Nonlinear Enhancement of Radiative Absorption by Black Carbon in Response to Particle Mixing Structure

Abstract

Global models estimate the effects of BC absorption based on its mass concentration, size distribution, particle morphology, and mixing structures of BC particles (Ramanathan & Carmichael, 2008;Riemer et al., 2019). Experimental evidence showed that the absorption enhancement, induced by mixing of BC with other nonabsorbing secondary aerosols, can be less than 1.05 (Cappa et al., 2012;Healy et al., 2015) or as large as 2. 4 (Peng et al., 2016). Furthermore, absorption enhancement obtained using the core-shell Mie theory based on BC coating thickness measured by single particle soot photometer (SP2) or soot particle-aerosol mass spectrometer (SP-AMS) is ∼14%-150% larger than the directly measured ones in field campaigns (

Quantifying the Fractal Dimension and Morphology of Individual Atmospheric Soot Aggregates

“…It should be noted that the method has been well used in Wang, Li, et al. (2021) through the volume proportion of BC embedded in coating. Based on the TEM/EDS, we simply classified the soot particles into three types: Bare‐like, partly coated, and embedded.…”

“…The 3D soot numerical models are generated from a tunable algorithm (Filippov et al., 2000) and one EMBS developed by Wang, Li, et al. (2021) based on the D f of soot particles and the numbers and sizes of monomers.…”

“…(2000) and the detailed information about how to construct the soot models is described by Wang, Li, et al. (2021) and Wang, Pang, et al. (2021).…”

Identifying the Fraction of Core–Shell Black Carbon Particles in a Complex Mixture to Constrain the Absorption Enhancement by Coatings

“…The method in identifying the fraction of the BC population with different degrees of sphericity is however independent of wavelengths, which can be applied to estimate E abs at other wavelengths. A recent study 35 found that E abs was nonlinearly related to the amounts of coatings but was importantly determined by the extent to which the BC was embedded in coatings. This may be essentially related to the particle shape distribution measured here, as embedded BC particles by coatings tend to be more spherical.…”

Significant Contribution of Coarse Black Carbon Particles to Light Absorption in North China Plain

“…The scanning/transmission electron microscope (SEM/TEM) can also be used to determine the aerosol size and mixing states. Although it is difficult to analyze the particle continuously, it is an ideal technique to obtain the detailed mixing structure of aerosol species for individual particles. − …”