| Summary: | 碩士 === 中興大學 === 環境工程學系所 === 94 === Dichotomous samplers were used to collect PM2.5 and PM2.5-10 aerosols at Nantou and Wufeng in the inland area of central Taiwan during the periods from 4/3-4/9 and 9/15-9/21 in 2005, The chemical compositions of samples were analyzed by ion chromatograph and elemental analyzer. Further more we used trajectory model to evaluate the relative contributions of PM10 and the precursor pollutants from adjacent county to the sampling sites.
Results showed the average concentration of PM10 at Nantou site in April was 109.6μg/m3, which was about 1.2 times of that at Wufeng site. However the concentration at Wufeng site in September was 77.4μg/m3 which was higher than those at Nantou site, PM2.5 concentrations were usually greater than those of PM2.5-10. The major chemical components of these aerosols were sulfate, nitrate, ammonium and carbonaceous components. During the period of particulate episodes, the percentage of nitrate in PM10 at Nantou and Wufeng sites raised from 9% and 7% to 13% and 20%, respectively. The significant increase of nitrate showed that nitrate was the primary component increased during the high pollution periods in the inland area. The source of the nitrate particulates might come from the vehicle emissions. Furthermore, the pattern of the trajectory indicated that the air mass from north east, the intensively polluted area, led to the increase of sulfate and nitrate at Nantou and Wufeng sites.
We utilized the trajectory model to analyze the pollutants emission attraction rates of Nantou and Wufeng sites, and compared the PM10 concentrations. The correlation coefficients between the simulation and the observed PM10 concentrations at these two sites were 0.72, 0.73, respectively. The relationship between the sources and the three receptors showed that the primary particulate (PM10), NOX and SO2 were apparently raised by 25%, 18%, 10% and 31%, 35%, 42% from Taichung county in Nantou and Wufeng sites as compared with non-episodes. And we employ the method to analyze the case in the Taichung site from 13th to 22nd April, results the local emissions were the major sources of Taichung site.
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