Characterizing the physicochemical properties of organic matter in atmospheric aerosols : effects of humic-like substances on hygroscopic growth and cloud activation
Abstract/Contents
- Abstract
- Organic matter may have a significant impact on the hygroscopic growth and cloud activation of atmospheric aerosols, thus affecting human health, atmospheric chemistry, and Earth's climate. The work presented in this dissertation characterizes the physicochemical properties of organic matter in atmospheric aerosols with the aim of improving current aerosol knowledge, and better informing global climate and chemistry models. To this end, I performed water activity and surface tension measurements on bulk solutions analogous to organic aerosol composition, using an in-house vapor pressure apparatus and a tensiometer. Experiments conducted focused on humic-like substances (HULIS), an important category of water-soluble organic compounds (WSOC), through the use of fulvic and humic acids as analogs. I have demonstrated the use of bulk water vapor pressure measurements coupled with thermodynamic calculations as an effective method to study the hygroscopic growth of organic aerosols. This method is a simple, inexpensive and reliable way to obtain accurate water activity data, and has several advantages over particle measurement instruments. Water activity parameterizations, and their variation with temperature and Kelvin effects, were reported for several pure and mixed WSOC particles. Hygroscopic growth versus relative humidity curves, individual hygroscopic growth factors and deliquescence measurements were also presented for these systems. The surface tensions of solutions representing HULIS and its mixtures were measured and parameterized for concentration ranges relevant to cloud droplet activation. These data suggest that the depression effects of the organic surfactant govern the surface tension behavior of aqueous solutions of HULIS and its mixtures. Water activity and surface tension parameterizations were input into the Köhler theory to predict cloud droplet activations for various mixed organic aerosol systems. Comparing these predictions with measured data highlighted the importance of considering both effects on modeling cloud formation accurately. Lastly, the critical supersaturations predicted for multicomponent mixtures representing biomass burning and continental polluted aerosol may provide an upper and lower bound for the cloud droplet activation of HULIS particles from biomass burning and urban origin.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2013 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Zamora, Idania Rodríguez |
|---|---|
| Associated with | Stanford University, Program in Earth, Energy and Environmental Sciences. |
| Primary advisor | Jacobson, Mark Z. (Mark Zachary) |
| Thesis advisor | Jacobson, Mark Z. (Mark Zachary) |
| Thesis advisor | Golden, David |
| Thesis advisor | Hildemann, Lynn M. (Lynn Mary) |
| Advisor | Golden, David |
| Advisor | Hildemann, Lynn M. (Lynn Mary) |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Idania Rodríguez Zamora. |
|---|---|
| Note | Submitted to the Program in Earth, Energy and Environmental Sciences. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2013. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2013 by Idania Rodriguez Zamora
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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