Air Toxics Modeling
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Air modeling is an important tool for assessing the impacts from air emissions of toxic chemicals (e.g., mercury, dioxins, benzene) on human health and environment. It is not always possible to make actual measurements of the concentrations of toxic chemicals in the air or the concentration of deposits from the air onto the ground or into surface water. Air dispersion and deposition models can provide information when actual measurements are not available. The modeling results can be used to assess the risk to human health and ecosystems from exposure to the toxic chemicals.
Risk assessments are an important part of many of the Community Based Environmental Protection (CBEP) projects currently underway in EPA Region 4. CBEP projects address multi-media (i.e., air, water, waste) environmental issues that are impacting individual communities. The following Region 4 CBEP includes air toxics modeling:
- Tri-State Geographic Initiative - Joint project with EPA Regions 3 & 5, and the Kentucky, Ohio, And West Virginia State Agencies
Additional guidance and resources for air toxics modeling are also available on the following websites:
- EPA's Support Center for Regulatory Air Models (SCRAM)
- EPA Region 6's Regional Air Impact Modeling Initiative (RAIMI)
Atmospheric deposition modeling of toxics (e.g., mercury) is also important for EPA's total maximum daily load (TMDL) program. TMDLs are established by EPA to ensure that water quality standards are maintained. More information on TMDLs is available on the EPA Region 4 TMDL website. A detailed analysis of the atmospheric deposition of mercury for a specific TMDL project is included in the following document:
- Analysis of the Atmospheric Deposition of Mercury to the Savannah River Watershed (PDF, size:414kb, 52 pages)
For additional information about these modeling projects, please contact Rick Gillam at 404-562-9049.