| Summary: | 碩士 === 國立臺灣大學 === 職業醫學與工業衛生研究所 === 91 === zzObjective: Apportion emission sources in the Hsin-Chuang areas by applying receptor models to measurements in the Supersite during 2002 -2003.
Methods: The environmental data in the Supersite include hourly real-time PM2.5, EC, OC, sulfate, and nitrate measurements, and 25 2-day integrated samples during collected by a R&P 2300 PM2.5 air sampler during March, 2002 and March, 2003. A series of mobile source fingerprints were established for diesel vehicles、passenger car and motorcycle by using Harvard Impactor to collect PM2.5 in emission tests. X-ray Fluorescence analyzed elemental compositions of air samples. The source profiles from US EPA SEPCIATE for receptor model were selected to represent the stationary source fingerprints. A Bayesian chemical mass balance (CMB) model by Chan and Hwang was used to perform the data analysis in PC.
Results: For the ambient PM2.5 concentrations in Hsin-Chuang, winter is higher than other seasons. For the compositions of ambient PM2.5, the total of nitrate, OC, EC, and sulfate account for 82% PM2.5 mass. For the PM2.5 emissions in ug/m3, 2-stroke motorcycles are higher than other vehicles. The emitted PM2.5 differed in elemental compositions, OC, EC, nitrate, and sulfate among vehicle types. The metal components of Ni,Sr,Mo,Rh in motorcycle exhausts are obviously higher than those in the exhausts of diesel vehicles and passenger cars. Sulfate is characteristically high in passenger car exhausts and OC is high in the two-stroke motorcycle exhausts. The receptor modeling results for 25 integrated samples reveal that PM2.5 in Hsin-Chuang areas are contributed by about 71.3% of mobile sources, including 44.5% passenger car, 10.2% 2-stroke motorcycle about, 8.2% diesel vehicle, and 2.9% 4-stroke motorcycles. Stationary and area sources account for the rest of emissions. The receptor modeling results for 13-month supersite real-time monitoring data also confirm that mobile source is the main contribution to PM2.5 in Hsin-Chuang areas. However, the contribution by stationary sources of chemical and steel factories to hourly PM2.5 becomes significant during the northeastern and southwestern winds.
Conclusions: Mobile source emissions from heavy traffics in freeways and road networks around Hsin-Chuang are the main sources of PM2.5 pollution in the areas. The passenger car is most important contributor among all vehicle types. Stationary sources contribute to PM2.5 in Hsin-Chuang only when the wind is in the northeastern or southwestern directions.
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