Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/4983
標題: 台灣中部大氣氣膠特性及粒徑分佈-阿里山測站案例分析
作者: 張維嘉
Chang, Wei-chia
關鍵字: size distributions;粒徑分佈;MOUDI;trimodal size distributions;VARIMAX-rotated principal component analyses;SOR;NOR;微孔均勻沈積衝擊器;三峰分佈;主成分因子分析;硫氧化比值;氮氧化比值
出版社: 環境工程學系
摘要: 
本研究目的為探討阿里山地區懸浮微粒之特性及其粒徑分佈。採樣地點選擇中台灣海拔2413公尺的阿里山氣象站,於1998年秋季及1999年春季,利用微孔均勻沈積衝擊器(MOUDI)及雙粒徑分道採樣器(DICHOT)採集阿里山地區之大氣懸浮微粒並分析其成分組成,分析項目包括了水溶性陰陽離子、碳成分及金屬成分。此外,為了瞭解高海拔地區的空氣品質狀況,於同一地點架設了氮氧化物、硫氧化物、臭氧以及-粉塵測定儀以監測當地的空氣品質。同一期間於台中都會區之崇倫國中及台中海岸平原區之梧棲國小也分別架設兩台雙粒徑分道採樣器,採集大氣懸浮微粒。
分析結果顯示採樣期間阿里山之大氣懸浮微粒PM2.5平均質量濃度為21.5 ±10.5ug/m3,PM2.5-10平均質量濃度為8.0±4.2ug/m3,台中都會區PM2.5及PM2.5-10平均質量濃度為55.7±9.1ug/m3及26.6±6.9ug/m3,台中海岸平原區大氣懸浮微粒PM2.5及PM2.5-10平均質量濃度為34.0±7.9ug/m3及27.5±6.3ug/m3。阿里山地區之PM10平均質量濃度約為台中都會區及海岸平原區的36及48 %。研究也顯示阿里山的細粒質量濃度約佔PM10質量濃度的73 %。阿里山地區大氣中之硫酸鹽、硝酸鹽以及銨鹽濃度明顯低於都會及海岸平原區,尤其以硝酸鹽差異性最大,都會區的硝酸鹽是海岸平原區的1.5 ~ 2倍,但在阿里山地區PM10氣膠中硝酸鹽佔不到5 %。
於粒徑分佈方面,阿里山之硫酸鹽、硝酸鹽及銨鹽粒徑皆呈現三峰分佈,硫酸鹽波峰粒徑分布在0.85 ~ 1.7um之粒徑範圍,與平地之硫酸鹽主要粒徑分佈範圍0.56 ~ 1.0um相比稍大,推測與阿里山高相對濕度有關。
主成分因子分析結果可解釋阿里山氣膠污染來源約60 %的變異量,解釋可能污染來源包含移動源、農廢燃燒及二次氣膠污染三種。阿里山地區的二氧化硫及氮氧化物濃度比台中平地低,分別約是平地的四分之一及七分之一,臭氧比平地高了約兩倍。阿里山地區的硫氧化比值(SOR)及氮氧化比值(NOR)分別為0.97及0.25,顯示阿里山地區的污染大多來自外地,並非當地污染所致。

The purpose of this study was to understand the chemical compositions and the size distributions of atmospheric particulates sampled in Mt. Ali remote area. The ambient particulates were sampled with a micro-orifice uniform deposit impactor (MOUDI) and two dichotomous samplers during September-November, 1998 and March, 1999. The sampling site was located at Mt. Ali weather service office at an elevation of 2413 m above sea level. The collected samples were analyzed for water soluble ions, elemental carbon (EC), organic carbon (OC), and metallic constituents. This study also monitored SOX, NOX, O3, and PM10 during the sampling period. In the same time, the aerosol sampling was conducted in Taichung urban area and coastal suburban area for comparison.
The results showed that the mean mass concentrations were 21.5  10.5 g/m3 for fine particles and 8.0  4.2 g/m3 for coarse particles in the Mt. Ali, 55.7  9.1 g/m3 for fine particles and 26.6  6.9 g/m3 for coarse particles in the Taichung urban area, and 34.0  7.9 g/m3 for fine particles and 27.5  6.3 g/m3 for coarse particles in the Taichung coastal suburban area. The PM10 concentration in remote site was roughly 36 % of those in Taichung city, and 48 % of those in the suburban area on average. The mass of PM2.5 was approximately 73 % of the PM10. Mean concentrations of SO42-, NO3-, and NH4+ in the Mt. Ali remote area were significantly lower than those in the urban and suburban areas. Particularly the nitrate in the urban area was approximately 1.5-2 times more than those in the coastal area. On average, nitrate was found less than 5 % of the PM10 particles in the remote area.
The size distributions of SO42-, NO3-, and NH4+ showed that the particles in the Mt. Ali remote area had trimodal size distributions. The major peak was located at 0.56 - 1.0 m size range in the urban and the coastal areas. Howeven, the peak was located at 0.85-1.7 m size range in the Mt. Ali. The sizes might grew according to relative humidity.
The VARIMAX-rotated principal component analyses identified three major components accounting for approximately 60 % of total variance. The possible three sources were traffic vehicles, agriculture burning ,and secondary aerosols.
SOX concentration in the Mt. Ali were roughly one - fourth of those at the surface, NOX concentration were roughly one-seventh of those at the surface, and O3 concentration were the double of those at the surface. The values of Sulphur oxidation ratio ( SOR ) at Mt. Ali was 0.97, while the Nitrogen oxidation ratio ( NOR ) was 0.25 indicating the sulfate and nitrate aerosol most likely brought by long-range transportation.
URI: http://hdl.handle.net/11455/4983
Appears in Collections:環境工程學系所

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