Motor Vehicle Contributions to Fine Carbonaceous Aerosol in Los Angeles

Pratsinis, Sotiris E.

doi:10.1080/02786829408959721

Cited by 8 publications

(8 citation statements)

References 13 publications

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“…In the urban environment, motor vehicle emissions are often the main anthropogenic source of air pollution, significantly contributing to the deterioration of urban air quality (5,6). Most of the research for motor vehicle particulate emissions has focused on mass concentrations in the exhaust, either as total mass concentration (7), or PM10 (mass concentration of particles smaller than 10 µm). The mass of submicrometer particles is often insignificant in comparison with the total mass of emitted particles due to the fact that a small number of large particles contribute most of the mass; submicrometer number concentrations can change by orders of magnitude without consequent changes in the total mass concentration measurements.…”

Section: Introductionmentioning

confidence: 99%

Submicrometer and Supermicrometer Particles from Diesel Vehicle Emissions

Morawska

Bofinger

Kocis

et al. 1998

Environ. Sci. Technol.

188

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There is growing evidence that fine airborne particulates could play the most important role in determining health effects. The aim of this work was to investigate the number concentration and size distributions of particulates in the exhausts of diesel vehicles (mainly buses) of different ages and make, operating under different loads. Particlesizing instruments used were the Scanning Mobility Particle Sizer (SMPS) and Aerodynamic Particle Sizer (APS). The average particle number concentration of the exhausts was in the range (0.7-3.9) × 10 7 cm -3 in the SMPS range (0.0075-0.304 µm) and (0.3-32) × 10 3 cm -3 in the APS range (0.5-30 µm). In most cases, particle number concentrations increased with the increased power output from the engine and, in both SMPS and APS ranges, varied significantly within each group of vehicles, but the differences between the groups were small. For individual vehicles, there was no relation between emissions in the smaller and larger particle ranges. Emission characteristics did not appear to be correlated with engine model or age. The implications of these findings to particle emission testing and control as well as to exposure and risk analysis are discussed.

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Section: Introductionmentioning

confidence: 99%

Submicrometer and Supermicrometer Particles from Diesel Vehicle Emissions

Morawska

Bofinger

Kocis

et al. 1998

Environ. Sci. Technol.

188

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“…However, the EGA profiles did provide a clear means of distinguishing black from organic carbon. Using carbon monoxide as a tracer, Pratsinis (1994) allocated 70% of the black carbon at Duarte for 1987-1988 to motor vehicle sources, or sources with the same black-carbon-to-carbon-monoxide ratio. For the same time period and general location, Kaplan and Gordon (1994) found that 30% of the black carbon was modern.…”

Section: Source Apportionmentmentioning

confidence: 99%

“…These results are consistent, and they indicate the importance of primary emissions from nonfossil sources. Pratsinis (1994) compared organic carbon/black carbon (OC/BC) ratios for ambient aerosols with those from primary motor vehicle emissions as measured in an automotive tunnel. Not surprisingly, he found that OC/BC ratios for ambient aerosol varied but at all times were at least as high as those from the tunnel.…”

Section: Source Apportionmentmentioning

confidence: 99%

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The Los Angeles Aerosol Characterization and Source Apportionment Study: An Overview

Young

Ellis

Hering

1994

Aerosol Science and Technology

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The Los Angeles Aerosol Characterization and Source nitrate, organic compounds and trace metals and ap-Apportionment Study (LA-ACSAS) is a decade-long portion their sources. This paper provides an overview laboratory and field study undertaken by the Southern of the study results and summarizes the important California Edison Company (SCE) to characterize the conclusions regarding the composition and sources of chemical composition of fine (d , < 3.5 pm) particles, PM,,, in the Los Angeles Basin, especially regarding PM,,,, in the Los Angeles Basin, in terms of sulfate, the organic fraction.

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“…The BC particles are generally very hydrophobic but it is converted as hydrophilic because of physical and/or chemical changes occurring during atmospheric aging process (Weingartner et al, 1997;Bauer et al, 2010). The BC aerosols have been well studied in terms of their lifetime, concentration, sources and optical properties on a fixed wavelength (Ogren and Charlson, 1983;Hildemann et al, 1994;Pratsinis, 1994;Hansen et al, 1993;Köhler et al, 2001;Streets et al, 2001). The optical properties of mineral dust externally and internally mixed with BC have been modeled by many scientists (Fuller et al, 1999;Bond and Bergstrom, 2006;Lesins et al, 2002;Jacobson, 2000).…”

Section: Introductionmentioning

confidence: 99%

Effects of particle shape, hematite content and semi-external mixing with carbonaceous components on the optical properties of accumulation mode mineral dust

Mishra

Tripathi

Aggarwal

et al. 2010

Preprint

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The radiative forcing estimation of the polluted mineral dust is limited due to lack of morphological analysis, mixing state with the carbonaceous components and the hematite content in the pure dust. The accumulation mode mineral dust has been found to mix with anthropogenically produced black carbon, organic carbon and brown carbon during long range transport. The above features of the polluted dust are not well accounted in the optical models and lead the uncertainty in the numerical estimation of their radiative impact. The Semi-external mixing being a prominent mixing of dust and carbonaceous components has not been studied in details so for compared to core-shell, internal and external mixing studies. In present study, we consider the pure mineral dust composed of non-metallic components (such as Quartz, Feldspar, Mica and Calcite) and metalic component like hematite (Fe2O3). The hematite percentage in the pure mineral dust governs its absorbance. Based on this hematite variation, the hematite fraction in pure mineral dust has been constrained between 0–8%. The morphological and mineralogical characterization of the polluted dust led to consider the three sphere, two sphere and two spheroid model shapes for polluted dust particle system. The pollution gives rise to various light absorbing aerosol components like black carbon, brown carbon and organic carbon (comprising of HUmic-Like Substances, HULIS) in the atmosphere. The entire above discussed model shapes have been considered for the mineral dust getting polluted with (1) organic carbon (especially HULIS component) (2) Brown carbon and (3) black carbon by making a semi-external mixture with pure mineral dust. The optical properties (like Single Scattering Albedo, SSA; Asymmetry parameter, g and Extinction efficiency, Qext) of above model shapes for the polluted dust have been computed using Discrete Dipole Approximation, DDA code. For above model shapes, the SSA was found to vary depending on hematite content (0–8%) and model shape composition. For the two sphere BC-mineral dust cluster, hematite was found to be dominating absorber compared to that of black carbon as the RBC/Rdust decreases. (i.e. with increase of dust sphere size compared to black carbon sphere in the composite 2-sphere cluster). SSA was found to be very sensitivity for the hematite content when both of the spheres (i.e. mineral dust and BC) are nearly of same size. The two spheroid system composed of organic carbon and dust with 0% hematite (OCD'-0) showed the maximum deviation of SSA (i.e.~5%) compared to the two sphere system of same composition and hematite content (OCD-0 ). Increase in hematite from 0 to 8% caused maximum SSA deviation of ~20% for two sphere organic carbon-dust system (OCD) while the same has been observed to be ~18% for two spheroid organic carbon-dust system (OCD'). SSA was ...

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Motor Vehicle Contributions to Fine Carbonaceous Aerosol in Los Angeles

Abstract: The contributions to the fine ( d , < 3.5 pm) carbona-

Cited by 8 publications

References 13 publications

Submicrometer and Supermicrometer Particles from Diesel Vehicle Emissions

Submicrometer and Supermicrometer Particles from Diesel Vehicle Emissions

The Los Angeles Aerosol Characterization and Source Apportionment Study: An Overview

Effects of particle shape, hematite content and semi-external mixing with carbonaceous components on the optical properties of accumulation mode mineral dust

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