Diesel Emissions Quantifier (DEQ)
Frequently Asked Questions (FAQs)
Revised April 4, 2013
SEPA
United States
Environmental Protection
Agency
Office of Transportation and Air Quality
EPA-420-F-13-008
April 2013
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Table of Contents
Administrative 3
Logging In 3
Saving Results 3
Changing Your Password 3
Activating Your Account 4
Uses and Limitations 4
Light-duty Vehicles 4
Congestion Mitigation and Air Quality Improvement Program (CMAQ) 4
State Implementation Plans (SIPs) 4
Fuel Savings/Fuel Economy Benefits 4
CO2 4
C3 Marine 4
Black Carbon 5
Defaults and Emission Rates 5
Defaults 5
Emission Rates 5
Calculations and Units 6
Calculations 6
Units 6
Use in the Grant Process 6
Choosing a Calculator 6
Cost-Effectiveness 7
Health Benefits 9
Pollutants and Health Effects 9
Counties 10
Calculations and Accuracy 11
Outputs and Uses 11
Cost Benefits (Explanation and Troubleshooting) 12
Other 13
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Data Entry 13
Multiple Technologies 13
Fuel Types 13
Replacement 14
Truck Stop Electrification 14
Trailer Refrigeration Unit 14
Uncertainty, Missing Information, Averaging, and Diverse Fleets 15
Fleets 15
Baseline Emissions 15
Idle Reduction 16
Maintenance and Operating Costs 16
Vehicle Definitions and Classes 16
Verification Information 17
Input Errors 17
Vehicle Groups 17
Model Year 17
Horsepower 17
Replacement (Engine and Vehicle) 17
Technologies 18
Fuels 18
Currently Documented Errors 18
Appendix: Grouping Vehicles for Calculations in the DEQ 20
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Administrative
Logging In
Question: I'm having trouble logging in.
Answer: Close the DEQ and try again. If this doesn't work, delete your internet browser's history and cookies
(usually found under "tools") and try logging in. If you still can't log in, please send an email to
cleandiesel@epa.gov with "DEQ User Account Problem" in the Subject Line, and include your DEQ user
account email. Meanwhile, you can create a new username and password or use the DEQ without
logging in.
Question: When I try to access the DEQ, I receive an error message.
Answer: The server that hosts the DEQ can get overloaded when too many users are trying to log on at the
same time. DEQ traffic will be high around the close of any National Clean Diesel grant competition.
Try using the DEQ during off-peak hours (early morning, late evening or weekends). Or you can try
closing your browser and re-accessing the DEQ using a different browser or without logging in.
If you still can't access the DEQ or cannot get through a calculation without the DEQ sending an error
message, send an email to cleandiesel@epa.gov with "Cannot Access or Complete DEQ run" in the
Subject Line. Please include a screenshot of the error message and your user account email (if you
logged in).
If you can replicate the error message, it's helpful to include all of the inputs entered before the DEQ
sent the error message. If you can't replicate the error, please provide a description of the calculation
you were trying to make.
Saving Results
Question: Is there a way to save more than three "fleets" in the DEQ under a single login account?
Answer: No. However, each "fleet" (with the exception of marine vessels) can accommodate up to 30
"vehicle groups". Currently, each marine vessel must be a separate "fleet" (each vessel can have up to
five marine engines). You may open multiple user accounts, but each account must have a unique email
address.
Question: Sometimes when trying to save DEQ results in an Excel format, the data is saved as a text (txt) file.
How can I get the results into Excel format?
Answer: The DEQ allows users to save both the Summary Results and Detailed Results in Excel or CSV
formats. Sometimes files won't save properly because of the download settings of your browser and/or
computer.
If your results are being saved as a text file, re-save or rename the file with an "xls" extension and Excel
should be able to open it. If you need the results in CSV format, save in the CSV format directly from the
DEQ, instead of saving to Excel and then converting to CSV.
Changing Your Password
Question: How do I change my DEQ password?
Answer: To change your password, go to www.epa.gov/cleandiesel/quantifier. select the "Use the
Quantifier" tab, log in, and click on "Edit Profile".
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Activating Your Account
Question: I've submitted my account registration information, but I am unable to log in. How does my
account get activated?
Answer: You should have received an activation email with a validation link. You must click on this
validation link to activate your account.
The activation email may have been caught in your SPAM filter or your email address may have been
mistyped on the registration form. If you can't find the activation email in your SPAM filter, try
registering the account again.
Occasionally the DEQ server doesn't recognize an email address ending in ".net". We are working to
resolve this and suggest that you register with an email address that ends with ".gov, .edu, or .com" if
possible.
Uses and Limitations
Light-duty Vehicles
Question: Can the DEQ be used for light-duty projects (i.e. diesel pickups)?
Answer: No. The DEQ calculates emission reductions for medium-heavy and heavy- heavy-duty vehicles
only. The Motor Vehicle Emissions Simulator (MOVES) model at www.epa.gov/otaq/models/moves can
be used to calculate emission reductions for light-duty or heavy-duty vehicles.
Congestion Mitigation and Air Quality Improvement Program (CMAQ)
Question: Can the DEQ be used to estimate benefits for the Congestion Mitigation and Air Quality
Improvement Program (CMAQ)?
Answer: Yes, the DEQ is an estimation tool that may be used for CMAQ planning purposes.
State Implementation Plans (SIPs)
Question: Can the DEQ be used for State Implementation Plan (SIP) calculations?
Answer: No. When the DEQ estimates emission reductions, some default values are used. SIP and
conformity calculations require more sophisticated modeling tools that use specific inputs. Please refer
to your SIP and conformity guidance documents or contact your regional EPA office at
www.epa.gov/cleandiesel/ncdc-cmt.htm for more information.
Fuel Savings/Fuel Economy Benefits
Question: Does the DEQ provide information on fuel savings?
Answer: No. However, when the quantity of saved diesel fuel is input to the DEQ, it can calculate the CO2
emission reductions.
C02
Question: Would replacing an engine reduce CO2 (carbon dioxide) emissions?
Answer: Maybe. In addition to reductions from burning less fuel, there is a potential for CO2 reduction from
the new engine. Because engines are not currently certified for CO2,the DEQ relies only the amount of
fuel reduced to estimate CO2 reductions.
C3 Marine
Question: How can I calculate emission reductions for C3 marine engines in ocean-going vessels?
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Answer: C3 marine engines are currently beyond the scope of the DEQ. Please see "Current Methodologies
in Preparing Mobile Source Port-Related Emission Inventories" at
www.epa.gov/cleandiesel/publications.htm for help in calculating these emission reductions or contact
EPA's Helpline at 1-877-NCDC-FACTS or cleandiesel@epa.gov.
Black Carbon
Question: Black carbon, also known as elemental carbon, is a potent climate change agent found in
diesel particulate matter. Does EPA have plans to include black carbon in the DEQ so its climate
change impacts can be estimated?
Answer: The agency is still working on guidance regarding black carbon. At this time, there are no definite
plans to include black carbon in the DEQ.
Defaults and Emission Rates
Defaults
Question: Can you provide more information about the DEQ default values?
Answer: The DEQ default values were compiled using various reports and models. For more information, see
the DEQ Default Values document at www.epa.gov/cleandiesel/documents/420bl0035.pdf.
Question: How does the DEQ calculate the life of a vehicle? Can that value be overridden?
Answer: For on-highway vehicles, the lifetime is set at 30 years based on our modeling. For nonroad
applications, the lifetime is usually shorter but will vary depending on equipment type and horsepower.
The default values for the life of a vehicle cannot be overridden in the DEQ.
Emission Rates
In November 2010, EPA updated DEQ emission rates for highway/on-road vehicles using data from the
Mobile Vehicle Emissions Simulator (MOVES2010) at www.epa.gov/otaq/models/moves. MOVES2010
incorporates a number of significant improvements over the old MOBILES.2 rates, particularly in baseline
emissions, activity data, and calculations used to estimate emissions in real-world driving conditions.
For current and future highway/on-road projects, it is highly recommended that you use the MOVES2010
emission rates by selecting retrofit year of 2011 or later.
Question: Which "Year of Retrofit Action" should I use if my project spans several years, for instance 2008 to
2011?
Answer: We recommend that you use MOVES2010 emissions rates by selecting 2011 or later as the "Year of
Retrofit Action" for the entire project, even if the retrofit activity took place before 2011.
Question: What should I do if my project spans 2008 -2011 and my initial calculations used the old MOBILE
6.2 emission rates in the DEQ?
Answer: We recommend that you perform your final calculations using the new MOVES2010 emission rates
by choosing 2011 as your "Year of Retrofit Action".
Question: My project has been completed and I've already done my calculations using the old DEQ
numbers. Do I need to re-run the DEQ using 2011 as the "Year of Retrofit Action"?
Answer: No. If your project is closed and you have already turned in your final report, there is no need to
re-run the DEQ to update the emissions savings.
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Question: What happens if I continue to use the old DEQ MOBILE 6.2 emission rates by selecting a "year of
Retrofit Action" prior to 2011?
Answer: You will not run into any problems using the DEQ. However, using the old MOBILE 6.2 numbers for
your calculations will severely underestimate your emission reductions.
Question: Why do DEQ emission factors vary from state to state for the same vehicle(s)?
Answer: The modeling tools used to generate emission factors for the DEQ take into account a variety of
state- and county-specific characteristics such as climate, geography, roads, and population. These
characteristics affect emission levels, causing them to differ by state and/or county. Neighboring states
and counties may see smaller differences than those that are farther apart.
For projects extending beyond a single state, select the state in which the majority of activity will take place.
Question: Can EPA provide the emission factors and methodology used by the DEQ in a spreadsheet format
so we can do the calculations ourselves?
Answer: The DEQ derives its emission factors from EPA's standard modeling tools - MOVES2010 for on-
highway calculations and NONROAD2008 for non-road calculations. For more information about these
factors and models, please visit the MOVES www.epa.gov/otaq/models/moves or the NONROAD
www.epa.gov/otaq/nonrdmdl website.
Calculations and Units
Calculations
Question: In calculating lifetime benefits, does the DEQ consider the remaining life of the vehicle or of the
emission control device?
Answer: Lifetime calculations are based on the remaining life of the vehicle, not the emission control device.
EPA assumes that once a vehicle is retrofitted, it will remain retrofitted until the vehicle is retired.
Question: Why do lifetime emission reductions use a vehicle's remaining life instead of the full life of the
vehicle? For instance, I am replacing a 20 year old school bus with a brand new one. The old bus has 10
years left while the new one has 30. The DEQ shows lifetime emission benefits for only the 10 remaining
years of the old bus. Doesn't this underestimate the emissions benefit of my new bus?
Answer: The most the old bus will emit pollutants is its remaining life (10 years) - it will be replaced in 10
years (when its remaining life is over) or some time before then. If it is replaced now (early
replacement), the full 10 years of emissions will be reduced. That is the maximum that can be claimed.
Units
Question: Does the DEQ give results in US short tons (2000 pounds), British long tons (2240 pounds) or
metric tons (2204 pounds)?
Answer: Short tons.
Question: Can the DEQ separate particulate matter (PM) by PM25 and PM10?
Answer: No. The DEQ only calculates PM2.5.
Use in the Grant Process
Choosing a Calculator
Question: If the DEQ is not a good match for my project, are there other calculation tools I can use?
Answer: You can use any model you wish as long as you explain and document your calculations.
Here are some other models for your consideration:
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1. Motor Vehicle Emission Simulator (MOVES) for on-road vehicles
www.epa.gov/otaq/models/moves
2. NONROAD Model for nonroad engines, equipment, and vehicles
www.epa.gov/otaq/nonrdmdl.htm
3. SmartWay FLEET Tools for freight shippers, logistics companies, and rail, trucks, drayage and
multi-modal carriers
www.epa.gov/smartway/partnership
4. Argonne National Laboratory GREET Model, for estimating vehicle lifecycles and carbon
footprints, greet.es.anl.gov
Cost-Effectiveness
Question: How does the DEQ calculate cost-effectiveness?
Answer: Cost-effectiveness can be calculated by the DEQ in two ways. Both calculations are simple and can
also be done by hand.
First, the DEQ can provide the dollar per ton of pollutant reduced for the entire project (Total Fleet Cost
Effectiveness). For this calculation, input the cost of the whole project before you add a "Vehicle
Group".
Second, the DEQ can provide the dollar per ton of pollutant reduced for each unit (Capital Cost
Effectiveness). For this calculation, enter the installation and unit costs per vehicle when you add a
technology to your vehicle group.
The Total Fleet Cost Effectiveness for the entire project appears only on the "Results" screen, while the
Capital Cost Effectiveness per unit appears both on the "Results" screen and the Summary and Detailed
results spreadsheets.
1) Total Fleet Cost-Effectiveness
a) The DEQ totals the entire project funding amounts entered on the first DEQ screen (shown
below). This is the Total Project Cost.
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Enter Fleet Information
Fleet Name School Bu
Fleet Type
State
On Highway NonRoad v
Maire
Do you want to estimate the total cost effectiveness of the project?Yes No
Total cost effectiveness numbers are based solely on the user inputs below
ERAS
Other Federal S
CMAQS
Local 5
200000
1500
Privates ^300
Match Lev. S 2EOOO
SEPS |o
Other S
Unknown S
State S
3333 |
1000 |
o H
b) After the Vehicle Groups have been entered, the DEQ calculates the total lifetime emission
reductions by pollutant (NOx, PM, HC, CO, and CO2) for the entire fleet. This is the Total Lifetime
Tons Reduced.
c) The DEQ then divides the Total Project Cost by the Total Lifetime Tons Reduced for each of the
five pollutants. The results are shown in dollars/ton on the bottom of the Emission Results
Page. The results are currently not shown in outputs that are downloadable in Excel and CSV
formats. However, it is a relatively simple calculation that can be done by hand using DEQ
results.
2) Capital Cost-Effectiveness is calculated using the installation and unit costs entered in the DEQ
screen shown below. It does not include things like project administration costs and overhead.
Capital Cost-Effectiveness is calculated by adding the Unit Cost and Installation Cost for each
technology and dividing the sum by the Total Lifetime Tons Reduced for each of the five pollutants.
This value is displayed both on the Emissions Results page and the outputs that are downloadable
in Excel and CSV formats.
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Enter Fleet Information
Start Over
Idle Reduction
Fleet Type On Highway Non-road
State Kentucky
Start Over
Long Haul Idle
Quantity 2
Type On Highway
Target Fleet Long Haul
Class Equipment Class 8a
(33,001-
60,000)
Model Year 1996
Retrofit Year of 2012
Action
Fuel Type Regular Diesel
(ULSD), 1 5 ppm
Fuel Volume 33334
Veh. Miles Traveled 1 00000
Idling Hours 2400
New Technology
Vehicle Grot
Technology
Technology Type
Emissions Control Devices
-
Technology
Diesel Oxidation Catalyst
Apply To \2
(out of 2} with no technology
Reduction by Pollutant
NOX % [iT
PM%|20
HC%[50~
CO%[30~
C02 % E"
Install Cost |1000
Unit Cost 6000
S per vehicle
S per vehicle
Edit Group
Save Technology
Delete
Cancel
Health Benefits
Pollutants and Health Effects
Question: Which health effects of diesel PM2.5 are included in the cost/benefit calculation in the Health
Benefits Module?
Answer: The benefits of reduced diesel emissions are based on avoided incidences of the following:
• Premature mortality
• Chronic bronchitis
• Acute bronchitis
• Upper and lower respiratory symptoms
• Asthma exacerbation
• Nonfatal heart attacks
• Hospital admissions
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• Emergency room visits
• Lost work days
• Restricted-activity days
Question: Does the DEQ estimate reductions in total particulate matter or fine particulate matter (PM2.5)?
Answer: The DEQ estimates reductions in PM2.5 and that is what is used for determining health benefits. For
additional information, please refer to the Health Benefits Methodology at
www.epa.gov/cleandiesel/documents/420bl0034.pdf.
Question: Is diesel particulate matter the only pollutant considered in the Health Benefits Module?
Answer: Yes. There are likely benefits from reducing other pollutants, such as ozone and air toxics, but the
DEQ cannot quantify these benefits at this time.
Counties
Question: How do I determine in which counties the emission reductions take place?
Answer: The DEQ requires you to choose one state where the retrofits take place. For projects that span
multiple states, such as long-haul trucks and locomotives, select the state where the majority of
emissions are generated.
Once the DEQ calculations are completed and you go to the Health Benefits tab, you can allocate the
emission reductions among up to five counties (in multiple states). Note that the Health Benefits
Module is not asking whether pollution from one county is drifting into another; it's asking where the
vehicles that are reducing their emissions are operating.
Question: My county is "flagged." What does that mean?
Answer: The Health Benefits Module will flag results for counties where there may be an under or over
estimate of health benefits due to the migration of emissions into or out of the county.
For counties with a large quantity of emissions flowing into the county, the results are flagged with the
following message: Benefits estimates are "flagged" for this county, indicating that we have less
confidence in these results due to a large amount of inter-county transport of emissions. The impacts
estimation tool may be overestimating the benefits for emission reduction projects in this county,
because it has relatively few emissions compared to surrounding areas. As a result, this county is likely to
be a net importer of diesel emissions, and air quality is significantly affected by emissions in upwind
counties. Please take this increased uncertainty into account when interpreting your results.
For counties with a large quantity of emissions flowing out of the county, the results are flagged with
the following message: Benefits estimates are "flagged" for this county, indicating that we have less
confidence in these results due to a large amount of inter-county transport of emissions. The impacts
estimation tool may be un derestim a tin a benefits for emissions reduction projects in this county, because
it has a relatively high density of emissions compared to surrounding areas. As a result, this county is
likely to be a net exporter of diesel emissions, and many of the benefits of reducing these emissions are
likely to take place in downwind counties. Please take this increased uncertainty into account when
interpreting your results.
Question: When I enter the same data for retrofit projects in different counties, why do I get different
health benefits?
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Answer: One of the main factors in determining the health benefits from reduced emissions is the
proximity of people to where those emissions would have been generated. If a certain level of
emission reduction is assigned to a census tract with a larger area, it will result in a lower
concentration as the pollution is being spread over a greater area. The opposite is true as well.
Assigning emission reductions to a smaller area census tract will result in higher concentrations.
In addition, if a certain level of emission reductions is assigned to a less populated census tract, fewer
people will be exposed resulting in a lower concentration ratio. Again, the opposite is true: emissions
assigned to higher-populated tracts leads to a higher concentration ratio.
Calculations and Accuracy
Question: How are benefits of reducing diesel particulate matter calculated?
Answer: The Health Benefits Module uses a county "look-up table", which includes estimated benefits per
ton of PM2.5 reduced for each county in the United States.
The user answers a set of questions about their project. Once the DEQ estimates the emission changes,
the Health Benefits Module uses the "look-up table" to estimate the health benefits associated with the
PM 2.5 reductions for the specified county. The combined monetary benefits of avoided mortality and
avoided morbidity (i.e. non-fatal illness) for the selected counties are displayed.
As part of the Quality Assurance process, EPA has also developed a table using on-road and nonroad
diesel PM 2.ssource tables. These tables and more are available in the Health Benefits Methodology at
www.epa.gov/cleandiesel/documents/420bl0034.pdf.
Question: How accurate are the Health Benefits Module estimates?
Answer: The methodology used to estimate health benefits was peer-reviewed both inside and outside EPA
and many of the suggestions were incorporated. The module includes data and modeling from several
existing EPA tools, such as the National Emissions Inventory (NEI), the National Air Toxics Assessment
(NATA), and the Environmental Benefits Mapping and Analysis Program (BenMap).
The benefits reflect reductions only in fine particulate matter. They do not include benefits from the
reduction of other pollutants, including air toxics.
The estimates are based primarily on county-level data and do not capture smaller-scale variability, such
as living very near a retrofitted diesel source or regularly riding a retrofitted school bus.
The results also do not include the impact of emission sources from Canada or Mexico. Results for
border states will not reflect these potentially significant sources of transported emissions.
The results are best used to assess the relative benefits among different locations or retrofit projects.
For a complete discussion of the accuracy of these estimates, please see the chapter titled
"Uncertainties, Limitations, and Quality Assurance" in the methodology document at
www.epa.gov/cleandiesel/documents/420bl0034.pdf.
Outputs and Uses
Question: What information does the Health Benefits Module provide?
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Answer: This module provides information on health benefits from reduced exposure to diesel PM 2.s
emissions.
The DEQ requires users to input detailed information regarding their retrofit projects. The DEQthen
calculates the emission reductions for particulate matter (PM), nitrogen oxides (NOx), hydrocarbons
(HC), carbon monoxide (CO), and carbon dioxide (CO2).
The Health Benefits Module allows users to identify the counties where the emission reductions are
taking place and to estimate the monetary impact of the resulting health benefits. These estimates are
based on the change in fine particle concentrations and do not reflect changes in any other pollutants.
Users can save and export files summarizing the emissions and health effects estimates. There is also a
Health Benefits Methodology at www.epa.gov/cleandiesel/documents/420bl0034.pdf that explains the
methodology used to estimate the health benefits and the limitations of the estimates.
Question: How can this health benefits information be used?
Answer: The Health Benefits Module is a helpful tool for preparing estimates and understanding benefits of
specific emission diesel reduction projects. It can help in making informed decisions by comparing the
benefits of several diesel retrofit options. It can also provide an estimate of benefits for EPA grant
applications and help build public support for such projects. It should not be used in the calculation of
emission reductions for State Implementation Plan (SIP) or conformity determination.
Cost Benefits (Explanation and Troubleshooting)
Question: Why does the Health Benefits Module use annual costs and benefits?
Answer: Diesel retrofit projects tend to be capital-intensive in the first year due to the purchase and
installation of new equipment or parts. The benefits, however, are spread out over many years as
people continue to receive health benefits from the reduced emissions.
In order to properly compare costs and benefits, this difference in timeframes must be addressed. We
annualize the costs and the benefits so the user can tell at a glance if the benefits outweigh the costs on
an annual basis. They also provide an indication of the scale and magnitude of the expected costs and
benefits over the lifetime of the project.
Annualized costs are not the out-of-pocket costs in the first year, but what would be paid each year if
the out-of-pocket costs were distributed the over the life of the engine. This is similar to the way a
mortgage distributes the purchase price of a home over 30 years. If you used a loan to purchase the
retrofit technology, the annualized costs are roughly what the loan payments might look like.
Lifetime costs and benefits can be estimated by multiplying the annual costs or benefits by the number
of remaining years in the life of the retrofitted vehicle. While the lifetime estimate does not take into
account factors such as discount rates for benefits in future years or population growth, it does provide
a rough estimate.
Question: Why are there no costs in the "Results" table of the Health Benefits Module?
Answer: The Health Benefits Module estimates the annualized costs from the "install cost" (labor) and
"unit cost" (equipment) of the project, which are entered into DEQ's Fleet Information screen under
"Add a New Technology." If no cost information is entered, no cost information will appear in the
benefits results table.
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Please note, funding information can also be entered on the first screen of the DEQ by answering yes to
"Do you want to estimate the total cost effectiveness of the project?" These are assumed to be total
project costs, including overhead, and are not used to estimate annual costs.
Question: I am trying to determine the health benefits for a marine engine repower project. While there
are significant PM reductions, why do the benefits come up as $0?
Answer: The health benefits calculation depends on the PM reduction in tons. Sometimes, that reduction
may be lower than you realize and the benefits may be so close to zero that they are accidentally
truncated. Please download the Summary Results for both the DEQ calculation and the Health Benefits
calculation in Excel or CSV and send it to cleandiesel@epa.gov
Other
Question: Where can I get more information about particulate matter in diesel exhaust?
Answer: For information about particulate matter, visit www.epa.gov/air/particlepollution
Data Entry
Multiple Technologies
Question: Can I select combined emission control devices like DOC+CCV (Diesel Oxidation Catalyst +
Closed Crankcase Ventilation) or DPF+CCV (Diesel Particulate Filter + Closed Crankcase Ventilation)?
How about CCV by itself?
Answer: CCV is included under "Emission Control Devices" as DOC+CCV, or DPF+CCV, but it is not listed as a
stand-alone retrofit technology. To use CCV as a stand-alone technology, select "Other Emission Control
Devices" from the "Technology" menu and enter the reduction percentages provided by the CCV
manufacturer.
Question: Can I select multiple technologies such as engine repower with DOC or DPF?
Answer: Some technologies cannot or should not be installed together (e.g. DPFs and Partial Flow filters).
However, many technologies can be used at the same time.
To add multiple technologies to a vehicle group, select the first technology and save it to the vehicle
group. Then select the second, saving it to the same vehicle group. The screen always returns to the
first vehicle group after adding a technology, so if there is more than one vehicle group, make sure the
technology being added to the correct group.
Fuel Types
Question: The emission factors for NOx, PM, HC, and CO do not change when I select a different fuel
type for my Vehicle Group. Why are these emissions not different for CNG and ULSD?
Answer: Fuel type and volume are used to calculate only C02 emissions. This is done by converting
non-diesel fuel amounts to diesel-equivalent gallons, and then calculating CO2 emissions based on
the diesel carbon content.
Question: How does the DEQ estimate emission savings for switching from one fuel type to another?
Answer: When you enter the vehicle information on the "New Vehicle Group" screen, select the fuel type
being used before the retrofit. Then go to "Add a New Technology," select "Fuel Options" and the fuel
type that will be used after the retrofit. You can apply as many additional technologies as you need to.
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Question: When I select CNG as the new fuel for my old diesel vehicle, all of the reduction percentages are
zero. Why is this?
Answer: The DEQ is primarily designed to calculate emission reductions for vehicles that use diesel fuel
(ULSD, LSD, etc). All other fuels (biodiesel, CNG, LNG, etc) are converted by the DEQ to a diesel
equivalent ("Calculated Fuel Volume") before any calculations are performed. Currently, the DEQ is not
able to provide emission reductions for CNG and LNG fuel conversions because fuel-specific emission
factors are not available in all cases. For more information, please visit the Alternative Fuel Conversion
website at www.epa.gov/otaq/consumer/fuels/altfuels/altfuels.htm
As a workaround for this, create two vehicle groups in the DEQ, one with a baseline engine using diesel
fuel, and one with a baseline engine using the new fuel (you would need to know the annual amount of
new fuel the used after the conversion, the annual of miles the vehicle would travel, and annual hours it
would idle). Comparing the outputs for these two vehicles provides the CO2 emission reductions from
the fuel conversion.
Replacement
Question: Does the DEQ calculate emission reductions for engine replacements?
Answer: Yes. Under "Technology Type," select "Engine Replacement/Repower." Then under "Technology"
select "Engine Replacement."
Question: Can the DEQ be used to calculate emission reductions from replacing a diesel engine with
electric technology?
Answer: Installing electric technology reduces diesel emissions to zero. To quantify the reductions, start by
entering the fleet information. For "Technology Type," select "Emission Control Devices," and for
"Technology, " select "Other Emissions Control Devices." In the "Reduction by Pollutant" box, enter
100% for each of the pollutants. The DEQ will quantify the project's emission reductions using
reductions of 100 percent.
Question: For engine repower or replacement projects, should "engine replacement/repower" be selected
as the technology or should the DEQ be run twice, first with the baseline engine and then with the new
engine?
Answer: Please select "engine replacement/repower" as a technology.
Truck Stop Electrification
Question: How are emission reductions determined for Truck Stop Electrification (TSE)?
Answer: The DEQ calculates TSE emission reductions the same way it does for other idle reduction
technologies. The best calculations will result from inputting your best estimates of the number and
type of trucks that would use the TSE facility, as well as the expected reduction in idle hours.
Trailer Refrigeration Unit
Question: How can I calculate the emissions reduced by replacing a trailer refrigeration unit (TRU) in a box
trailer?
Answer: TRUs are not currently a technology option in the DEQ. As a workaround, create a Vehicle Group
for the TRU by selecting "Non Road", "Stationary" and "Power Generation". Then select "Engine
Replacement" as the technology. Be sure that all Vehicle Group inputs (model year, hp, usage rate, fuel
usage, etc) are for the TRU and not for the tractor-trailer.
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Uncertainty, Missing Information, Averaging, and Diverse Fleets
Question: We have a project with a variety of fleet components, but we are unsure of the exact vehicles
that will be in the program. What should we use for the DEQ calculations?
Answer: If you are unsure of the exact fleet, you should use your best judgment and any past history you
have with such a program to make estimates in the DEQ.
Question: What if I don't have all of the information required to use the DEQ?
Answer: The DEQ will self-populate some default values when you select "Get Default Values." Other
defaults must be input manually. They can be found in the DEQ Default Values document at
www.epa.gov/cleandiesel/documents/420bl0035.pdf. You can also make your own estimates;
however, using real-life data is highly recommended.
Question: For nonroad vehicles, the DOC unit cost varies depending on engine size. Can we average the
costs per unit or must we do a separate run for each application?
Answer: You can either do separate runs for each unit or average them, but the separate runs will give you
more precise results.
Question: How do you estimate emissions for a fleet with multiple, diverse vehicles? Must a separate
calculation be performed for each vehicle?
Answer: You may generate a report for each vehicle or group of similar vehicles. Alternately, you may run a
single report using "average" inputs to minimize the number of runs. Separate runs will give you more
precise results. For more information on the best ways to group vehicles and still ensure accuracy, refer
to the Appendix of this document.
Question: How do I handle a project with both on-road and nonroad vehicles?
Answer: The DEQ can support multiple Vehicle Groups, including a mix of on-highway and nonroad in the
same Fleet. Include the on-road/highway vehicles in one vehicle group and the nonroad in another.
Fleets
Question: Which inputs are for a single vehicle and which are for the entire fleet?
Answer: All of the inputs except for Fuel Volume should be entered for per vehicle or engine. Fuel Volume
should be entered as a total for the entire Vehicle Group.
Baseline Emissions
Question: How can I calculate baseline emissions using the DEQ?
Answer: To calculate baseline emissions, begin by entering the information about your fleet. When you
"Add a New Technology," select "Emission Control Devices" for "Technology Type" and "Other Emission
Control Devices" for "Technology." This will default the reduction percentages to zero and the DEQ will
calculate only the baseline emissions. Please note, if you do not add any technology to your fleet, the
DEQ will calculate baseline emissions and display them on the Emission Results Screen, but the results
won't appear on the DEQ Summary Results spreadsheet.
Question: For engines with OEM catalysts, adding a new retrofit device sometimes requires the removal of
the original catalyst. How does the DEQ take the removal of the catalyst into consideration when
calculating emission reductions?
Answer: The DEQ's baseline emission factors are always based on certified engine configurations, which
include OEM catalysts. Whether a retrofit device is added to a vehicle with an OEM catalyst or to a
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vehicle that has had the catalyst removed to accommodate a new device, the DEQ calculates emission
reductions from the certified OEM baseline. Please keep in mind that project can only claim emission
reductions from a vehicle/engine's certified baseline.
Idle Reduction
Question: Are idling hours included in the nonroad "Usage Rate"?
Answer: Idling hours are included in the default "Usage Rate" for nonroad vehicles. If you are entering
actual "Usage Rate" hours, be sure to include idling hours.
Question: The idle reduction technologies display emission reductions for NOx, PM, and CO2 only. What
about HC and CO?
Answer: Although idle reduction technologies may reduce HC and CO emissions, idling emission factors are
available only for NOx, PM, and CO2 and only for on-highway vehicles.
Question: When calculating emission reductions for idle reduction technology, the reduction percentages
that populate the input screen are not the same as those shown on the downloaded spreadsheet. Why?
Answer: For on-highway vehicle calculations, the DEQ uses two sets of emission factors, idle emissions and
running emissions. When a user applies an idle reduction technology, the reduction percentages that
populate the input screen reflect only the idle emissions. The downloaded spreadsheet shows the
reduction percentages for both idling and running emissions. For instance, an idle reduction technology
may reduce a vehicle's idle emissions by 90%, but it may reduce the vehicle's overall emissions by only
10%. This will vary based on the vehicle idling hours relative total usage hours.
Maintenance and Operating Costs
Question: How can I include project maintenance and operating costs in the DEQ estimates?
Answer: These costs do not have specific input fields in the DEQ. They may be included as part of the total
project costs. Enter them as part of the total funding on the first screen by answering "yes" to the
question "Do you want to estimate the total cost-effectiveness of the project?".
Vehicle Definitions and Classes
Question: How does the DEQ define a bus? Does it include hotel or airport shuttles?
Answer: The DEQ calculates emission for only medium heavy-duty and heavy heavy-duty vehicles
(Classes 5-8). This includes school buses and transit buses. Shuttle buses are usually Class 4 or 5, but
please verify this is the case for your specific fleet. For a more information on vehicles and weight
classes, please see the DEQ Default Values document at
epa.gov/cleandiesel/documents/420bl0035.pdf.
Question: Where can I find the definition of the different vehicle classes? Are they the same as DOT classes?
Answer: For highway vehicles, medium heavy-duty and heavy heavy-duty vehicles are included in the DEQ.
The classes are defined by US DOT by gross vehicle weight rating (GVWR).
• Class 5; 16,001 -19,500 Ibs GVWR
• Class 6; 19,501 - 26,000 Ibs GVWR
• Class 7; 26,001 - 33,000 Ibs GVWR
• Class 8a; 33,001 - 60,000 Ibs GVWR
• Class 8b; 60,001 Ibs GVWR and over
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For further definitions of vehicles and weight classes, please see the DEQ Default Values document at
epa.gov/cleandiesel/documents/420bl0035.pdf.
Verification Information
Question: Does EPA have a list of engine family names that have been approved for verified products?
Answer: No. Unlike CARB, EPA does not issue a list of engine family names for each technology that
has been verified. Please refer to the Verified Technology Listing at
www.epa.gov/cleandiesel/verification/verif-list.htmtfretrofit for specific engine model
applicability and general operating criteria. Engine certification data, including engine family
names, are available at www.epa.gov/otaq/certdata.htmtflargeng
Input Errors
Vehicle Groups
Question: I get the following error message when I try to add a vehicle group to a saved fleet: "An
Unexpected Error has Occurred. We are sorry, the Diesel Emissions Quantifier has experienced an
unexpected error. The details of this error have been logged and the development team has been
notified. If you left your browser inactive for over 30 minutes, this error is due to your session timing
out." What should I do?
Answer: If possible, take a screenshot of the error page and send an email to cleandiesel@epa.gov. with
"Could not Update Saved Fleet" in the subject line. Also include as much info as you can about the
inputs you entered, info about the vehicle group, etc, as well as your DEQ user email. Meanwhile, try
logging out, closing the browser and then logging back in again. You can also try running the DEQ
without signing.
Question: Is there a limit to how many Vehicle Groups can be included in one Fleet? I have entered 47
Vehicle Groups and when I try to quantify emissions, I get an error message saying the DEQ is
experiencing an error.
Answer: We recommend that you keep the number of Vehicle Groups under 30.
Model Year
Question: Sometimes the DEQ does not allow me to select a specific model year for my vehicles.
Answer: Depending on the vehicle type, the DEQ may assume that only certain model years are able to be
retrofitted. If the model year of your vehicle is not displayed as an option, select the closest model year
that is available.
Horsepower
Question: The DEQ does not list the horsepower of my nonroad vehicle. The nearest available horsepower
option is either too high or too low. What should I do?
Answer: We recommend using the closest available horsepower option. At this time, the DEQ does not have
data for every available horsepower, as data collection and approval of emission factors may take years.
Replacement (Engine and Vehicle)
Question: How do I calculate emission reductions for vehicle replacement using the DEQ?
Answer: The DEQ does not offer an option for vehicle replacement. To calculate emission reductions for a
vehicle replacement project, please select "Engine Replacement" for "Technology Type".
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Technologies
Question: If idle reduction is not an option for nonroad equipment, how can I quantify emission reductions
for automatic shutdown devices on nonroad vehicles?
Answer: At this time the DEQ does not support idling strategies in nonroad engines. Please consider using
another calculation method.
Question: When using the DEQ, only technologies that have been verified are listed. How can I include an
Emerging Technology in the calculations?
Answer: Please refer to the Emerging Technology List at www.epa.gov/cleandiesel/verification/emerg-
list.htm and manually input the projected emission reductions for PM NOx, HC and CO.
Question: The emission reduction results for several technologies I'm using, such as direct fired heaters, are
0%. What might be the problem?
Answer: If the "Idle Hours Reduced" was left blank, then you will get 0% reductions. Be sure to enter the
number of idle hours in this field.
Fuels
Question: How do I calculate emissions reductions if the fuel blends we are using, like high blends of
Biodiesel plus ULSD, are not listed?
Answer: The DEQ results are estimates, so please select the option that is closest to your real-world
situation.
Question: The DEQ has selections for B-20 and B-100 but nothing in between. The National Clean Diesel RPF
indicates that any blend of Biodiesel (B-5 to B100) is eligible. How do I calculations on something other
than B20 and B100?
Answer: The DEQ can't accommodate blends other than B20 and B100 at this time. You may select the
option that is closest to the fuel you are using or use another calculation tool more geared to fuels.
Question: My organization has 20 trucks and we'll be replacing the engines in 10 of them. For the "Fuel
Volume" for the fleet, do we enter the total fuel consumed by the 20 trucks in the fleet or just the 10
that are going to be replaced?
Answer: Create a Vehicle Group of 20 vehicles, then select "Engine Replacement" and apply it to 10 of the
20 vehicles. For "Fuel Volume", enter the combined fuel consumption for the entire Vehicle Group (all
20 trucks).
Currently Documented Errors
The DEQ is an estimation tool only and users may not be able to quantify all possible scenarios. EPA suggests
you familiarize yourself with the options. These are outlined in
• Health Benefits Methodology www.epa.gov/cleandiesel/documents/420bl0034.pdf
• Current Methodologies in Preparing Mobile Source Port-Related Emission Inventories
www.epa.gov/cleandiesel/publications.htmtfports.
If the DEQ is not a good fit for your project, you may want to download the emission factors from
www.epa.gov/otaq/nmim.htm and make your own calculations. You can also use other available data
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sources. If you are using the DEQfor a DERA application, you can use any documented methodology to
calculate emission reductions as long as you cite the source in the application.
Below are some common errors and suggested work-around solutions. If the problem you are encountering
is not listed, please log out, restart the DEQ, and try again. If the error occurs again, please send your inputs
and error message (screen shot or copied and pasted) to cleandiesel@epa.gov.
Problem: I can't log in to my user account.
Solution: Send an email to cleandiesel@epa.gov with the subject line "User Account Problem" and include
your log-in email. Meanwhile, you can create a new user account using a different email address.
Problem: My previously saved scenarios are not working.
Solution: Due to updates to the DEQ structure, some saved scenarios may no longer work properly. If you
encounter this, please delete the old Fleets and recreate them. In some cases, users are able to access a
saved Vehicle Group, but are not able to quantify it. This can be fixed by deleting the existing
technology, re-entering it, and then clicking on "Quantify Emissions."
Problem: I can't find Total Cost-Effectiveness on the exported Results spreadsheets.
Solution: Total Cost-Effectiveness is displayed on the Summary Results screen, but it is not yet available on
the spreadsheets. Please refer to the screen directly after clicking "Quantify Emissions," or calculate
yourself:
• The DEQ calculates Total Cost-Effectiveness by taking the total project funding and dividing it by the
total Lifetime Tons Reduced of each pollutant.
• The DEQ calculates Capital Cost-Effectiveness by taking the total Unit Cost and Installation Cost for each
technology added and dividing that by the Lifetime Tons Reduced for each pollutant.
Problem: The Lifetime Emissions equal the Annual Emissions.
Solution: Based on our modeling, the DEQ uses standard lifetimes for vehicles and non-road equipment,
even though they may be used longer. The DEQ assumes if a vehicle is older than its standard life, its
remaining life is just one year, resulting in Lifetime Emissions equaling Annual Emissions. One work-
around is to multiply the Annual Emissions by your estimate of the vehicle's remaining life.
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Appendix: Grouping Vehicles for Calculations in the DEQ
The DEQ is designed to provide emission reduction estimates for a variety of fleet and technology options. If
your project has a mix of vehicle and engine types, you do not have to run the DEQ for each vehicle. You can
divide the fleet into several groups and run the DEQ several times. The following guidelines are based on the
on-road and nonroad emission standards. For more information, see
• On-Highway Heavy Duty Compression Ignition Exhaust Certification Emission Standards
www.epa.gov/otaq/standards/heavy-dutv/hdci-exhaust.htm
• Non Road Compression Ignition Exhaust Emission Standards
www.epa.gov/otaq/standards/nonroad/nonroadci.htm
1) First, separate the DEQ Calculation Groups for multi-sector projects into Highway/On-road, Nonroad, and
Marine. Marine retrofits require a separate DEQ run for each vessel, so the following will apply only to
Highway/On-road and Nonroad vehicles.
a) On Highway.
i) First, group all on-highway vehicles into their respective Target Fleets:
(1) City/County Vehicle
(2) Delivery Truck
(3) School Bus
(4) Transit Bus
(5) Refuse Hauler
(6) Emergency Vehicle
(7) Long Haul
(8) Short Haul
ii) Within each Target Fleet, group vehicles based on the Class/Equipment:
(1) School Buses
(2) Transit Busses
(3) Class 5
(4) Class 6
(5) Class?
(6) Class 8a
(7) Class 8b
iii) Next, divide the Class/Equipment groups by the following Model Year ranges (based on the On-
Highway PM level emission standards ) :
(1) Pre-1987
(2) 1988-1990
(3) 1991-1993
(4) 1994-1997
(5) 1998-2003
(6) 2004-2006
(7) 2007-2010
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iv) Finally, within each Model Year group, divide your vehicles based on the type of retrofit technology
that will be applied (i.e. Diesel Oxidation Catalyst + CCV, Engine Replacement, etc)
b) Nonroad (non-marine vessels/engines)
i) First, group all nonroad vehicles into their respective Target Fleets:
(1) Agriculture
(2) Construction
(3) Ports and Airports
(4) Rail
(5) Stationary
ii) Within each Target Fleet, divide the vehicles based on the Class/Equipment (too many to list here,
and realize that some nonroad equipments can overlap so you could have fewer groups than you
realize).
iii) Within each Class/Equipment group, divide by the following Horsepower/Model Year combinations
(based on nonroad emission standards for NOx, PM, NMHC+NOx and CO):
(a) <11 hp and pre-2000 (Tier 0)
(b) <11 hp and 2000-2004 (Tier 1)
(c) 750 hp and pre-2000
(w) > 750 hp and 2001-2010
iv) Finally, within each Horsepower/Model Year group, divide your vehicles based on the type of
retrofit technology that will be applied (i.e. Engine Replacement, Engine repower, Hybrid
Replacement, etc.)
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