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dc.contributor.advisorFarmer, Delphine
dc.contributor.authorFulgham, S. Ryan
dc.contributor.committeememberHam, Jay M.
dc.contributor.committeememberRavishankara, Akkihebbal R.
dc.contributor.committeememberVan Orden, Alan
dc.date.accessioned2020-08-31T10:12:04Z
dc.date.available2020-08-31T10:12:04Z
dc.date.issued2020
dc.descriptionIncludes bibliographical references.
dc.description2020 Summer.
dc.description.abstractThe biosphere-atmosphere exchange of organic gases over forests contributes to the formation of air pollution and the availability of forest nutrients. Forests can be both sources and sinks of volatile and semi-volatile organic compounds to the atmosphere. The role that forests play in controlling organic acid concentrations remains poorly understood, with multiple model-measurement comparisons reporting missing sources of formic acid. Large, missing sources of organic acids have been identified over different forested environments. Despite substantial seasonal variability in forest productivity and environmental conditions, a paucity of observations, during seasons other than summertime, is available. Although forest fires are a major source of hazardous organic gases and particulate matter, few measurements of semi-volatile organic compounds emitted by forest fires are available from within 1 km of the fire. Detection further-afield cannot disambiguate between chemistry at the source of the fire and chemical aging as a smoke plume traverses the atmosphere. Near-field observations are needed to characterize emissions attributable to combustion and pyrolysis processes. To improve understanding of processes that control the atmospheric budgets of organic acids, water-soluble pollutants with physicochemical properties similar to organic acids, and fire-emitted phenolic compounds, this dissertation reports measurements of the biosphere-atmosphere exchange of a suite of organic gases over a Rocky Mountain ponderosa pine forest in Colorado over four, seasonally-representative measurement campaigns. First, we report seasonally persistent, upward fluxes of organic acids, which are neither explained by direct emissions nor secondary production. Second, we present evidence for equilibrium partitioning into and out of water films on forest surfaces as both a missing source and sink of isocyanic acid and small alkanoic acids. Finally, we report significant enhancement of organic acids, phenolic compounds, and other nitrogen containing compounds during initiation of a controlled forest fire compared with the remainder of the burn. Nitrated phenols are rapidly produced and enhanced more than phenolic precursors during initial, higher temperature conditions. We attribute greater enhancement of nitrated phenols to high NOx emissions under higher temperature conditions.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierFulgham_colostate_0053A_16195.pdf
dc.identifier.urihttps://hdl.handle.net/10217/211809
dc.languageEnglish
dc.publisherColorado State University. Libraries
dc.relation.ispartof2020- CSU Theses and Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.subjectCIMS
dc.subjectorganic acids
dc.subjectsurface wetness
dc.subjectflux
dc.subjectbiosphere-atmosphere exchange
dc.subjectphenolic compounds
dc.titleInsights into the biosphere-atmosphere exchange of organic gases from seasonal observations over a ponderosa pine forest
dc.typeText
dcterms.rights.dplaThe copyright and related rights status of this Item has not been evaluated (https://rightsstatements.org/vocab/CNE/1.0/). Please refer to the organization that has made the Item available for more information.
thesis.degree.disciplineChemistry
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)


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