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Title 環境中奈米物質量測及特性分析技術開發
Abstract 本研究持續至新莊、中山及竹東三個空品測站進行大氣PM採樣，並結合前期計畫的數據，對各測站微粒的粒徑分佈、質量濃度、水溶性離子成分、金屬成分的季節變化及汙染物來源作整合分析。此外報告中也針對空品測站貝他計測值和本研究手動採樣結果間系統性之誤差做深入探討。此外，本研究也利用濃縮片將樣本濃縮，解決了前期Dichot樣本上微粒分布不均勻導致LA-ICP/MS的分析結果不佳的問題。今年度的另一目標為解決LA-ICP-MS量測標準品與真實樣本測值差異太大的問題。結果顯示雷射剝蝕系統經過能量強度的最佳化之後，大部份元素的校正曲線均有明顯的改善，且檢量線均能有良好的回歸。為了找出合適本國大氣條件的細微粒分徑器，本研究也針對WINS衝擊杯及VSCC旋風器做微粒收集效率曲線的校正以及現場採樣比對測試。結果顯示VSCC旋風器相較WINS衝擊杯有較準確的截取氣動直徑(dpa50)及較高的微粒負荷能力。因此基於監測數據準確性及分徑器維護成本的考量，本研究建議應以VSCC旋風器取代目前國內各個空品測站所使用的WINS衝擊杯。本研究也利用改裝後的多濾紙PM10-PM2.5採樣器(Multi-Filter PM10-PM2.5 Sampler, MFPPS)和市售之手動採樣器(Partisol®-FRM Model 2000 Air Sampler with WINS, Dichotomous)及自動即時監測器(TEOM-FDMS)進行並列採樣，探討細微粒手動採樣與自動即時監測間之誤差以及細微粒採樣誤差問題。研究結果顯示，手動採樣在採樣過程中確實會因為微粒揮發而造成負向誤差的問題，這些揮發性物質又以無機化合物為主，有機物質揮發不明顯。在不規則微粒物理特性研究方面，本團隊使用包覆氣流(sheath flow rate, Qsh)控制在5及9 L/min的微分電移動度篩分器(differential mobility analyzer, DMA)，篩選出30-300 nm範圍內的單徑銀團粒，再以掃描式電移動度微粒粒徑分析儀(scanning mobility particle sizer, SMPS)量測所篩選出微粒的數目中間粒徑(number median diameter, NMD)。結果顯示六種篩選出之微粒的NMD與DMA所設定篩選的粒徑之間的平均相對偏差介於在-2.0%及-4.0%之內，若降低Qsh則會使篩選出來之粒徑偏小進而增加兩者間的相對偏差。此外，本團隊也發現可利用動力形狀因子(dynamic shape factor, Df)與碎形維度(fractal dimension, κ)的變化來描述微粒經燒結後形貌的變化趨勢。最後，本研究也對氣膠質譜儀(Aerosol Mass Spectrometer, AMS)的技術理論以及AMS在環境氣膠中之應用方面相關的文獻做了詳盡的回顧，可供國內將來欲使用AMS之相關單位作參考。
EngTitle Development of analytical tools for measuring and characterizing nanomaterials in the environment
EngAbstract This study continues to conduct ambient PM studies at Shinjhung, Jhongshan and Judong air monitoring stations. The sampling data were incorporated with those from previous year's project for the seasonal variation analysis of particle size distributions, mass concentrations, water soluble ions and metal elements and pollutant sources analysis. The difference between the PM2.5 data measured by the beta attenuation monitor (BAM, Model 1020, Met One) and those by the Dichotomous sampler (Dichot, Model SA241, Andersen) were discussed. Furthermore, after using a concentrating filter cassette to concentrate the samples, the problem of nonuniform particle deposition on Dichot filter samples, which resulting poor LA-ICP/MS analysis, was solved.One of the main objectives of this project is to overcome the problem of a large difference between the LA-ICP-MS measurement data of standard samples and those of actual samples. Results show that after optimizing the energy strength of the Laser ablation system, the calibration curves of most of elements were improved with good regression coefficient. In order to choose a suitable size-selective inlet for fine particles in the atmospheric conditions of our country, the collection efficiency curves of the WINS impactor and very sharp cut cyclone (VSCC) were calibrated, and the field sampling comparison by the sampler equipped with the WINS and that with the VSCC were also conducted. Results show that the VSCC has more accurate cutoff aerodynamic diameter (dpa50) and higher particle loading ability as compared to the WINS. To obtain more accurate monitoring data and lower maintenance cost for the classifier, the VSCC was recommended to replace the WINS impactor which is currently used in all air monitoring stations in our country.To evaluate the fine particle artifacts of manual samplers, the ambient fine particle sampling were conducted by using the modified Multi-Filter PM10-PM2.5 Sampler (MFPPS) and other collocated instruments including Partisol®-FRM Model 2000 Air Sampler with WINS, Dichot and TEOM-FDMS. Negative artifacts due to particle evaporation during manual sampling process was found, in which the inorganic compounds were the main volatile species. The evaporation of organic matters was not significant.For the study of physical characteristics of irregular particles, the differential mobility analyzer (DMA) with sheath flow rate (Qsh) of 5 and 9 L/min was used to classify monodisperse silver agglomerate particles with diameter from 30 to 300 nm. The number median diameters (NMDs) of classified particles were measured by a scanning mobility particle sizer (SMPS). Results show that when the Qsh is 9 L/min, the average relative difference between the NMD of classified particles and the DMA classifying size ranges from -2.0 to -4.0 %. This difference will increase and the NMD of classified particle will become smaller when the Qsh is decreased to 5 L/min. Moreover, the dynamic shape factor (Df) and the fractal dimension (κ)were obtained to describe the morphologies of sintered agglomerate particles.Finally, the literature related to the technology and theory of Aerosol Mass Spectrometer (AMS) and its application in ambient aerosol studies were reviewed in details in a hope to provide a reference to the community who intends to apply the AMS in the future.
ProjectYear 101
SponsorOrg 環檢所
ExecutingOrg 國立交通大學環境工程研究所
PublicFullVersionURL http://epq.epa.gov.tw/project/FileDownload.aspx?fid=41685