| Summary: | 碩士 === 國立中興大學 === 環境工程學系所 === 96 === Abstract
This study mainly investigated the chemical compositions of ambient particulates in the coastal and urban areas in central Taiwan, and applied chemical mass balance receptor model to analyze the source contributions. Both PM2.5 (particulate matter with aerodynamic diameter less than 2.5 μm) and PM2.5-10 (particulate matter with aerodynamic diameter 2.5-10 μm) aerosols were collected for coastal area at Lukang site during spring 2007, whereas the samples were collected for the urban area at Chung Hsing site during 2005. For coastal site, the additional particle samples were also collected to be analyzed by using an electron microscope in order to identify the emission sources. Qualitative and quantitative analyses were performed by using chemical mass balance (CMB) model.
The CMB modeling results showed that the major sources of PM2.5 included secondary aerosols and agricultural waste burning in the coastal area, whereas vehicle exhaust and ammonium sulfate were the dominant sources in the urban area. The significant sources of PM2.5-10 included crustal materials, vehicle exhaust and marine spray in the coastal area, yet vehicle exhaust, crustal materials were the major sources in the urban area. Therefore, the secondary aerosols and vehicle exhaust was the major source of PM10 in the coastal and urban area, respectively.
The episodic events in 2005 were categorized as agricultural waste burning episodes (11/25~11/27), Asian dust storm events (11/29) and winter PM10 episode (12/23~12/25). The results showed that the contribution of agricultural burning in PM2.5 during the agricultural waste burning episodes was 6.2 times higher than that during non-episodes. During the Asian dust storm events, the crustal materials were the major contributory sources in PM2.5-10 and about 8 times higher than that during non-episodes. In winter PM10 episode, the vehicle exhaust and agricultural burning were the major contributory sources in PM2.5, and there were 3 and 6 times higher than those during non-episode, respectively. Furthermore, the other sources were also increased during the episodes.
The scanning electron microscopic pictures of the individual particles sampled at Lukang site, showed three major types of sources. These particles were identified as sulfate, soil dust and vehicular emissions, which were similar to the results obtained by CMB receptor modeling.
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