Comparison of Source Apportionment and Sensitivity Analysis in a Particulate Matter Air Quality Model

Two efficient methods to study relationships between particulate matter (PM) concentrations and emission sources are compared in the three-dimensional comprehensive air quality model with extensions (CAMx). Particulate source apportionment technology (PSAT) is a tagged species method that apportions...

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Bibliographic Details
Published in:Environmental science & technology 2009-09, Vol.43 (17), p.6669-6675
Main Authors: Koo, Bonyoung, Wilson, Gary M, Morris, Ralph E, Dunker, Alan M, Yarwood, Greg
Format: Article
Language:English
Subjects:
Airborne particulates
Applied sciences
Comparative analysis
Emissions control
Environmental Modeling
Exact sciences and technology
Pollution
Sensitivity analysis
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Summary:Two efficient methods to study relationships between particulate matter (PM) concentrations and emission sources are compared in the three-dimensional comprehensive air quality model with extensions (CAMx). Particulate source apportionment technology (PSAT) is a tagged species method that apportions concentrations of PM components to their respective primary precursors, e.g., sulfate is apportioned to SO x , nitrate to NO x , etc. The decoupled direct method (DDM) calculates first-order sensitivities of PM concentrations to model inputs. Both tools were applied to two month long (February and July) PM modeling episodes and evaluated against changes in PM concentrations due to various emission reductions. The results show that source contributions calculated by PSAT start to deviate from the actual model responses as indirect effects from limiting reactants or nonprimary precursor emissions become important. The DDM first-order sensitivity is useful for determining source contributions only if the model response to input changes is reasonably linear. For secondary inorganic PM, the response is linear for emission reductions of 20% in all cases considered and reasonably linear for reductions of 100% in the case of on-road mobile sources. The model response for secondary organic aerosols and primary PM remains nearly linear to 100% reductions in anthropogenic emissions.
ISSN:0013-936X
1520-5851
DOI:10.1021/es9008129