出版社：Chinese Association for Aerosol Research in Taiwan
摘要：Size-segregated ultrafine particles (UFPs) in diesel exhaust were investigated to characterizecarbonaceous substances, metals, and organic compounds originating from a medium-dutydiesel engine dynamometer using the 13 driving mode. Organic carbon (OC) and elementalcarbon (EC) peaked at 330–550 nm, but the OC/EC ratio showed two peaks in the ultrafine andaccumulation modes. The distribution trend of metal elements was opposite to that of the sizesegregated OC/EC ratio. The amounts of toxic Pb, As, and Cd were less than 0.03–2.5% in dieselexhaust particles (DEPs), but their cumulative fractions in the ultrafine mode exceeded 50%.Most organic compounds (76.6%) and alkanes (67.0%) were emitted in the accumulation mode(170–1000 nm). More than 70% of the identified polycyclic aromatic hydrocarbons (PAHs) wereemitted in the accumulation mode (94–1000 nm), with phenanthrene being the most abundant.Two significant size ranges of toxicity equivalent quantity peaks in the ultrafine (34–66 nm) andaccumulation (170–330 nm) modes were observed for the size-segregated DEPs. Contrary to thetrends for PAHs and organic compounds, the identifiable nitrogen-containing polycyclic aromaticcompounds were more abundant in the ultrafine mode. Overall toxicity was high as UFPs can bedeposited with high efficiency throughout the human respiratory tract.
