Optimization of use of Fourier transform infrared to measure the composition of fine particulate matter
Item
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Title
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Optimization of use of Fourier transform infrared to measure the composition of fine particulate matter
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Identifier
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d_2009_2013:f994b01bd3ee:10831
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identifier
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11217
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Creator
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Arriaran La Torre, Vilma Maria,
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Contributor
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Beth Wittig | Mumtaz K. Kassir
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Date
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2011
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Language
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English
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Publisher
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City University of New York.
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Subject
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Civil engineering | Environmental engineering | Atmospheric chemistry | Air | Particulate Matter | Pollution
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Abstract
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The goal of this dissertation is to evaluate the feasibility of, and develop and optimize a method that uses FTIR to measure the detailed chemical composition of organics and inorganics in ambient fine particulate matter, PM2.5. The use of FTIR will lead to the analysis of a PM2.5 sample using a single technique, without the need for extraction, nondestructively and free of analysis artifacts.;This method has been used quantitatively despite issues that may limit its accuracy. This research has developed and evaluated optimal approaches of the FTIR operation, spectra interpretation and data reduction. Each component is addressed in a separate chapter of this dissertation, in terms of the challenges and issues, prior work to address the issue, the goal and proposed research to address the issue, and the results that have been obtained.;An algorithm that does not depend on path length and uses all parameters calculated during the spectral analysis was developed in order to determine the concentrations of the functional groups present in the sample and in the actual ambient air. For accurate quantitation results, all issues related with the spectral interpretation must be solved first before inserting them into the algorithms developed.;Sample analysis experiments were designed to effectively handle the sample analysis in the FTIR spectrometer. These experiments will help to get sample spectra free of interferents that may obscure the sample interpretation. FTIR may use two different techniques for analyzing the sample that may affect the signal to noise ratio if light does not penetrate through the whole sample, therefore aerosol samples collected on the optimal substrates must be analyzed by both techniques.;Experiments for sample interpretation were designed to select the best approach to interpret the IR spectra of aerosol samples. These spectra can be difficult to interpret since the samples contain billions of particles, each of which can contain millions of chemicals. Functional groups in the aerosol spectra has to be identified and their ABS areas accurately measured by defining the correct baselines and end points of the functional group peaks. ABS measurements of targeted functional group at different concentrations were evaluated to determine the linearity of ABS and their relative molar absorptivities. This information will be used to identify, evaluate and determine the correct approaches to split overlapping functional group peaks.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Engineering
