Research Projects

Project at a Glance

Project Status: complete

Title: Asbestos fibers in ambient air of California.

Principal Investigator / Author(s): Murchio, Jack C.

Contractor: School of Public Health, UC Berkeley

Contract Number: 4-054-1

Research Program Area: Atmospheric Processes


Fiber content of freeway air was compared to that of ambient air upwind from the freeway. Portions of Millipore AA filters containing suspended particulates collected in Los Angeles at four freeway and four upwind sites were examined for fiber content with microscopy and transmission electron microscopy (TEM). Electron micrographs of selected samples are shown. The TEM method is described and compared with three other TEM methods for asbestos analysis. The technique used in this study leaves fiber or fiber bundles intact; fibers in unbroken clumps were not counted. Chrysotile, amphiboles and glass fibers were identified; length and diameter were measured. Single fibers were counted, including a group of unknowns which were a substantial part (65%) of the total fibers. Results are tabulated for 120 samples. At freeway sites, chrysotile, amphiboles, glass fibers and unknowns ranged from 0-100, 0-10, 0-4 and 0-18 f/l, respectively; upwind sample ranges were 0-9, 0-8, and 0-30 f/l, respectively. Freeway samples differed from upwind samples in fibril content, 15% and 3%, respectively.


For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893

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