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National Clean Diesel Campaign (NCDC)

Working Together for Cleaner Air

Input Checklist
Diesel Emissions Quantifier (DEQ)

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Need help?  DEQ Trouble Shooting

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DEQ Inputs

For on-highway and nonroad calculations

  • A fleet is an entire population of vehicles and/or equipment which can be on-highway and/or nonroad (e.g., school buses and construction equipment). If a fleet operates in multiple states, select the state where most of the operations or emissions occur.
  • A vehicle group is a subset of a fleet and should include similar vehicles of similar age. If the fleet consists of school buses and transit buses, there would be at least two vehicle groups. More specific vehicle groups will provide more precise estimates (e.g., Group 1: school buses of model year 1995; Group 2: school buses of model year 2000)

For marine calculations

  • A fleet refers to a single vessel, which can have up to five engines. Emissions must be calculated for each vessel individually.
  • An engine group contains propulsion or auxiliary engines for a single vessel and are grouped by age or other similar characteristics.

DEQ Inputs for Highway/On-road Vehicles

For Each Fleet:

  • Fleet Type - On Highway/Nonroad
  • State
  • Funding Amount and Source (optional)

For Each Group:

  • Group Quantity
  • Type (On Highway)
  • Target Fleet
  • Class/Equipment
  • Model Year
  • Year Retrofit Installed (Year of Retrofit Action)
  • Current Fuel Type
  • Fuel Volume (gal/year for group)
  • Vehicle Miles Traveled (miles/vehicle/year)
  • Idling Hours (hours/vehicle/year)

For Each Technology

  • Technology Type
  • Technology
  • New Model Year - if replacing engine/vehicle
  • Idling Hours Reduced - if using an idle reduction technology
  • Number of Vehicles (Apply to)
  • Installation Cost (Install Cost) $ per vehicle (optional)
  • Technology Cost (Unit Cost) $ per vehicle (optional)

DEQ Inputs for Nonroad Vehicles

For Each Fleet:

  • Fleet Type - On Highway/Nonroad
  • State
  • Funding Amount and Source (optional)

For Each Group:

  • Group Quantity
  • Type (Nonroad)
  • Target Fleet
  • Class/Equipment
  • Model Year
  • Year Retrofit Installed (Year of Retrofit Action)
  • Current Fuel Type
  • Fuel Volume (gal/year for group)
  • Usage Rate (hours/vehicle/year) - annual hours per vehicle
  • Horsepower (per vehicle)

For Each Technology

  • Technology Type
  • Technology
  • New Model Year (if replacing engine/vehicle)
  • Diesel Fuel Reduced (if replacing engine/vehicle)
  • Number of Retrofitted Vehicles
  • Installation Cost (Install Cost) $ per vehicle (optional)
  • Technology Cost (Unit Cost) $ per vehicle (optional)

DEQ Inputs for Marine Vessels

Each vessel must be calculated individually, but each may have up to five engines (including propulsion and auxiliary).

For each vessel:

  • Fleet Type (Marine)
  • State
  • Applications (Choose from list - Container, Ferry/Excursion, Fishing, Tugboat, Ocean Going Vessel, etc
  • Engines - up to five
  • Funding Amount and Source (optional)

For each engine group, enter the following

  • Group Quantity
  • Type Engine
  • Engine Model Year
  • Retrofit Year Installed (year of action)
  • Activity Hours (hours/year/engine) - annual hours per engine)
  • Horsepower
  • Fuel Type
  • Fuel Volume (gal/year for group)
  • Displacement (liters per cylinder)

For Each Technology

  • Technology Type
  • Technology
  • New Model Year (if replacing engine)
  • Diesel Fuel Reduced (if replacing engine)
  • Installation Cost (Install Cost) $ per vehicle (optional)
  • Technology Cost (Unit Cost) $ per vehicle (optional)

Getting the Most Accurate DEQ Results

To get the most accurate DEQ results, select 2011 or later for the ‘Year of Retrofit Action.’

In November 2010, the DEQ was updated with significantly improved emissions factors and calculations. One of the most important changes for heavy-duty diesel vehicles was the incorporation of data from in-use vehicles. Previously only engine certification data from new engines was included.

To get the most accurate results, select a retrofit year of 2011 or later even if the retrofit took place before 2011 or your initial calculations assumed the retrofit would take place before 2011.

If a retrofit year prior to 2011 is selected, the DEQ will use outdated emission factors and calculations, resulting in severely underestimated emission reductions.

If the project has been closed and the final report has been submitted, there is no need to re-run the DEQ with the updated emissions factors.

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