The spectroscopic characterisation of UV absorbing nanoparticles in fuel rich soot forming flames

D’Alessio, Antonio; D’Anna, Andrea; Gambi, G.; Minutolo, P.

doi:10.1016/s0021-8502(97)00457-6

Cited by 105 publications

(73 citation statements)

References 15 publications

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“…BC is emitted as a result of incomplete combustion of carbon-rich fuels. The other component, OA, though present in much higher mass concentrations than BC for ambient samples, is more elusive as its origins as well as optical and chemical properties vary greatly with source, transformation, and sink (D'Alessio et al, 1998). OA exhibits many molecular forms that have different physical and chemical properties and often exists independently of BC (Jacobson et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Photoacoustic optical properties at UV, VIS, and near IR wavelengths for laboratory generated and winter time ambient urban aerosols

et al. 2012

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Abstract. We present the laboratory and ambient photoacoustic (PA) measurement of aerosol light absorption coefficients at ultraviolet wavelength (i.e., 355 nm) and compare with measurements at 405, 532, 870, and 1047 nm. Simultaneous measurements of aerosol light scattering coefficients were achieved by the integrating reciprocal nephelometer within the PA's acoustic resonator. Absorption and scattering measurements were carried out for various laboratorygenerated aerosols, including salt, incense, and kerosene soot to evaluate the instrument calibration and gain insight on the spectral dependence of aerosol light absorption and scattering. Ambient measurements were obtained in Reno, Nevada, between 18 December 2009 and 18 January 2010. The measurement period included days with and without strong ground level temperature inversions, corresponding to highly polluted (freshly emitted aerosols) and relatively clean (aged aerosols) conditions. Particulate matter (PM) concentrations were measured and analyzed with other tracers of traffic emissions. The temperature inversion episodes caused very high concentration of PM 2.5 and PM 10 (particulate matter with aerodynamic diameters less than 2.5 µm and 10 µm, respectively) and gaseous pollutants: carbon monoxide (CO), nitric oxide (NO), and nitrogen dioxide (NO 2 ). The diurnal change of absorption and scattering coefficients during the polluted (inversion) days increased approximately by a factor of two for all wavelengths compared to the clean days.The spectral variation in aerosol absorption coefficients indicated a significant amount of absorbing aerosol from traffic emissions and residential wood burning. The analysis of single scattering albedo (SSA),Ångström exponent of absorption (AEA), andÅngström exponent of scattering (AES) for clean and polluted days provides evidences that the aerosol aging and coating process is suppressed by strong temperature inversion under cloudy conditions. In general, measured UV absorption coefficients were found to be much larger for biomass burning aerosol than for typical ambient aerosols.

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Section: Introductionmentioning

confidence: 99%

Photoacoustic optical properties at UV, VIS, and near IR wavelengths for laboratory generated and winter time ambient urban aerosols

et al. 2012

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“…3 However, a complete chemical and physical characterization of the class of species with MW between PAH and soot particles (>20 nm) is still lacking, even though many techniques have been developed and applied to this purpose. [4][5][6][7][8][9][10][11] Our previous work has been concerned mainly with the qualitative and quantitative evaluation of PAH along the axis of premixed flames 12,13 and spray flames 14 in the MW range appropriate for detection by gas chromatography/ mass spectrometry (GC/MS) (up to 300 Da). The use of particle beam mass spectrometry (PB-MS) has allowed the extension up to 398 Da (C 32 H 14 ).…”

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confidence: 99%

Separation and measurement of flame‐formed high molecular weight polycyclic aromatic hydrocarbons by size‐exclusion chromatography and laser desorption/ionization time‐of‐flight mass spectrometry

Apicella

Millán

Herod

et al. 2006

Rapid Comm Mass Spectrometry

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The partial contribution of polycyclic aromatic hydrocarbons (PAH), capable of being detected by gas chromatography (GC-PAH), both to the total mass of the extractable organic fraction of flame-formed carbon particulates and to its UV-visible absorption and fluorescence spectra, has been determined by previous work. This contribution indicates the presence of PAH of molecular weight (MW) greater than 400 Da not accessible to conventional analysis. The detection of species in this higher MW range is important for both their potential toxicology and their possible role in soot formation. In the present work extracts of soots have been analyzed by linear mode laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF-MS) to extend the MW range that can be analyzed beyond the GC-PAH. The results have been compared with both analysis by reflector mode LDI-TOF-MS and the MW evaluation obtained by SEC analysis, as the shortcomings and advantages of both techniques appear to be complementary. Matching the results from the two techniques could give interesting insights in the molecular mass range between GC-PAH and the first soot particles (of mass > 2000 Da). Mass spectra in this molecular mass range have been obtained with a main ion sequence spacing of 24 Th and a minor ion sequence also with a spacing of 24 Th but off-set by 12 Th with respect to the main sequence. The two ion progressions have been interpreted by attributing the predominant peaks mainly to PAH with even-carbon numbers and the smaller ones to cyclopenta-fused ring PAH. These distributions indicate the occurrence of two competitive mechanisms in the growth of PAH and soot nucleation, i.e. the addition of acetylene (HACA mechanism) and the incorporation of pentagons by large polycyclic aromatic molecules into their aromatic bonding network.

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“…7,8 Our results show that after only few milliseconds these small particles have grown rapidly, reaching 60-150 nm ( Figure 5 and 6).…”

Section: Resultsmentioning

confidence: 67%

“…2,6 Furthermore, the emission of fine particles (organic carbon aerosols and soot) into the atmosphere, generated by combustion systems, is directly related to respiratory illness and mortality. 7,8 The chemistry of soot formation is a very complex phenomenon involving homogeneous and heterogeneous processes and the continuous competition between formation and oxidation reactions. 9 The overall mechanism of soot production is normally described as three steps: nucleation, surface growth and coalescence, then aggregation.…”

Section: Introductionmentioning

confidence: 99%

Temporal Evolution of Soot Particles from C2H2/O2 Combustion in a Closed Chamber

Bertran¹,

Marques²,

Benvenutti³

2002

J. Braz. Chem. Soc.

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0.75 ou de C2H2/O2/Ar com razão C/O = 1.00 é de cerca de 3.0-4.0 ms, após o início da reação. O máximo de emissão dos radicais excitados e o máximo da pressão nestas reações, ocorrem praticamente neste mesmo intervalo de tempo. Observou-se a formação de partículas de fuligem compactas e aproximadamente esféricas com 60-150 nm de diâmetro. Entretanto, os agregados não são compactos e mostram uma estrutura de rede que se assemelha a de um aerogel.]]>

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The spectroscopic characterisation of UV absorbing nanoparticles in fuel rich soot forming flames

Cited by 105 publications

References 15 publications

Photoacoustic optical properties at UV, VIS, and near IR wavelengths for laboratory generated and winter time ambient urban aerosols

Photoacoustic optical properties at UV, VIS, and near IR wavelengths for laboratory generated and winter time ambient urban aerosols

Separation and measurement of flame‐formed high molecular weight polycyclic aromatic hydrocarbons by size‐exclusion chromatography and laser desorption/ionization time‐of‐flight mass spectrometry

Temporal Evolution of Soot Particles from C2H2/O2 Combustion in a Closed Chamber

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