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Investigating sources and sinks of organic aerosols: nitrate radical initiated oxidation of isoprene and heterogeneous oxidation of organic aerosol

Citation

Kwan, Alan J. (2011) Investigating sources and sinks of organic aerosols: nitrate radical initiated oxidation of isoprene and heterogeneous oxidation of organic aerosol. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:06222010-150731880

Abstract

Secondary organic aerosol (SOA) are important components in atmospheric processes and significantly impact human health. The complexity of SOA composition and formation processes has hampered efforts to fully characterize their impacts, and to predict how those impacts will be affected by changes in climate and human activity. Here, we explore SOA formation in the laboratory by coupling an environmental chamber with a suite of analytical tools, including a gas-phase mass spectrometry technique that is well suited for tracking the hydrocarbon oxidation processes that drive SOA formation. Focusing on the oxidation of isoprene by the nitrate radical, NO_3, we find that reactions of peroxy radicals (RO_2) to form ROOR dimers is an important process in SOA formation. The other gas-phase products of these RO_2 reactions differ from what is expected from studies of simpler radicals, indicating that more studies are necessary to fully constrain RO2 chemistry. Finally, we examine the role of heterogeneous oxidation as a sink of organic aerosol and a source of oxygenated volatile organic compounds in the free troposphere.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:isoprene; chamber studies; secondary organic aerosol; nitrate radical; peroxy radicals;
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Environmental Science and Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Wennberg, Paul O.
Thesis Committee:
  • Seinfeld, John H.
  • Sessions, Alex L. (chair)
  • Okumura, Mitchio
  • Wennberg, Paul O.
Defense Date:8 June 2010
Record Number:CaltechTHESIS:06222010-150731880
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:06222010-150731880
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5955
Collection:CaltechTHESIS
Deposited By: Alan Kwan
Deposited On:17 May 2011 22:59
Last Modified:26 Dec 2012 04:29

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PDF (Full Thesis) - Final Version
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PDF (Title, Acknowledgments, Table of Contents) - Final Version
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PDF (Chapter 1: Introduction) - Final Version
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PDF (Chapter 2: SOA from isoprene-NO3 reactions) - Final Version
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PDF (Chapter 3: Products of isoprene-NO3 RO2-RO2 reactions) - Final Version
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PDF (Chapter 4: Potential OVOC flux from organic aerosol oxidation) - Final Version
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PDF (Chapter 5: Conclusions and future directions) - Final Version
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PDF (Appendix: Publication list) - Final Version
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