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IDENTIFICATION OF POSSIBLE SOURCES OF PARTICULATE MATTER IN THE PERSONAL CLOUD USING SEM/EDX
Citation:
Conner, T L. AND R W. Williams. IDENTIFICATION OF POSSIBLE SOURCES OF PARTICULATE MATTER IN THE PERSONAL CLOUD USING SEM/EDX. ATMOSPHERIC ENVIRONMENT 38(31):5305-5310, (2004).
Impact/Purpose:
The NERL SEM/EDX facility was established to provide a state-of-the-art resource for individual particle analysis. Specific goals of the laboratory are as follows: 1) Provide chemical, morphological, and size characterization of particles in support of ambient air characterization studies, source apportionment, exposure and health studies, and other particulate matter research.; 2) Develop analytical capabilities to support research objectives; 3) Communicate results to clients and the scientific community.
Description:
The United States Environmental Protection Agency (U.S. EPA) conducted the Baltimore Particulate Matter (PM) Epidemiology-Exposure Study of the Elderly during the summer of 1998. The study design included PM2.5 samples obtained from elderly (65+ years of age) retirement facility residents using personal exposure sampling devices. These sampling devices were also used to obtain PM2.5 samples at fixed locations within the personal monitoring subjects' apartments. Selected personal and apartment samples were examined using scanning electron microscopy with individual-particle X-ray analysis (SEM/EDX), providing a qualitative assessment of the chemical and physical characteristics of geological and trace element particles collected within these micro-environments at the retirement facility. This information was used to identify possible indoor source particles. The manual surveys of the personal samples revealed that some particles larger than 2.5 um reached the filter surface. Using SEM/EDX , several particle types with possible indoor origins were identified. The Al-Zr-Cl particle is likely to have originated from a personal antiperspirant product. Particles with a talc or alumino-silicate composition point to cosmetics as a possible source. Large cadmium-containing particles were also found, which may indicate the use of art pigments or ceramic glazes, or emissions from television screen phosphors. A greater variety of particles was observed in a personal sample compared with its corresponding fixed-location apartment sample.
The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under contract #68-D5-0040 to the Research Triangle Institute and contract #68-D5-0049 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication.