Single Parameter for Predicting the Morphology of Atmospheric Black Carbon

Chen, Chao; Enekwizu, Ogochukwu; Fan, Xiaoliang; Dobrzanski, Christopher D.; Ivanova, E. V.; Ma, Yan; Gor, Gennady Y.; Khalizov, Alexei F.

doi:10.1021/acs.est.8b04201

Cited by 27 publications

(31 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As evident from Table 2, the MMD values during ICARB-2018 mostly fall in the category of BC from the continental outflow and originated from mixed sources (McMeeking et al, 2010(McMeeking et al, , 2011Ueda et al, 2016;Cheng et al, 2018). 2) and mass size distributions over different regions covered in this study (Fig.…”

Section: Spatial Distribution Of Rbc Mass/number Concentrations and Size Distributionsmentioning

confidence: 69%

“…where D p,i and D c,i are the diameters of coated and core rBC, respectively, for each single particle i. In addition to RCT, we have used bulk volume-weighted absolute coating thickness (ACT, in nm), defined as (D p − D c )/2 (both D p and D c used here are volume averaged diameters) based on the assumption of a concentric core-shell morphology, as another diagnostic of the coating on the population of rBC particles (Gong et al, 2016;Cheng et al, 2018;Brooks et al, 2019). More details about the parameters bulk RCT and ACT, the methodology used here, and uncertainties as-sociated were described elsewhere (Liu et al, 2017(Liu et al, , 2019Sedlacek et al, 2018;Brooks et al, 2019;Kompalli et al, 2020b).…”

Section: Discussionmentioning

confidence: 99%

“…The size distributions of rBC are influenced by the source, sinks, and transformation processes taking place during advection and are known to be important in assessing the light absorption characteristics (Reddington et al, 2013). The MMD values of the rBC size distributions are strongly influenced by the source of BC emissions (e.g., Ko et al, 2020;Cheng et al, 2018). Recently, Ko et al (2020) compared the MMD and NMD values of rBC size distributions from different dominant sources.…”

Section: Spatial Distribution Of Rbc Mass/number Concentrations and Size Distributionsmentioning

confidence: 99%

“…Brooks et al (2019) noticed thickly coated BC particles (ACT ∼ 50-200 nm) across northern India, especially the IGP and north-east India, during their recent aircraft experiments. As Cheng et al (2018) and Ko et al (2020) have highlighted, coating parameters derived from the SP2 instruments having different system configurations (detection limits of scattering intensity and range of volume equivalent diameters covered) and different techniques used in the estimation of the optical diameters from scattering amplitudes (Metcalf et al, 2012;Gong et al, 2016;Raatikainen et al, 2017;Cheng et al, 2018;Liu et al, 2019;Ko et al, 2020) can vary considerably. This caveat needs to be borne in mind when making inter-study comparisons.…”

Section: The Bulk Coating Parameters: Rct and Actmentioning

confidence: 99%

See 3 more Smart Citations

Mixing state of refractory black carbon aerosol in the South Asian outflow over the northern Indian Ocean during winter

et al. 2021

View full text Add to dashboard Cite

Abstract. Regional climatic implications of aerosol black carbon (BC), which has a wide variety of anthropogenic sources in large abundance, are well recognized over South Asia. Significant uncertainties remain in its quantification due to a lack of sufficient information on the microphysical properties (its concentration, size, and mixing state with other aerosol components) that determine the absorption potential of BC. In particular, the information on the mixing state of BC is extremely sparse over this region. In this study, the first observations of the size distribution and mixing state of individual refractory black carbon (rBC) particles in the South Asian outflow to the south-eastern Arabian Sea and the northern and equatorial Indian Ocean regions are presented based on measurements using a single particle soot photometer (SP2) aboard the Integrated Campaign for Aerosols, gases, and Radiation Budget (ICARB-2018) ship during winter 2018 (16 January to 13 February). The results revealed significant spatial heterogeneity of BC characteristics. The highest rBC mass concentrations (∼938±293 ng m−3) with the highest relative coating thickness (RCT; the ratio of BC core to its coating diameters) of ∼2.16±0.19 are found over the south-east Arabian Sea (SEAS) region, which is in the proximity of the continental outflow. As we move to farther oceanic regions, though the mass concentrations decreased by nearly half (∼546±80 ng m−3), BC still remained thickly coated (RCT∼2.05±0.07). The air over the remote equatorial Indian Ocean, which received considerable marine air masses compared to the other regions, showed the lowest rBC mass concentrations (∼206±114 ng m−3) with a moderately thick coating (RCT∼1.73±0.16). Even over oceanic regions far from the landmass, regions that received the outflow from the more industrialized east coast/the Bay of Bengal had a thicker coating (∼104 nm) compared to regions that received outflow from the west coast and/or peninsular India (∼86 nm). Although different regions of the ocean depicted contrasting concentrations and mixing state parameters due to the varied extent and nature of the continental outflow as well as the atmospheric lifetime of air masses, the modal parameters of rBC mass–size distributions (mean mass median diameters ∼ 0.19–0.20 µm) were similar over all regions. The mean fraction of BC-containing particles (FBC) varied in the range of 0.08–0.12 (suggesting significant amounts of non-BC particles), whereas the bulk mixing ratio of coating mass to rBC mass was highest (8.31±2.40) over the outflow regions compared to the remote ocean (4.24±1.45), highlighting the role of outflow in providing condensable material for coatings on rBC. These parameters, along with the information on the size-resolved mixing state of BC cores, throw light on the role of sources and secondary processing of their complex mixtures for coatings on BC under highly polluted conditions. Examination of the non-refractory sub-micrometre aerosol chemical composition obtained using the aerosol chemical speciation monitor (ACSM) suggested that the overall aerosol system was sulfate-dominated over the far-oceanic regions. In contrast, organics were equally prominent adjacent to the coastal landmass. An association between the BC mixing state and aerosol chemical composition suggested that sulfate was the probable dominant coating material on rBC cores.

show abstract

Section: Spatial Distribution Of Rbc Mass/number Concentrations and Size Distributionsmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 99%

Section: Spatial Distribution Of Rbc Mass/number Concentrations and Size Distributionsmentioning

confidence: 99%

Section: The Bulk Coating Parameters: Rct and Actmentioning

confidence: 99%

See 2 more Smart Citations

Mixing state of refractory black carbon aerosol in the South Asian outflow over the northern Indian Ocean during winter

et al. 2021

View full text Add to dashboard Cite

show abstract

“…For example, after condensation of gaseous species such as sulfuric acid or water (under high-relative-humidity (RH) environments) on soot particles, or coagulation with the pre-existing particles, soot particles can experience restructuring, and the shape of the soot particles becomes more similar to a spherical particle (Zhang et al, 2008). The morphology of BC particles can be measured directly by using scanning electron microscopy (SEM) or transmission electron microscopy (TEM) (Fu et al, 2006;Chen et al, 2018;Ellis et al, 2016). However, the SEM/TEM approach only provides particle shape information in two dimensions and does not provide real-time characterisation.…”

Section: Introductionmentioning

confidence: 99%

Physical and chemical properties of black carbon and organic matter from different combustion and photochemical sources using aerodynamic aerosol classification

Alfarra

Szpek

et al. 2021

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. The physical and chemical properties of black carbon (BC) and organic aerosols are important for predicting their radiative forcing in the atmosphere. During the Soot Aerodynamic Size Selection for Optical properties (SASSO) project and a EUROCHAMP-2020 transnational access project, different types of light-absorbing carbon were studied, including BC from catalytically stripped diesel exhaust, an inverted flame burner, a colloidal graphite standard (Aquadag) and controlled flaming wood combustion. Brown carbon (BrC) was also investigated in the form of organic aerosol emissions from wood burning (pyrolysis and smouldering) and from the nitration of secondary organic aerosol (SOA) proxies produced in a photochemical reaction chamber. Here we present insights into the physical and chemical properties of the aerosols, with optical properties presented in subsequent publications. The dynamic shape factor (χ) of BC particles and material density (ρm) of organic aerosols was investigated by coupling a charging-free Aerodynamic Aerosol Classifier (AAC) with a Centrifugal Particle Mass Analyzer (CPMA) and a Scanning Mobility Particle Sizer (SMPS). The morphology of BC particles was captured by transmission electron microscopy (TEM). For BC particles from the diesel engine and flame burner emissions, the primary spherule sizes were similar, around 20 nm. With increasing particle size, BC particles adopted more collapsed/compacted morphologies for the former source but tended to show more aggregated morphologies for the latter source. For particles emitted from the combustion of dry wood samples, the χ of BC particles and the ρm of organic aerosols were observed in the ranges 1.8–2.17 and 1.22–1.32 g cm−3, respectively. Similarly, for wet wood samples, the χ and ρm ranges were 1.2–1.85 and 1.44–1.60 g cm−3, respectively. Aerosol mass spectrometry measurements show no clear difference in mass spectra of the organic aerosols in individual burn phases (pyrolysis or smouldering phase) with the moisture content of the wood samples. This suggests that the effect moisture has on the organic chemical profile of wood burning emissions is through changing the durations of the different phases of the burn cycle, not through the chemical modification of the individual phases. In this study, the incandescence signal of a Single Particle Soot Photometer (SP2) was calibrated with three different types of BC particles and compared with that from an Aquadag standard that is commonly used to calibrate SP2 incandescence to a BC mass. A correction factor is defined as the ratio of the incandescence signal from an alternative BC source to that from the Aquadag standard and took values of 0.821 ± 0.002 (or 0.794 ± 0.005), 0.879 ± 0.003 and 0.843 ± 0.028 to 0.913 ± 0.009 for the BC particles emitted from the diesel engine running under hot (or cold idle) conditions, the flame burner and wood combustion, respectively. These correction factors account for differences in instrument response to BC from different sources compared to the standardised Aquadag calibration and are more appropriate than the common value of 0.75 recommended by Laborde et al. (2012b) when deriving the mass concentration of BC emitted from diesel engines. Quantifying the correction factor for many types of BC particles found commonly in the atmosphere may enable better constraints to be placed on this factor depending on the BC source being sampled and thus improve the accuracy of future SP2 measurements of BC mass concentrations.

show abstract

Environmental fate and transformation of TiO₂ nanoparticles: A comprehensive assessment

Sundaram,

Rajendran,

Natarajan

et al. 2025

Alexandria Engineering Journal

View full text Add to dashboard Cite

Single Parameter for Predicting the Morphology of Atmospheric Black Carbon

Cited by 27 publications

References 72 publications

Mixing state of refractory black carbon aerosol in the South Asian outflow over the northern Indian Ocean during winter

Mixing state of refractory black carbon aerosol in the South Asian outflow over the northern Indian Ocean during winter

Physical and chemical properties of black carbon and organic matter from different combustion and photochemical sources using aerodynamic aerosol classification

Environmental fate and transformation of TiO₂ nanoparticles: A comprehensive assessment

Contact Info

Product

Resources

About