Model Selection and Scenarios Sample Clauses

Model Selection and Scenarios. ERG has selected the AMS/EPA Regulatory Model (AERMOD) for use in determining impacts from sources of interest in this study. We believe AERMOD is the most appropriate model to implement based on the following reasons: 1. AERMOD is the U.S. EPA preferred air dispersion model for near-field (Appendix W to 40 CFR Part 51, Guideline on Air Quality Models, ▇▇▇▇://▇▇▇.▇▇▇.▇▇▇/ttn/scram/guidance/guide/appw_05.pdf, Page 68253); 2. AERMOD is widely accepted and used in the scientific and regulatory community; 3. The study domain falls within the distance limits of AERMOD (50 km or ~30 miles); 4. AERMOD supports multiple sources types (vents, stacks, area sources for piping); 5. AERMOD needs only a single meteorological station, along with upper air data to execute, unlike grid models; and 6. Special meteorological circumstances are not at issue in this case (complex wind flows, stagnation, complex terrain); therefore, alternate models, such as CALPUFF, are unnecessary. ERG proposes local modeling of a limited number of proposed sites spread throughout the city. Although several areas of the city are affected by the industry, it may be of interest to the City to intensely study a handful of sites, representing operations across the various phases of the gas drilling and production cycle. In consultation with the City, ERG will select sites for more detailed modeling study. For example, we might consider a simple wellpad, a more complex wellpad with lift engines and/or a dehydrator, a gas gathering station or compressor station, and a site affected by both a wellpad and a compressor station. Each analysis will include analysis of impacts at facility property lines, at setback distances proscribed by the city, and at local sensitive receptors (such as nearby parks, schools and homes). This analysis will include our estimates of actual emissions as determined through source testing, downwash effects (if applicable), locally collected meteorological data, and detailed land use analysis.