Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"Secondary organic aerosol (SOA)"”.
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Measurement and characterization of low volatility organic compounds in the atmosphere
Organic aerosol is a central topic in environmental science due to its role in climate forcing and negative health effects. The transformation of organic species from primary gas phase emissions to secondary organic aerosol (SOA) is highly complex and poorly understood, proving difficult for even …
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Characterization and source apportionment of ambient PM2.5 in Atlanta, Georgia: on-road emission, biomass burning and SOA impact
… Georgia: On-Road Emission, Biomass Burning and SOA Impact Bo Yan 260 Pages Directed by Drs. Armistead G. Russell and Mei Zheng Various airborne PM2.5 samples were collected in the metropolitan Atlanta and surrounding areas, which are directly impacted or dominated by on-road mobile and other …
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Development & Testing of Novel Atmospheric Chemistry Technologies
<p>Atmospheric aerosols play an important role in global atmospheric chemistry and climate and have a detrimental impact on human health. Advancements in measurement technologies allow for better monitoring of atmospheric composition and dynamics, creating better predictive models and understanding …
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Biomass burning emissions on regional-global scales
… factor (EF) measurements for non-methane organic compounds (NMOC), which are highly reactive and can influence secondary organic aerosol (SOA) and ozone formation. New EF should improve the input for atmospheric models along with regional-global BB emissions estimates. We present an …
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Biomass burning emissions on regional-global scales
… factor (EF) measurements for non-methane organic compounds (NMOC), which are highly reactive and can influence secondary organic aerosol (SOA) and ozone formation. New EF should improve the input for atmospheric models along with regional-global BB emissions estimates. We present an …
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Investigating the ice nucleation activity of organic aerosol
Emissions of aerosol particles and their precursors affect climate directly by scattering radiation and indirectly by altering cloud properties. Aerosol-induced ice nucleation includes several processes that impact cloud formation, lifetime, albedo, and precipitation efficiency. Ice nucleating …
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Role of Water in the Formation, Transformation and Fate of Secondary Organic Aerosol
… water is the most abundant atmospheric aerosol constituent, yet the importance of water for the formation, transformation and fate of secondary organic aerosol (SOA) remains not fully characterized. In order to address this knowledge gap, this thesis explores the role of water in SOA …
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Aqueous-phase Organic Chemistry in the Atmosphere
Atmospheric aqueous phases (i.e. cloud, fog and aerosol liquid water) are important reaction media for the processing of organic compounds. Quantitative data on aqueous-phase organic chemistry under the atmospheric context are sparse compared to the data from comparable gas-phase processes. A …
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Cellular and acellular assays for measuring oxidative stress induced by ambient and laboratory-generated aerosol
… intracellular ROS/RNS produced as a result of aerosol exposure. The area under the dose-response curve was identified as a robust metric to represent ROS/RNS for comparison with different endpoints. A large ambient study with samples collected from urban and rural sites around the greater …
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Atmospheric chemistry and aerosol associated with the coastal urban environment
… aims to understand the dynamics of atmospheric secondary organic aerosol (SOA) in Houston, Texas. It (1) explores the relationship between sea breeze and air quality, (2) investigates the spatiotemporal characteristics of aerosols and SOA formation rates, and (3) analyzes factors that impact new …
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Aqueous Atmospheric Species, a Dual Study: 1. Comparison of the Effects of Temperature, Oxygen Level, Ionic Strength, and pH on the Reaction of Benzene with Hydroxyl Radicals at the Air-water Interface to the Bulk Aqueous Phase. 2. Determination of Carbonyl Compounds in Fog Water Samples via Online Concentration and HPLC
… given surface area inside the reactor. Volatile organic compounds (VOCs), like benzene, can also degrade in the environment by oxidation to form carbonyl compounds, which, like benzene, are also ubiquitous air, cloud, and fog water pollutants. Furthermore, they also form secondary organic aerosol …
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Elucidating the chemistry of particulate and chlorinated nitrates in the troposphere through method development, and chamber and field studies
… impact the budgets of atmospheric oxidants and aerosol. Mixing ratios of nitryl chloride (ClNO2) were measured by chemical ionization mass spectrometry (CIMS) during the ORCA campaign in July 2015 on the west coast of Vancouver Island. Mean ClNO2 mixing ratios were small (< 10 pptv) with a …
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Laboratory studies of atmospheric photochemistry in indoor and outdoor environments
Secondary organic aerosol (SOA), fine particulate matter formed through indirect photochemical reactions, influences the climate and contributes to air pollution harmful to human health. While these two effects act at different scales, they are governed by similar chemical processes. This work …
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Investigating volatile organic compound composition in Houston, Texas amidst an atmospheric regime shift.
… and, consequently, public health. Volatile organic compounds (VOCs) are a key component of urban air quality, emitted from anthropogenic and biogenic sources. Over decades, researchers have characterized VOC emission sources to better understand their role in forming ozone and secondary …
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Chemical and Physical Studies of Secondary Organic Aerosol Formed from Beta-pinene Photooxidation
Atmospheric organic aerosols have a significant impact on climate and human health. However, our understanding of the physical and chemical properties of these aerosols is inadequate, thus their climate and health influences are poorly constrained. In this study, we investigated the secondary …
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Modeling secondary organic aerosol formation from biogenic hydrocarbons
<p>Secondary organic aerosol (SOA) is formed generally by the oxidation of gas-phase volatile organic compounds (VOCs) to form semi- or non-volatile products that then undergo gas to particle partitioning. In this work, the Caltech Atmospheric Chemistry Mechanism (CACM) and the Model to Predict the …
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Investigating volatile organic compound composition in Houston, Texas amidst an atmospheric regime shift.
… and, consequently, public health. Volatile organic compounds (VOCs) are a key component of urban air quality, emitted from anthropogenic and biogenic sources. Over decades, researchers have characterized VOC emission sources to better understand their role in forming ozone and secondary …
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New Measurement Approaches to the Study of Secondary Organic Aerosol
Aerosol particles constitute a class of atmospheric pollutants that are detrimental to human health and influence the Earth’s climate. A significant fraction of aerosol mass is composed of organic material, produced by photochemical reactions of organic trace gases which form secondary organic …
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Investigating the Molecular Composition of Rainwater and Secondary Organic Aerosol using Ultra-High Resolution Mass Spectrometry
… provide complete molecular characterisation of organic aerosol. However atmospheric aerosol often has complex, mixed organic and inorganic composition and soft ionisation techniques that have been developed to ionise organic aerosol specifically, are susceptible to salt suppression effects and …
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Ambient measurements of chemical and physical properties of organic aerosols: Insights into formation, growth, and heterogeneous chemistry
<p>Organic aerosols are a ubiquitous component of the troposphere, from heavily polluted cities to the remote Arctic. In Chapters II, III, and V of this dissertation, the formation of organic aerosol through observations of ambient size distributions is addressed. Chapter IV presents a new pathway …
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