ALL4 Ambient Group Attends Modeling Conference

On October 8 and 9, 2008, ALL4’s Ambient Group attended the 9th Conference on Air Quality Modeling in Research Triangle Park, NC, hosted by U.S. EPA.  The conference provided an update on the latest developments in air quality modeling and represented a public forum for discussion on how air quality models can be used for new air permit applications in the future.  Speakers from U.S. EPA, state environmental agencies, and private companies presented on a variety of topics, including the following future developments related to Prevention of Significant Deterioration (PSD) air quality modeling:

• Meteorological Data Representativeness:  Obtaining a complete set of representative meteorological data for use in an air quality modeling evaluation continues to be challenging for many facilities.  U.S. EPA discussed approaches to address a lack of complete data within existing meteorological data sets.  U.S. EPA also discussed the AERSURFACE preprocessor, which can be used to estimate micrometeorological variables as part of a meteorological data representativeness evaluation.
• PM2.5 Modeling:  Issues related to modeling PM2.5 emissions and the proposed PM2.5 PSD ambient concentration standards were discussed.  U.S. EPA has initiated an extensive process to address the challenges associated with PM2.5 modeling, and is developing guidance for those facilities that are required to model PM2.5 emissions through the New Source Review (NSR) permitting process.