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Single-Particle Characterization of Atmospheric Aerosols
EPA Grant Number: U915170Title: Single-Particle Characterization of Atmospheric Aerosols
Investigators: Noble, Christopher A.
Institution: University of California - Riverside
EPA Project Officer: Thompson, Delores
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. , Ecosystem Protection/Environmental Exposure & Risk, Air, Scientific Discipline, RFA, Air Pollutants, particulate matter, Environmental Chemistry, Monitoring/Modeling, Ecology and Ecosystems, Environmental Monitoring, aerosols, ambient measurement methods, real time monitoring, time resolved apportionment, aerosol analyzers, chemical characteristics, speciation, particulate matter mass, aerosol time of flight mass spectrometry, chemical speciation sampling, air sampling, aerosol time-of-flight mass spectrometry (ATOFMS), particle sampler, PM2.5, air pollution, ambient particle properties, ambient pollution control, aerodyne aerosol mass spectrometry, ambient aerosol, atmospheric transport, particle size