Single-particle characterization of aerosol particles using a quantitative energy-dispersive electron probe

Single-particle characterization of aerosol particles using a quantitative energy-dispersive electron probe
실라 마스키
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During the last few decades, numerous studies on the chemical composition of aerosols in various places around the world have been carried out every year. In such studies bulk analysis procedures have been extensively used to explore information on average chemical composition of particulate samples. Atmospheric aerosol particles are heterogeneous mixture of different types of chemical species, so that the average compositions do not well represent the dispersion of particles in the sample. In the present work, a single-particle analytical technique, called low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA), was applied for the characterization of aerosol samples collected from different places. The low-Z particle EPMA uses an X-ray detector equipped with an ultra-thin window and thus allows the quantitative determination of concentrations of low-Z elements such as C, N, and O as well in individual particles of micrometer size. The capability of the quantitative determination of low-Z elements in individual environmental particles improves the applicability of single-particle analysis; many important environmental atmospheric particles (e.g., sulfates, nitrates, ammonium salt and carbonaceous particles) contain low-Z elements. Therefore, this low-Z particle EPMA is expected to provide more conclusive and detailed analysis on the characterization of individual particles. The first work presented in this dissertation investigates the influence of three different collecting substrate materials, i.e., Ag and Al foils and grids for transmission electron microscopy (TEM grid), on the morphological and chemical compositional analysis of individual particles collected at an underground shopping area in Seoul, Korea. The feasibility of the application of three substrates in a quantitative single-particle analysis was evaluated by comparing particle morphologies, X-ray spectra, and elemental quantification results obtained for each substrate. The morph
Chapter I. Introduction 1 Chapter II. Experimental section 6 1. Sampling 6 1.1. Dekati PM10 impactor 6 1.2. Atomizer 7 1.3. Optical particle counter 7 2. Low-Z particle EPMA measurements 7 3. Data Analysis 8 3.1. Evaluation of X-ray intensity 8 3.2. Quantification 10 3.3. Classification 17 4. ATR-FT-IR measurement 20 5. Hygroscopic property measurement 21 Chapter III. The influence of collecting substrates on the single-particle characterization of real atmospheric aerosols 25 1. Introduction 25 2. Experimental section 29 2.1. Samples 29 2.2. Low-Z particle EPMA measurements and data analysis 31 3. Results and Discussion 31 3.1. Characteristics of Ag and Al foils and TEM grids as collecting substrates 31 3.2. SEIs and X-ray spectra of indoor aerosol particles on the different collecting substrates 35 3.3. Data analysis of X-ray spectra obtained from the different collecting substrates 44 4. Conclusions 50 Chapter IV. Single-particle characterization of indoor aerosol particles collected at an underground shopping area in Seoul, Korea 51 1. Introduction 51 2. Experimental section 53 2.1. Samples 53 2.2. Low-Z particle EPMA measurements and data analysis 56 3. Results and Discussion 56 3.1. Particle types and morphology of underground shopping area aerosols 56 3.1.1. Primary and secondary soil-derived particles 59 3.1.2. Carbonaceous particles 61 3.1.3. Fe-containing particles 68 3.1.4. NaCl particles 69 3.1.5. Secondary sea-salt particles 3.1.6. Ammonium sulfate, fly ash, and other particles 70 3.2. Relative abundances of various types of particles observed in underground shopping area 71 4. Conclusions 79 Chapter V. Single-particle characterization of Antarctic aerosols collected at King George Island, Chile 80 1. Introduction 80 2. Experimental section 82 2.1 Samples 82 2.2. Low-Z particle EPMA measurements and data analysi
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College of Natural Science(자연과학대학) > Chemistry (화학) > Theses(화학 석박사 학위논문)
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