| Abstract |
This document describes EPA’s National Mobile Inventory Model (NMIM) and explains how it works. NMIM is a consolidated emissions modeling system for EPA’s MOBILE6 and NONROAD models. It generates county inventories using MOBILE6 and NONROAD at scales ranging from individual counties to the nation. Its primary improvements over MOBILE6 and NONROAD are 1) the inclusion of all the required county data for the nation in a single database, 2) a graphical user interface, 3) “shortcuts� for generating national inventories, 4) tools for aggregation and post-processing, 5) estimation of 33 HAPS and 17 dioxin/furan congeners, and 6) distributed processing capability to enhance performance. Previously, when national inventories have been constructed from MOBILE6 and NONROAD, the necessary input data have been widely scattered in disparate formats and have required additional specialized software to convert this data into input files for MOBILE6 and NONROAD, to run the models, to integrate the results into a final inventory, and to post-process the results into forms suitable for the national inventories. NMIM accomplishes all of these tasks in a single package. NMIM’s initial version in 2003 was intended to approximate the procedures previously used for calculating nationwide emissions for EPA’s National Emissions Inventory. EPA subsequently has added the capability of incorporating much more county-specific information into the database, including monthly average hourly temperature and humidity, fleet distributions, speed distributions, and diesel fractions for MOBILE6 and county-specific allocation and activity files for NONROAD |
