| Summary: | 博士 === 國立成功大學 === 環境工程學系 === 86 === The characteristics of polycyclic aromatic hydrocarbons (PAHs)
and metal elements in the atmospheric environment were
searchingly investigated. Twenty-one individual PAHs were
analyzed primarily by a gas chromatography/mass spectrometer
(GC/MS) and the metal elements were analyzed by an inductively
coupled plasma/ atomic emission spectrometry (ICP/AES). In
addition to the establishment of the native emission factor
database, the receptor model was applied to apportion the source
emissions. The emission sources of PAHs and metal elements in
the atmosphere include the stationary sources: industrial
stacks, road dust, sea spray and the mobile source: diesel
vehicle. The results of this investigation are as follows: 1.
The particle-bound PAHs is highly correlated with the SOF
exhausted from the diesel-powered engine. (R2 =0.82) 2. The
average reduction fractions of total particle-bound PAHs are 36%
and 50% by using the 400 mg/L Mn-contained additive and 800 mg/L
Ba-contained additive for the heavy-duty diesel engine,
respectively. 3. The ratios of the concentrations exhausted from
the turbocharged engine and the natural aspirated one are
between 0.019 ~ 0.199 for ten higher molecular weight PAHs (gas+
particle) over steady-state test conditions. The turbocharged
diesel engine slashes the emissions of carcinogenic high
molecular weight PAHs. 4. Two catalysts (Catalyst 1 and Catalyst
2) and one particulate trap reduce the total particle-bound PAHs
effectively. The reduction fractions are 20.5%, 54.8% and 50.4%
at the high low (HL) driving mode, and are 87.2%, 90.9% and
95.3% at the low load (LL) driving mode. The reduction fractions
of high molecular weight particle-bound PAHs are (45.3%, 77.4%),
(72.9%, 23.4%) and (41.5%, 19.4%) at (HL, LL) driving conditions
for Catalyst 1, Catalyst 2 and particulate trap, respectively.
5. The indicatory PAHs are primarily 4- and 5-ringed PAHs (BaP,
BaA, PER, BeP, CYC and DBA) from various emission sources in
this investigation. The indicatory PAHs of the cement plant are
AcPy, Acp and Ant, which are all 3-ringed PAHs, while those of
the industrial waste incinerator are IND and CHR. The indicatory
PAHs are AcPy, FL and Flu, CHR for diesel- and gasoline-powered
vehicles, respectively. 6. The total-PAHs size distribution of
ambient air at traffic intersections is unimodal distribution.
The peaks are less than 1.0 m. The total-PAHs size
distribution for the engine-exhaust of gasoline-powered car and
motorcycle are also both unimodal size distribution. The peaks
are located at 0.32 0.56 m. The MMDs of total-PAHs mass are
0.453 and 0.346 m for the engine-exhaust of gasoline-powered
car and motorcycle, respectively. As to the resuspendable road
dust, the MMDs of total-PAHs mass is 62.5 m. MMDs of total-
PAHs mass are 0.500 m for the ambient air of traffic
intersection. 7. The average dry deposition flux contribution of
gas phase PAHs is 1.88% for the traffic intersection. The dry
deposition fluxes are 27.0% and 36.5% for Nap and AcPy,
respectively. The average contribution of total-PAH dry
deposition flux by the mobile exhaust is 3.05%. In other words,
the contribution of total-PAH dry deposition flux by the road
dust is higher than 95%.
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