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Constraining the Formation and Fate of Hydroperoxides in the Remote Atmosphere

Citation

Allen, Hannah Marie (2021) Constraining the Formation and Fate of Hydroperoxides in the Remote Atmosphere. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/1108-c936. https://resolver.caltech.edu/CaltechTHESIS:06012021-172201123

Abstract

Atmospheric hydroperoxides form as second generation products in the atmospheric oxidation of many volatile organic compounds (VOCs) during reactions of these VOCs with OH and HO2 (i.e. HOx), where HOx are among the atmosphere's main oxidants and thus drivers of the majority of atmospheric chemistry. Once formed, the lifetime and ultimate fate of hydroperoxides are set by a variety of potential chemical and physical pathways that have different impacts on the atmosphere's oxidizing capacity, including either recycling HOx or removing HOx. This dissertation explores the role of hydroperoxides with several different structures through field and laboratory studies using CF3O- chemical ionization mass spectrometry (CIMS) to understand the role of these hydroperoxides in the oxidation chemistry of the remote atmosphere.

Hydrogen peroxide (H2O2) and methyl hydroperoxide (MHP, CH3OOH) are two of the most abundant hydroperoxides found in oceanic environments. Both hydroperoxides were measured using time of flight and tandem quadrupole CIMS aboard the NASA DC-8 aircraft during the Atmospheric Tomography Mission, enabling a seasonal investigation into their global distribution with near pole-to-pole coverage across the Pacific and Atlantic Oceans and ranging in altitude from the marine boundary layer to the upper troposphere and lower stratosphere. Hydroxymethyl hydroperoxide (HMHP, HOCH2OOH) and isoprene hydroxy hydroperoxides (ISOPOOH, HOC5H8OOH) are organic hydroperoxides derived from the oxidation of isoprene, one of the dominant biogenic VOCs in forested environments. The loss of HMHP from the atmosphere via reaction with OH is investigated in the laboratory using time of flight CIMS and laser induced fluorescence along with theoretical chemical modeling methods. To better distinguish the varying roles of structurally complex hydroperoxides, a novel field-deployable gas chromatograph integrated with a high resolution time of flight CIMS is developed that sensitively detects hydroperoxides along with a number of other oxidation products. This instrument is deployed at a rural forested site in northern Michigan during the PROPHET field campaign to probe the relative contribution of different ISOPOOH isomers to the oxidation pathways of isoprene.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Atmospheric chemistry; chemical ionization mass spectrometry; hydroperoxides; field measurements; Atmospheric Tomography campaign; PROPHET campaign; troposphere; oxidation mechanisms
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Restricted to Caltech community only
Research Advisor(s):
  • Wennberg, Paul O.
Thesis Committee:
  • Okumura, Mitchio (chair)
  • Seinfeld, John H.
  • Stoltz, Brian M.
  • Wennberg, Paul O.
Defense Date:19 May 2021
Funders:
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE-1144469
NSFAGS-1428482
NSFAGS-1240604
NASAUNSPECIFIED
Record Number:CaltechTHESIS:06012021-172201123
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:06012021-172201123
DOI:10.7907/1108-c936
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/acs.jpca.8b04577DOIAdapted for Chapter 4
https://doi.org/10.5194/amt-11-6815-2018DOIAdapted for Appendix A
ORCID:
AuthorORCID
Allen, Hannah Marie0000-0002-4218-5133
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14221
Collection:CaltechTHESIS
Deposited By: Hannah Allen
Deposited On:02 Jun 2021 17:55
Last Modified:02 Jun 2021 17:55

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