D.2.11 Background Concentrations  .........................................................................86 APPENDIX E - Roadway Dispersion Modeling (Hot-Spot Analysis) .............................. 87 E.1  Overview ................................................................................................................... 87 E.2  Methodology ............................................................................................................. 89 E.2.1  Determine Analysis Year(s)  ..........................................................................89 E.2.2  Select Critical Roadway Intersections  ..........................................................90 E.2.3  Obtain Project Data ......................................................................................91 E.2.4  Estimate On-Road Vehicle Emissions ...........................................................92 E.2.4.1  CO Emissions Modeling ............................................................... 92 E.2.4.2  PM Emissions Modeling............................................................... 94 E.2.5  Select Receptor Site Locations ......................................................................97 E.2.6  Select Dispersion Models ..............................................................................98 E.2.6.1  Roadway Geometry ...................................................................... 99 E.2.6.2  Traffic Data ................................................................................. 100 E.2.6.3  Meteorological Data.................................................................... 100 E.2.6.4  Vehicular Emission Rates ........................................................... 101 E.2.7  Estimate Background Data .........................................................................101 APPENDIX F - Data and Information Sources................................................................ 102 iv 