UCSD | Department of Chemistry&Biochemistry -- Faculty & Research

Kimberly Prather
Environmental, physical/analytical chemistry: gas/particle processes of tropospheric significance; mass spectrometry; laser-based analysis techniques.

Contact Information

Professor

Dept. of Chemistry and Biochemistry

Scripps Institution of Oceanography

Office: UHA 3020C

Phone: (858) 822-5312

Fax: (858) 534-7042

Email: kprather@ucsd.edu

Group Website: http://atofms.ucsd.edu/

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Education and Appointments
1990-92	Postdoc, University of California, Berkeley Physical Chemistry
1990	Ph.D., University of California, Davis
1985	B.S., University of California, Davis

Awards and Academic Honors
2008	Selected as Member of the National Academy Board for Atmospheric Science and Climate
2005	Selected as Member of EPA PM2.5 Clean Air Scientific Advisor Board
2000	ACS Analytical Chemistry Arthur F. Findeis Award
1999	Kenneth T. Whitby Award
1998	GAeF Smoluchowski Award
1997	National Science Foundation Special Creativity Award
1994	University of California, Berkeley; American Society for Mass Spectrometry Award
1994	National Science Foundation Young Investigator

Research Interests
Our research involves making real world measurements of atmospheric aerosols and developing and using new analytical methods for these measurements. Aerosols occur in the environment in a variety of forms: clouds of ice or water droplets, salt particles from ocean spray, and smoke from a variety of combustion sources. They play an enormous role in our daily lives from affecting visibility and global climate change to endangering our health. Due to applications in research, medicine, and industry, there is great scientific interest in aerosols, however relative to their gas phase counterparts, very little information exists regarding their chemistry. Conventional analytical methods for analyzing aerosols involve isolating particles on filters with subsequent analysis performed in the laboratory. These isolation processes often disturb the aerosol and thus render the data questionable because the particles evaporate or react before analysis. In order to overcome these difficulties, we developed aerosol-time-flight mass spectrometry (ATOFMS). This represented the first analytical technique capable of providing the precise size and chemical composition of individual aerosol particles in real time. Some examples of aerosol systems which we are characterizing in the laboratory using ATOFMS include suspended dust, sea salt, and a variety of combustion particles. Most recently, we developed a much smaller ATOFMS which was just flown on the C-130 in flights over Colorado. In field studies, we strategically position our transportable instruments at sites that allow us to monitor the evolution of single particles in the atmosphere over time. In regional and international studies, these instruments are being used to study the direct effect of aerosols on visibility, pollution levels, cloud formation, and the global radiation balance. Another major thrust of our research involves the development of new techniques for the analysis of organic species in aerosol particles. This is an extremely complex problem as there are hundreds of organic species in particles yet only 10-20% of the mass has been identified. We are approaching this problem by using tunable laser wavelengths and selective reagent ions in chemical ionization. Another area of interest involves using an ATOFMS instrument as an on-line probe for monitoring heterogeneous gas-particle reactions in the laboratory. The ATOFMS is interfaced to a flow tube where heterogeneous reactions of tropospheric concern are simulated. Aerosols of known size and composition are created and reacted under controlled conditions. The fundamental question of which factors (i.e. size, composition, charge) influence heterogeneous gas-particle reactions are being addressed. Controlled laboratory studies such as these assist in sorting out data obtained from atmospheric studies, complicated by the numerous chemical processes occurring at any time. The information obtained will be used to generate new models for atmospheric processes which will be directly applicable in efforts to control ozone depletion, improve air quality, and develop an understanding of the impact of aerosols on global climate.
Primary Research Area:	Interdisciplinary Specialties:
Physical/Analytical Chemistry	Atmospheric and Environmental Materials
Image Gallery:

Figure 1: C-130 "Shirley" took her first flight on....	Figure 2: Picture of aircraft-ATOFMS (Shirley)

Figure 3: Schematic of ATOFMS which can collect information on aerosol size, chemistry, and optical properties.

Selected Publications

Effects of Meteorological Conditions on Aerosol Composition and Mixing State in Bakersfield, CA. With J.R. Whiteaker and D.T. Suess. Environ. Sci. Tech. 36, 2345 (2002).

A Field-Based Approach for Determining ATOFMS Instrument Sensitivities to Ammonium and Nitrate. With P.V. Bhave, J.O. Allen, B.D. Morrical, D.P. Fergenson, and G.R. Cass. Environ. Sci & Technol. 36, 4868 (2002).

Characterization of carbonaceous aerosols outflow from India and Arabia: Biomass/biofuel burning and fossil fuel combustion. With S.A. Guazzotti, D.T. Suess, K.R. Coffee, K.R., P.K. Quinn, T.S. Bates, A. Wisthaler, A. Hansel, W.P. Ball, R.R. Dickerson, C. Neusüß, and P.J. Crutzen. J. Geophys. Res. 108, 4485 (2003).

Detection of Pesticide Residues on Individual Particles. With J.R. Whiteaker. Anal. Chem. 75, 49 (2003).

Aerosol Time-of-Flight Mass Spectrometry During the Atlanta Supersite Experiment: 1. Measurements. With D-Y. Liu and R.J. Wenzel. J. Geophys. Res. 108, 14-1 (2003).

Hydroxymethanesulfonate as a tracer for fog processing of individual aerosol particles. Atmos. Environ. With J.R. Whiteaker. 37, 1033 (2003).

Mineral dust is a sink for chlorine in the marine boundary layer. Atmos. Environ. With R.C. Sullivan, S.A. Guazzotti, D.A. Sodeman, Y.H. Tang, G.R. Carmichael, 41, 7166-7179 (2007).

Direct observations of the atmospheric processing of Asian mineral dust. Atmospheric Chemistry and Physics, With R. C. Sullivan, S.A. Guazzotti, D.A. Sodeman, 7, 1213-1236 (2007).

Chemically segregated optical and microphysical properties of ambient aerosols measured in a single particle mass spectrometer. Journal of Geophysical Research-Atmospheres, With R.C. Moffet, X. Qin, T.P. Rebotier, H. Furutani, in press (2008).

Simultaneous measurement of the effective density and chemical composition of ambient aerosol particles. Environmental Science & Technology, With M.T. Spencer, L.G. Shields, and K.A. Prather, 41, 1303-1309 (2007).