Trans-spectral absorption and scattering of electromagnetic radiation by diesel soot

Bruce, Charles W.; Stromberg, Thor F.; Gurton, Kristan P.; Mozer, J. B.

doi:10.1364/ao.30.001537

Cited by 68 publications

(42 citation statements)

References 25 publications

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“…The result of 10.9 obtained by the integrating plate technique was also calibrated by using photoacoustic spectroscopy (Szkarlat and Japar 1983). The reported values range from 17 m 2 /g at 416.6 nm for soot generated by a propane ame (Truex and Anderson 1979) to 4.55 m 2 /g at 488 nm for open combustion of diesel soot in air (Bruce et al 1991). Although these values represent different kinds of soot and span a wide range of results, their average value of 9.8 m 2 /g agrees well with the value of 10.5 m 2 /g obtained at the center of the sphere.…”

Section: Resultsmentioning

confidence: 99%

An Empirical Method for the Determination of the Complex Refractive Index of Size-Fractionated Atmospheric Aerosols for Radiative Transfer Calculations

Marley¹,

Gaffney²,

Baird³

et al. 2001

Aerosol Science and Technology

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To adequately assess the effects of atmospheric aerosols on climate, their optical constants (scattering and absorption coef cients) must be known. The absorption and scattering coef cients of the aerosols are derived from the real and imaginary parts of the complex refractive index and are dependent on their size and chemical composition. Because aerosol properties vary signi cantly with location, it is dif cult to assign values for the absorption and scattering of solar radiation by aerosols in models of global climate change. This study reports a new method of collecting size-fractionated atmospheric aerosol samples for the purpose of directly measuring their transmission and re ectance spectra followed by the determination of the complex refractive index across the entire atmospherically relevant spectral range. The samples were collected with a modi ed Sierra high-volume cascade impactor with the usual lter collection surfaces replaced with Te on sheets machined to hold quartz (ultraviolet [UV]/visible transparent) and/or silver chloride (infrared transparent) sample collection plates. Re ectance and transmission spectra can be obtained on the aerosol samples directly as a function of wavelength, from 280 nm to 2.5 m, with an integrating sphere coupled to an UV/visible or a Fourier transform infrared (FTIR) spectrophotometer. The effective real and imaginary components of the refractive index of the bulk sample material can then be approximated, as a function of wavelength, from the sample spectra. Preliminary results are presented for carbon soot samples generated in the laboratory and for standard diesel soot samples in the UV/visible spectral range. These are compared to results obtained for size-fractionated atmospheric aerosol samples collected near Pasco, WA, West Mesa, AZ, and Argonne, IL.

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Section: Resultsmentioning

confidence: 99%

An Empirical Method for the Determination of the Complex Refractive Index of Size-Fractionated Atmospheric Aerosols for Radiative Transfer Calculations

Marley¹,

Gaffney²,

Baird³

et al. 2001

Aerosol Science and Technology

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“…To compare the instruments, the MAAP B abs measurement is converted to 870 nm assuming an inverse wavelength relationship, which has been observed for BC-containing particles in previous studies (i.e., B abs = Cλ −1 , where C is a dimensionless proportionality constant) (Bruce et al 1991;Horvath et al 1997;Bergstrom et al 2002;Sheridan et al 2005). Figure 6 is a plot of the MAAP B abs versus the PAS B abs for GC spheres.…”

Section: Comparison Of Maap To Pasmentioning

confidence: 99%

An Inter-Comparison of Instruments Measuring Black Carbon Content of Soot Particles

Slowik

Cross

Han

et al. 2007

Aerosol Science and Technology

288

245

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Inter-comparison studies of well-characterized fractal soot particles were conducted using the following four instruments: Aerosol Mass Spectrometer-Scanning Mobility Particle Sizer (AMS-SMPS), Single Particle Soot Photometer (SP2), Multi-Angle Absorption Photometer (MAAP), and Photoacoustic Spectrometer (PAS). These instruments provided measurements of the refractory mass (AMS-SMPS), incandescent mass (SP2) and optically absorbing mass (MAAP and PAS). The particles studied were in the mobility diameter range from 150 nm to 460 nm and were Address correspondence to P. Davidovits, Chemistry Department, Boston College, Merkert Chemistry Center 223, 140 Commonwealth Avenue, Chestnut Hill, MA 02467, USA. E-mail: paul.davidovits@ bc.edu generated by controlled flames with fuel equivalence ratios ranging between 2.3 and 3.5. The effect of organic coatings (oleic acid and anthracene) on the instrument measurements was determined. For uncoated soot particles, the mass measurements by the AMS-SMPS, SP2, and PAS instruments were in agreement to within 15%, while the MAAP measurement of optically-absorbing mass was higher by ∼50%. Thin organic coatings (∼10 nm) did not affect the instrument readings. A thicker (∼50 nm) oleic acid coating likewise did not affect the instrument readings. The thicker (∼60 nm) anthracene coating did not affect the readings provided by the AMS-SMPS or SP2 instruments but increased the reading of the MAAP instrument by ∼20% and the reading of the PAS by ∼65%. The response of each instrument to the different particle types is discussed in terms of particle morphology and coating material.

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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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Trans-spectral absorption and scattering of electromagnetic radiation by diesel soot

Cited by 68 publications

References 25 publications

An Empirical Method for the Determination of the Complex Refractive Index of Size-Fractionated Atmospheric Aerosols for Radiative Transfer Calculations

An Empirical Method for the Determination of the Complex Refractive Index of Size-Fractionated Atmospheric Aerosols for Radiative Transfer Calculations

An Inter-Comparison of Instruments Measuring Black Carbon Content of Soot Particles

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

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