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Physico-chemical Characteristics and...

Sowlat, Mohammad Hossein.

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Physico-chemical Characteristics and Sources of Ambient PM Mass and Number Concentrations and Their Associated Toxicity, and Development of Novel Techniques for High Time-resolution Measurement of PM-bound Metals for Application in Source Apportionment Studies.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Physico-chemical Characteristics and Sources of Ambient PM Mass and Number Concentrations and Their Associated Toxicity, and Development of Novel Techniques for High Time-resolution Measurement of PM-bound Metals for Application in Source Apportionment Studies./
Author:	Sowlat, Mohammad Hossein.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2019,
Description:	133 p.
Notes:	Source: Dissertations Abstracts International, Volume: 81-09, Section: B.
Contained By:	Dissertations Abstracts International81-09B.
Subject:	Aeronomy. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27798703
ISBN:	9781392848210

Physico-chemical Characteristics and Sources of Ambient PM Mass and Number Concentrations and Their Associated Toxicity, and Development of Novel Techniques for High Time-resolution Measurement of PM-bound Metals for Application in Source Apportionment Studies.
Sowlat, Mohammad Hossein.

Physico-chemical Characteristics and Sources of Ambient PM Mass and Number Concentrations and Their Associated Toxicity, and Development of Novel Techniques for High Time-resolution Measurement of PM-bound Metals for Application in Source Apportionment Studies. - Ann Arbor : ProQuest Dissertations & Theses, 2019 - 133 p.

Source: Dissertations Abstracts International, Volume: 81-09, Section: B.

Thesis (Ph.D.)--University of Southern California, 2019.

This item must not be sold to any third party vendors.

The research presented herein provides valuable information on the physical and chemical characteristics of ambient PM number and mass under different atmospheric conditions, provides insight into their sources, and finally, offers a novel approach for high time-resolution measurement of the chemical components of ambient PM that can be used in source apportionment studies. Our work begins by the study of physical characteristics and sources of ambient PM number concentrations in central Los Angeles, in a location significantly influenced by traffic-related emissions. In this study, particle number size distributions were measured over a year-long sampling campaign in central Los Angeles, CA, covering the full size spectrum from 13 nm to 10 µm. Particle number size distributions were then used as inputs to the USEPA's Positive Matrix Factorization (PMF) model (version 5.0) to identify the sources of particle number concentrations in central Los Angeles. The contribution of each source was quantified and the temporal (seasonal and diurnal) variations for each sources were compared and discussed. In the next work, we present the chemical composition and toxicity of ambient PM and fog water in a rural location in the Po Valley, Italy, an area that experiences severe fog episodes during the winter time, explore the sources that contribute to ambient PM, fog water, and their associated toxicity, and determine how fog partitioning impacts the chemical composition and toxicity of ambient PM. For this purpose, we collected fog water samples using a fog water collector, while daytime and nighttime particles were also collected using a high-volume sampler. Samples were analyzed for their carbonaceous, ionic, elemental and metallic components. We also analyzed the samples for oxidative potential, using the alveolar macrophage (AM) assay. We then explored how fog formation might impact the chemical composition and, in turn, toxicity of ambient PM. The results from study have important implications for other areas, such as Los Angeles, that experience fog episodes, because, as described in detail in the paper, this phenomenon can critically increase the toxicity of ambient PM through aqueous-phase chemistry. And, finally, in the third and last study, we developed an online metal monitor for time-resolved measurement of (a time resolution of 2-hr) three important redox-active metals, namely Iron (Fe), Manganese (Mn), and Chromium (Cr), that are bound to ambient coarse particulate matter (PM) (i.e., 10₁₀₋₂.₅). To this end, we used virtual impactors (VIs) to first enrich coarse PM concentration into the target flow and then capture them in water slurry using a Biosampler. We then added specific chemical reagents (pertinent to each metal) to the slurry samples, which lead to the formation of colored complexes, the intensity of which (which is proportional to metal concentrations) was then measured using a Micro Volume Flow Cell (MVFC) coupled with UV/VIS spectrophotometry. The monitor was then deployed in the field, and its performance was measured and compared with that of a standard method (i.e., inductively coupled plasma-mass spectrometry (ICP-MS)) over a four-month period from January through April 2016. The data collected by the monitor were then used to obtain time-resolved time-series and diurnal variations plots of metal concentrations, which were used in combination of wind rose plots in infer information about the sources.

ISBN: 9781392848210Subjects--Topical Terms:

2102064
Aeronomy.
Subjects--Index Terms:

Ambient PM number

Physico-chemical Characteristics and Sources of Ambient PM Mass and Number Concentrations and Their Associated Toxicity, and Development of Novel Techniques for High Time-resolution Measurement of PM-bound Metals for Application in Source Apportionment Studies.
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500 $a Source: Dissertations Abstracts International, Volume: 81-09, Section: B.
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506 $a This item must not be sold to any third party vendors.
520 $a The research presented herein provides valuable information on the physical and chemical characteristics of ambient PM number and mass under different atmospheric conditions, provides insight into their sources, and finally, offers a novel approach for high time-resolution measurement of the chemical components of ambient PM that can be used in source apportionment studies. Our work begins by the study of physical characteristics and sources of ambient PM number concentrations in central Los Angeles, in a location significantly influenced by traffic-related emissions. In this study, particle number size distributions were measured over a year-long sampling campaign in central Los Angeles, CA, covering the full size spectrum from 13 nm to 10 µm. Particle number size distributions were then used as inputs to the USEPA's Positive Matrix Factorization (PMF) model (version 5.0) to identify the sources of particle number concentrations in central Los Angeles. The contribution of each source was quantified and the temporal (seasonal and diurnal) variations for each sources were compared and discussed. In the next work, we present the chemical composition and toxicity of ambient PM and fog water in a rural location in the Po Valley, Italy, an area that experiences severe fog episodes during the winter time, explore the sources that contribute to ambient PM, fog water, and their associated toxicity, and determine how fog partitioning impacts the chemical composition and toxicity of ambient PM. For this purpose, we collected fog water samples using a fog water collector, while daytime and nighttime particles were also collected using a high-volume sampler. Samples were analyzed for their carbonaceous, ionic, elemental and metallic components. We also analyzed the samples for oxidative potential, using the alveolar macrophage (AM) assay. We then explored how fog formation might impact the chemical composition and, in turn, toxicity of ambient PM. The results from study have important implications for other areas, such as Los Angeles, that experience fog episodes, because, as described in detail in the paper, this phenomenon can critically increase the toxicity of ambient PM through aqueous-phase chemistry. And, finally, in the third and last study, we developed an online metal monitor for time-resolved measurement of (a time resolution of 2-hr) three important redox-active metals, namely Iron (Fe), Manganese (Mn), and Chromium (Cr), that are bound to ambient coarse particulate matter (PM) (i.e., 10₁₀₋₂.₅). To this end, we used virtual impactors (VIs) to first enrich coarse PM concentration into the target flow and then capture them in water slurry using a Biosampler. We then added specific chemical reagents (pertinent to each metal) to the slurry samples, which lead to the formation of colored complexes, the intensity of which (which is proportional to metal concentrations) was then measured using a Micro Volume Flow Cell (MVFC) coupled with UV/VIS spectrophotometry. The monitor was then deployed in the field, and its performance was measured and compared with that of a standard method (i.e., inductively coupled plasma-mass spectrometry (ICP-MS)) over a four-month period from January through April 2016. The data collected by the monitor were then used to obtain time-resolved time-series and diurnal variations plots of metal concentrations, which were used in combination of wind rose plots in infer information about the sources.
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