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Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Combustion Soot Nanoparticles: Mechanism Of Restructuring And Mechanical Properties, Ali Hasani Dec 2022

Combustion Soot Nanoparticles: Mechanism Of Restructuring And Mechanical Properties, Ali Hasani

Dissertations

Soot, a product of incomplete combustion of fossil fuels, is a global warming agent. The effect of soot particles on climate depends on their morphology. Freshly released soot particles are fractal lacey aggregates, but they often appear collapsed in atmospheric samples collected away from emission sources. A body of work has concluded that the collapse is caused by liquid shells when they form by vapor condensation around soot aggregates. However, some recent studies argue that soot remains fractal even when engulfed by the shells, collapsing only when the shells evaporate. To reconcile this disagreement, the effects of the condensation and …


The Aging And Impacts Of Atmospheric Soot: Closing The Gap Between Experiments And Models, Ogochukwu Yvonne Enekwizu Dec 2020

The Aging And Impacts Of Atmospheric Soot: Closing The Gap Between Experiments And Models, Ogochukwu Yvonne Enekwizu

Dissertations

The main goal of this dissertation is to generate data and parameterizations to accurately represent soot aerosols in atmospheric models. Soot from incomplete combustion of fossil fuels and biomass burning is a major air pollutant and a significant contributor to climate warming. The environmental impacts of soot are strongly dependent on the particle morphology and mixing state, which evolve continuously during atmospheric transport via a process known as aging. To make predictions of soot impacts on the environment, most atmospheric models adopt simplifications of particle structure and mixing state, which lead to substantial uncertainties. Using an experimentally constrained modeling approach, …


Effect Of Carbonaceous Nanoparticles On Naturally Occurring Iron Reduction By Carboxylates, Ashleen Reddy Jan 2019

Effect Of Carbonaceous Nanoparticles On Naturally Occurring Iron Reduction By Carboxylates, Ashleen Reddy

All Master's Theses

The emission of ambient particulate matter (PM) is regulated by many institutions due to the detrimental effects on health, environment and climate; yet many underlying mechanisms of PM reactivity are still not well understood. In the current study, the effect of carbonaceous nanoparticles (CNPs), contained within ultrafine PM (particle diameter ≤ 100 nm), is investigated on naturally occurring processes that increase the abundance of bioavailable iron. Enhancing iron bioavailability (i) increases primary productivity of iron-limited microorganisms, affecting the carbon cycle and global climate, and (ii) increase toxicity of inhaled particles through the associated production of reactive oxygen species (ROS). Specifically, …


Field Evaluation Of Portable Air Quality Monitors And Evaluation Of Short-Lived Plume Events Of Atmospheric Pollutants, Joseph Peter Marto Jan 2018

Field Evaluation Of Portable Air Quality Monitors And Evaluation Of Short-Lived Plume Events Of Atmospheric Pollutants, Joseph Peter Marto

Legacy Theses & Dissertations (2009 - 2024)

Availability of low cost optical sensors has allowed for the supplementation of existing air quality infrastructure with portable, adaptive monitors. While these sensors generally cannot offer the same accuracy and precision as established analysis methods, they can still reliably detect changes in pollutant concentration. This study evaluates the performance of two portable air quality enclosures deployed at collocated research sites to determine their accuracy and usefulness in field deployments. One system deployed collocated sensors for measurement of particulate matter mass concentration (Thermo pDR 1500 and TSI DustTrak DRX for PM2.5) and the second system deployed sensors for measurement of black …