为了解四川盆地大气中单颗粒气溶胶理化特征，分别在该区域典型城市（成都市）和背景地区（峨眉山）进行了大气单颗粒样品采集.基于带能谱的透射电子显微镜（TEM-EDS）对两地累计3923个单颗粒的化学组成、形貌特征及混合状态等进行了全面观测和分析，并对两地颗粒物差异性进行了对比分析.结果发现：两地气溶胶颗粒主要包括有机物、富硫、矿物、烟尘和飞灰/金属颗粒，除了以单独的外混形式存在外，大多数颗粒以两种及两种以上颗粒类型混合（即内混）形式存在.通过对成都市不同污染状况下单颗粒特征对比发现，"污染天"的内混颗粒占比高于"清洁天"，分别为74.2%和68.6%；相比"清洁天"，"污染天"颗粒物粒径分布范围更广且峰值区间更大，表明污染过程中颗粒物的大气混合趋于更强.对比成都市与峨眉山分析结果得知，成都市以内混的有机物-硫颗粒为主导（占比为50.2%），而峨眉山以外混的有机物颗粒为主导（占比为50.5%）；成都市含硫类颗粒物（如有机物-硫颗粒）贡献高于峨眉山，而峨眉山两种含碳类颗粒（如烟尘和有机物-烟尘颗粒）占比高于成都市；此外，成都市与峨眉山两地大气颗粒物粒径分布范围及峰值区间均存在一定差异，进一步体现了两地颗粒物来源和老化混合的差异.在峨眉山，与非降雨天相比，一些易溶于水的颗粒物（如含硫类颗粒）在降雨天占比明显降低，而源自当地燃烧过程、粒径较小且疏水性强的颗粒物（如烟尘和有机物-烟尘颗粒）占比相应升高.
Abstract
To understand the physiochemical characteristics of individual aerosol particles in Sichuan Basin, samples of atmospheric individual aerosol particles were collected in a typical city (Chengdu) and a background area (Mt. Emei) in Sichuan Basin. Then the chemical composition, morphology and mixing state of 3923 aerosol particles in the two regions were observed and analyzed by transmission electron microscopy coupled with energy dispersive X-ray spectroscopy (TEM-EDS). The results showed that the individual aerosol particles in the two regions mainly included organic matter, S-rich, mineral, soot and fly ash/metal particles. In addition to a small amount of external mixing, most particles existed in the form of internal mixing, i.e., two or more particles mixed with each other. Through the comparative of the characteristics of aerosol particles in different pollution conditions in Chengdu, it can be found that the proportion of the internal mixing particles in the "polluted days" (74.2%) was higher than that of "clean days" (68.6%). Moreover, compared with "clean days", the particles size distribution range of "pollution days" was wider and the peak range was larger, indicating that the mixing of particles tends to be stronger with the aggravation of pollution. The comparison between Chengdu and Mt. Emei showed that the OM-S particles dominated the particles in Chengdu (accounted for 50.2%), while the particles in Mt. Emei were dominated by OM particles (accounted for 50.5%). Meanwhile, the contribution of sulfur-containing particles (such as OM-S) in Chengdu was higher than that of Mt. Emei, while the proportion of two carbon-containing particles (such as soot and OM-soot) in Mt. Emei was higher than that of Chengdu. In addition, the range of particle size distribution and peak range between Chengdu and Mt. Emei were different, which highlighted the differences of the sources and aging mixture of particles between the two regions. In Mt. Emei, the proportion of soluble particles (such as sulfur-containing particles) in rainfall day significantly decreased compared with that of non-rainfall day, while the proportion of particles with small particle size and strong hydrophobicity (such as soot and OM-soot particles) increased correspondingly.
关键词
单颗粒气溶胶 /
混合状态 /
区域差异 /
形貌
Key words
individual aerosol particles /
mixing state /
morphology /
regional differences
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 毛节泰,张军华,王美华.中国大气气溶胶研究综述[J]. 气象学报, 2002,60(5):625-634.Mao J T, Zhang J H, Wang M H. Summary comment on research of atmospheric aerosl in China[J]. Acta Meteorologica Sinica, 60(5):625-634.
[2] 张小曳.中国大气气溶胶及其气候效应的研究[J]. 地球科学进展, 2007,22(1):12-16.Zhang X Y. Aerosol over China and their climate effect[J]. Advances in Earth Science, 2007,22(1):12-16.
[3] Li W, Wang Y, Jr J, et al. Microscopic evaluation of trace metals in cloud droplets in an acid precipitation region[J]. Environmental Science & Technology, 2013,47(9):4172-4180.
[4] 何映月,张松林.2000~2016年中国PM2.5时空格局[J]. 中国环境科学, 2020,40(8):3284-3293.He Y Y, Zhang S L. Spatiotemporal pattern of PM2.5 from 2000 to 2016 in China[J]. China environmental science, 2020,40(8):3284-3293.
[5] 危诗敏,冯鑫媛,王式功,等.四川盆地多层逆温特征及其对大气污染的影响[J]. 中国环境科学, 2021,41(3):1005-1013.Wei S M, Feng X Y, Wang S G, et al. Characteristics of multi-layer inversions in Sichuan Basin and their influences on air pollution[J]. China environmental science, 2021,41(3):1005-1013.
[6] 四川省生态环境厅.2020年各市(州)环境空气质量通报[EB/OL]. http://sthjt.sc.gov.cn/sthjt/c104150/2021/1/21/e5b8dc576f1e4ba1a071b2ca46711cdd.shtml/2021-01-22. Department of Ecology and Environment of Sichuan Province. Environmental Air Quality Bulletin of Cities (States) in 2020[EB/OL]. http://sthjt.sc.gov.cn/sthjt/c104150/2021/1/21/e5b8dc576f1e4ba1a071b2ca46711cdd.shtml/2021-01-22.
[7] Wang H, Tian M, Chen Y, et al. Seasonal characteristics, formation mechanisms and source origins of PM2.5 in two megacities in Sichuan Basin, China[J]. Atmospheric Chemistry and Physics, 2018,18(2):865-881.
[8] Zhang J, Huang X, Wang Y, et al. Characterization, mixing state, and evolution of single particles in a megacity of Sichuan Basin, southwest China[J]. Atmospheric Research, 2018,209:179-187.
[9] 刘琴,张军科,黄小娟,等.成都春季气溶胶理化性质及不同时段污染特征[J]. 中国环境科学, 2019,39(12):5009-5017.Liu Q, Zhang J K, Huang X J, et al. The physicochemical properties of aerosol and its pollution characteristics in different periods in spring in Chengdu[J]. China environmental science, 2019,39(12):5009-5017.
[10] 李欣悦,张凯山,武文琪,等.成都市城区大气细颗粒物水溶性离子污染特征[J]. 中国环境科学, 2021,41(1):91-101.Li X Y, Zhang K S, Wu W Q, et al. Characterization of water-soluble ions pollution of atmospheric fine particles in Chengdu city[J]. China environmental science, 2021,41(1):91-101.
[11] 李培荣,肖天贵.成都地区秋冬季污染天气形势下PM2.5的扩散与输送[J]. 中国环境科学, 2020,40(1):63-75.Li P R, Xiao T G. The diffusion and transport of PM2.5 under the polluted weather conditions during autumn and winter seasons in Chengdu[J]. China environmental science, 2020,40(1):63-75.
[12] 许艳玲,易爱华,薛文博.基于模型模拟的成都市PM2.5污染来源解析[J]. 环境科学, 2020,41(1):50-56.Xu Y L, Yi A H, Xue W B. Modeling studies of source contributions to PM2.5 in Chengdu, China[J]. Environmental Science, 2020,41(1):50-56.
[13] Xu L, Lingaswamy A P, Zhang Y, et al. Morphology, composition, and sources of individual aerosol particles at a regional background site of the YRD, China[J]. Journal of environmental sciences (China), 2019, 77(3).
[14] Zhang J, Liu L, Wang Y, et al. Chemical composition, source, and process of urban aerosols during winter haze formation in Northeast China[J]. Environmental Pollution, 2017,231(5):357-366.
[15] Xu L, Zhang D, Li W. Microscopic comparison of aerosol particles collected at an urban site in North China and a coastal site in Japan[J]. Science of The Total Environment, 2019,669:948-954.
[16] 成都市统计局.统计年鉴2020[EB/OL]. http://cdstats.chengdu.gov.cn/tjgzxxw/xhtml/tjxx_content.html?id=333304&channel=?0201_02010923/2021-02-07. Statistic Bureau of Chengdu. Chengdu statistical yearbook 2020[EB/OL]. http://cdstats.chengdu.gov.cn/tjgzxxw/xhtml/tjxx_content.html?id=333304&channel=?0201_02010923/2021-02-07.
[17] 中华人民共和国生态环境部.中国移动源环境管理公报(2020年)[EB/OL]. http://www.mee.gov.cn/hjzl/sthjzk/ydyhjgl/2020-08-10. Ministry of Ecology and Environment of the People's Republic of China. China mobile source environmental management annual report (2020)[R].
[18] Pratt K A, Prather K A. Aircraft measurements of vertical profiles of aerosol mixing states[J]. Journal of Geophysical Research, 2010, 115(D11).
[19] Li W, Shao L, Zhang D, et al. A review of single aerosol particle studies in the atmosphere of East Asia:Morphology, mixing state, source, and heterogeneous reactions[J]. Journal of Cleaner Production, 2016,112(JAN. 20PT. 2):1330-1349.
[20] Laskin A, Iedema M J, Ichkovich A, et al. Direct observation of completely processed calcium carbonate dust particles[J]. Faraday Discuss, 2005,130:453-468.
[21] Fu H, Zhang M, Li W, et al. Morphology, composition and mixing state of individual carbonaceous aerosol in urban Shanghai[J]. Atmospheric Chemistry and Physics, 2011,11(2):20973-21011.
[22] Li W, Zhou S, Wang X, et al. Integrated evaluation of aerosols from regional brown hazes over northern China in winter:Concentrations, sources, transformation, and mixing states[J]. Journal of Geophysical Research:Atmospheres, 2011,116(D9).
[23] GB 3095-2012环境空气质量标准[S].GB 3095-2012 Ambient air quality standards[S].
[24] Xu L, Fukushima S, Sobanska S, et al. Tracing the evolution of morphology and mixing state of soot particles along with the movement of an Asian dust storm[J]. Atmospheric Chemistry and Physics, 2020,20(22):14321-14332.
[25] Zhang Y, Yuan Q, Huang D, et al. Direct observations of fine primary particles from residential coal burning:insights into their morphology, composition, and hygroscopicity[J]. Journal of Geophysical Research:Atmospheres, 2018,123(22).
[26] Sun J, Liu L, Xu L, et al. Key role of nitrate in phase transitions of urban particles:implications of important reactive surfaces for secondary aerosol formation[J]. Journal of Geophysical Research:Atmospheres, 2018,123(2):1234-1243.
[27] Lesins G, Chylek P, Lohmann U. A study of internal and external mixing scenarios and its effect on aerosol optical properties and direct radiative forcing[J]. Journal of Geophysical Research:Atmospheres, 2002,107(D10):AAC-1-AAC 5-12.
基金
国家自然科学基金项目资助项目（41805095）；四川省科技计划重点研发项目（2019YFS0476）
PDF(3331 KB)
京公网安备 11010802030352号 
