| Summary: | 碩士 === 朝陽科技大學 === 環境工程與管理系碩士班 === 93 === Size distributions of particulate matter and polycyclic aromatic hydrocarbons emitted from motorcycles were investigated by testing these vehicles on a chassis dynamometer. Measurements were performed on a standard driving cycle (CNS 11386). The exhaust from the tested vehicle was passed to a dilution tunnel and collected by using a Micro-Orifice Uniform Deposit Impactor (MOUDI). The particulate was separated into 11 size ranges of 0.056-10 �慆 aerodynamic diameter fitted with aluminum substrates. The filter was weighted under a controlled temperature and humidity. PAH samples were Soxhlet extracted, concentrated, purified, re-concentrated and analyzed by gas chromatography/mass spectrometer (GC/MS). Twenty-one PAHs were analyzed in this study. The results are as follows: (1) Particulate matter shows unimodal size distribution with a peak at 0.056-0.32 �慆 for 2-stroke and 4-stroke carburetor motorcycles. (2) For various ringed PAHs, the size distribution is similar, showing bimodal size distribution with a peak at 0.056-0.1 �慆 and 0.18-0.32 �慆. (3) Nap was the highest PAHs in total PAHs emission factors of the test motorcycles. Higher molecular weight PAHs (HMW-PAHs) were predominated in 2-stroke carburetor motorcycle emission; Low molecular weight PAHs (LMW-PAHs) were predominated in 4-stroke carburetor motorcycle emission. (4) For low molecular weight PAHs, there is a significant peak in the coarse mode; for middle and high molecular weight PAHs, there are significant peaks in accumulate mode. MMW-PAHs and HMW-PAHs show bimodal size distribution with peak at 0.18-0.32 �慆 and 0.056-0.1 �慆. (5) The PAH content decreases as the particulate size increases. It is caused by the fact of higher surface area of fine particulate. (6) Two significant peaks located at 0.056-0.1 �慆 and 0.18-0.56 �慆 for the size distribution of total benzo[a]pyrene toxic equivalency emission factor for the test motorcycle. The BaPeq emission factor of 2-stroke carburetor motorcycle was higher than that of 4-stroke carburetor motorcycle, especially for higher molecular weight PAHs.
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