November 2002 Meeting Announcement, Delaware Valley Mass Spectrometry Discussion Group
- Topic: "Single Particle Mass Spectrometry for the Analysis of Vehicle Emissions: A Tale of Three Studies"
- Speaker:Deborah Gross ,
- Date: Monday, November 11, 2002. 6:30 PM
- Time: Social Hour: 6:30 PM. (Pizza and Beer)
Talk: 7:30 PM.
- Place: Widener University, Webb Room.
- Abstract: Atmospheric aerosol particles are generated by both natural and anthropogenic sources. They affect visibility and climate and have been correlated with adverse effects for humans and the environment. Traditionally, bulk properties of aerosols have been analyzed to obtain information about the composition of atmospheric particles. While these techniques provide a huge amount of information, they cannot resolve the compositional differences in particles of the same nominal size, and they lack sufficient time resolution to observe rapid changes in aerosol populations. Recent advances in the field of single-particle mass spectrometry have made it possible to interrogate the atmospheric aerosol one particle at a time, and in real time. Aerosol Time-of-Flight Mass Spectrometry (ATOFMS) , a single-particle technique that obtains size and two mass spectra (positive and negative ions) for each particle sampled, was used to obtain the data described in this presentation.
Vehicle emissions are a significant source of particulate pollution which most of us come in frequent contact with, and the composition of these emissions depends strongly on the type of vehicle and conditions under which it is operating. Sources of particulate emissions into the atmosphere can be characterized directly with transportable versions of the ATOFMS. Three studies of the particulates from vehicle emissions will be described in this presentation: 1) Carleton College and the University of California, Riverside conducted a study in July 2000 in the Caldecott Tunnel in Berkeley, CA to examine, characterize, and differentiate on-road gasoline and diesel particulate emissions on the individual particle level. 2) Non-exhaust emissions also contribute to the "vehicle emissions" aerosol. Last spring, Carleton College and the University of Wisconsin, Madison, looked at resuspended brake dust and ground brake pads, to assess the contribution of this emission source to the on-road emissions. 3) In another Carleton/UW Madison study, the emissions from a heavy-duty diesel research engine were sampled under a variety of steady and changing conditions. The results obtained from these studies will be compared to filter-based bulk collections of particles and to the conditions under which the engine is operating. Overall, studies such as the three described in this presentation will help us to better characterize the various emissions from both gasoline and diesel vehicles, as well as to better apportion the ambient aerosol to specific sources.
 Gard, E., Mayer, J.E., Morrical, B.D., Dienes, T., Fergenson, D.P., Prather, K.A. Anal. Chem. 1997, 69, 4083-4091.
Deborah Gross received a B. A. in Chemistry from Haverford College (1991), and then attended graduate school in Physical/Analytical Chemistry at the University of California, Berkeley. At Berkeley, she worked with Evan Williams, and got experience with Fourier-Transform Mass Spectrometry methods for the investigation of the gas-phase structure of biomolecule ions. After receiving a Ph.D. in 1996, she worked for two years as a Postdoctoral Fellow in the lab of Kimberly Prather at the University of California, Riverside. At Riverside, Deborah worked both in the lab and in the field with transportable Aerosol Time-of-Flight Mass Spectrometers, studying the composition and chemistry of atmospheric aerosol particles. In 1998, she began a tenure-track position in the Chemistry Department at Carleton College, Northfield, MN, where she teaches General, Analytical, and Environmental Chemistry.
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