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AEROSOL INORGANICS AND ORGANICS MODEL (AIOM) WITH USER DEFINED PROPERTIES FOR ORGANIC COMPOUNDS
Citation:
Clegg, S. L. AND E. O. Edney. AEROSOL INORGANICS AND ORGANICS MODEL (AIOM) WITH USER DEFINED PROPERTIES FOR ORGANIC COMPOUNDS. U.S. Environmental Protection Agency, Washington, DC, EPA/600/C-04/105, 2004.
Impact/Purpose:
1. Using laboratory and field study data generated during FY99-FY04, develop a science version of a PM chemistry model for predicting ambient concentrations of water, inorganics, and organics in PM2.5 samples. The model will include the Aerosol Inorganic Model for predicting concentrations of inorganic compounds and a computational chemistry-based method for predicting concentrations of organic compounds.
2. Identify and evaluate methods for analyzing the polar fraction of PM2.5 samples.
3. Carry out short term field studies in Research Triangle Park, North Carolina in the summer and the winter to determine the composition of the organic fraction of ambient PM2.5 samples, with special emphasis placed on identifying and determining ambient concentrations of polar compounds.
4. Conduct laboratory studies to establish the chemical composition of secondary organic aerosol (SOA) and to determine source signatures for aromatic and biogenic SOA.
5. Conduct laboratory and theoretical investigations of thermodynamic properties of polar organic compounds.
6. Evaluate the science version of the PM chemistry model using laboratory and field data generated under this task as well as other available data in the literature.
7. Conduct PM chemistry-related special studies for OAQPS
Description:
The Aerosol Inorganics Model (AIM) is widely used to calculate gas/liquid/solid phase equilibrium in aerosol systems containing the species H+-NH4+-SO42--NO3--H2O over a range of tropospheric temperatures. In this internal report the model is extended to include organic compounds in order to treat the behavior and interactions of the organic component of PM2.5. This report describes the extension of the AIM model, using the method of Clegg to include an arbitrary number of aerosol organic compounds. These compounds have thermodynamic properties defined by the user and can partition between gas, aqueous, solid, mixed solid, and separate organic-water phases. The organic compounds can also dissociate (to produce H+ ion) in the liquid phase(s). In this report the underlying theory of the extended model is described, followed by its capabilities and features, and then instructions on how it is used. Also included are diskettes containing the executable code for the completed model, and a secondary executable code for fitting activity data for organic-water solutions.
The United States Environmental Protection Agency through its Office of Research and Development partially funded and collaborated in the research described here under contracts 68D-00206 to ManTech Environmental Technology, Inc. and 3D-5095-NAEX to the University of East Anglia. It has been subjected to Agency review and approved for dissemination.