A Caltech Library Service

Investigations of Global Chemistry-Climate Interactions and Organic Aerosol Using Atmospheric Modeling


Pye, Havala Olson Taylor (2011) Investigations of Global Chemistry-Climate Interactions and Organic Aerosol Using Atmospheric Modeling. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/WCT5-RM26.

This is the latest version of this item.


Aerosol, or particulate matter (PM), is an important component of the atmosphere responsible for negative health impacts, environmental degradation, reductions in visibility, and climate change. In this work, the global chemical transport model, GEOS-Chem, is used as a tool to examine chemistry-climate interactions and organic aerosols.

GEOS-Chem is used to simulate present-day (year 2000) and future (year 2050) sulfate, nitrate, and ammonium aerosols and investigate the potential effects of changes in climate and emissions on global budgets and U.S. air quality. Changes in a number of meteorological parameters, such as temperature and precipitation, are potentially important for aerosols and could lead to increases or decreases in PM concentrations. Although projected changes in sulfate and nitrate precursor emissions favor lower PM concentrations over the U.S., projected increases in ammonia emissions could result in higher nitrate concentrations.

The organic aerosol simulation in GEOS-Chem is updated to include aerosol from primary semivolatile organic compounds (SVOCS), intermediate volatility compounds (IVOCs), NOx dependent terpene aerosol, and aerosol from isoprene + NO3 reaction. SVOCs are identified as the largest global source of organic aerosol even though their atmospheric transformation is highly uncertain and emissions are probably underestimated. As a result of significant nighttime terpene emissions, fast reaction of monoterpenes with the nitrate radical, and high aerosol yields from NO3 oxidation, biogenic hydrocarbons reacting with the nitrate radical are expected to be a major contributor to surface level aerosol concentrations in anthropogenically influenced areas such as the United States. Globally, 69 to 88 Tg/yr of aerosol is predicted to be produced annually, approximately 22 to 24 Tg/yr of which is from biogenic hydrocarbons.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:atmospheric chemistry; chemical transport modeling; aerosol; sulfate; nitrate; ammonium; organic aerosol; POA; SOA; climate change
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemical Engineering
Minor Option:Environmental Science and Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Seinfeld, John H.
Thesis Committee:
  • Seinfeld, John H. (chair)
  • Wennberg, Paul O.
  • Flagan, Richard C.
  • Yung, Yuk L.
Defense Date:13 August 2010
Record Number:CaltechTHESIS:08172010-150049831
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5993
Deposited By: Havala Pye
Deposited On:16 Sep 2010 21:02
Last Modified:09 Oct 2019 17:05

Available Versions of this Item

  • Investigations of Global Chemistry-Climate Interactions and Organic Aerosol Using Atmospheric Modeling. (deposited 16 Sep 2010 21:02) [Currently Displayed]

Thesis Files

PDF - Final Version
See Usage Policy.


Repository Staff Only: item control page