Project at a Glance

Title: Assessment of contribution of contemporary carbon sources to size-fractionated PM and time-resolved bulk PM using the measurement of radiocarbon

Principal Investigator / Author(s): Hyun-Min Hwang, Thomas M. Young, Bruce A. Buchholz

Contractor: University of California, Davis (UC Davis); Lawrence Livermore National Laboratory

Contract Number: 06-339

Research Program Area: Atmospheric Processes, Emissions Monitoring & Control

Topic Areas: Greenhouse Gas Emissions, Monitoring, Natural (Biogenic) Sources


This study was motivated by a desire to improve understanding of the sources contributing to the carbon that is an important component of airborne particulate matter (PM). The ultimate goal of this project was to lay a ground work for future tools that might be easily implemented with archived or routinely collected samples. A key feature of this study was application of radiocarbon measurement that can be interpreted to indicate the relative contributions from fossil and non-fossil carbon sources of atmospheric PM. Size-resolved PM and time-resolved PM10 collected from a site in Sacramento, CA in November 2007 (Phase I) and March 2008 (Phase II) were analyzed for radiocarbon and source markers such as levoglucosan, cholesterol, and elemental carbon. Radiocarbon data indicates that the contributions of non-fossil carbon sources were much greater than that from fossil carbon sources in all samples. Radiocarbon and source marker measurements confirm that a greater contribution of non-fossil carbon sources in Phase I samples was highly likely due to residential wood combustion. The present study proves that measurement of radiocarbon and source markers can be readily applied to archived or routinely collected samples for better characterization of PM sources. More accurate source apportionment will support ARB in developing more efficient control strategies.

For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

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