A study of the morphology and effective density of externally mixed black carbon aerosols in ambient air using a size-resolved single-particle soot photometer (SP2)

doi:10.5194/amt-12-4347-2019

IEECAS OpenIR > 粉尘与环境研究室

	A study of the morphology and effective density of externally mixed black carbon aerosols in ambient air using a size-resolved single-particle soot photometer (SP2)
	Wu, Yunfei 1; Xia, Yunjie 1,2; Huang, Rujin 3; Deng, Zhaoze 4; Tian, Ping 5; Xia, Xiangao 4; Zhang, Renjian 1
通讯作者	Wu, Yunfei(wuyf@mail.iap.ac.cn) ; Zhang, Renjian(zrj@mail.iap.ac.cn)
	2019-08-12
发表期刊	ATMOSPHERIC MEASUREMENT TECHNIQUES
ISSN	1867-1381
卷号	12 期号:8 页码:4347-4359
摘要	The morphology and effective density of externally mixed black carbon (extBC) aerosols, important factors affecting the radiative forcing of black carbon, were studied using a tandem technique coupling a differential mobility analyzer (DMA) with a single-particle soot photometer (SP2). The study extended the mass-mobility relationship to large extBC particles with a mobility diameter (d(mob)) larger than 350 nm, a size range seldom included in previous tandem measurements of BC aggregates in the atmosphere. The experiment was conducted at an urban site in Beijing during a 19 d winter period from 23 January to 10 February 2018. Ambient dry particles were selected by the DMA, and the size-resolved extBC particles were distinguished from particles with a thick coating (internally mixed) according to the time delay between the incandescence signal peak and the scattering peak detected by the SP2. The masses of the extBC particles were then quantified. The time differences between the DMA size selection and the SP2 measurement were processed previously. The normalized number size distributions were investigated at the prescribed d(mob) sizes in the range of 140-750 nm to provide the typical mass of extBC at each d(mob). On this basis, the mass-mobility relationship of the ambient extBC was established, inferring a mass-mobility scaling exponent (D-fm) (an important quantity for characterizing the morphology of fractal-like BC aggregates) with a value of 2.34 +/- 0.03 in the mobility range investigated in this study. This value is comparable with those of diesel exhaust particles, implying a predominant contribution of vehicle emissions to the ambient extBC in urban Beijing. Compared to the clean period, a higher D-fm value was observed in the polluted episode, indicating a more compact BC aggregate structure than that in the clean period. The effective densities (rho(eff)) of the extBC in the same d(mob) range were also derived, with values gradually decreasing from 0.46 g cm(-3) at 140 nm mobility to 0.14 g cm(-3) at 750 nm mobility. The rho(eff) values were slightly lower than those measured using the DMA-aerosol particle mass analyzer (APM) system. The difference in rho(eff) values was likely due to the lower BC masses determined by the SP2 compared to those measured by the APM at the same mobility, since the SP2 measured the refractory BC (rBC) mass instead of the total mass of the BC aggregate, which consists of both rBC and a possible fraction of nonrefractory components measured by the APM. The rho(eff) values in the 280-350 nm d(mob) range were much closer to the values for soot aggregates reported in the literature. It might be related to the more compact structure of BC aggregates in this range, resulting from the reconstruction effect by volatile and/or semivolatile components in the atmosphere. The reconstruction effect might also result in a hiatus in the increased dynamic shape factor in the range of 200-350 nm, which presented an overall increase from 2.16 to 2.93 in the 140-750 nm d(mob) range.
DOI	10.5194/amt-12-4347-2019
关键词[WOS]	DIFFERENTIAL MOBILITY ANALYZER ; WINTER HAZE EPISODES ; MIXING STATE ; LIGHT-ABSORPTION ; DIESEL EXHAUST ; SOURCE APPORTIONMENT ; OPTICAL-PROPERTIES ; MASS ; PM2.5 ; AMPLIFICATION
收录类别	SCI ; SCI
语种	英语
资助项目	National Key Research and Development Program of China[2017YFC0209601] ; National Key Research and Development Program of China[2017YFC0212701] ; National Natural Science Foundation of China[41575150] ; National Natural Science Foundation of China[41775155] ; National Natural Science Foundation of China[91644217] ; National Natural Science Foundation of China[91644219]
WOS研究方向	Meteorology & Atmospheric Sciences
项目资助者	National Key Research and Development Program of China ; National Natural Science Foundation of China
WOS类目	Meteorology & Atmospheric Sciences
WOS记录号	WOS:000480463400001
出版者	COPERNICUS GESELLSCHAFT MBH
引用统计	被引频次：19[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.ieecas.cn/handle/361006/13608
专题	粉尘与环境研究室
通讯作者	Wu, Yunfei; Zhang, Renjian
作者单位	1.Chinese Acad Sci, Inst Atmospher Phys, Key Lab Reg Climate Environm Temperate East Asia, Beijing 100029, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Chinese Acad Sci, Inst Earth & Environm, Key Lab Aerosol Chem & Phys, State Key Lab Loess & Quaternary Geol, Xian 710061, Shaanxi, Peoples R China 4.Chinese Acad Sci, Inst Atmospher Phys, Key Lab Middle Atmosphere & Global Environm Obser, Beijing 100029, Peoples R China 5.Beijing Weather Modificat Off, Beijing 100089, Peoples R China
推荐引用方式 GB/T 7714	Wu, Yunfei,Xia, Yunjie,Huang, Rujin,et al. A study of the morphology and effective density of externally mixed black carbon aerosols in ambient air using a size-resolved single-particle soot photometer (SP2)[J]. ATMOSPHERIC MEASUREMENT TECHNIQUES,2019,12(8):4347-4359.
APA	Wu, Yunfei.,Xia, Yunjie.,Huang, Rujin.,Deng, Zhaoze.,Tian, Ping.,...&Zhang, Renjian.(2019).A study of the morphology and effective density of externally mixed black carbon aerosols in ambient air using a size-resolved single-particle soot photometer (SP2).ATMOSPHERIC MEASUREMENT TECHNIQUES,12(8),4347-4359.
MLA	Wu, Yunfei,et al."A study of the morphology and effective density of externally mixed black carbon aerosols in ambient air using a size-resolved single-particle soot photometer (SP2)".ATMOSPHERIC MEASUREMENT TECHNIQUES 12.8(2019):4347-4359.