气候变化领域集成服务门户(CCPortal): Droplet activation behaviour of atmospheric black carbon particles in fog as a function of their size and mixing state

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DOI	10.5194/acp-19-2183-2019
	Droplet activation behaviour of atmospheric black carbon particles in fog as a function of their size and mixing state
	Motos G.; Schmale J.; Corbin J.C.; Zanatta M.; Baltensperger U.; Gysel-Beer M.
发表日期	2019
ISSN	16807316
起始页码	2183
结束页码	2207
卷号	19 期号:4
英文摘要	Among the variety of particle types present in the atmosphere, black carbon (BC), emitted by combustion processes, is uniquely associated with harmful effects to the human body and substantial radiative forcing of the Earth. Pure BC is known to be non-hygroscopic, but its ability to acquire a coating of hygroscopic organic and inorganic material leads to increased diameter and hygroscopicity, facilitating droplet activation. This affects BC radiative forcing through aerosol-cloud interactions (ACIs) and BC life cycle. To gain insights into these processes, we performed a field campaign in winter 2015-2016 in a residential area of Zurich which aimed at establishing relations between the size and mixing state of BC particles and their activation to form droplets in fog. This was achieved by operating a CCN counter (CCNC), a scanning mobility particle sizer (SMPS), a single-particle soot photometer (SP2) and an aerosol chemical speciation monitor (ACSM) behind a combination of a total- and an interstitial-aerosol inlet. Our results indicate that in the morning hours of weekdays, the enhanced traffic emissions caused peaks in the number fraction of externally mixed BC particles, which do not act as CCN within the CCNC. The very low effective peak supersaturations (SS peak ) occurring in fog (between approximately 0.03% and 0.06% during this campaign) restrict droplet activation to a minor fraction of the aerosol burden (around 0.5% to 1% of total particle number concentration between 20 and 593nm) leading to very selective criteria on diameter and chemical composition. We show that bare BC cores are unable to activate to fog droplets at such low SS pea , while BC particles surrounded by thick coating have very similar activation behaviour to BC-free particles. Using simplified κ-Köhler theory combined with the ZSR mixing rule assuming spherical core-shell particle geometry constrained with single-particle measurements of respective volumes, we found good agreement between the predicted and the directly observed size- and mixing-state-resolved droplet activation behaviour of BC-containing particles in fog. This successful closure demonstrates the predictability of their droplet activation in fog with a simplified theoretical model only requiring size and mixing state information, which can also be applied in a consistent manner in model simulations. © 2019 Author(s).
语种	英语
scopus关键词	aerosol; black carbon; combustion; concentration (composition); droplet; fog; particle size; prediction; Acis
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/144631
作者单位	Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, 5232, Switzerland; Measurement Science and Standards, National Research Council Canada, 1200 Montreal Road, Ottawa, K1A 0R6, Canada; Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
推荐引用方式 GB/T 7714	Motos G.,Schmale J.,Corbin J.C.,et al. Droplet activation behaviour of atmospheric black carbon particles in fog as a function of their size and mixing state[J],2019,19(4).
APA	Motos G.,Schmale J.,Corbin J.C.,Zanatta M.,Baltensperger U.,&Gysel-Beer M..(2019).Droplet activation behaviour of atmospheric black carbon particles in fog as a function of their size and mixing state.Atmospheric Chemistry and Physics,19(4).
MLA	Motos G.,et al."Droplet activation behaviour of atmospheric black carbon particles in fog as a function of their size and mixing state".Atmospheric Chemistry and Physics 19.4(2019).