- 學位論文
The determinations of inorganic elements in nano, submicron and micron airborne particulates in Taiwan area
台灣地區大氣奈米、次微米及微米微粒中無機元素之成分分析
摘要
本篇研究使用電子式低壓衝擊器(ELPI)結合雷射剝蝕感應耦合電漿質譜儀(LA-ICP-MS)技術來偵測大氣奈米(0.030~0.108μm)、次微米(0.108~1.000μm)及微米微粒(1.000~9.970μm)中的無機元素。使用不同的雷射剝蝕模式將收集在濾紙上的大氣微粒氣化達到完全剝蝕的效果。研究結果發現:在雷射波長213nm 的條件下，將雷射系統參數設定為100%雷射能量，1.5mm 離焦距離(defocus distance)，10Hz重複速率(repetition rate)和8秒停留時間(dwell time)，可以完全剝蝕採集在濾紙上的懸浮微粒樣品。實驗室製備的標準濾紙樣品是在實驗中將標準溶液滴在濾紙上模擬ELPI所收集到的樣品。分析方法的偵測極限範圍介於0.002奈克(Cd)至1.062奈克(Si)之間。重複分析(五次)標準品濾紙的結果顯示其精密度(RSD)範圍為3~18%。研究過程中應用本分析方法偵測在中部科學園區附近測站所收集的奈米、次微米及微米微粒中的元素濃度。分析元素的範圍包含Na、Mg、Al、Si、K、Ca、Fe、Ti、V、Cr、Mn、Ni、Cu、Zn、As、Sr、Cd、Ba 及 Pb等19種主要及次要元素。研究結果顯示，細微粒(＜1μm)中的As跟Si可能來自於科學園區內半導體產業或玻璃基板製造業的排放；細微粒中高含量的K跟Zn與附近焚化爐的排放有相關；Pb主要來自於交通的貢獻；而Cr、V、Mn、Ni、Cu 及 Cd則與傳統工業區的排放有關。為了探討因施放煙火對大氣中懸浮微粒的貢獻，本研究亦嘗試針對元宵節的鹽水蜂炮進行空氣污染調查。結果顯示，蜂炮施放後空氣中的元素濃度為平日的1.9~20倍高。比較不同元素在蜂炮施放前後的質量粒徑分佈情形(mass size distribution)，顯示K、V、Cr、Mn、Cu、Zn、As、Sr、Cd、Ba 及 Pb等元素的次微米微粒濃度在蜂炮施放後有明顯升高的現象。
並列摘要
This study proposed a novel method for determining inorganic elements in nano (0.030~0.108μm), submicron (0.108~1.000μm) and micron (1.000~9.970μm) airborne particulates collected by electrical low pressure impactor (ELPI) using laser ablation- inductively coupled plasma-mass spectrometry (LA-ICP-MS). Different grid laser patterns have been performed to completely ablate the airborne particulates collected on the filter. It was found that a 213nm laser with 100% laser energy and 1.5mm defocus distance, at 10Hz repetition rate and 8 seconds dwell time can ablate the real sample spots appropriately. Laboratory-made standard filter samples were prepared by dropping liquid standard solution on the filter to simulate samples collected by ELPI. The limits of detection ranged from 0.002ng for Cd to 1.062 ng for Si. The mean relative standard deviation (RSD) for five replicates of standard filter ranged from 3 to 18%. The proposed analytical method was applied to determine elemental concentrations of nano, submicron, and micron particles collected from the surrounding of Central Taiwan Science Park (CTSP). Total of 19 major and minor elements, including Na, Mg, Al, Si, K, Ca, Fe, Ti, V, Cr, Mn, Ni, Cu, Zn, As, Sr, Cd, Ba and Pb were determined in this work. The results showed that nearby CTSP was possibly responsible for As and Si in fine particles (＜1μm). High contents of K and Zn in fine particles were strongly associated with the emission from incinerator. The Pb contents in fine particles were mainly from road traffic, while the Cr, V, Mn, Ni, Cu and Cd in fine particles might be emitted from the traditional industries. Otherwise, to understand the chemical composition of suspended particles generated by rocket firecrackers or fireworks, a case study during Yanshuei Fireworks was also performed by the proposed method. The elemental concentrations in aerosol samples (0.03~9.97μm) collected by ELPI after the fireworks were about 1.9~20 times higher than those of normal days. Comparison of particle mass size distributions for each analyte element showed that the concentrations of K, V, Cr, Mn, Cu, Zn, As, Sr, Cd, Ba and Pb increased significantly in the submicron size range after the fireworks.