Date of Award
Chemistry and Biochemistry
Brian J. Majestic, Ph.D.
Bryan J. Cowen
Rebecca L. Powell
Fe speciation, Hybrid single particle Lagrangian integrated trajectory, Ion-exchange chromatography, MC-ICP-MS, Multi-collector inductively coupled plasma mass spectrometry, PCA, Principal component analysis, Strontium isotopes, Lead isotopes
The work presented herein details the source apportionment of atmospheric particulate matter in developing countries (Kyrgyzstan in Central Asia, metropolitan cities in Northern India, and Shenzhen in China) using trace elements and stable metal isotope ratios. The first study focused on the development of a novel method for the concomitant separation of rare-earth elements in environmental samples of any geological origin. The separation procedure is based on three extraction chromatographic materials, referred to as Sr.Spec, TRU.Spec, and Ln.Spec. This triple column arrangement enables the simultaneous isolation of pure Sr and Nd fractions in less than one day and with great reproducibility. This procedure greatly minimizes the consumption of acids necessary for the separation, allows high yields of Sr and Nd, and realizes very low blank levels.
Using the aforementioned method, the second study focused on if Aral Sea sediments are an important source of particulate matter in Central Asia. Central Asia is dominated by an arid climate and desert-like conditions, leading to the potential for long-range transport of desert dust within and out of the region. One potential source of dust within Central Asia is the Aral Sea, which has receded in size due to water diversion. As a result, newly exposed sediments and associated contaminants are resuspended by the wind and are a potential new source of particulate matter within in the region. Results from this study showed that Central Asia is impacted by yet unidentified regional and distant dust that requires additional measurements of desert sands in and around Central Asia.
The third study focused on the outcome of imposed pollution restrictions in Shenzhen during the 16th Universiade, an international multi-sport event, hosted in 2011. During this time, officials instituted several restrictions in the region in order to enhance the air quality of Shenzhen. The airborne PM2.5 was collected during the controlled (when the restrictions were in place) and uncontrolled periods. Results from this study showed a significant increase in the elemental concentrations during the uncontrolled periods. These studies describe the transport of dust and identify some of the geological characteristics of important source areas.
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Dewan, Nitika, "Source Apportionment of Atmospheric Particulate Matter in Developing Countries Using Trace Elements and Stable Metal Isotope Ratios" (2016). Electronic Theses and Dissertations. 1193.
Received from ProQuest
Atmospheric Chemistry, Chemistry