Deposition of fractal-like soot aggregates in the human respiratory tract

Broday, David M.; Rosenzweig, Ravid

doi:10.1016/j.jaerosci.2011.03.001

Cited by 80 publications

(61 citation statements)

References 70 publications

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“…Lapuerta et al observed that while biodiesel soot possessed a more ordered and graphitic (and therefore in theory less reactive) structure than diesel soot, it was more efficiently oxidised in the particulate filter due to smaller primary particles increasing available surface area, and differences in cake formation on the filter [26]. The morphology and reactivity of soot emitted into the ambient environment has also been observed to affect the extent of inhalation and of deposition in lungs [27], contribute to global warming via light extinction and interaction with reactive ambient species [28], and disrupt marine bacterial ecosystems [29].…”

Section: Introductionmentioning

confidence: 99%

Comparative nanostructure analysis of gasoline turbocharged direct injection and diesel soot-in-oil with carbon black

Pfau

Rocca

Haffner-Staton

et al. 2018

Carbon

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a b s t r a c tTwo gasoline turbocharged direct injection (GTDI) and two diesel soot-in-oil samples were compared with one flame-generated soot sample. High resolution transmission electron microscopy imaging was employed for the initial qualitative assessment of the soot morphology. Carbon black and diesel soot both exhibit core-shell structures, comprising an amorphous core surrounded by graphene layers; only diesel soot has particles with multiple cores. In addition to such particles, GTDI soot also exhibits entirely amorphous structures, of which some contain crystalline particles only a few nanometers in diameter. Subsequent quantification of the nanostructure by fringe analysis indicates differences between the samples in terms of length, tortuosity, and separation of the graphitic fringes. The shortest fringes are exhibited by the GTDI samples, whilst the diesel soot and carbon black fringes are 9.7% and 15.1% longer, respectively. Fringe tortuosity is similar across the internal combustion engine samples, but lower for the carbon black sample. In contrast, fringe separation varies continuously among the samples. Raman spectroscopy further confirms the observed differences. The GTDI soot samples contain the highest fraction of amorphous carbon and defective graphitic structures, followed by diesel soot and carbon black respectively. The A D1 :A G ratios correlate linearly with both the fringe length and fringe separation.

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Section: Introductionmentioning

confidence: 99%

Comparative nanostructure analysis of gasoline turbocharged direct injection and diesel soot-in-oil with carbon black

Pfau

Rocca

Haffner-Staton

et al. 2018

Carbon

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“…BC may exist in the same particle as OA and others species (internally mixed) or in separate particles (externally mixed). The mixing state and morphology of BC particles can influence their radiative absorption properties (Cappa et al, 2012) and deposition in the human respiratory tract (Broday and Rosenzweig, 2011). The mixing state and physiochemical characteristics of BC particles evolve as they undergo atmospheric processing and aging (Adachi and Buseck, 2013;Subramanian et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway

2018

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Abstract. We present spatial measurements of particle volatility and mixing state at a site near a North Carolina interstate highway (I-40) applying several heating (thermodenuder; TD) experimental approaches. Measurements were conducted in summer 2015 and winter 2016 in a roadside trailer (10 m from road edge) and during downwind transects at different distances from the highway under favorable wind conditions using a mobile platform. Results show that the relative abundance of semi-volatile species (SVOCs) in ultrafine particles decreases with downwind distance, which is consistent with the dilution and mixing of traffic-sourced particles with background air and evaporation of semi-volatile species during downwind transport. An evaporation kinetics model was used to derive particle volatility distributions by fitting TD data. While the TD-derived distribution apportions about 20–30 % of particle mass as semi-volatile (SVOCs; effective saturation concentration, C∗ ≥ 1µm−3) at 10 m from the road edge, approximately 10 % of particle mass is attributed to SVOCs at 220 m, showing that the particle-phase semi-volatile fraction decreases with downwind distance. The relative abundance of semi-volatile material in the particle phase increased during winter. Downwind spatial gradients of the less volatile particle fraction (that remaining after heating at 180 °C) were strongly correlated with black carbon (BC). BC size distribution and mixing state measured using a single-particle soot photometer (SP2) at the roadside trailer showed that a large fraction (70–80 %) of BC particles were externally mixed. Heating experiments with a volatility tandem differential mobility analyzer (V-TDMA) also showed that the nonvolatile fraction in roadside aerosols is mostly externally mixed. V-TDMA measurements at different distances downwind from the highway indicate that the mixing state of roadside aerosols does not change significantly (e.g., BC mostly remains externally mixed) within a few hundred meters from the highway. Our analysis indicates that a superposition of volatility distributions measured in laboratory vehicle tests and of background aerosol can be used to represent the observed partitioning of near-road particles. The results from this study show that exposures and impacts of BC and semi-volatile organics-containing particles in a roadside microenvironment may differ across seasons and under changing ambient conditions.

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“…In addition to the size characteristics of PM, the toxicity of PM may depend upon the composition, surface chemistry, and surface charge (Bakand et al 2012). Modeling studies have shown that morphology can affect the deposition of soot aggregates in the human respiratory tract (Broday and Rosenzweig 2011).…”

Section: Introductionmentioning

confidence: 99%

Particle Emission Characteristics of a Gas Turbine with a Double Annular Combustor

Boies

Stettler

Swanson

et al. 2015

Aerosol Science and Technology

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The total climate, air quality, and health impact of aircraft black carbon (BC) emissions depend on quantity (mass and number concentration) as well as morphology (fractal dimension and surface area) of emitted BC aggregates. This study examines multiple BC emission metrics from a gas turbine with a double annular combustor, CFM56-5B4-2P. As a part of the SAMPLE III.2 campaign, concurrent measurements of particle mobility, particle mass, particle number concentration, and mass concentration, as well as collection of transmission electron microscopy (TEM) samples, allowed for characterization of the BC emissions. Mass-and number-based emission indices were strongly influenced by thrust setting during pilot combustion and ranged from <1 to 208 mg/kg-fuel and 3 £ £ 10 12 to 3 £ £ 10 16 particles/kg-fuel, respectively. Mobility measurements indicated that mean diameters ranged from 7 to 44 nm with a strong dependence on thrust during pilot-only combustion. Using aggregation and sintering theory with empirical effective density relationships, a power-law relationship between primary particle diameter and mobility diameter is presented. Mean primary particle diameter ranged from 6 to 19 nm; however, laserinduced incandescence (LII) and mass-mobility-calculated primary particle diameters demonstrated opposite trends with thrust setting. Similarly, mass-mobility-calculated aggregate mass specific surface area and LII-measured surface area were not in agreement, indicating both methods need further development and validation before use as quantitative indicators of primary particle diameter and mass-specific surface area.

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Deposition of fractal-like soot aggregates in the human respiratory tract

Cited by 80 publications

References 70 publications

Comparative nanostructure analysis of gasoline turbocharged direct injection and diesel soot-in-oil with carbon black

Comparative nanostructure analysis of gasoline turbocharged direct injection and diesel soot-in-oil with carbon black

Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway

Particle Emission Characteristics of a Gas Turbine with a Double Annular Combustor

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