The impact of organic carbon on soot light absorption

Kelesidis, Georgios A.; Bruun, Christian A.; Pratsinis, Sotiris E.

doi:10.1016/j.carbon.2020.10.032

Cited by 44 publications

(24 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…LII measures the thermal emission emitted from soot particles heated by the Nd:YAG pulsed laser (usually 1064 nm) to temperatures in the range from 2500 K to 4500 K. The laser fluence is set to a value, which heats the soot particles below their sublimation threshold values (4000 K for BC) [44][45][46]. The LII is by default insensitive to liquid particles and metal salts, which vaporise during the heating, although some impact of OC coating of soot in LII response has been reported [47,48]. The size of the soot agglomerates may have an impact on the LII response, which needs to be taken into account in calibration of the LII signal to the BC concentration [49].…”

Section: Introductionmentioning

confidence: 99%

Suitability of Different Methods for Measuring Black Carbon Emissions from Marine Engines

et al. 2021

View full text Add to dashboard Cite

Black carbon (BC) emissions intensify global warming and are linked to adverse health effects. The International Maritime Organization (IMO) considers the impact of BC emissions from international shipping. A prerequisite for the anticipated limits to BC emissions from marine engines is a reliable measurement method. The three candidate methods (photoacoustic spectroscopy (PAS), laser-induced incandescence (LII), and filter smoke number (FSN)) selected by the IMO were evaluated with extensive ship exhaust matrices obtained by different fuels, engines, and emission control devices. A few instruments targeted for atmospheric measurements were included as well. The BC concentrations were close to each other with the smoke meters (AVL 415S and 415SE), PAS (AVL MSS), LII (Artium-300), MAAP 5012, aethalometers (Magee AE-33 and AE-42), and EC (TOA). In most cases, the standard deviation between instruments was in the range of 5–15% at BC concentrations below 30 mg Sm−3. Some differences in the BC concentrations measured with these instruments were potentially related to the ratio of light-absorbing compounds to sulphates or to particle sizes and morphologies. In addition, calibrations, sampling, and correction of thermophoretic loss of BC explained differences in the BC results. However, overall differences in the BC results obtained with three candidate methods selected by the IMO were low despite challenging exhaust compositions from marine diesel engines. Findings will inform decision making on BC emission control from marine engines.

show abstract

Section: Introductionmentioning

confidence: 99%

Suitability of Different Methods for Measuring Black Carbon Emissions from Marine Engines

et al. 2021

View full text Add to dashboard Cite

show abstract

“…This is due to the enhanced light scattering by the BC coating. 41 The SSA of BC agglomerates (solid line, light green-shaded area) is smaller than that of equivalent spheres (broken line, purple-shaded area) at m c /m = 1−10. This is attributed to the internal light scattering between the constituent primary particles of agglomerates that increases their light absorption (Figure S1) but reduces their external light scattering.…”

Section: Resultsmentioning

confidence: 99%

“…The MAC of bare BC spheres and agglomerates derived here at λ = 532 nm are interfaced with an absorption Angstrom exponent of 1.1 to estimate their MAC at λ = 550 nm accounting for the wavelength dependence of C-rich BC . Furthermore, the MAC c of coated BC is estimated directly from the MAC of emitted BC by a scaling law from DDA simulations: where m and m c are the mass of BC before and after coating with non-absorbing compounds, respectively.…”

Section: Methodsmentioning

confidence: 99%

Enhanced Light Absorption and Radiative Forcing by Black Carbon Agglomerates

Kelesidis

Neubauer

Fan

et al. 2022

Environ. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

The climate models of the Intergovernmental Panel on Climate Change list black carbon (BC) as an important contributor to global warming based on its radiative forcing (RF) impact. Examining closely these models, it becomes apparent that they might underpredict significantly the direct RF for BC, largely due to their assumed spherical BC morphology. Specifically, the light absorption and direct RF of BC agglomerates are enhanced by light scattering between their constituent primary particles as determined by the Rayleigh−Debye−Gans theory interfaced with discrete dipole approximation and recent relations for the refractive index and lensing effect. The light absorption of BC is enhanced by about 20% by the multiple light scattering between BC primary particles regardless of the compactness of their agglomerates. The resulting light absorption agrees very well with the observed absorption aerosol optical depth of BC. ECHAM-HAM simulations accounting for the realistic BC morphology and its coatings reveal high direct RF = 3−5 W/m 2 in East, South Asia, sub-Sahara, western Africa, and the Arabian peninsula. These results are in agreement with satellite and AERONET observations of RF and indicate a regional climate warming contribution by 0.75−1.25 °C, solely due to BC emissions.

show abstract

“…The three sets of curves represent different assumptions about particle density in Equation 8. In particular, the curves assume the density of mature soot, nascent (young) soot, or a maturity-dependent density based on the carbon/hydrogen-ratio (C/H) and parameterized by [74]. Although the parameterization of [74] assumed 𝐸 𝑔 = 0.25 eV for mature soot, we have extrapolated down to 0 eV for illustration.…”

Section: S17mentioning

confidence: 99%

“…In particular, the curves assume the density of mature soot, nascent (young) soot, or a maturity-dependent density based on the carbon/hydrogen-ratio (C/H) and parameterized by [74]. Although the parameterization of [74] assumed 𝐸 𝑔 = 0.25 eV for mature soot, we have extrapolated down to 0 eV for illustration. This parameterization may not be applicable for all flames discussed in the main text, and it does not predict the upper range of MACs reported in the main text.…”

Section: S17mentioning

confidence: 99%