Submicrometer and Supermicrometer Particles from Diesel Vehicle Emissions

Abstract

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.

On-Road Measurements of Ultrafine Particles and Associated Air Pollutants in a Densely Populated Area of Seoul, Korea

“…The higher correlations of UFP number concentrations in the 60 < D p < 220 nm particle size range with PM-PAHs, BC, and particle surface area strongly reflect the dominant contribution of diesel vehicles to emissions of relatively larger particles (60 < D p < 220 nm) over the measurement period in our sampling area because PM-PAHs and BC are known to be emitted from diesel engines. Furthermore, as noted in the Introduction, the greater part of the particle number concentration from vehicle exhausts is in the 20-130 nm size range for diesel engines (Kittelson, 1998;Morawska et al, 1998) and in the 20-60 nm range for gasoline engines (Kittelson, 1998;Ristovski et al, 1998). Therefore, the linear relationships of the 60 < D p < 220 nm particle size range with PAHs and BC indicate the dominance of diesel exhaust emissions for relatively larger particles in our study area, although it was difficult to determine the relative contributions of vehicle emissions for smaller particles (6 < D p < 60 nm).…”

“…Among the anthropogenic particulate matter (PM) sources, emissions of industrial combustion processes and traffic-related emissions account for the highest contributions of both UFPs and FPs (Schauer et al, 1996;Shi et al, 1999;Cass et al, 2000;EPA, 2000;Harrison et al, 2000;Hitchins et al, 2000). For traffic-related emissions, the greater part of the particle number concentration from vehicle exhaust is in the 20-130 nm size range for diesel engines (Kittelson, 1998;Morawska et al, 1998) and in the 20-60 nm for gasoline engines (Kittelson, 1998;Ristovski et al, 1998). PM emissions from internal combustion engines have traditionally been regulated solely on the basis of total PM mass emissions (Kittelson et al, 2004a).…”

Urban aerosol number size distributions

“…In Brisbane, Australia, the concentration of submicrometer particles correlated strongly with the concentrations of NO x and CO Morawska et al, 1998b), suggesting that motor vehicle emissions constituted the main source of ultrafine particles. Under varying conditions, the number of emitted particles increased with increasing engine load, whereas the mean particle diameter decreased (Franz et al, 2000;Morawska et al, 1998a). In cities, cars are usually not driven at a constant speed; there is continuous acceleration and deceleration.…”

Análisis de la influencia de las características de los materiales pulverulentos sobre su poder de emisión de polvo

“…Cabe destacar la emisión de partículas ultrafinas o nanopartículas en el rango de tamaño 20-130 nm (Kittelson 1998;Morawska et al 1998). …”