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A Best Fit Approach to Estimating Multiple Diffuse Source Terms Using Ambient Air Monitoring Data and an Air Dispersion Model

MacQueen, Donald; Bertoldo, Nicholas; Wegrecki, Anthony*

doi: 10.1097/HP.0b013e318293f201
Operational Topic

Lawrence Livermore National Laboratory uses CAP88-PC Version 1.0 modeling software to demonstrate compliance with the Code of Federal Regulations Title 40 Part 61 Subpart H (National Emission Standards for Emissions of Radionuclides Other Than Radon From Department of Energy Facilities). Annual air emissions from both well characterized stack sources and difficult to characterize diffuse sources must be assessed. This paper describes a process that uses a mathematical optimization routine to find a set of estimated diffuse source terms that together with the measured stack source terms provides a best fit of modeled air concentrations to measured air concentrations at available sampling locations. The estimated and measured source terms may then be used in subsequent CAP88-PC modeling to estimate dose at the off-site maximally exposed individual. LLNL has found this process to be an effective way to deal with the required assessment of diffuse sources that have otherwise been difficult to assess.

*Lawrence Livermore National Laboratory, 7000 East Ave. L-627, Livermore, CA 94550.

The authors declare no conflicts of interest.

Don MacQueen, M.S. (California State University East Bay, statistics), has been working for the environmental monitoring and restoration programs at Lawrence Livermore National Laboratory for about 22 years. He supports the programs with data analysis and statistics, statistical graphics, environmental database design, environmental sampling design, detection limit theory, and other related topics. His email is

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