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National Clean Diesel Campaign (NCDC)

Working Together for Cleaner Air

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Diesel Emissions Quantifier (DEQ)

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Need help?  DEQ Trouble Shooting

The DEQ is an interactive tool that evaluates clean diesel projects and options for medium-and heavy-heavy duty diesel engines by estimating emission reductions, cost effectiveness, and health benefits. This quantifier was developed for users with little or no modeling experience.

The DEQ does not currently provide estimates for light-heavy duty or non-heavy duty engines or vehicles, non-diesel engines or vehicles, pre-1980 engines or ocean going vessels

DEQ results can be downloaded to a spreadsheet that provides the following information:

  • Estimates of baseline emissions (annual and lifetime)
  • Estimates of emission reductions, cost effectiveness and health benefits (annual and lifetime)
  • Comparison of emission reductions, cost effectiveness and health benefits for different emission control strategies (annual and lifetime)
  • Assistance to EPA grantees and SmartWay carrier partners in developing data reports for submission to EPA

Before using the DEQ, please also read

  • Input Checklist 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
  • Having Trouble for help in resolving issues with your login or DEQ run

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 is unable to perform the following calculations due to the unavailability of certain data.

  • Fuel economy benefits for nonroad engines with idle reduction technologies or engine replacements
  • CO2 and other greenhouse gases (GHG) reductions for retrofit devices and engine repowers and/or replacements
  • Health benefits from NOx, HC, and CO reductions
  • Black Carbon reductions

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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.

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For questions, technical assistance, or more information: Contact Us

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