The Diesel Emissions Quantifier (DEQ) is an interactive tool that evaluates clean diesel projects and options for medium-heavy and heavy-heavy duty diesel engines by estimating baseline emissions, reduced emissions, cost effectiveness and health benefits. This quantifier was developed for users with little or no modeling experience.  Results may be used to estimate or compare the benefits of diesel emission projects or for Clean Diesel grants.

The DEQ may not be used for State Implementation Plans (SIPs) and Conformity. Please consult your EPA Regional Office or relevant SIP and conformity guidance documents.

The DEQ does not provide estimates for

• light-heavy duty, non-heavy duty, gasoline or pre-1980 engines
• C3 marine diesel engines used on ocean going vessels and lakers
• black carbon or greenhouse gas reductions, except for CO2 when fuel usage is reduced
• health benefits from NOx, HC and CO reductions

Before using the DEQ, please also read:

• Input Check list to learn what inputs you'll need, some basic terms and how to get the most accurate results.
• Results and Outputs to learn how to download and interpret your results.
• More Help for FAQs and other documentation.

Other Emission Reduction Calculators

Users with air quality modeling experience may wish to use one of EPA’s more technical models for quantifying the benefits of retrofit projects.

• Motor Vehicle Emission Simulator (MOVES) for on-road vehicles
• NONROAD Model for nonroad engines, equipment, and vehicles
• SmartWay Tools for shippers, logistics companies, and truck, multimodal, rail, barge and air carriers
• Argonne National Laboratory GREET Model for lifecycle emissions from vehicles and fuels

DEQ Inputs

For on-highway and nonroad calculations

• A fleet consists of the vehicles and/or equipment for which emission reductions will be estimated.  A fleet 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 includes similar vehicles with similar age and usage characteristics. If the fleet consists of school buses and transit buses, there will be at least two vehicle groups. More specific vehicle groups will provide better estimates (e.g., Group 1: school buses of model year 1995; Group 2: school buses of model year 2000; Group 3: transit buses of model year 2005)

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 similar age and usage 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

  • 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)

DEQ Results and Outputs

The DEQ estimates emission reductions based on retrofit technologies and other user data that has been entered into the DEQ. After clicking on ‘Quantify Emissions’, you will see the ‘Emissions Results’ page with two tabs.

Emissions Results Tab

This is a summary of emission results for your fleet. At the bottom of the page, you will find 'Capital Cost Effectiveness', 'Total Cost Effectiveness' and the remaining lifetime for each vehicle group within the fleet.  Below that, you can download your DEQ results as a printable spreadsheet or in a format that can be imported into DRIVER.

The DEQ calculates emission reductions for four criteria pollutants, NOx, PM 2.5, HC, CO, as well as CO2. The following eight outputs are calculated for each pollutant.

• Annual Results (in short tons)
  • Baseline for Retrofitted Vehicles is the annual baseline emissions before the fleet is retrofitted.
  • Amount Reduced is the annual emissions reduced after the fleet has been retrofitted.
  • Percent Reduced (%) is the percent by which emissions are reduced after the fleet has been retrofitted.
• Lifetime Results (in short tons)
  • Baseline for Retrofitted Vehicles is the lifetime baseline emissions before the fleet is retrofitted.
  • Amount Reduced is the lifetime emissions reduced after the fleet has been retrofitted.
  • Percent Reduced (%) is the percent by which emissions are reduced after the fleet has been retrofitted.
• Capital Cost Effectiveness ($/short ton) is 'Capital Costs' (Unit Cost plus Installation Cost) for retrofit technologies divided by ‘Lifetime Amount Reduced’ emissions. These fields will be blank if the costs have not been entered on the ‘Add a New Technology’ screen.
• Total Cost Effectiveness ($/short ton) is 'Total Project Costs' divided by ‘Lifetime Amount Reduced’ emissions. These fields will be blank if the costs have not been entered on the 'Enter Fleet Information' screen.

Health Benefits Tab

This tab shows estimated health benefits based on the annual reductions of PM 2.5. Costs are the Capital Costs (unit cost plus installation cost) entered on the 'Add a New Technology' screen. Benefits are the monetized health benefits resulting from reduced PM 2.5. Both costs and benefits have been annualized over the remaining life of the fleet.

• Diesel Emissions Quantifier (DEQ) Frequently Asked Questions (FAQs) (PDF)(22 pp, 958 K, April 5, 2013, EPA-420-F-13-008a)
• Diesel Emissions Quantifier Default Values (PDF)(6 pp, 607 K, August 11, 2010, EPA-420-B-10-035)
  On highway defaults now come from MOVES 2014. This document will be updated.
• Diesel Emissions Quantifier Health Benefits Methodology (PDF)(48 pp, 1 MB, August 11, 2010, EPA-420-B-10-034)
• Guidance for quantifying and using long duration switch yard locomotive idling emission control programs in State Implementation Plans and conformity