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EES staff has conducted numerous dispersion modeling studies to evaluate impacts of air pollutants from stationary, mobile and area sources. EES's air quality specialists are experienced in the use of a wide range of computerized air fate and transport models. Our staff has conducted modeling studies using the EPA Guideline dispersion models for simple terrain, such as ISCLT3, ISCST3 PAL, BLP, TSCREEN and SCREEN3. We have also performed numerous modeling studies for sources in complex terrain. These studies have involved the use of both simple and sophisticated complex terrain models including CXOMPLEX1, RTDM, CTDMPLUS, SHORTZ, LONGZ and VALLEY.
In addition, EES's staff is proficient in using specialized models applicable to specific source configurations or accidental releases of toxic substances (including dense gases) (e.g., DEGADIS and SLAB). This practical experience is critical to determining the appropriate model(s) for particular applications and for interpretation of model results. Model predictions are used directly to evaluate source compliance with applicable regulatory thresholds and as a component in air toxic health risk assessments. EES staff has also been retained to conduct rigorous dispersion model performance evaluations (e.g., EPA's AERMOD), as well as focused field studies to obtain the data needed for such studies. The list to the right presents examples of our projects in applying, testing and evaluating air quality dispersion models.
Evaluation of Area and Volume Source Dispersion Models
American Petroleum Institute and Chemical Manufacturers Association EES staff conducted a comprehensive evaluation of the performance of available area source and volume source dispersion models for applications involving petroleum and chemical industry sources of air pollutants. The first task identified candidate area and/or volume source models and evaluated their dispersion algorithms in terms of the reasonableness of their representation of the relevant physical processes. The second task has been to identify and evaluate field measurement program data sets that could potentially be used to support a formal performance evaluation of the identified models. Dispersion algorithms from six different models have been evaluated, and data from seven field studies are currently being prepared for the execution of model performance evaluations.
Air Dispersion Modeling
UCAR Carbon EES staff conducted multiple emission source air dispersion modeling for PM-10 and NOx emissions in support of a PSD permit application. Using EPA's Buoyant Line and Point Source model, we simulated potential offsite air concentrations from 22 point and two line emission sources at 400 receptor locations. Modeling results indicated no significant deterioration to offsite receptor locations. |
Overview
Evaluation of Area and Volume Source Dispersion Models Air Dispersion Modeling |