Phase and Size Distribution of Polycyclic Aromatic Hydrocarbons in Diesel and Gasoline Vehicle Emissions
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- 作者：B. Zielinska ; J. Sagebiel ; W. P. Arnott ; C. F. Rogers ; K. E. Kelly ; D. A. Wagner ; J. S. Lighty ; A. F. Sarofim ; and G. Palmer
- 刊名：Environmental Science & Technology
- 出版年：2004
- 出版时间：May 1, 2004
- 年：2004
- 卷：38
- 期：9
- 页码：2557 - 2567
- 全文大小：473K
- 年卷期：v.38,no.9(May 1, 2004)
- ISSN：1520-5851
文摘
Emission measurements were obtained for a variety ofmilitary vehicles at Hill Air Force Base (Ogden, UT) inNovember 2000 as part of a Strategic Environmental Researchand Development Program. Aircraft ground supportequipment vehicles using gasoline, diesel, and JP8 fuelswere tested using chassis dynamometers under predetermined load. The exhaust from the tested vehicle waspassed to a dilution tunnel where it was diluted 30-40 timesand collected using Micro-Orifice Uniform DepositImpactor (MOUDI) fitted with aluminum substrates, an XAD-coated annular denuder, and a filter followed by a solidadsorbent. All MOUDI substrates were analyzed for massand for organic and elemental (EC) carbon by the thermal/optical reflectance method and for polycyclic aromatichydrocarbons (PAHs) by GC/MS. Black carbon was measuredwith a photoacoustic instrument. The denuder and filter/solid adsorbent samples were analyzed for semivolatile PAH.Overall, there is more mass and higher EC contributionwhen the vehicle is run under higher load in comparisonwith the low load. However, older vehicles generally showmore mass and EC emissions than newer vehicles, andthere is a shift toward smaller particle sizes for the low load,which is most pronounced for newer vehicles. The particle-associated semivolatile PAHs and nonvolatile four-through six-ring PAHs are present predominantly on thesubmicron particles collected on MOUDI stages 0.1-0.18,0.18-0.32, and 0.32-0.56 
m. For the low-load runs, thedistribution of PAHs seems to be shifted toward smaller sizeparticles. The gas-particle phase distribution of semivolatilePAHs depends also on the engine loading. For idle, notonly are the more volatile two- and three-ring PAHs, fromnaphthalene to dimethylphenanthrenes, retained on thedenuder portion, but also less volatile four-ring PAHs, suchas fluoranthene and pyrene, are retained by the denuderat the 80-90% range, which implies that they are presentpredominantly in the gas phase. In contrast, for enginesunder high loads, a much larger portion of three- and four-ring PAHs are partitioned to the particle phase.
m. For the low-load runs, thedistribution of PAHs seems to be shifted toward smaller sizeparticles. The gas-particle phase distribution of semivolatilePAHs depends also on the engine loading. For idle, notonly are the more volatile two- and three-ring PAHs, fromnaphthalene to dimethylphenanthrenes, retained on thedenuder portion, but also less volatile four-ring PAHs, suchas fluoranthene and pyrene, are retained by the denuderat the 80-90% range, which implies that they are presentpredominantly in the gas phase. In contrast, for enginesunder high loads, a much larger portion of three- and four-ring PAHs are partitioned to the particle phase.