Detailed Characterization of Morphology and Dimensions of Diesel Particulates via Thermophoretic Sampling

Lee, Kyeong Ook; Cole, R. L.; Sekar, R.; Choi, Mijin; Zhu, Jingyi; Kang, Jae-Hoon; Bae, Choongsik

doi:10.4271/2001-01-3572

Cited by 103 publications

(43 citation statements)

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“…This usually meant that particles on the ends of fractal chains were selected as opposed to those in the center of the agglomerates. Previous work on flame-generated agglomerates has shown that the primary particle diameters follow a normal distribution with a mean between 28.5 and 34.4 nm (Koylu and Faeth, 1992;Lee et al, 2001). Figure 2.…”

Section: Morphology Of Freshly Emitted Biomass Burning Aerosolmentioning

confidence: 90%

Experimentally measured morphology of biomass burning aerosol and its impacts on CCN ability

2015

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Abstract. This study examines the morphological properties of freshly emitted and atmospherically aged aerosols from biomass burning. The impacts of particle morphology assumptions on hygroscopic predictions are examined. Chamber experiments were conducted at the University of California, Riverside, Center for Environmental Research and Technology (CE-CERT) atmospheric processes lab using two biomass fuel sources: manzanita and chamise. Morphological data was obtained through the use of an aerosol particle mass analyzer (APM), scanning mobility particle sizer (SMPS) system and transmission electron microscope (TEM). Data from these instruments was used to calculate both a dynamic shape factor and a fractal-like dimension for the biomass burning emissions. This data was then used with κ-Köhler theory to adjust the calculated hygroscopicity for experimentally determined morphological characteristics of the aerosol. Laboratory measurement of biomass burning aerosol from two chaparral fuels show that particles are nonspherical with dynamic shape factors greater than 1.15 for aerosol sizes relevant to cloud condensation nuclei (CCN) activation. Accounting for particle morphology can shift the hygroscopicity parameter by 0.15 or more. To our knowledge, this work provides the first laboratory chamber measurements of morphological characteristics for biomass burning cloud condensation nuclei and provides experimental particle shape evidence to support the variation in reported hygroscopicities of the complex aerosol.

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Section: Morphology Of Freshly Emitted Biomass Burning Aerosolmentioning

confidence: 90%

Experimentally measured morphology of biomass burning aerosol and its impacts on CCN ability

2015

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“…The shape of the low-OC and high-OC particles differs notably. The primary soot particle size has been reported to vary depending on engine operating conditions, injector type, and injector conditions but most primary particles sizes range from 20 to 70 nm (Bruce et al, 1991;Lee et al, 2001). These morphological characteristics of soot agglomerates reflect the size of the primary soot particles as well as the OC concentration of the particles collected and observed.…”

Section: Morphological Characteristics Of Collected Particlesmentioning

confidence: 99%

Characteristics of Atmospheric Elemental Carbon (Char and Soot) in Ultrafine and Fine Particles in a Roadside Environment, Japan

Kim

Sekiguchi

Kudo

et al. 2011

Aerosol Air Qual. Res.

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Atmospheric carbonaceous components, particularly char and soot in ultrafine particles (UFPs; Dp < 0.1 μm) and fine particles (FPs; Dp < 2.5 μm), were measured four times during one year in Saitama City, Japan, to observe the concentrations of elemental carbon (EC) and the relationship between the EC concentrations in UFPs and FPs, and to examine the possible emission sources of char and soot that constitute UFPs and FPs in a roadside environment. It was found that EC accounts for 33-37% of total carbon (TC) in FPs, whereas EC accounts for 12-20% of TC in UFPs. Both char-EC and soot-EC account for similar proportions of the total EC concentration in UFPs, while soot-EC accounts for only a small amount of the total EC in FPs. Positive and negative correlations between OC and soot-EC were observed for UFPs and FPs, respectively. The observed positive correlation in the case of UFPs possibly reflects the compactness (high density) of UFPs coated with condensed material, such as unburned fuel or lubricating oil emitted by motor vehicles, whereas the negative correlation in the case of FPs possibly indicates that whether or not the spaces between primary soot particles in FPs can be filled depends on the engine load of diesel vehicles operated near the sampling site. The positive and negative correlations were stronger for UFPs (r 2 = 0.69, n = 29, p < 0.001) and FPs (r 2 = -0.62, n = 29, p < 0.001) when the data collected at wind speeds greater than 2.5 m/s were excluded. The different morphological characteristics of the particles observed by transmission electron microscopy also support the observed correlations between OC and soot-EC. The possible emission of char or char-like particles from motor vehicles was shown and discussed in this study.

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“…The effect of engine operating conditions on the particle size and nanostructure was studied by numerous research groups (Zhu et al, 2005;Lapuerta et al, 2007;Lee et al, 2011). Stevenson, 1982 investigated the morphology and crystallography of DPM.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Morphological Study of Primary and Aged Particles Emitted from a Biodiesel (B20) vis-à;-vis Diesel Fuelled CRDI Engine

Shukla

Gupta

Agarwal

2014

Aerosol Air Qual. Res.

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A comparative morphological analysis was performed on the exhaust particles emitted from a common rail direct injection (CRDI) sports utility vehicle (SUV) engine for primary and aged particulates. In this study, soot particles were collected from the CRDI engine fuelled with mineral diesel and 20% biodiesel blend (B20). The engine was operated at a constant speed of 1800 rpm for five different loads (0%, 25%, 50%, 75%, 100% rated load) for primary and aged particulate collection. Primary particulate samples were collected on pre-conditioned quartz filter papers from the exhaust stream after partial dilution. For collection of aged particles, the diluted exhaust was passed through a customized photochemical chamber with 2 hour retention time. This allowed photochemical reactions to proceed in presence of ultraviolet light leading to particulate aging in simulated daylight conditions and particulates were collected downstream of the photochemical chamber. Particulate laden filters were observed by scanning electron microscopy (SEM). It was observed that B20 emitted significantly lower primary particulates in comparison to mineral diesel for all the loads. B20 emitted lower particulates at lower load conditions for aged samples. At higher engine loads (75% and 100%), this reduction in aged particulates for B20 compared to mineral diesel was quite significant.

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Detailed Characterization of Morphology and Dimensions of Diesel Particulates via Thermophoretic Sampling

Cited by 103 publications

References 1 publication

Experimentally measured morphology of biomass burning aerosol and its impacts on CCN ability

Experimentally measured morphology of biomass burning aerosol and its impacts on CCN ability

Characteristics of Atmospheric Elemental Carbon (Char and Soot) in Ultrafine and Fine Particles in a Roadside Environment, Japan

A Comparative Morphological Study of Primary and Aged Particles Emitted from a Biodiesel (B20) vis-à;-vis Diesel Fuelled CRDI Engine

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