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National Mobile Inventory Model (NMIM)

The National Mobile Inventory Model (NMIM) is a free, desktop computer application developed by EPA to help you develop estimates of current and future emission inventories for on-road motor vehicles and nonroad equipment. NMIM uses MOBILE6 and NONROAD to calculate emission inventories. Note, MOBILE6, used in NMIM, has been replaced by MOVES as EPA’s official model for estimating emissions from cars, trucks and motorcycles.  Thus, NMIM cannot be used for official modeling of these emissions. 

  • How to install NMIM on a Windows computer.
  • NMIM User Guide (PDF)(77 pp, 1.63 MB, EPA-420-B-09-015, April 2009 About PDF), also available via the NMIM HELP menu, provides detailed information on how to run NMIM.
  • How NMIM Works: EPA's National Mobile Inventory Model (NMIM), A Consolidated Emissions Modeling System for MOBILE6 and NONROAD (PDF) (27 pp, 155 K, EPA420-R-05-024, December 2005, About PDF)
    • This documentation begins with an overall explanation of how NMIM works, followed by the details of how it runs MOBILE6 and NONROAD.
    • Next, it discusses the pollutant and source category inventories available from running NMIM.
    • Then, it describes the NMIM County Database (NCD) and procedures for updating and improving it through the National Emission Inventory (NEI) process.
    • Next, it explains how NMIM estimates various air toxic pollutants that are not direct outputs of MOBILE6 and NONROAD.
    • Finally, it describes how user-specified retrofit programs and fleets are modeled by NMIM.