sampling period were (33±21) μg·m, (26±44) ng·m, and (0.76±1.0) ng·m, respectively. During the entire campaign, 35% of the collected PM samples were of a particle loading larger than the first grade of the China National Air Quality Standard (35 μg·m), suggesting that further mitigation with respect to air pollution in Chongming Island remains imperative. In the period with a PM concentration higher than 35 μg·m, which was classified as the pollution period, concentrations of -alkanes and PAHs were one order of magnitude higher than those in the period with PM less than 15 μg·m, which was classified as the clean period. During the entire campaign, OC was higher in the daytime than in the nighttime, mainly due to the daytime photooxidation that enhanced the formation of secondary organic aerosols. During the pollution period, concentrations of EC and other pollutants were higher in the nighttime than in daytime, mainly due to the transport of the inland pollutants by the nighttime land breeze. Such a diurnal difference was not observed for the pollutants in clean periods, mainly due to the relatively clean breeze from East China Sea that diluted the air pollution. Diagnostic ratios showed that 67% of -alkanes in PM was derived from fossil fuel combustion. PMF analysis further showed that during the pollution period, vehicle exhausts and industrial emissions were the largest sources of PAHs, both accounting for 51% of the total in PM. In contrast, during the clean periods ship emissions were the largest source, contributing about 45% of the total PAHs, exceeding the sum (38%) of vehicle and industrial emissions.
为研究长江三角洲一个背景站点有机气溶胶的污染特征和来源，于2018年5月30日至8月15日在中国崇明岛采集了昼间和夜间的PM样本，并采用气相色谱 - 质谱技术测定了其中正构烷烃（n - 烷烃）和多环芳烃（PAHs）的含量。整个采样期间PM、n - 烷烃和PAHs的浓度分别为(33±21) μg·m³、(26±44) ng·m³和(0.76±1.0) ng·m³。在整个采样活动中，35%的采集PM样本的颗粒物负荷高于中国国家空气质量标准一级（35 μg·m³），这表明崇明岛空气污染的进一步缓解仍然势在必行。在PM浓度高于35 μg·m³的时期（被归类为污染期），n - 烷烃和PAHs的浓度比PM浓度低于15 μg·m³的时期（被归类为清洁期）高一个数量级。在整个采样活动中，OC在白天高于夜间，主要是由于白天的光氧化作用增强了二次有机气溶胶的形成。在污染期，EC和其他污染物的浓度在夜间高于白天，主要是由于夜间陆风对内陆污染物的输送。在清洁期，污染物未观察到这种日变化差异，主要是由于来自东海的相对清洁的海风稀释了空气污染。诊断比值表明，PM中67%的n - 烷烃源自化石燃料燃烧。PMF分析进一步表明，在污染期，机动车尾气和工业排放是PAHs的最大来源，两者均占PM中总量的51%。相比之下，在清洁期船舶排放是最大来源，贡献了约45%的PAHs总量，超过了机动车和工业排放的总和（38%）。
