Single Particle Studies of Heterogeneous Atmospheric Chemistry
EMSL Project ID
2410
Abstract
It is becoming increasingly clear that heterogeneous processes involving particulate matter in the atmosphere can greatly perturb the chemical composition of both the troposphere and the stratosphere. Mineral dust and seasalt represent major and ubiquitous tropospheric aerosol components. While there are a growing number of modeling studies which suggest that reactions on the surface of mineral and sea salt aerosols may play an important role in the tropospheric NOy, SOy and O3 budgets, there is very little detailed understanding of the chemistry which occurs on the surface of aerosol particles. In order to incorporate heterogeneous chemistry into atmospheric chemistry models, the rates and mechanisms of these reactions must be understood. Kinetic studies of heterogeneous chemistry is complicated by the fact that these studies are typically done using bulk samples which contain many particles. Diffusion into the sample and how to take the diffusion into account has caused disagreement between scientists in the literature. Studies of single particles will circumvent this problem. In the proposed studies, we plan to investigate the heterogeneous chemistry of mineral dust and sea salt using single particle analysis. These studies will be done in collaboration with Dr. Alexander Laskin, EMSL Research Scientist, Dr. James Cowin, EMSL Chief Scientist, and James Young, EMSL Science/Engineering Associate. Brenda Krueger, a graduate student at the University of Iowa, will work with Dr. Laskin at EMSL on these experiments. The experiments will involve using the scanning electron microscope and the energy dispersive x-ray analysis coupled to that microscope at EMSL. Dr. Laskin has shown in field studies that this instrument is capable of single particle analysis and thus will be appropriate for the type of studies that we plan to do. The relative rates of reaction for nitric acid on NaCl, a major component of sea salt, to CaCO3 and SiO2, components of mineral dust, will be compared. Based on recent field studies by Laskin and coworkers, it is anticipated that the NaCl particles will be the most reactive, CaCO3 particles the next most reactive and SiO2 particles being relatively unreactive. These particles will be imaged and analyzed prior to reaction with nitric acid and then imaged and analyzed after reaction. It is anticipated in the case of NaCl and CaCO3 that the nitrogen content of the particles will increase with time according to the reactions NaCl + HNO3 -> NaNO3 + HCl CaCO3 + 2HNO3 -> Ca(NO3)2 + H2O + CO2 These studies are important from the perspective of increasing our understanding of heterogeneous chemistry in the atmosphere and increasing our ability to use single particle analysis to study reaction chemistry. The team of scientists, Professor Grassian, University of Iowa, Brenda Krueger, University of Iowa, Dr. Alexander Laskin, EMSL Research Scieintist, Dr. James Cowin, EMSL Chief Scientist, and James Young, EMSL Science/Engineering Associate, are uniquely suited to accomplish the proposed studies. Professor Grassian and Mrs. Krueger have expertise in the kinetics of heterogeneous atmospheric chemistry. Drs. Laskin and Cowin have expertise in single particle analysis using SEM and EDXA. These studies combine the expertise of these two groups.
Project Details
Project type
Exploratory Research
Start Date
2002-01-15
End Date
2002-01-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
31st Annual Solid-State NMR meeting,Breckenridge, CO, July 2008.
poster presentation
Comparative Dynamics of Leucine Methyl Groups in FMOC-Leucine and in a Protein Hydrophobic Core Probed by Solid-State Deuteron Nuclear Magnetic Resonance over 7-324 K Temperature Range. Liliya Vugmeyster, Dmitry Ostrovsky, Mark Moses, Joseph J. Ford, Andrew S. Lipton, Gina L. Hoatson, and Robert L. Vold , J. Phys. Chem. B. Web Publication November 15, 2010; doi: 10.1021/jp1082467
Krueger BJ, VH Grassian, JP Cowin, and A Laskin. 2004. "Heterogeneous Chemistry of Individual Mineral Dust Particles from Different Dust Source Regions: The Importance of Particle Mineralogy." Atmospheric Environment 38(36):6253-6261.
Krueger BJ, VH Grassian, MJ Iedema, JP Cowin, and A Laskin. 2003. "Probing Heterogeneous Chemistry of Individual Atmospheric Particles Using Scanning Electron Microscopy and Energy-Dispersive X-ray Analysis." Analytical Chemistry 75(19):5170-5179.
Probing the Dynamics of a Protein Hydrophobic Core by Deuteron Solid-State Nuclear Magnetic Resonance Spectroscopy
Liliya Vugmeyster, Dmitry Ostrovsky, Joseph J. Ford, Sarah D. Burton, Andrew S. Lipton, Gina L. Hoatson, and Robert L. Vold
Publication Date (Web): September 3, 2009 | doi: 10.1021/ja902977u
SC07 Booth Poster