Document Type

Thesis

Date of Degree

Summer 2015

Degree Name

MS (Master of Science)

Degree In

Chemical and Biochemical Engineering

First Advisor

Vicki H. Grassian

Abstract

Currently, there exists a great deal of uncertainty regarding atmospheric aerosols and the role that they play within the Earth’s atmosphere. It is known that atmospheric aerosols can play a role in the Earth’s climate by scattering and absorbing solar radiation or acting as a cloud condensation nuclei. The purpose of this work is to obtain an improved understanding of the chemistry of atmospheric aerosols to better determine their impacts the environment, air quality, and climate.

This work revolves around one specific type of atmospheric aerosol, i.e. sea spray aerosol. Sea spray aerosol is generated via breaking waves, through wind-driven mechanisms. Ocean water covers roughly 71% of the Earth’s surface, and from this over 1300 Tg of sea spray aerosols is emitted into the atmosphere every year. However, until recently, the study of sea spray was very challenging and often inconclusive due to the inability to filter background particles out. In this work, the understanding of sea spray aerosol is progressed by taking a two-pronged approach. First, this work focuses on the study of model systems of simple ocean surfactants and NaCl and the change in chemistry that occurs when the two are in the presence of each other. Second, sea spray samples generated during a biological bloom are isolated and analyzed. Using this two pronged approach, it is shown that model systems can provide supporting evidence for hypotheses created from trends discovered in more complex samples. Finally, common aerosol generation, storage, and analysis techniques are studied in order to improve our understanding of their effects on aerosol particles.

Public Abstract

For many decades, global warming has been a worldwide concern due to its potential harmful effects on society. In addition to the more commonly known cause of this global phenomenon, greenhouse gases, another important component of the Earth’s atmosphere is atmospheric aerosols. Atmospheric aerosols are small, solid and/or liquid particles suspended in the air that vary greatly in size and chemical composition. Much of these variations are a result of the wide variety of natural and man-made sources that emit aerosols into the atmosphere. Like greenhouse gases, these particles can significantly influence the Earth’s climate. However, in contrast to greenhouse gases, it is not well understood as how and to what extent, do aerosols impact the climate.

In this work, we learn more about one of the most abundant types of atmospheric aerosol, namely sea spray. Although invisible to the naked eye, millions of tiny sea spray aerosols are constantly being released from the Earth’s ocean into the atmosphere via breaking waves. Here we take a look at how the chemical components and processes of the ocean can alter the properties of sea spray aerosols. This knowledge will bring us one step further in understanding the influence these aerosols have on our climate.

Keywords

publicabstract, CAICE, Chloride Depletion, Climate, Model System, Ocean, Sea Spray Aerosol

Pages

xiii, 68

Bibliography

60-68

Copyright

Copyright 2015 Joshua Ryan Grandquist

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