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National Clean Diesel Campaign (NCDC)

Working Together for Cleaner Air

Having Trouble?
Diesel Emissions Quantifier (DEQ)

More Help

Troubleshooting

Please select from the topics below to submit your request. Depending on the complexity of your inquiry, we will respond within 3-5 business days for resolution of your issue.

If you have an immediate need, such as a grant application or project report deadline, please contact the NCDC helpline at 1-877-623-2322.

Do you have a question regarding your User Account?

User Account Problem

Please provide a description of your user account problem and we will get back to you within 3-5 business days

In the meantime, you can continue using the DEQ without logging in. If possible, download the Results Detailed Summary which lists your inputs and you will be able to replicate your results once your log in problem is resolved.

DEQ login E-mail (if different from E-mail entered above)

Please Explain Your Problem:

Did you receive a DEQ Error Message?

DEQ Error Message

DEQ errors can be caused by high traffic volume or a number of other factors.

To help us resolve this issue, please provide the text of the error message (copy and paste) as well as the inputs listed below. Some errors will take time to replicate and may not be easily resolved. Please allow 5 business days for resolution of your issue.

As a workaround, try a different browser and/or not logging in. You can also try using the DEQ during non-peak hours (early in the morning, late in the evening, or on weekends/holidays).

DEQ login E-mail (if different from E-mail entered above)

Error Text: if available

All fields below are optional, however, we ask that you please fill out as many fields that apply to your calculation/question as possible. The more details and accuracy you provide, the easier it will be for us to pin-point the issue and find a solution.

Optional inputs to calculate cost effectiveness (EPA $, Other Federal $, CMAQ $, Local $, etc.)

For On Highway / Nonroad

Number of vehicles in the fleet

Class of equipment:

Engine model year for vehicles in group

Year in which the reduction technology will be installed

Currently used by the vehicle group

Gallons/year/vehicle group

For On Highway

Annual miles per vehicle

Annual idle hours per vehicle

For NonRoad

Annual engine hours per vehicle

Engine horsepower rating

For Marine

per vessel

Engine model year for vehicles in group

Year in which the reduction technology will be installed

Hours/year/engine

Gallons/year/vehicle group

Liters per cylinder

Technology 1

Number of vehicles to which you would like this technology applied

For Idle Reduction Technologies

Idling hours reduced per vehicle (if applicable)

If Replacement / Repower

New model year of replaced vehicle/engine (if applicable)

Gallons/year/vehicle group

User-input emission reduction percents for the pollutants (if applicable)

Unit and install cost in dollars per vehicle (if applicable)

Technology 2

Number of vehicles to which you would like this technology applied

For Idle Reduction Technologies

Idling hours reduced per vehicle (if applicable)

If Replacement / Repower

New model year of replaced vehicle/engine (if applicable)

Gallons/year/vehicle group

User-input emission reduction percents for the pollutants (if applicable)

Unit and install cost in dollars per vehicle (if applicable)

Health Benefits

Health benefits states, counties and percentages: (if applicable)

Did you encounter problems during a DEQ calculation?

DEQ Input or Calculation Problems

If you are having DEQ inputs or calculation problems, please review:

The DEQ Overview and Input Checklist pages describe what the DEQ can and cannot do. The DEQ FAQs document lists user questions that have been answered in the past including an extensive Table of Contents. Users who have reviewed these documents generally get more accurate and meaningful results.

To help us resolve this issue:

  • If you have or can download a Detailed Report with your inputs and results, please attach it to an Email along with a description of the issue. Send to cleandiesel@epa.gov
  • -- OR --
  • Provide all information entered into the DEQ in the form below

Some issues will take time to replicate and may not be easily resolved. Please allow 5 business days for resolution of your issue.

DEQ login Email (if different from Email entered above)

Describe your calculation problem and be as specific as possible:

All fields below are optional, however, we ask that you please fill out as many fields that apply to your calculation/question as possible. The more details and accuracy you provide, the easier it will be for us to pin-point the issue and find a solution

Optional inputs to calculate cost effectiveness (EPA $, Other Federal $, CMAQ $, Local $, etc.)

Number of vehicles in the fleet

Class of equipment:

Engine model year for vehicles in group

Year in which the reduction technology will be installed

Currently used by the vehicle group

Gallons/year/vehicle group

For On Highway

Annual miles per vehicle

Annual idle hours per vehicle

For NonRoad

Annual engine hours per vehicle

Engine horsepower rating

For Marine

per vessel

Engine model year for vehicles in group

Year in which the reduction technology will be installed

Hours/year/engine

Gallons/year/vehicle group

Liters per cylinder

Technology 1

Number of vehicles to which you would like this technology applied

For Idle Reduction Technologies

Idling hours reduced per vehicle (if applicable)

If Replacement / Repower

New model year of replaced vehicle/engine (if applicable)

Gallons/year/vehicle group

User-input emission reduction percents for the pollutants (if applicable)

Unit and install cost in dollars per vehicle (if applicable)

Technology 2

Number of vehicles to which you would like this technology applied

For Idle Reduction Technologies

Idling hours reduced per vehicle (if applicable)

If Replacement / Repower

New model year of replaced vehicle/engine (if applicable)

Gallons/year/vehicle group

User-input emission reduction percents for the pollutants (if applicable)

Unit and install cost in dollars per vehicle (if applicable)

Health Benefits

Health benefits states, counties and percentages: (if applicable)

Do your DEQ results seem too low, too high, or don't match your expectations?

DEQ Results seem "off"

For questions about a specific emission factor or DEQ result:

  • If you have or can download a Detailed Report with your inputs and results, please attach it to an Email along with a description of the issue and what you are using for a comparison. Send to cleandiesel@epa.gov
  • -- OR --
  • Provide all information entered into the DEQ in the form below

This process will take time and may not result in a suitable answer or solution. All models have limitations, including those approved by the EPA.

DEQ login Email (if different from Email entered above)

Describe what you believe to be wrong and why. Please cite any outside sources which you are using for comparison.

All fields below are optional, however, we ask that you please fill out as many fields that apply to your calculation/question as possible. The more details and accuracy you provide, the easier it will be for us to pin-point the issue and find a solution

Optional inputs to calculate cost effectiveness (EPA $, Other Federal $, CMAQ $, Local $, etc.)

Number of vehicles in the fleet

Class of equipment:

Engine model year for vehicles in group

Year in which the reduction technology will be installed

Currently used by the vehicle group

Gallons/year/vehicle group

For On Highway

Annual miles per vehicle

Annual idle hours per vehicle

For NonRoad

Annual engine hours per vehicle

Engine horsepower rating

For Marine

per vessel

Engine model year for vehicles in group

Year in which the reduction technology will be installed

Hours/year/engine

Gallons/year/vehicle group

Liters per cylinder

Technology 1

Number of vehicles to which you would like this technology applied

For Idle Reduction Technologies

Idling hours reduced per vehicle (if applicable)

If Replacement / Repower

New model year of replaced vehicle/engine (if applicable)

Gallons/year/vehicle group

User-input emission reduction percents for the pollutants (if applicable)

Unit and install cost in dollars per vehicle (if applicable)

Technology 2

Number of vehicles to which you would like this technology applied

For Idle Reduction Technologies

Idling hours reduced per vehicle (if applicable)

If Replacement / Repower

New model year of replaced vehicle/engine (if applicable)

Gallons/year/vehicle group

User-input emission reduction percents for the pollutants (if applicable)

Unit and install cost in dollars per vehicle (if applicable)

Health Benefits

Health benefits states, counties and percentages: (if applicable)

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