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Appendix G <br />Air Quality Analysis Modeling Report <br />4.0 Far-Field Analysis (Class I Air Quality Related Values Impact) <br />Far-field impacts up to 200 km from the proposed mine site were assessed by modeling <br />projected emission rates in the USEPA-recommended CALPUFF model. The CALPUFF <br />model is an advanced, integrated Gaussian puff-type modeling system that can incorporate <br />four-dimensional varying wind fields, wet and dry deposition, and atmospheric gas and <br />particle phase chemistry. The three main components are CALMET (a diagnostic <br />3-dimensional meteorological model), the CALPUFF air dispersion model, and CALPOST (a <br />post processing package). Additionally, the CALPUFF modeling suite includes numerous <br />other processors that may be used to prepare geophysical data, meteorological data, and <br />interfaces to other models. The model is designed to simulate the dispersion of buoyant, puff, <br />or continuous point and area pollution sources as well as the dispersion of buoyant, <br />continuous line sources. It is the only EPA-approved model that can be used for source- <br />receptor distances greater than 50 km. <br />The far-field analysis focuses on AQRVs, including comparison of modeled concentrations to <br />SILs, and PSD increments, assessment of visibility impacts, and a deposition evaluation. <br />Ambient air quality impacts were evaluated for the following areas. <br />Utah <br />• Arches National Park (Class I Area) <br />• Canyonlands National Park (Class I Area) <br />Colorado <br />• Black Canyon of the Gunnison Wilderness (Class I area) <br />• Flat Tops Wilderness (Class I area). <br />• Maroon Bells - Snowmass Wilderness (Class I area) <br />• Colorado National Monument (sensitive Class II area) <br />• Dinosaur National Monument (sensitive Class II area) <br />4.1 Meteorological Data <br />Per recommendation from CDPHE air quality modeling staff, ISCST-3 format meteorological <br />data was obtained from the NCDC. Data from 1986-1990, collected at the Grand Junction <br />NWS, pre Automated Surface Observing System (ASOS), was obtained and processed with <br />1986-1990 Grand Junction NWS Mixing Height data in the CPRAMMET processor. <br />Meteorology domain (grid boundary) values are shown in Table 4-14 (CALPUFF/CALPOST <br />Modeling Options). Figure 4-1 is a representative wind rose for this processed meteorology. <br />G-15 <br />DBMS 527 <br />