Date of Award

Fall 2013

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry & Biochemistry

Program/Concentration

Chemistry

Committee Director

Patrick G. Hatcher

Committee Member

James W. Lee

Committee Member

Jingdong Mao

Committee Member

Balasubramanian Ramjee

Call Number for Print

Special Collections LD4331.C45 G87 2013

Abstract

Aerosol particulate matter is acknowledged to have effects on health and the environment and further investigation into the molecular characteristics of aerosols is necessary in order to fully understand the potential links between the molecular characteristics and the impacts that these particles have on health and the environment. Aerosols are often discussed with reference to their size because particles of different sizes can often be associated with different primary sources. This study presents a molecular-level chemical characterization of the water soluble organic matter fraction of 17 aerosol impactor samples representing 3 air mass influences (North American, North African, and marine) collected over the North Atlantic Ocean as part of the 2011 US GEOTRACES cruise via electrospray ionization Fourier transfor1n ion cyclotron resonance mass spectrometry. Aerosol water soluble organic matter of the different size fractions within each sample showed unique molecular-level chemical characteristics, with the smallest size fractions showing the biggest differences. The results suggest that the water soluble organic matter complexity lies in the fine fraction of North American and North African-influenced aerosols, and in the coarser fraction of marine-influenced aerosols. The presence of highly oxidized compounds in the fine fractions indicates atmospheric aging. Carboxylic acid-like compounds were identified in the coarse fractions of each sample. The presence of these compounds could play a role in metal-ligand binding which may increase the solubility of metals in aerosols. Condensed compounds, which can affect the global climate by absorbing solar radiation, were detected in all size fractions, indicating their ubiquitous nature in the atmosphere. The remarkable differences between the molecular characteristics of the water soluble organic matter from the coarser and finer size fractions in these samples demonstrates the importance of collecting size resolved aerosols in order to obtain a full molecular characterization of the aerosol water soluble organic matter.

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DOI

10.25777/8s3d-qd64

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