UV-VIS-NIR spectral optical properties of soot and soot-containing aerosols

Schnaiter, M.; Horváth, H.; Möhler, Ottmar; Naumann, K.‐H.; Saathoff, H.; Schöck, O.W.

doi:10.1016/s0021-8502(03)00361-6

Cited by 445 publications

(366 citation statements)

References 35 publications

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“…where E(m) λ is the soot absorption refractive index function (21)(22)(23)(24)(25)(26) and F sa * is the ratio of the light scattering to light absorption by the plume. As discussed in ref 12 it necessary to consider both out-scattering and in-scattering in the calculation of F sa * .…”

Section: Introductionmentioning

confidence: 99%

Quantitative Field Measurement of Soot Emission from a Large Gas Flare Using Sky-LOSA

Johnson

Devillers

Thomson

2010

Environ. Sci. Technol.

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Particulate matter emissions from unconfined sources such as gas flares are extremely difficult to quantify, yet there is a significant need for this measurement capability due to the prevalence and magnitude of gas flaring worldwide. Current estimates for soot emissions from flares are rarely, if ever, based on any form of direct data. A newly developed method to quantify the mass emission rate of soot from flares is demonstrated on a large-scale flare at a gas plant in Uzbekistan, in what is believed to be the first in situ quantitative measurement of soot emission rate from a gas flare under field conditions. The technique, named sky-LOSA, is based on line-of-sight attenuation of skylight through a flare plume coupled with image correlation velocimetry. Monochromatic plume transmissivities were measured using a thermoelectrically cooled scientific-grade CCD camera. Plume velocities were separately calculated using image correlation velocimetry on high-speed movie data. For the flare considered, the mean soot emission rate was determined to be 2.0 g/s at a calculated uncertainty of 33%. This emission rate is approximately equivalent to that of 500 buses driving continuously and equates to approximately 275 trillion particles per second. The environmental impact of large, visibly sooting flares can be quite significant.

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Section: Introductionmentioning

confidence: 99%

Quantitative Field Measurement of Soot Emission from a Large Gas Flare Using Sky-LOSA

Johnson

Devillers

Thomson

2010

Environ. Sci. Technol.

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“…25 When the true BC AAE is in doubt, one can alternatively investigate BC AAE by measuring the absorption of BC particles in the atmosphere, which turns out to be more challenging. BC AAE has been empirically estimated in numerous studies (e.g., Schnaiter et al, 2003;Kirchstetter et al, 2004;Bahadur et al, 2012;Chung et al, 2012). Schnaiter et al (2003) found diesel soot to have an AAE of 1.1 and Palas soot to have an AAE of 2.1.…”

mentioning

confidence: 99%

“…BC AAE has been empirically estimated in numerous studies (e.g., Schnaiter et al, 2003;Kirchstetter et al, 2004;Bahadur et al, 2012;Chung et al, 2012). Schnaiter et al (2003) found diesel soot to have an AAE of 1.1 and Palas soot to have an AAE of 2.1. Even if different soot particles would have different 30 AAE values, the difference between 1.1 and 2.1 is quite significant.…”

mentioning

confidence: 99%

The Absorption Ångström Exponent of black carbon: from numerical aspects

Liu¹,

Chung²,

Yin³

2017

Preprint

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Abstract. The Absorption Ångström Exponent (AAE) is an important aerosol optical parameter used for aerosol 10 characterization and apportionment studies. The AAE of black carbon (BC) is widely accepted to be 1.0, although observational estimates give a quite wide range of 0.6~1.1. With considerable uncertainties related to observations, a numerical study is a powerful method, if not the only one, to provide a better and more accurate understanding on BC AAE.This study calculates BC AAE using realistic particle geometries based on fractal aggregate and an accurate numerical optical model (namely the Multiple-Sphere T-Matrix method). At odds with the expectations, BC AAE is not 1.0, even when 15 BC is assumed to have small sizes and a wavelength independent refractive index. With a wavelength independent refractive index, the AAE of fresh BC is approximately 1.05, and is quite insensitive to particle size distribution. BC AAE goes lower when BC particles are aged (compact structures or coated by other scattering materials). For coated BC, we prescribed the coating thickness distribution based on a published experimental study, where smaller BC cores were shown to develop thicker coating than bigger BC cores. Both Compact and Coated BC the AAE ranges, at realistic particle sizes. For both 20Compact and Coated BC, the AAE is highly sensitive to particle size distribution, ranging from approximately 0.8 to 1.0 for relatively large BC with wavelength-independent refractive index. When the refractive index is allowed to vary with wavelength, a feature with observational backing, the BC AAE shows a much wider range. We propose that the presented results herein serve as a comprehensive guide for the response of BC AAE to BC size, refractive index, and geometry.

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“…Much lesser values of the albedo have been observed by Schnaiter. [12] on diesel soot but with lesser particle diameter Dpp (27nm).…”

Section: Dimensionless Soot Extinction Coefficient K Ementioning

confidence: 92%

“…Recently, Schnaiter et al [12] have found 7 m 2 /g and 5m 2 /g respectively at 632 and 1064 nm for diesel soot. This is less than the previous results, and this can be explained by the formation process which are very different in a diesel engine and in over-ventilated flames produced at atmospheric pressure.…”

Section: Measurement Of Mass Specific Extinction Coefficientmentioning

confidence: 97%

Measurement of the Mass Specific Extinction Coefficient of Acetylene, Toluene and Polymethyl Methacrylate Soot Particles in Visible and Near-Infrared Wavelengths

Ouf¹,

Coppalle²,

Yon³

et al. 2008

Fire Saf. Sci.

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An experimental set-up has been developed to determine the mass specific σ s and the dimensionless extinction K t coefficients of soot particles at visible (632 nm) and near-infrared (1064 nm) wavelengths. Near-infrared measurements have been carried out with a multiple-path extinction cell to increase the measurement accuracy. The extinction coefficient K ext has been analysed as a function of the mass concentration, measured by a Tapered Element Oscillating Microbalance (TEOM 1105 R&P) in order to retrieve the soot mass specific extinction coefficient, σ e , in the smoke plume of acetylene, toluene and PolyMethyl MethAcrylate (PMMA) burning under turbulent, well-ventilated and small-scale conditions.

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UV-VIS-NIR spectral optical properties of soot and soot-containing aerosols

Cited by 445 publications

References 35 publications

Quantitative Field Measurement of Soot Emission from a Large Gas Flare Using Sky-LOSA

Quantitative Field Measurement of Soot Emission from a Large Gas Flare Using Sky-LOSA

The Absorption Ångström Exponent of black carbon: from numerical aspects

Measurement of the Mass Specific Extinction Coefficient of Acetylene, Toluene and Polymethyl Methacrylate Soot Particles in Visible and Near-Infrared Wavelengths

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