Grantee Research Project Results
2001 Progress Report: Development and Evaluation of Modeling Techniques for the Study of Interactions between Urban and Point Source Plumes and Regional Atmospheres in the Formation of Secondary Pollutants
EPA Grant Number: R827028Title: Development and Evaluation of Modeling Techniques for the Study of Interactions between Urban and Point Source Plumes and Regional Atmospheres in the Formation of Secondary Pollutants
Investigators: Odman, Mehmet Talat , McRae, D. Scott
Institution: Georgia Institute of Technology
EPA Project Officer: Hahn, Intaek
Project Period: January 15, 1999 through January 14, 2002 (Extended to March 31, 2002)
Project Period Covered by this Report: January 15, 2001 through January 14, 2002
Project Amount: $468,324
RFA: Air Pollution Chemistry and Physics (1998) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air , Safer Chemicals
Objective:
The objective of the study is to develop new modeling techniques while also building on existing techniques to improve the representation of emission sources in air quality models (AQMs). The interaction of point and urban source plumes with the surrounding atmosphere involves processes of critical importance to the formation, long-range transport and fate of secondary pollutants such as ozone. The relevant scale of these interactions are smaller than typical scales used in regional AQMs; therefore, plumes are generally considered subgrid scale. There are various uncertainties involved in the treatment of subgrid scale processes. This research focuses on increasing the resolution of plume interactions, thereby reducing the associated uncertainties.Progress Summary:
In the third year, we developed a technique for determining when information from a plume-in grid model can be accurately represented on a mesh with typical regional AQM scales. The idea that the computational mesh is a band-pass filter used to develop automated hand over criteria. These criteria are designed to consider the chemical nature of the plume, as well as the numerical diffusion due to the grids on which the plume evolves. We tested the criteria on numerically obtained 2-D and 3-D plume data. Initial results show that direct comparisons can be made between an initial distribution from the sub-grid model and an approximation to the distribution, as it would exist if interpolated to the coarse mesh of a regional AQM. We used an energy measure to quantify the loss of information when this comparison is made. The results are promising and warrant further exploration of this technique.
An adaptive grid AQM was developed. To verify the model, the July 7-17, 1995, ozone episode in the Tennessee Valley was simulated. The grid adapted to dynamic changes in the NO fields and nodes clustered around major emission sources with grid resolutions as small as 200 m. The NO and O3 fields showed gradients with a level of detail that is likely to be unprecedented for a regional simulation at this scale. Estimates of NO and ozone were compared to those from static grid models that require comparable computational resources. By placing higher resolution near point sources, the adaptive grid AQM estimated ozone concentrations more consistent with observations at downwind stations. Several ways of improving the model were identified during this application. We started the development of adaptation criteria that would consider the errors not only in NO but also in other species.
Future Activities:
During the next year, which is the final year of this project, the following activities are planned: (1) finalize the design of hand-over criteria for plume-in-grid models; (2) Finalize the design of grid adaptation criteria for more accurate ozone simulations; and (3) Prepare the final report and finish the remaining papers.Journal Articles on this Report : 4 Displayed | Download in RIS Format
| Other project views: | All 14 publications | 7 publications in selected types | All 4 journal articles |
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Khan MN, Odman MT, Karimi HA. Evaluation of algorithms developed for adaptive grid air quality modeling using surface elevation data. Computers, Environment and Urban Systems 2005;29(6):718-734. |
R827028 (2001) |
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Srivastava RK, McRae DS, Odman MT. An adaptive grid algorithm for air-quality modeling. Journal of Computational Physics 2000;165(2):437-472. |
R827028 (1999) R827028 (2001) |
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Srivastava RK, McRae DS, Odman MT. Simulation of a reacting pollutant puff using an adaptive grid algorithm. Journal of Geophysical Research-Atmospheres 2001;106(D20):24245-24257. |
R827028 (2000) R827028 (2001) |
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Srivastava RK, McRae DS, Odman MT. Simulation of dispersion of a power plant plume using an adaptive grid algorithm. Atmospheric Environment 2001;35(28):4801-4818. |
R827028 (2000) R827028 (2001) |
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Supplemental Keywords:
tropospheric, oxidants, nitrogen oxides, mathematics, analytical, Northeast., RFA, Air, Scientific Discipline, Geographic Area, Chemistry, East Coast, mobile sources, Environmental Chemistry, Engineering, Chemistry, & Physics, tropospheric ozone, Physics, urban air, plume dispersion models, nitrogen removal, point source effluents, secondary pollutants, measurement methods , troposphere, air pollution models, fate and transport, subgrid scale models, urban air , air quality models, air quality standards, regional atmospheres, air modeling, Fourier Transform Infrared measurementRelevant Websites:
http://environmental.gatech.edu/~odman/page2.html Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.