Constructing Shapes and Mixing Structures of Black Carbon Particles With Applications to Optical Calculations

Geophysical Research Letters

Huang

et al. 2021

Self Cite

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 (

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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

Geophysical Research Letters

Huang

et al. 2021

Self Cite

“…The multiphase processes, condensation and coagulation of coating materials influenced the coating thickness and mixing state of BC particles in the atmosphere. And the mixing structure between BC coating and its core, coating shape and morphology of BC core directly influence the absorption enhancement of BC particles (Wang et al, 2021).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Effects of Volatile Components on Mixing State and Size Distribution of Individual Black Carbon Aerosols

et al. 2022

Aerosol Air Qual. Res.

In this study, the effects of different volatile components on the mixing state and size distribution of ambient individual black carbon (BC) aerosols were measured using thermo-denudation with single-particle soot photometry and single-particle aerosol mass spectrometry from September 9 to September 27, 2018, in Shanghai, China. The volatility, chemical composition, size distribution, and core-shell structure of BC aerosol were also analysed. To understand the influence of heating temperature on the BC core-shell structure, the mixing state of ageing particles at room temperature (25°C) and the mixing state of residual material heated to 150°C and 300°C were analysed. BC was internally mixed with secondary components, such as ammonium nitrate, ammonium sulphate, a small amount of sodium nitrate, potassium nitrate, sodium sulphate and potassium sulphate, and other nonvolatile components.At 300°C, the secondary components with low volatility escaped, resulting in a thinner BC coating. However, several low-volatile non-BC substances remained, namely organic species, potassium chloride, potassium nitrate, and other nonvolatile substances. The extremely strong photochemical reaction may have produced large amounts of secondary organic carbon on the BC surface in the afternoon, with the high temperature volatilising the whole particle. However, fresh BC particles emitted from traffic during morning rush hour had ultralow volatility, with relatively fewer low-volatile components on the surface.

“…A N U S C R I P T 4 2019; Wang et al, 2021). Accordingly, two important properties, morphology (including the overall size and shape factor) and density, will change along with the chemical mixing state of BC, which further leads to variations in their optical properties and radiative forcing.…”

Section: A C C E P T E D Mmentioning

confidence: 99%

“…Currently, the morphology of BC particle has been considered in climate model when investigating its direct effect due to its impact for the optical properties (China et al, 2013;Wu et al, 2016). Wang et al (2021) investigated the optical properties of BC particles based on TEM observations and highlighted that the morphology of BC core within the BC-containing particle and coating shape can influence optical properties and should be considered as important variables in climate models.…”

Section: A C C E P T E D Mmentioning

confidence: 99%

Measurement of Density and Shape for Single Black Carbon Aerosols in a Heavily Polluted Urban Area

Zhou

et al. 2021

Aerosol Air Qual. Res.

Black carbon (BC) aerosol imposes adverse effects on atmospheric visibility, climate, and health.The particle density and morphology are often needed to investigate the mixing state and aging process of BC particles. A method, combining an aerodynamic aerosol classifier (AAC), a differential mobility analyzer (DMA), a single-particle soot photometer (SP2) and a single particle aerosol mass spectrometer (SPAMS), was developed to determine the density and dynamic shape factor (𝜒𝜒 ) of ambient BC particles with three different aerodynamic diameters (𝐷𝐷 𝑎𝑎 , 200 nm, 350 nm, and 500 nm) in Shanghai, China, a typical urban area. The BC particles were either classified as "BC-dominated particle" which is mainly made of black carbon or "BC-mixed particle" which is a mixture of both BC and non-BC substances. The results show that BC-dominated particles whose BC core mass (~2.2 fg) was almost equal to particle mass (~2.3fg) were observed in particles with 200 nm 𝐷𝐷 𝑎𝑎 . The morphology of these BC-dominated particles was near-spherical (𝜒𝜒 ≈1.02), indicating that they had undergone rapid morphology modification from the initial highly irregular morphology to near-spherical shape. Most BC particles with 350 nm or 500 nm 𝐷𝐷 𝑎𝑎 were BCmixed particles. Combining the effective densities (1.62~1.77 g cm -3 ) and average single particle mass spectra of particle, the ammonium sulfate and ammonium nitrate were found to be the main secondary substances of these BC-mixed particles, indicating that condensation of inorganic species such as nitrates and sulfates could play a significant role in the aging process of fresh BC A C C E P T E D MA N U S C R I P T 2 in Shanghai. Generally, the morphology and density information of single BC particle is crucial to identify the mixing state and aging process of BC aerosols.