HR: 0800h
AN: A51A-0026    [Abstracts]
TI: Real-time Characterization of Particle-bound Polycyclic Aromatic Hydrocarbons in Ambient Aerosols and From Motor-Vehicles Exhausts
AU: * Polidori, A
EM: polidori@usc.edu
AF: University of Southern California, Department of Civil and Environmental Engineering, 3620 South Vermont Avenue, Los Angeles, CA 90089, United States
AU: Hu, S
EM: shaohuah@usc.edu
AF: University of Southern California, Department of Civil and Environmental Engineering, 3620 South Vermont Avenue, Los Angeles, CA 90089, United States
AU: Biswas, S
EM: subhasib@usc.edu
AF: University of Southern California, Department of Civil and Environmental Engineering, 3620 South Vermont Avenue, Los Angeles, CA 90089, United States
AU: Sioutas, C
EM: sioutas@usc.edu
AF: University of Southern California, Department of Civil and Environmental Engineering, 3620 South Vermont Avenue, Los Angeles, CA 90089, United States
AB: During the spring of 2007 a diffusion charger (DC), a photoelectric aerosol sensor (PAS), and a condensation particle counter (CPC) were operated a) in Wilmington (CA), an urban area near the Los Angeles port heavily influenced by a mix of industrial and gasoline- / diesel-fuelled vehicle emissions, and b) at the California Air Resource Board (CARB) Heavy-Duty Diesel Emissions Test Laboratory (HDETL), a dynamometer testing facility in downtown Los Angeles (CA). During the dynamometer tests, we characterized the exhausts of several individual types of vehicles, equipped with different emission control technologies, and operated under different driving conditions. Information about the chemical composition, active surface area, and particle number concentration from the PAS, DC, and CPC were combined to identify the main chemical and physical characteristics of the studied aerosols. In particular, the ratio between the PAS and the DC signals (PAS/DC) provided a reliable measurement of the amount of particle-bound Polycyclic Aromatic Hydrocarbon (pPAH) per unit area of the active surface of the particles. This quantity may be directly related to the amount of pPAHs transported into the human respiratory tract. Plots of the PAS/DC ratio versus the average surface particle diameter (Dp; estimated by combining DC and CPC measurements) were then used to distinguish between the presence/absence of nuclei mode particles and the presence/absence of an adsorbed layer on accumulation mode particles, for both ambient and dynamometer-tests data. All results were then complemented with measurements of the particle size distribution (SMPS) and of the black carbon (BC) aerosol content to obtain further insights on the pPAHs emitted by motor-vehicles and other sources. Integrated 24-h filter samples were also collected in Wilmington, solvent extracted and analyzed by GC/MS to determine the relative concentrations of the 11 most abundant pPAHs found at the urban site. Finally, these results were used to establish correlations between the concentrations of each individual PAH species and the measured PAS signal (from fA to μ g/m3).
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting