Undergraduate Honors Thesis

Abstract

• Reduced reactive nitrogen species, which primarily consist of ammonia and low-mass amines, occur in the gas-phase and the particle-phase of the atmosphere. Despite being present at trace concentrations, these species can have severe effects on eutrophication, biodiversity, human pulmonary and cardiac health, and deposition. Long-term sampling of these species is infrequent, and such sampling that has taken place is focused around agricultural sources rather than urban environments. A greater understanding of the gas-particle partitioning of these species elucidates our understanding of the roles they play in the aforementioned environmental effects. 

  I adapted the EPA’s procedure for the sampling of ambient air using annular denuders and performed troubleshooting techniques on an ion chromatograph to develop a method to collect and analyze reduced nitrogen species; with this method, phases can be examined separately, thus allowing for a greater understanding of the magnitude of each risk associated with the gas and particle-phases rather than conflating the total concentration together. Method development is a crucial step in initiating long-term sampling, because consistency is the foundation of accuracy. I began preliminary ambient sampling with a focus on ensuring the procedure works and exploring potential trends. 

   

  While further sampling over the course of years will be necessary to confirm trends, some trends are beginning to emerge: gas-phase ammonia is present in higher concentrations when the average temperature is greater. The total concentration and the ratio of gas-to-particle concentrations are still being considered, as are these apparent trends. For the future, focus should be directed towards identifying the dominant source of analyte in the second annular denuder, observing effects of different filters, refining the gradient method, and considering the maximum collectable concentration on the denuders and filter.

Creator

• Schlenker, Jared A W

Date Awarded

• 2023-11-07

Academic Affiliation

• Chemistry

Advisor

• Browne, Eleanor Carol

Committee Member

• Parson, Robert
• Wing, Boswell A

Granting Institution

• University of Colorado Boulder

Last Modified

• 2022-11-14

Resource Type

• Undergraduate Honors Thesis

Rights Statement

• In Copyright

Language

• English [eng]

Relationships

In Collection:

• Arts and Sciences Honors Program

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