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DOI	10.5194/acp-20-5771-2020
	Mixing characteristics of refractory black carbon aerosols at an urban site in Beijing
	Liu H.; Pan X.; Liu D.; Liu X.; Chen X.; Tian Y.; Sun Y.; Fu P.; Wang Z.
发表日期	2020
ISSN	1680-7316
起始页码	5771
结束页码	5785
卷号	20 期号:9
英文摘要	Black carbon aerosols play an important role in climate change because they directly absorb solar radiation. In this study, the mixing state of refractory black carbon (rBC) at an urban site in Beijing in the early summer of 2018 was studied with a single-particle soot photometer (SP2) as well as a tandem observation system with a centrifugal particle mass analyzer (CPMA) and a differential mobility analyzer (DMA). The results demonstrated that the mass-equivalent size distribution of rBC exhibited an approximately lognormal distribution with a mass median diameter (MMD) of 171 nm. When the site experienced prevailing southerly winds, the MMD of rBC increased notably, by 19 %. During the observational period, the ratio of the diameter of rBC-containing particles (Dp) to the rBC core (Dc) was 1.20 on average for Dc D 180 nm, indicating that the majority of rBC particles were thinly coated. The Dp=Dc value exhibited a clear diurnal pattern, with a maximum at 14:00 LST and a D p growth rate of 2.3 nm h-1; higher Ox conditions increased the coating growth rate. The microphysical properties of rBC were also studied. Bare rBC particles were mostly found in fractal structures with a mass fractal dimensions (Dfm) of 2.35, with limited variation during both clean and polluted periods. The morphology of rBC changed with coating thickness increasing. When the mass ratio of nonrefractory matter to rBC (MR) was <1.5, rBC-containing particles were primarily found in external fractal structures, and they changed to a core-shell structure when MR>6, at which point the measured scattering cross section of rBC-containing particles was consistent with that based on the Mie-scattering simulation. We found that only 28 % of the rBC-containing particles were in core-shell structures with a particle mass of 10 fg in the clean period but that proportion increased considerably, to 45 %, in the polluted period. Due to the morphology change, the absorption enhancement (Eabs) was 12 % lower than that predicted for core-shell structures. © 2020 Author(s).
语种	英语
scopus关键词	aerosol; black carbon; climate effect; climate forcing; computer simulation; Mie theory; mixing; numerical model; photometer; size distribution; urban atmosphere; Beijing [Beijing (ADS)]; Beijing [China]; China
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/247781
作者单位	State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China; College of Earth Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China; Department of Atmospheric Sciences, School of Earth Sciences, Zhejiang University, Hangzhou, Zhejiang, 310027, China; Center for Excellence in Regional Atmospheric Environment, Chinese Academy of Science, Xiamen, 361021, China; Institute of Surface-Earth System Science, Tianjin University, Tianjin, 300072, China
推荐引用方式 GB/T 7714	Liu H.,Pan X.,Liu D.,et al. Mixing characteristics of refractory black carbon aerosols at an urban site in Beijing[J],2020,20(9).
APA	Liu H..,Pan X..,Liu D..,Liu X..,Chen X..,...&Wang Z..(2020).Mixing characteristics of refractory black carbon aerosols at an urban site in Beijing.ATMOSPHERIC CHEMISTRY AND PHYSICS,20(9).
MLA	Liu H.,et al."Mixing characteristics of refractory black carbon aerosols at an urban site in Beijing".ATMOSPHERIC CHEMISTRY AND PHYSICS 20.9(2020).