Frequent Questions

How can I estimate a Nonroad inventory using my own local data?

We generally recommend not modifying internal tables of the Nonroad model, as this can lead to unintended consequences.

Instead, you can apply your own local nonroad equipment population or activity (hours of use) data by:

  1. Executing a Nonroad run in MOVES for your county
  2. Applying a Nonroad Emission Factors post-processing script on your Nonroad output database to generate emissions factors (Post-processing ->Run MySQL script on Nonroad Output Database)
  3. Multiplying the emission factors produced by the script by the appropriate local values to generate an inventory

The “per_OperatingHours” scripts produce an output table which reports emission factors in g/hour per day (for each equipment type; equipment type and horsepower bin; or SCC, based on the script selected). To produce an inventory, these emission factors should be multiplied by the appropriate daily hours of operation.

The “per_Vehicle” scripts produce an output table which reports emission factors in g/vehicle per day (for each equipment type; equipment type and horsepower bin; or SCC, based on the script selected). These can be multiplied by the appropriate number of vehicles (units) operating daily to create an inventory.

The “per_hphr” scripts produce an output table which reports emission factors in g/hp-hr per day (for each equipment type; equipment type and horsepower bin; SCC; or SCC and model year, based on the script selected). To produce an inventory, these emission factors should be multiplied by the appropriate daily horsepower-hours. This can generally be calculated as:

rated horsepower × load factor × hours per vehicle × number of vehicles operating

Default load factor assumptions are available in Appendix A of the Median Life, Annual Activity, and Load Factor Values for Nonroad Engine Emissions Modeling technical report:

http://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P10081RV.pdf

If you do not wish to incorporate your own load factor or horsepower assumptions into your inventory, we recommend using a “per_Vehicle” or “per_OperatingHours” script instead due to their simpler application.

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