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Grantee Research Project Results

Grantee Research Project Results

Single-Particle Characterization of Atmospheric Aerosols

EPA Grant Number: U915170
Title: Single-Particle Characterization of Atmospheric Aerosols
Investigators: Noble, Christopher A.
Institution: University of California - Riverside
EPA Project Officer: Jones, Brandon
Project Period: January 1, 1997 through January 1, 2000
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1997)
Research Category: Academic Fellowships , Engineering and Environmental Chemistry , Fellowship - Chemistry and Materials Science

Description:

Objective:

The objective of this research project is to analyze atmospheric aerosols on a single-particle basis, while measuring both particle size and composition.

Approach:

This research involves the characterization and application of the new instrument technique aerosol time-of-flight mass spectrometry (ATOFMS), which measures both the size and composition of individual particles in real time. Both model and ambient aerosols have been analyzed with this method.

The laboratory-based ATOFMS instrument has been operating consistently for more than 3 years. System characterization is essentially completed. Preliminary studies have been performed that demonstrate the capabilities of the ATOFMS analysis for a variety of aerosol samples. Various studies have included instrumental characterization experiments focusing on instrumental sampling efficiencies, particle-sizing capabilities, and laser desorption/ionization characteristics associated with single-particle mass spectral analysis. Model aerosols that have been analyzed include particles compose of both chemically homogeneous and heterogeneous inorganic salts as well as pharmaceutical aerosols.

The recent emphasis of this research project includes detailed analyses of atmospheric aerosols. These may be divided into two categories. The first focuses on monitoring variations in atmospheric aerosols over time. We have observed a relative increase in sea salt particle concentration due to winter rainstorms in southern California. We also are interested in exploring the temporal resolution of ATOFMS for the purpose of monitoring transient variations occurring in atmospheric aerosols. Transient variations that are of interest include changes in composition, particle size distribution, and aerosol concentration. The second area of interest is the qualitative and semiquantitative analysis of both common and trace metals in atmospheric aerosols. This research project will attempt to determine the particle size distributions of various metals in the atmosphere, which compounds these metals are associated with, and a semiquantitative determination of the amount of these metals in the atmosphere.

Supplemental Keywords:

fellowship, model aerosols, ambient aerosols, single-particle characterization, atmospheric aerosols, aerosol time-of-flight mass spectrometry, ATOFMS, trace metals., RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, particulate matter, Environmental Chemistry, Air Pollutants, Monitoring/Modeling, Environmental Monitoring, Ecology and Ecosystems, ambient aerosol, particle size, time resolved apportionment, ambient particle properties, chemical characteristics, aerosol time-of-flight mass spectrometry (ATOFMS), ambient measurement methods, air pollution, air sampling, atmospheric transport, speciation, particulate matter mass, particle sampler, aerodyne aerosol mass spectrometry, PM2.5, real time monitoring, aerosol analyzers, aerosols, chemical speciation sampling, ambient pollution control, particle transport

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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