Real-Time Characterization of Particle-Bound Polycyclic Aromatic Hydrocarbons in Ambient Aerosols and from Motor-Vehicle Exhaust

摘要

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the urban atmosphere and are typically produced from incomplete combustion of fossil fuels and organic compounds. Fine and ultrafine particles and, thus, the PAHs bound to them can penetrate deeply into the human lungs, where their deposit and accumulation has been associated with short and long term health effects (Pope et al., 2004; Nel, 2005). In the present study, photoelectric aerosol sensor (PAS), diffusion charger (DC), continuous particle counter (CPC) and other real-time measurements were taken a) in Wilmington (CA), an urban area near the Los Angeles port and b) at a dynamometer testing facility in downtown Los Angeles (CA). The dynamometer tests enabled us to characterize the exhausts of several individual types of diesel trucks operated under different driving conditions. Information about the particle-bound PAH (p-PAH) content, active surface area, and particle number concentration (measured by the PAS, DC, and CPC, respectively) were combined to provide insights on the chemical and physical characteristics of the studied aerosols. Integrated 24-hr Teflon filter samples were also collected in Wilmington, and analyzed by GC/MS to determine the relative concentrations of the most abundant p-PAHs found at the urban site.