Transcript Document

MOBILE SOURCES 101
Presented by:
Rob Klausmeier
de la Torre Klausmeier Consulting, Inc
Harold Garabedian
Vermont Agency of Natural Resources
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Estimation of In-Use Emissions
What will be covered:
• EPA’s MOBILE model
– What are emission factor models
– Description of MOBILE6
– How does MOBILE6 differ from MOBILE5
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Background
Attainment demonstrations must be made
using estimates of emissions from vehicles in
actual use.
Vehicles in actual use often do not receive
proper maintenance, and in some cases, their
emission control systems are deliberately
tampered with.
As a result, the average emission rate for
vehicles in actual use often exceeds the
appropriate emission standard.
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EPA’s MOBILE Model
States must use EPA’s MOBILE model to estimate
emission factors. The current model is MOBILE6.
MOBILE6 estimates emission rates for each pollutant in
terms of grams per mile, i.e. grams emitted per vehicle
mile traveled (VMT).
Emission factors are calculated for different vehicle
types; then they are multiplied by appropriate weighting
factors to develop a composite emission factor for each
VMT in an area.
Total emissions are calculated by multiplying emission
factors by total VMT.
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What is MOBILE6?
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Computer model written in FORTRAN which is based on US EPA’s MOBILE5a model
Calculates emission factors (g/mi) for a “Fleet Average Vehicle”
Used for gasoline and diesel, on-road vehicles
Calculates EF for:
– light duty gasoline vehicles
– light duty gasoline trucks (3 categories)
– heavy duty gasoline vehicles (8 categories)
– light duty diesel vehicles
– light duty diesel trucks (2 categories)
– heavy duty diesel vehicles (8 categories)
– motorcycles
– gasoline buses
– diesel buses (transit/urban and school)
Exhaust and Evaporative Hydrocarbon Emissions (HC)
Exhaust Carbon Monoxide (CO)
Exhaust Nitrogen Oxides (NOx)
Future Enhancements likely to include:
– PM
– Toxics
– Greenhouse gases
Developed by US EPA, Office of Mobile Sources, Ann Arbor Michigan
Introduction
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What Can the Model Do?
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Analytical Tool that can be applied for Air Quality Planning
Can be used to estimate emission impacts from:
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Future Vehicle Fleets
Diesel/Alternate Fuel Use
Vehicle Speeds
Roadway types
Ambient Temperature
Fuel RVP/Oxygen content/Sulfur content/RFG
Air Conditioning
Cold Starts
Inspection/Maintenance Programs
On-Board Diagnostics
Vehicle Tampering
New Vehicle Standards
Other Strategies
• Evaporative Controls
• Refueling Controls
Introduction
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REFER TO BARRETT CAC
MOBILE6 PRESENTATION
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Emission Factor Assumptions
The emission factors in the MOBILE model
are based upon assumptions about how
different factors affect vehicle emissions.
Emission factors take into consideration the
following:
A. Vehicle emission control technology (i.e.,
the emission standards that the vehicles
were designed to comply with);
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Emission Factor Assumptions Cont.
B. Deterioration of emission control
performance. How vehicle emissions
increase as a vehicle accumulates miles.
The Basic Emission Rate (BER) = zero mile level +
(Deterioration Factor) x accumulated mileage.
The BER is a function of the following:
- Assumed owner maintenance and tampering habits
- Vehicle age assumptions
- Mileage accumulation assumptions
- Emission Control Technology
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Emission Factor Assumptions Cont.
C. Vehicle types:
- Gasoline powered cars vs. light trucks
- Diesel powered heavy-duty vehicles
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Emission Factor Assumptions Cont.
D. Vehicle use assumptions:
- Ave speed
- % cold start, % hot start, % hot transient
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Emission Factor Assumptions Cont.
E. Ambient parameters:
- Temperature
- Cloud cover (new MOBILE6 input)
- Altitude (high or low)
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Emission Factor Assumptions Cont.
F. Fuel parameters:
- Reformulated gasoline (RFG)
- % sulfur
- % oxygenates
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Emission Factor Assumptions Cont.
G. I/M Program parameters
- Vehicle coverage: type and model year
- Emission Test Type
• OBDII
• Tailpipe test: IM240, ASM, idle, etc.
- Evap test type: gas cap pressure test, tank pressure
test, purge (not done but modeled)
- Anti-tampering program, e.g. cat inspection
- Start date
- I/M credits are calculated assuming that the program
identifies certain percentages of high emitting vehicles
and brings the emission levels for these vehicles to
assumed values based upon the emission test
standards (cutpoints).
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Emission Factor Assumptions Cont.
User can vary inputs for items C to G. User
cannot vary BERs and responses to user
inputs.
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Changes for MOBILE6
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Emissions, fleet and activity data
Structural changes
Input and output formats
Documentation
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Basic Exhaust Emissions
• Update in-use deterioration estimates for light
duty cars and trucks.
• New emission standards (LD and HD)
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Effects of Fuel Composition
• Updated effects of oxygenated fuels on
CO emissions
• Explicit effects of sulfur on exhaust
emissions
– including long-term and irreversibility effects.
• Explicit modeling of natural gas vehicles
Fuel
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Overview
• Most modern gasoline-fueled vehicles use
catalysts to reduce HC, CO, and NOx
emissions
• Sulfur is a catalyst poison. Increased
sulfur levels in fuels thereby increase
emissions through catalyst deactivation
Fuel
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% Increase in Emissions from 30 ppm
baseline
LEV Normal Emitter Composite
Emission Effects Based on
Regression Coefficients
200
150
NOx
100
CO
HC
50
NMHC
0
0
100
200
300
400
500
600
700
Sulfur, ppmW
Fuel
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“Gross Liquid Leakers”
• Many vehicles may have leaks of liquid
gasoline, but NOT all are “Gross Liquid
Leakers”
• Only the highest emitting of the leakers are
“Gross Liquid Leakers”
• Some vehicles may be “Gross Liquid
Leakers” on only some of the tests
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OBD Assumptions
• Equal Treatment for all three pollutants
• MIL-on Rate:
– Ability of the OBD system to work properly.
– Assumed to be 85 percent - (Based on 2x stds Highs)
– No Deterioration with Mileage or Time
• Motorist Response Rate to OBD Outside of I/M
– Under 36,000 miles:
90 percent
– Between 36,000 and 80,000 miles:
percent
– Over 80,000 miles:
percent
0
I/M
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OBD Assumptions (Con’t)
• I/M Identification Rate
– Ability of the OBD system to find high emitters in an I/M
program.
– Assumed to be 90 percent.
• After I/M Repair Emission Level of OBD Failures
– Assumed to be 1.5 times FTP standard. No change over
time or mileage.
I/M
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Phase-in IM240 vs. Phase-in
ASM2525 for 1988-93 PFI HC
Emissions
NO I/M
Phase ASM
Phase IM240
2.00
1.80
FTP HC (g/mi)
1.60
1.40
1.20
1.00
0.80
0.60
0.40
0.20
0.00
0
50
100
150
200
250
Mileage (in thousands)
I/M
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Phase-in IM240 vs. Phase-in
ASM2525 for 1988-93 PFI NOx
Emissions
NO I/M FTP
Phase 2525 ASM
Phase IM240
2.00
1.80
FTP NOx (g/mi)
1.60
1.40
1.20
1.00
0.80
0.60
0.40
0.20
0.00
0
50
100
150
Mileage
I/M (in thousands)
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200
250
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FTP HC Emission Effect of OBD
and OBD I/M on Tier1 Cars
No OBD
OBD Only
OBD I/M
2.00
1.80
FTP HC (g/mi)
1.60
1.40
1.20
1.00
0.80
0.60
0.40
0.20
0.00
0
50
100
150
Mileage
I/M
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200
250
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FTP NOx Emission Effect of OBD
and OBD I/M on Tier1 Cars
No OBD
OBD Only
OBD I/M
2.00
1.80
FTP NOx (g/mi)
1.60
1.40
1.20
1.00
0.80
0.60
0.40
0.20
0.00
0
50
100
150
Mileage
I/M
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200
250
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Heavy Duty Emissions
• New emission standards
• New conversion factors
• Will be adjusted for HD NOx excess
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Excess NOx Emission Levels Due to the HD Defeat
Device and Mitigation Strategies (Offsets)
Draft MOBILE6
Total Excess
After Offset Excess
1,600,000
1,400,000
NOx (Tons)
1,200,000
1,000,000
800,000
600,000
400,000
200,000
0
1980
1990
2000
2010
2020
2030
2040
Calendar Year
Heavy-Duty
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Running MOBILE6
• Prepare a M6 input file and save
• From Windows, double-click on the
M6DRAFT.EXE application icon
• A DOS window will appear
• Enter the input file name at the prompt
Note: remember to include path if input file is
in a different directory/folder than the RUN
folder
• Hit return
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Example: Simplest Input File
Header
Run
Scenario
MOBILE6 INPUT FILE:
RUN DATA
MIN/MAX TEMP
FUEL RVP
:
:
SCENARIO REC
:
CALENDAR YEAR :
64.
7.0
92.
Scenario Title Text
2010
END OF RUN
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EXAMPLE MOBILE6 RUNS
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1.5
1
0.5
0
10% below
Vehicle Type
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LD
DT
HD
DV
LD
DV
HD
GV
Default
LD
...
LD
GV
LD
...
VOC Emissions
(g/mile)
Harris County 2007 - MOBILE6 Composite
VOC Emissions by Mileage Accumulation
Rates
10% above
VOC Emissions (g/mile)
Harris County 2007 - MOBILE6 VOC
Emissions by Vehicle Type and Fuel Type
1
Exhaust, No RFG
0.8
Exhaust, RFG
0.6
Non-Exhaust, No RFG
Non-Exhaust, RFG
0.4
0.2
0
LDGV LDGT12 LDGT34 HDGV
Vehicle Type
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NOx Emissions (g/mile)
Harris County 2007 - MOBILE6 NOx
Emissions by Vehicle Type and Fuel Type
4
3.5
3
2.5
2
1.5
1
0.5
0
No RFG
RFG
LDGV
LDGT12
LDGT34
Vehicle Type
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HDGV
VOC Emissions
(g/mile)
Harris County 2007 - MOBILE6 VOC
Emissions by Fuel RVP Level for LDGVs
0.5
0.4
0.3
0.2
0.1
0
RVP 6.5
RVP 6.8
RVP 7.1
RVP 7.4
RVP 7.8
Exhaust
Non-Exhaust
Fuel RVP level
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COMPARISON OF HIGHWAY
MOBILE SOURCE
EMISSIONS INVENTORY FROM
MOBILE1 THROUGH MOBILE6
Alison K. Pollack1, Christian E. Lindhjem1,
Dave Brzezinski2, Rosa Chi1
1ENVIRON
International Corporation
101 Rowland Way, Suite 220, Novato, CA 94945
2Office
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of Transportation and Air Quality, EPA
Ann Arbor, MI 48105
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Model
Comments
Applicable Emission Standards
MOBILE1
(1978)
No LDDV or LDDT.
Only produced emission values to calendar year
1999.
Couldn’t get evaporative emissions to work.
Added substantial field data.
Added diurnal and hot soak emissions.
Added tampering rates.
Eliminated California vehicles.
Added RVP effects on evaporative emissions.
Added running loss emissions.
Added RVP effects on exhaust emissions.
Added pressure/purge failure
Added CO adjustments.
Changed basic emission rates through use of the
I/M data. Added adjustment for in-use sulfur level.
Added resting losses.
Minor changes from MOBILE5a except for
additional I/M programs, on-board refueling, fuel
standards, and detergent gasoline.
Wholesale changes in basic emission rates
including facility cycles, air conditioning effects,
HDDV off-cycle NOX emissions.
Completely revised evaporative emissions
methodology using real-time test data, including
adding effects of liquid leakers.
Revised fleet characterization and activity4 data.
1975 and 1981 Light-duty standards for exhaust
emissions.
MOBILE2
(1981)
MOBILE3
(1984)
MOBILE4
(1989)
MOBILE41
(1991)
MOBILE5a
(1993)
MOBILE5b
(1996)
MOBILE6
(2001)
Added Heavy-Duty Diesel Vehicle (HDDV)
1985 emission standard.
Added HDDV standards 1990, 1991, and 1998
through the NEWFLG.
Added HDDV 2004 and HDGV 2005 standards
through the NEWFLG.
Added Tier 1 and NLEV Light-duty standards.
Added Tier 2 Light-duty standards and lower
sulfur gasoline. Added 2007 Heavy-duty
standards.
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TWO TYPES OF RUNS
PERFORMED
• Runs with the 1990 Clean Air Act Amendments
(CAAA) turned off. Basic emissions rates (g/mile)
calculated by the models are shown for direct
comparisons across models.
• Runs with all emissions regulations applicable at the
time of release and those additions (shown in the
table describing each model) of the models for a
'typical' high ozone southern metropolitan region.
The results (in tons per day) show the changes in
total on-road emission inventories with different
versions of the model.
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Basic Evaporative THC (w/o 1990 CAAA)
(A ve ra ge of a ll ve hic le s a t 24.4 m ph)
4
M OB I LE2
M OB I LE3
M OB I LE4
M OB I LE41
M OB I LE5A
M OB I LE5B
M OB I LE6
3
2
1
0
1980
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1985
1990
1995
40
2000
2005
2010
Basic THC Emissions (w/o 1990 CAAA)
(A ve ra ge of a ll ve hic le s a t 24.4 m ph)
12
M OB I LE2
M OB I LE3
M OB I LE4
M OB I LE41
M OB I LE5A
M OB I LE5B
M OB I LE6
10
8
6
4
2
0
1980
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1985
1990
1995
41
2000
2005
2010
Basic NOx Emissions (w/o 1990 CAAA)
(A ve ra ge of a ll ve hic le s a t 24.4 m ph)
6.5
5.5
4.5
1980
1985
1990
1995
2000
2005
2010
3.5
2.5
1.5
0.5
M OB I LE1
M OB I LE3
M OB I LE2
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M OB I LE41
M OB I LE5B
M OB I LE4
M OB I LE5A
M OB I LE6
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Metropolitan Area Inputs
 July 1
 Southern State
 RVP: 8.3 until 1991, 7.8 starting in 1992
 RFG starting in 1996
 Temperature range 70 – 95.5F
 No Inspection/Maintenance or Anti-tampering Program
 Runs performed by facility class
Facility Class
Local
Arterial
Freeway
Average Speed (mph)
Percent of VMT
24.4
36.8
63.8
18
38
44
VMT growth rate 2% per year (exponential)
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2000 THC Emissions by Vehicle Class for a Metropolitan Area
(de fa ult VM T m ix a nd a pplic a ble sta nda rds)
225
MC
HD D V
200
LD D T
LD D V
HD G V
175
LD G T3 4
LD G T12
150
LD G V
125
100
75
50
25
0
M OB I LE1
M OB I LE3
M OB I LE2
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M OB I LE41
M OB I LE5B
M OB I LE4
M OB I LE5A
M OB I LE6
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2010 NOx Emissions by Vehicle Class for a Metropolitan Area
(de fa ult VM T m ix a nd a pplic a ble sta nda rds)
450
MC
HD D V
400
LD D T
LD D V
350
HD G V
LD G T3 4
LD G T12
300
LD G V
250
200
150
100
50
0
M OB I LE1
M OB I LE3
M OB I LE2
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M OB I LE41
M OB I LE5B
M OB I LE4
M OB I LE5A
M OB I LE6
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2010Default Vehicle Mix
MC
HDDV
LDDT
LDDV
HDGV
LDGT34
LDGT12
LDGV
M OB I LE1
M OB I LE3
M OB I LE41
M OB I LE5b
M OB I LE2
M OB I LE4
M OB I LE5a
M OB I LE6
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OTHER EMISSION FACTOR
MODELS
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EPA Non-Road Emissions Model
EPA has recently developed a model to
estimate Non-road emissions.
The model is similar in concept to MOBILE5 in
that it projects emission factors for a wide
variety of vehicle types under different operating
conditions.
This model is described in detail in supporting
documentation provided by EPA.
http://www.epa.gov/otaq/nonrdmdl.htm
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Other Models Used for Projecting
Mobile Source Emissions
In addition to MOBILE5/6 and EPA’s off-road
model, other models are used to estimate
mobile source emissions.
• EPA’s Complex Model for fuel evaluation;
• EPA’s mobile-toxics model (MOBTOX5b);
and
• PART5 – EPA’s particulate emission factor
model.
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Gasoline Fuel Properties – The
Complex Model
The Complex Model estimates the impact of changes in fuel
properties on exhaust and evaporative emissions.
It is a useful tool for evaluating the impact of reductions in fuel
sulfur content on vehicle emissions.
In addition, it provides a means of estimating the impact of fuel
properties on toxic emissions as it outputs toxic emission factors for
the key toxic compounds; benzene, 1,3butadyene, etc.
The state of California has developed a similar model that
estimates the impact of fuel properties on toxic and criteria
pollutants.
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EPA’s MOBTOX5b Model
• MOBTOX5b has been developed to estimate toxic emission
factors for in-use highway vehicles.
• MOBTOX5b applies exhaust and evaporative toxic adjustment
factors for various vehicle classes and technologies to
MOBILE5b TOG emission factors.
• It allows the user to model benzene, formaldehyde,
acetaldehyde, 1,3-butadiene, and MTBE emissions.
• The model allows the user to specify a large number of
alternative scenarios:
– basic emission rates, and the vehicle mileage level at which rates
of deterioration begin to increase.
– differences in exhaust toxic fractions of TOG between normal and
high emitting vehicles in calculating emission rates.
– Impacts of aggressive driving and air conditioning usage on toxics.
– impacts of fuel reformulation programs and changes in vehicle
emission control technology can also be addressed with the model.
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PART 5
PART5 is EPA's model for estimating
particulate matter (PM; from vehicle exhaust
and from vehicle interaction with roads) and
sulfur dioxide (SO2) emission factors for
gasoline and diesel on-road vehicles.
As with MOBILE5a, the emission factors are
expressed in grams of pollutant emission per
mile traveled.
You have been provided with the code and
Users’ Guide for PART5
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Estimating Vehicles Miles Traveled
(VMT)
Vehicle miles traveled (VMT) is usually estimated based
upon traffic demand models. Fuel consumption also is
used to estimate VMT.
For example, ConnDOT uses their PERFORM travel
demand forecasting model to develop VMT estimates.
This model estimates trip generation based on land use,
employment, census and car ownership data.
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