The National Stone, Sand & Gravel Association has released a CD titled, “Modeling Fugitive Sources with AERMOD.” Some 30 state regulatory agencies require aggregate facilities to complete air quality dispersion modeling analyses before receiving operating permits, NSSGA reports. One of the most subjective and time-consuming aspects of air dispersion modeling is modeling fugitive sources, typical of what is found at most aggregate production facilities.

AERMOD is an advanced plume model that incorporates updated treatments of the boundary layer theory, understanding of turbulence and dispersion, and includes handling of terrain interactions. The model was proposed by the EPA in 2000.

NSSGA's AERMOD version 2.0 reportedly can estimate ambient concentrations from these fugitive sources. For example, the “Modeling Fugitive Sources with AERMOD” CD:

• defines fugitive sources and provides examples of typical fugitive sources found at aggregate facilities;
• describes source types available in AERMOD for modeling fugitive sources including point sources, area sources and volume sources;
• provides suggestions for the most appropriate methods of characterizing fugitive sources;
• provides an overview of meteorological data and terrain data, including how to select the proper and additional requirements for AERMOD;
• discusses options such as averaging periods and depletion;
• describes output options;
• includes a review of all modeling guidance.

For more information about the CD's capabilities, contact NSSGA's John Hayden at jhayden@nssga.org.