AVS 47th International Symposium
    Incorporating Principles of Industrial Ecology Tuesday Sessions
       Session IE-TuM

Paper IE-TuM10
Structure and Composition of Size- and Time-Resolved Outdoor Aerosols Determined Using TOF-SIMS

Tuesday, October 3, 2000, 11:20 am, Room 304

Session: Methods of Industrial Ecology Analysis / Global Concerns
Presenter: D.J. Gaspar, Pacific Northwest National Laboratory
Authors: D.J. Gaspar, Pacific Northwest National Laboratory
M.A. Carpenter, Pacific Northwest National Laboratory
J.P. Cowin, Pacific Northwest National Laboratory
D.R. Baer, Pacific Northwest National Laboratory
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The study of aerosol particles has been identified as a top priority in atmospheric research due to their importance as heterogeneous reaction sites and the potential health consequences of particulate inhalation. Aerosols are known to have highly variable composition, with non-volatile, semi-volatile, and volatile organic and inorganic constituents. Although much work has been done recently, further understanding of structure and composition remains important. Thus, the composition of outdoor aerosols have been investigated using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Particles were collected using a multiple stage impactor, which time tagged and sorted incident particles from 0.1 to 10 microns into discrete size ranges. A PHI TRIFT TOF-SIMS instrument was used with a Ga@super +@ liquid metal ion gun (LMIG) for both depth-profiling and analysis, and a Cs@super +@ ion source for more extensive depth-profiling. Mass spectra for both negative and positive secondary ions were obtained for the time- and size-sorted particles. Data was obtained for both collections of particles and a number of individual particles. The mass spectra have been analyzed to determine the inorganic and organic fractions of the aerosol particles. Three-dimensional molecular and atomic maps have been constructed for key environmentally important components of several characteristic particles. We relate the composition to environmental factors such as daylight and road traffic, and inferences are drawn concerning sample chemical history.