Polycyclic Aromatic Hydrocarbons Distribution in Fine and Ultrafine Particles Emitted from Diesel Engines

摘要

This paper presents the results of PAH determination adsorbed on fine and ultrafine particles emitted to the air from diesel exhaust, with a special emphasis on sample preparation procedure prior to HPLC-FL analysis. Samples were taken with a personal environmental monitor and personal cascade impactor in order to ensure size-segregated sampling of air particulate matter (in the range of the following particles' diameters <0.25, 0.25-0.5, 0.5-1.0, 1.0-2.5, and 2.5-10 μrn). Application of solid phase extraction with a BakerBond PolarPlus column and mixture of acetonitrile/isopropanol (1:1 v/v) for PAH's elution ensures recovery values of 94%. The mean content of total PAHs collected at the Diesel engine came to (68.0±3.4) and (78.1±3.9) ng·m~(-3) in PM_(2.5) and PM_(10) fractions, respectively. The sum of pyrene, fluoranthene, and benzo(a)anthracene contributed to 74% in the PM_(2.5) and 66% in PM_(10) fraction of total PAH content. Average total PAH's concentrations in smaller fractions of 0.5-1.0 μm, 0.25-0.5 μm, and <0.25 μm separated with PCI sampler were determined at the level of (15.5±0.7), (2.05±0.1), and (40.9±2.1) ng·m~(-3), respectively. In the ultrafine particles' fraction (diameters below 0.25 μm), such compounds as phenanthrene, fluoranthene, pyrene, benzo(a)anthracene, benzo(k)fluoranhene, and benzo(ghi)perylene were identified and determined. The percentage of PAH's input in PM_(0.25) fraction came to the level of 52% on average, in comparison to total PAH concentrations in the PM_(10) fraction.