-------
K-19
TABLE 18
HIGH ALTITUDE
NOx EMISSION FACTORS (GRAMS/MILE)
AIR CONDITIONING USAGE = 100 %
WET BULB TEMPERATURE = 79 F
DRY BULB TEMPERATURE = 86 F
LDGV
EMISSION FACTORS
§ TRAILER TOWING
CAL. EXTRA LOAD PERCENTAGE
YEAR PERCENTAGE 0% 5% 10%
LDGT
EMISSION FACTORS
§ TRAILER TOWING
PERCENTAGE
0% 5% 10%
EMISSION FACTORS
FOR 8 VEHICLE TYPES
@>LDG TRAILER TOWING
PERCENTAGE
0% 5% 10%
1985
1985
1985
1985
1988
1988
1988
1988
1990
1990
1990
1990
1995
1995
1995
1995
0 %
5V
/O
10 %
15 %
0 %
5Q/
To
10 %
15 %
0 %
5y
A»
10 %
15 %
0 %
5V
fa
10 %
15 %
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
.48
.49
.49
.50
.30
.30
.31
.31
.23
.23
.24
.24
.15
. 15
. 15
.16
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
.51
.51
.52
.52
.32
.33
.33
.34
.25
.25
.26
.26
.17
.17
.18
.18
1.53
1 .54
1 .54
1.55
1 .35
1 .35
1 .36
1 .36
1 .27
1.28
1 .28
1 .29
1.19
1 . 19
1 .20
1 .20
2.48
2.49
2.50
2.50
2.43
2.44
2.44
2.45
2.27
2.28
2.29
2.30
1.89
1.90
1.91
1.91
2.52
2.53
2.54
2.54
2.47
2.48
2.49
2.50
2.31
2.32
2.33
2.34
1.93
1.94
1.94
1.95
2.56
2.57
2.58
2.58
2.51
2.52
2.53
2.54
2.35
2.36
2.37
2.38
1.97
1 .97
1.98
1.99
2.81
2.81
2.82
2.82
2.42
2.43
2.43
2.44
2. 18
2.19
2. 19
2.20
1.89
1 .89
1 .90
1 .90
2.83
2.84
2.84
2.85
2.45
2.45
2.46
2.46
2.21
2.21
2.21
2.22
1.91
1.91
1.92
1 .92
2.86
2.86
2.87
2.87
2.47
2.48
2.48
2.49
2.23
2.23
2.24
2.24
1.93
1 .93
1.94
1.94
*EMISSION FACTORS ARE CALCULATED FOR JANUARY 1 OF CALENDAR YEAR
UNDER CONDITIONS OF 20.6 % COLD START VMT, 27.3 % HOT START VMT,
86 F AMBIENT TEMPERATURE, 19.6 MPH AVERAGE SPEED,
AND 75 GRAINS WATER/LB OF DRY AIR HUMIDITY.
TABLE 18 : NOx f» 100 % A/C USAGE
-------
APPENDIX L
SIZE SPECIFIC TOTAL
PARTICIPATE EMISSION FACTORS
FOR MOBILE SOURCES
Final Report
EPA Contract No. 68-03-1865
Work Assignment No. 1
Prepared for:
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Mobile Source Air Pollution Control
Ann Arbor, Michigan 48105
Prepared by:
ENERGY AND ENVIRONMENTAL ANALYSIS, INC,
1655 North Fort Myer Drive, Suite 600
Arlington, Virginia 22209
August 1985
-------
TABLE OF CONTENTS
Page
1. INTRODUCTION 1-1
2. PROJECTING SIZE SPECIFIC TOTAL PARTICIPATE
EMISSION FACTORS 2-1
2.1 Overview of Methodology 2-1
2.2 Light-Duty Vehicles and Light-Duty Trucks
I and II 2-5
2.2.1 Lead Emission Factors 2-6
2.2.1.1 Mis fueling and Fuel Switching 2-10
2.2.2 Organic and Sulfate Emission Factors 2-11
2.2.2.1 Control System Fractions 2-11
2.2.2.2 Organic and Sulfate Emission
Factor Components 2-13
2.2.3 Diesel Emission Factors (Light-Duty) 2-16
2.3 Heavy-Duty Vehicles 2-17
2.3.1 Lead Emission Factor Components 2-18
2.3.2 Organic Emission Factor Components 2-19
2.3.3 Sulfate Emission Factor Components 2-20
2.3.4 Diesel Particulate Emission Factors 2-21
2.4 Motorcycle Emission Factors 2-21
2.5 Brake and Tire Wear Particulate Emission
Factor Components 2-22
3. EXAMPLE CALCULATION OF AUTOMOBILE PARTICULATE
EMISSIONS LESS THAN 10 MICRONS 3-1
REFERENCES
-------
LIST OF TABLES
Page
2-1 Emission Factors of Motor Vehicle Engine Total
Particulate Emissions 2-25
2-2 Lead Content of Gasoline 2-27
2-3 Fraction of Light-Duty Vehicle Model Year Sales Equipped
With Different Emission Control (Low-Altitude Non-
California 2-28
2-4 Fleet Sales Fractions Light-Duty Vehicles 2-29
2-5 Travel Weighting Factor Calculation Light-Duty Vehicles 2-30
2-6 City/Highway Combined On-Road Fuel Economy (Miles/
Gallons 2-31
2-7 Fuel Economy Correction Factors at Various Speeds, Cs
(Normalized to 32.7 Miles/Hour-Cyclic Driving) 2-32
2-8 Fraction of Light-Duty Truck I Model Year Sales Equipped
With Different Emission Control Systems (Low-Altitude
Non-California 2-33
2-9 Fleet Sales Fractions Light-Duty Trucks I 2-34
2-10 Travel Weighting Factor Calculation Light-Duty
Gas Trucks I 2-35
2-11 Fraction of Model Year Sale of Light-Duty Trucks II
By Emission Control Systems 2-36
2-12 Fleet Sales Fractions Light-Duty Trucks II 2-37
2-13 Travel Weighting Factor Calculation Light-Duty
Gas Trucks II 2-38
2-14 Travel Weighting Factor Calculation Light-Duty
Diesel Trucks I and II 2-39
2-15 Fleet Sales Fractions Heavy-Duty Gasoline Vehicles
(HDGV) 2-40
2-16 Travel Weighting Factor Calculation Heavy-Duty
Gasoline Vehicle (HDGV) 2-41
2-17 Travel Weighting Factor Calculation For Heavy-Duty
Diesel Vehicles in Calendar Year 1987 2-42
2-18 Travel Weighting Factor Calculation Motorcycles 2-43
Lli
-------
LIST OF TABLES (cont'd)
Page
2-19 Rates of Misfueling (r^) For Different Vehicle Classes 2-44
2-19a Rates of Misfueling (r^) For Different Vehicle
Ages and Classes 2-45
2-20 Average Data on Particulate Size Distribution 2-46
2-21 Low Altitude HDDV Conversion Factors 2-48
2-22 Fraction of Lead Burned That is Emitted, as 2-49
2-23 Fraction of Catalyst Equipped Vehicles With
Catalyst Removed, P^ 2-50
3-1 Example Calculations Light-Duty Vehicle Particulate
Emission Rate Less Than 10 Microns For the Year 1985 3-7
A-l Average Annual Mileage By Vintage For Heavy-Duty Trucks A-l
A-2 Projections of Heavy-Duty Vehicles in Operation A-2
Liii
-------
LIST OF FIGURES
Page
2-1 Leaded Gasoline Particulate Size Distribution 2-51
2-2 Unleaded Gasoline Particulate Size Distribution 2-52
2-3 Diesel Particulate Size Distribution 2-53
2-4 Brake Wear Particulate Size Distribution 2-54
Liv
-------
1. INTRODUCTION
The following material was developed to predict total particulate
emission factors for gasoline and diesel fueled on-road vehicles, trucks
and motorcycles at various vehicle speeds for particles in the respir-
able size range (less than 10 microns). Particulate emissions from
these vehicles may also be determined at other size intervals less than
10 microns (e.g.,. less than 7.5, 5, or 2.5 microns).
User inputs to the equations to determine these emission factors include
area travel fractions by vehicle class, vehicle miles traveled, vehicle
speed, particle size limits of interest and calendar year.
This report presents particulate emission factor equations as the sum of
individual masses of lead salt, organic and sulfate components for
leaded and unleaded gasoline fueled vehicles. Composite (i.e., total
particulate mass) equations are presented for diesel fueled vehicles and
motorcycles, and tire and brake wear particulate. These equations are
subsequently accompanied by tabulated emission factors which may be
inserted into the appropriate particulate component equations. Fleet
sales fractions and travel fractions by model year are included for each
vehicle class. The fractions within each vehicle class that are
equipped with different emission control systems also are provided.
Cumulative distributions of particle size for leaded and unleaded
gasoline and diesel fuel are presented both graphically and tabularly.
Also, for the benefit of the user, an example calculation of particulate
emissions from light-duty vehicles is provided.
t 1-1
-------
The procedure herein can be used to project automotive particulate
emissions by those agencies developing State Implementation Plans for
particulate matter or by other interested parties within or outside the
EPA concerned with size specific particulate emission factor projections
for mobile sources.
This document is an updated version of an April 1984 report prepared by
the Environmental Protection Agency, Office of Mobile Sources. It has
been revised to include estimates of travel fractions and fleet
characteristics from the June 1984 EPA report, User's Guide to MOBILE3
447
(Mobile Source Emissions Model), EPA 460/3-84-002. Revised estimates
of emission control technology fractions also have been included. The
methodology presented in this document is consistent with the procedure
outlined in the April 15, 1983 EPA report, Supplementary Guidelines for
Lead Implementation Plans — Updated Projections for Motor Vehicle Lead
Emissions which also was recently updated by Energy and Environmental
457
Analysis, Inc. That report can be used to project the lead component
of total particulate emissions for vehicles using leaded and unleaded
gasoline. In addition to the lead component, the methodology outlined
in this document can be used to develop estimates of three other components
of particulate emission factors. Emission factors for organics, sulfates
on the Federal Test Procedure (FTP) cycle, and heavy-duty gasoline trucks
came from the Draft Study of Farticulate Emissions From Motor Vehicles
(for Section 214 of the Clean Air Act), by the Environmental Sciences
Research Laboratory, Office of Research and Development, U.S. EPA, July
8/
1983. Sulfates on the Sulfate Emission Test (SET) cycle and motorcycle
emission factors came from the March 1981 EPA report, Compilation of Air
2/
Pollutant Emission Factors: Highway Mobile Sources EPA-460-3-81-005.
Light- and heavy-duty diesel particulate emission factors are referenced
*/ = Reference at end of text.
LI-2
-------
from the Draft Diesel Particulate Study, Emission Control Technology
Division, Office of Mobile Sources, Office of Air and Radiation, U.S.
A/
EPA, October 1983. Emission factor estimate updating is an ongoing
process and, in many cases, these values are based on testing of only a
few vehicles.
This document has been revised to reflect changes in the lead content of
gasoline. On March 7, 1985, EPA issued regulations which require petroleum
refiners to drop the average lead content of leaded gasoline to 0.5 g/gallon
by July 31, 1985 and 0.1 g/gallon by January 1, 1986 to: 1) reduce the
health hazards associated with lead, and 2) to discourage the practice
of misfueling which deteriorates the efficiency of vehicle emission control
systems. (See Federal Register, Volume 50, No. 45, March 7, 1985.)
Li-3
-------
2. PROJECTING SIZE SPECIFIC TOTAL PARTICIPATE EMISSION FACTORS
This report provides a methodology to project areawide total particulate
emissions from mobile sources in a given calendar year. Particulate
emissions can consist of lead salts, organics and sulfate emissions.
The relative amounts vary for different vehicle types, emission control
strategies and vehicle operating modes. Analysis of lead particulate
indicates that most of the exhausted lead appears as salts, PbClBr.
Therefore, estimates of the mass of lead particulate will be consider-
ably larger than those predicted by the lead document, which predicts
the mass of lead alone. Organic emissions include both soluble organics
and elemental carbon and are important contributors to total particulate
emissions from all vehicles, especially diesels. Sulfate emissions,
mostly from unleaded gasoline-fueled vehicles equipped with catalysts,
also are important contributors to total vehicular particulate emis-
sions.
Section 2.1 provides an overview of: 1) the methodology used to calcu-
late total areawide particulate emissions, and 2) the computations
required to estimate the individual emission factor components by
vehicle category and type of particulate. The detailed emission factor
component equations for light-duty vehicles and light-duty trucks are
discussed in Section 2.2. Equations for heavy-duty vehicles are
described in Section 2.3. Section 2.4 presents the calculations
required for motorcycles and Section 2.5 provides brake and tire wear
particulate emission factor components.
2.1 OVERVIEW OF METHODOLOGY
Areawide particulate emissions (shown in Equation (2-1)) are a function
of calendar year, average vehicle speed, vehicle class travel fractions,
the particle size range of interest and the vehicle class emissions
L2-1
-------
associated with the calendar year and vehicle speed. With the excep-
tions of the vehicle class emission factors, all of the above parameters
are inputs selected by the user on an areawide basis to obtain the
desired output of mobile source particulate emissions for the area of
interest.
EF = t. EF, + EF, , (M_) + EF,. . (2-1)
pm,n,s £ ~> i,n i,n,s brakes B tires
1-1
where EF = size specific all-vehicle class total particulate
' ' emission factor on January 1 of calendar year n at
vehicle speed s (g/mile)
i = vehicle class designator; 1 = light-duty vehicles
(LDV), 2 = light-duty trucks I (LDT1) , 3 = light-
duty trucks II (LDT2) , 4 = heavy-duty gas vehicles
(HDGV) , 5 = heavy-duty diesel vehicles (HDDV) ,
6 = motorcycles (MC)
s = vehicle speed; avg. Federal Test Procedure (FTP) =
19.6, avg. Sulfate Emissions Test (SET) - 34.8
(miles/hr) ; (Note: The FTP and SET are driving
cycles used for the determination of emission
factors . )
t. = area travel fraction of vehicle class i in calendar
i,n
year n
EF. = particulate emission factor for vehicle class i in
' ' calendar year n at vehicle speed s (g/mile)
EF, . = airborne brake wear particulate emission factor
h f* a \f& ^
component = 0.0128 grams/mile; this emission factor
component is assumed to be the same for all vehicle
classes, vehicle speeds and calendar years (all i,
s, and n) due to lack of separate information for
each i, s, and n
EF . = airborne tire wear particulate emission factor
component = 0.002 grams/mile; this emission factor
component is assumed to be the same for all vehicle
classes, vehicle speeds and calendar years (all i,
s, and n) due to lack of separate information for
each i, s, and n
L 2-2
-------
M_ = fraction of airborne particles less than a user-
specified size cutoff (0.1-lOy) that are
attributable to vehicle brake wear, from Table 2-20
or Figure 2-4
The vehicle classes for which emission factor estimates may be obtained
include: 1) light-duty vehicles (passenger cars), 2) light-duty trucks
I (0-6000 Ibs. GVWR), 3) light-duty trucks II (6001-8500 Ibs. GVWR),
4) heavy-duty gas vehicles (greater than 8,501 Ibs. GVWR), 5) heavy-duty
diesel vehicles (greater than 8,501 Ibs. GVWR), and 6) motorcycles.
The exhaust emission factors for each vehicle class for a given calendar
year (EF. ) are broken down into component emission factors in Equation
i,n, s
(2-2). The components represent the masses of lead salt, organic and
sulfate emissions from both leaded and unleaded gasoline fueled vehicles
and total particulate mass from diesel vehicles—all of which are multiplied
by the fraction of total vehicles of a given model year designed for use
on these three fuel types. The sum of these components for each model
year is also multiplied by the fraction of the vehicle class travel
(disaggregated by gasoline and diesel fuel types for all vehicle categories
except light-duty vehicles) that is attributable to that model year in
the calendar year of interest. For example, the component (EF. . . )
*•» J > K»n» ^
represents the emissions in grams per mile of lead salts (k=l) from vehicle
class i emitted from model year j gasoline vehicles that are on the road
in calendar year n and are designed for use on leaded fuel. These emission
components must be summed up over the twenty model years prior to the
calendar year of interest to include all the contributing fractions of
emissions from vehicles on the road.
^ f
?i,n,s - 2- (EFi,j,M,n,L + EFi,j,k2,L + EFi? j >k3>L) (FL> if j)
j=n-19 L
+ NL + EFi)jfk3>NL)(FNL>ijj)] mi,j>
+ D)(FD>i>j) mi>j>D
L 2-3
-------
where j = model year j = n-19, n-18, .... n-2, n-1, n
L = vehicles designed for use on leaded fuel
NL = vehicles designed for use on unleaded fuel
k = component of total particulate emission factor
(k. = lead, k_ = organic, k = sulfate) expressed
individually for gasoline vehicles and trucks
(except motorcycles) and cumulatively for diesel
vehicles and trucks and motorcycles
F . . = fraction of the vehicle class i fleet designed for
' use on leaded gasoline in model year j
F . = fraction of the vehicle class i fleet designed for
' '-1 use on unleaded gasoline in model year j
FD . = fraction of the vehicle class i fleet designed for
* use on diesel fuel in model year j
m. . „ = travel fraction for all gasoline vehicles in class
'^' i in model year j
m. . = travel fraction for all diesel vehicles in class i
'^' in model year j
Component emission factors are derived for each vehicle class over
different model years at average speeds of 19.6 mph (cyclic driving
comparable to average speed of the Federal Test Procedure) and 34.8 mph
(cruising conditions comparable to the average speed of the Sulfate
Emissions Test). Emission factors for speeds between 19.6 mph and 34.8
mph can be linearly interpolated.
As the reader will note in the following sections, the calculation of
these component emission factors is highly dependent on the assumptions
made concerning particle size distribution. Distributions of particle
size are different for leaded gasoline, unleaded gasoline and diesel
fueled vehicles as well as brake and tire wear particles. They are also
L 2-4
-------
different for various conditions of vehicle driving cycle (speed) and
load. For the purposes of this report, however, typical or average
conditions are presented to facilitate the determination of vehicle
particulate emissions versus particle size.
Particle size distributions for leaded, unleaded and diesel fueled
vehicles and brake wear particles are contained in Table 2-20 and also
in Figures 2-1, 2-2, 2-3, and 2-4 (no distributions are available for
tire wear particulate). Typically, the average diameter of particles
emitted from vehicles fueled with leaded gasoline are the largest,
particles emitted from vehicles fueled with unleaded gasoline are
somewhat smaller and particles emitted from diesel fueled vehicles are
smaller yet. Some of the data for the size distribution of lead parti-
cles are conflicting (e.g., Moran et al, 1971 which shows a larger
fraction of the lead in smaller size ranges than the other leaded
gasoline references). Thus, these data are less certain than those for
unleaded and diesel particles. References for those reports used in the
determination of particle size distributions of leaded, unleaded and
diesel fueled vehicle emissions and brake wear emissions are listed in
Table 2-20.
Values for IL , M^ , M^ , VL, and K., should be expressed as dimen-
sionless fractions of total particulate by weight emitted below a given
size cutoff. Values may be read directly from Table 2-20 for the data
points listed therein, or may be read off the graphs of continuous
cumulative particle size distributions in Figures 2-1, 2-2, 2-3, and 2-4
for interpolated size cutoffs (e.g., 6.5 u, 2.5u).
2.2 LIGHT-DUTY VEHICLES AND LIGHT-DUTY TRUCKS I AND II
This section presents the lead, sulfate and organic emission factor
equations for gasoline-fueled light-duty vehicles and light-duty trucks
I and II. In addition, composite particulate emission factors are
L2-5
-------
presented for light-duty diesel vehicles and light-duty diesel trucks.
The fractions of light-duty vehicles and light-duty trucks by model year
which operate on leaded or unleaded gasoline or diesel fuel are presented
in Tables 2-4, 2-9, and 2-12. Tables 2-5, 2-10, 2-13, and 2-14 contain
information on light-duty vehicle and light-duty truck travel fractions
from model years n to n-19. To remain consistent with the data used in
MOBILES, travel fractions are assumed to be identical for gas and diesel
light-duty vehicles; but separate travel fractions are used to characterize
gasoline versus diesel light-duty trucks 1 and light-duty trucks II.
2.2.1 Lead Emission Factors
Lead emission factors are calculated in the same manner as in the recent
report entitled, Supplementary Guidelines for Lead Implementation Plans
— Updated Projections for Motor Vehicle Lead Emissions^ereinaf ter
referred to as the "lead document." These lead emission estimates are
multipled by a factor of 1.557 to account for the halogens, typically
bromine and chlorine, which combine with lead to form total lead salt
particulate emissions. This factor was obtained £rom a report by the
Ethyl Corporation entitled Composition, Size, and Control of Automotive
Exhaust Particulates, and is the ratio of PbClBr mass to Pb mass based
227
on FTP results of 16 test vehicles.
LDV (Pre-1971) and LPT (Pre-1971); Leaded Fuel
For i=l,2,3 j=n-19,...,1970 k=l Cs=from Table 2-7 asl?j=(0.75):
EFifj,kl,n,L = [pbL,n(0.887)(ML) + (2-3a)
(0.75X1.557)
OK (n MIUM ^1 (0-75X
PbNL>n(0.113)(MNL>NC)J (Ec>i>j
L2-6
-------
where a 3 fraction of lead burned that is exhausted; for
3 all non-catalyst vehicles and for catalyst
vehicles using unleaded gasoline a = 0.75
(i.e., 75 percent); for catalyst vehicles using
unleaded gasoline in 1975-1980, a 9 . * 0.40; for
sz, j
catalyst vehicles using leaded gasoline in 1981 and
later, a 0 . = 0.44 (see Table 2-22)
sZ, j
C * speed-dependent fuel economy correction factor
based on steady cruise or cyclic driving; available
from Table 2-7 (nondimensional)
Pb » lead content of unleaded gasoline in calendar year n
'n from Table 2-2 (g/gal)
Pb «• average lead c itent of leaded gasoline in calendar
'n year n from Table 2-2 (g/gal)
E . . * city/highway combined on-road fuel economy for model
' year j and vehicle class i from Table 2-6 (miles/
gallon)
M. * fraction of particles less than a user specific
size cutoff (0.1-lOlj ) that are emitted from
vehicles that are fueled with leaded gasoline, from
Table 2-20 or Figure 2-1
M^ s fraction of particles less than a user specified
' size cutoff (0.1-lOy ) that are emitted from
catalyst vehicles that are fueled with unleaded
gasoline, from Table 2-20 or Figure 2-2
M - fraction of particles less than a user specified
' size cutoff (0.1-lOy ) that are emitted from non-
catalyst vehicles that are fueled with unleaded
gasoline, from Table 2-19 or Figure 2-2
LDV (MY 1971-1974) and LPT (MY 1971-1978); Leaded Fuel
For i=l,2 j=1971,...,1974 k=l C3=from Table 2-7 asljj=0.75:
and For i = 3 j-1971,...,1978
(2-3b)
PK rn na^UM ^1 (0-75)(1.5
PbNLjn(0.084)(MNL>NC)J (Ec>i)m)(C
557)
)
L 2-7
-------
LDV (MY 1975+) and LPT (MY 1979+) ; Leaded Fuel
For i-1,2 j-1975,...,n k=l C8=»from Table 2-7 asifj-0.75:
and For i=3 j»1979, . . . ,n
EFi, j,kin,L " [pbL>n(0.724)(ML) + (2-4)
PbNL,n(0.276)(MNL,NC)l
J
LDV (MY 1975-*-) and LPT (MY 1975+) ; Unleaded Fuel
For i»l,2,3 j=1975,...,n k=l Cg»from Table 2-7 ag=from Table 2-22
) + (2-5)
PbL>n(ri)(ML)(l-Pi)(Fi>j>NL>CAT)(as>2>j)] U55J
J C»1->J »'
where r£ = misfueling rate for vehicle class i from Table 2-19
P^ = fraction of catalyst equipped vehicles with catalysts
removed from Table 2-23
The calculation of area lead particulate emissions necessitates the
determination of the percentage of burned lead exhausted (a ). A value
for a of 0.75 (i.e., 75 percent of the lead burned is exhausted) should
be used for non-catalyst equipped, gasoline-powered vehicles. The 0.75
value is based on tests which measured exhaust emissions under cyclic
driving conditions and found that 17 percent of the lead is retained by
the engine (in the oil and combustion chamber) and 8 percent is retained
by the muffler and exhaust pipes. For gasoline powered vehicles
equipped with catalysts, a value of a =0.40 for 1975 to 1980 and a =0.44
L2-8
-------
for 1981 and later model year vehicles that have been misfueled, should
be used. (For properly fueled catalyst vehicles the values of a for
5
all model years is 0.75.) The value of a was computed from lead
s
retention of monolithic and pelleted catalysts, respectively, and
weighted for the sales mix of these catalysts in each time frame. The
values of a are not assumed to vary with speed, since a is more
i s s
correlated with driving mode, e.g., acceleration, cruise or decelera-
tion, rather than speed alone, and little data is available to make a
s
sensitive to all of these variables.
Combined city/highway fuel economy (E . ) is yet another factor
c > i, j
affecting area lead particulate emissions. Fuel economy versus model
year is provided in Table 2-6.
Lead particulate emissions can be determined at any speed by using
Equations (2-3), (2-4), and (2-5) (for light-duty vehicles and trucks)
and the appropriate value of the speed dependent fuel economy correction
factor (C ) for the vehicle speed of interest. Values of C at various
s s
speeds are provided in Table 2-7. It should be noted that average
vehicle speed and C can be determined for an area by either of two
approaches. One approach is to base C on the average vehicle speed for
S
the area of concern. The average area vehicle speed should be a weight-
ed average based on average speeds and VMT data for the various roadway
classifications, such as limited access (greater than 5 mph), suburban
roads (35 mph) and urban streets (25 mph or less). The other approach,
which is considered more accurate, is to determine C and area emissions
s
separately for each roadway classification (and average speed).
Area lead particulate emissions also are dependent upon the lead content
of gasoline in a given calendar year. Values for the lead content of
leaded (PbT ) and unleaded gasoline (Pb.TT ) are contained in Table
L,n NL,n
2-2. Values for future years will be updated as new information becomes
available.
L 2-9
-------
2.2.1.1 Misfueling and Fuel Switching
EPA has observed that misfueling rates (i.e., percentage of vehicles
designed for use on unleaded gasoline that use leaded gasoline) are
dependent on vehicle mileage and increase with vehicle mileage accumu-
lation. Strictly speaking, this dependence on mileage should be
reflected in the calculation of particulate emissions, with each model
year receiving its own misfueling rate. However, this further compli-
cates an already complex calculation. To give the user a choice, this
report offers both the option of using a single average misfueling rate
for all model years of a given vehicle class and exact misfueling rates
for each vehicle class by vehicle age. The single average rates are
determined for the weighted average mileage accumulated for each vehicle
class and are listed in Table 2-19 for inspection and maintenance (I/M)
and non-I/M areas. In other words, in the calculation of emission
factors from 1975 on, the misfueling rate (r.) depends only on which
vehicle class (i) is being considered and whether the area of interest
has an I/M program. As a result, misfueling rates and particulate
emissions will be slightly overestimated, with the degree of overestima-
tion declining with later evaluation years and essentially disappearing
in 1995. For users who desire more accuracy, Table 2-19a gives exact
misfueling rates for different vehicle ages and classes affected by
misfueling.
The use of leaded gasoline on vehicles designed for unleaded fuel
results in lead salt emissions. Since most of these vehicles have
catalysts, the lead results in poisoning of the catalyst so that organic
particulate emissions can be assumed to increase to the levels found
with non-catalyst vehicles. Also, catalyst poisoning should result in
no sulfur dioxide oxidation to sulfates. Sulfate levels are therefore
assumed to be the same as those from non-catalyst vehicles.
L2-10
-------
Discretionary fuel switching (i.e., percentage of vehicles designed for
use on leaded gasoline that use unleaded gasoline) is assumed to equal
11.3 percent of the leaded fleet prior to 1971, and 8.4 percent from
1971 to 1974 for the LDV and LDT I categories. The discretionary rate
for the LDT II class is 8.4 percent from 1971 to 1978, and 27.6 percent
thereafter. For the LDV and LDT1 classes, discretionary switching is
assumed to be 27.6 percent after 1974. These discretionary rates apply
only to the lead salt component of light-duty vehicle and light-duty
truck I and II emissions. The misfueling rates employed here were used
in the December 1983 EPA report, Anti-Tampering and Anti-Misfueling
Programs to Reduce In-Use Emissions from Motor Vehicles,
EPA-AA-TSS-83-10. The discretionary fuel switching rates were
obtained from Energy and Environmental Analysis, Inc., Assessment of
Current and Projected Trends in Light-Duty Vehicle Fuel Switching, June
1984.7/
2.2.2 Organic and Sulfate Emission Factors
2.2.2.1 Control System Fractions
Organic and sulfate emissions of gasoline-fueled vehicles depend on the
type of vehicle emission control system in addition to the vehicle model
year. The fraction of vehicles with different emission control systems
to which different emission factors are applied are handled similarly to
the fleet sales fractions for leaded, unleaded and diesel vehicles
versus model year. The main difference is that these are fractions of
the total number of vehicles designed for use of unleaded fuel and not
the total number of vehicles in each vehicle class. These fractions are
listed in Tables 2-3, 2-8, and 2-11 for light-duty vehicles and light-
duty trucks I and II, respectively. These vehicle classes have a
relatively wide range of control technology and, as a result, have a
wide range of emission factor estimates. It should be noted that a
small number of non-catalyst equipped vehicles have been certified for
use on unleaded gasoline since 1975. These vehicles constitute a very
L 2-11
-------
small percentage of the total non-catalyst fleet, but are nonetheless
considered in this report and have been given their own control system
fraction category (F^ . }NL>NOCAT) •
The light-duty vehicle and truck emission control system fractions were
obtained from the "sales-weighted" EPA emission factor in-use vehicle
test data base. This data base contains gasoline-fueled vehicle m,ixes
approximating the sales mixes for the 1975 through 1982 model years.
All vehicles and trucks prior to 1975 models are assumed to be designed
for use on leaded fuel (i.e., no diesel or catalyst vehicles). Emission
control system fractions for 1983 and later LDVs are determined from
recent projections by Energy and Environmental Analysis, Inc. in a report
387
entitled, Forecasts of Emission Control Technology 1983-1990.
Data for 1975 through 1978 light-duty truck I technology fractions were
obtained by combining EPA fuel economy data base sales figures by engine
displacement and model type and Federal Certification Test Results for
these years from the Federal Register, Volume 40, No. 48, March 11,
1975;9^ Volume 41, No. 46, March 8, 1976;10' Volume 42, No. 110, June 8,
1977;ll/ and Volume 43, No. 181, September 18, 1973.12/ The certification
data provided emission control systems by model type and engine displacement
which were matched with fuel economy sales fractions. These two data
sources also served as the basis for deriving the 1979-1981 light-duty
truck technology fractions.
Data for 1982 through 1984 light-duty trucks I and II technology frac-
tions were obtained by subtracting California sales figures by engine
family from Federal sales figures given in the EPA Certification data
base for those years. Forecasts of post-1984 light-duty truck I and II
technology fractions were developed internally and are consistent with
data used for EPA emission factor projections.
L 2-12
-------
2.2.2.2 Organic and Sulfate Emission Factor Components
Organic and suifate emission factors for light-duty vehicles and light-
duty trucks vary by model year, control system, vehicle speed and fuel
type (leaded versus unleaded). These emission factors are derived from
emission test data and are listed in Table 2-1 in terms of grams per
mile. This table of emission factors is used in the following sets of
equations to calculate LDV and LDT organic and suifate emission factor
components. (Table 2-1 also refers the user to the proper equation(s)
listed below to which each emission factor should be applied.)
Organic Emission Factor Components
LDV and LDT (Pre-1970); Leaded Fuel.Avg. Speed = All
For i-1,2,3 j-n-19,...,1969 k=2:
£Fi,j,k2,L = 0.193 ML (g/mile) (2-6)
LDV AND LDT (1971-1974): Leaded Fuel.Avg. Speed = All
For i=l,2,3 j-1970, . . . , 1974 k=2 :
EFi,j,k2,L = °-068 ML (gMile) (2-7)
LDV and LDT (I975+): Leaded Fuel.Avg. Speed = All
EFi,j,k2,L = °-030 ML (g/mile) (2-8)
L 2-13
-------
LDV and LPT (1975+): Unlf aded Fuel^Avg. Spe o i - All
0.017)(MNL>c) (2-9)
(Fif j,NL,NOCAT> (0.030) (MNL)NC)
where F^ j CAT = fraction of the unleaded vehicle class i
fleet equipped with a catalyst in model year j
^i i NL NOCAT = fraction of the unleaded vehicle class i fleet
without a catalyst in model year j
Sulfate Emission Factor Components
LDV and LPT (All Model Years); Leaded Fuel,Avg. Speed = 19.6 mph
For 1*1,2,3 j=n-19,...,n k»3 s=19.6:
EFi»J'k3L = °-002 ML (g/mile) (2-10)
LDV and LPT (All Model Years); Leaded Fuel.Avg. Speed = 34.8 mph
For 1=1,2,3 j=n-19,...,n k=3 s=34.8
EFi,j,k3,L = 0.001 ML (g/mile) (2-11)
L 2-14
-------
LDV and LPT (1975+); Unleaded Fuel.Avg. Speed = 19.6
For i-1,2,3 j-1975, . . . ,n k-3 3=19.6
> (2-12)
(0-016)(MNL>c)
<*if j, NL,NOCAT><0.002)(MNL>NC)J
(ri)(0.002)(ML)
where ?£,j,CAT/NOAIR = fraction of Che unleaded vehicle class i fleet
equipped with a catalyst but no air pump in
model year j; this includes oxidation catalyst
and three w«y catalyst (Fifjf3WCAT)
vehicles with no air pump
F£ : CAT/AIR * fraction of the unleaded vehicle class i fleet
equipped with a catalyst and an air pump in
model year j; this includes oxidation catalyst
(Fi,j OCAT/AIR) an<* three-way plus oxidation
catalyst (Fi?j,3WCAT/OXCAT) vehicles with air
pumps
LDV and LPT (1975+); Unleaded Fuel Avg. Speed - 34.8 mph
For i*l,2,3 j-1975,... ,n k=»3 s-SA.S r^ = from Table 2-19:
- d-*i> [^i,j,NL,NOCAT)(0.001)(MNL>NC) (2-13)
+ (Fi>j>OXCAT><0-005)(MNL>c) + (Fifj,3WCAT)(0.001)(MNLfc)
* (Fi,j,OXCAT/AIR)(0-020)(MNL,c) * ^Fi,j,3WCAT/OXCAT>
(0.025)(MNL)C)1 + (ri)(0.001)(ML)
L2-15
-------
where F, : OXCAT = fraction of the unleaded vehicle class i equpped
with an oxidation catalyst but no air pump in
model year j
F£ i 3WCAT = fraction of the unleaded vehicle class i equipped
with a three-way catalyst in model year j; note
these vehicles are sometimes equipped with air
pumps that are usually only used during vehicle
start-up; therefore, the vehicle category as a
whole is assumed to emit sulfates at the same rate
as non-air pump-equipped vehicles for emission
factor consideration
Fi i OXCAT/AIR ~ fraction of the unleaded vehicle class i equipped
with an oxidation catalyst and an air pump in
model year j
2.2.3 Diesel Emission Factors (Light-Duty)
Diesel particulate emission factors for different model years are listed
separately for light-duty vehicles and light-duty trucks in Table 2-1.
These emission factors are derived from test data and are used in the
equations below to calculate total diesel particulate emission factor
components for LDVs and LDTs. (Table 2-1 also refers the user to the
proper equation below to which each emission factor should be applied.)
LDV (Pre-1981); Diesel Fuel
For i=l j=n-19, . . . ,1980:
EFi,j,D = 0.700 MD (g/mile) (2-14)
where Mp = fraction of particles less than a user-specified
size, cutoff (0.1-10 M ) that are emitted from vehicles
that are fueled with diesel fuel, from Table 2-20 or
Figure 2-3
LDV (1981-1986); Diesel Fuel
For i=l j=1981,...,1986:
EFi,j,D = °-3°0 MD (gMile) (2-15)
2-16
-------
LDV (I987-O; Diesel Fuel
For i=l j=1987,...,n:
EFi,j,D = °-200 MD (g/mile) (2-16)
— _ — ——__ — — __ — — .— -— — — _- — —. — _- — — — — — — — — — — — — — — — —. — — _ — _ _ ..._.__.... _ —•.— ______.,.. _ _ _ _.___>____ «•
LPT (Pre-1981); Diesel Fuel
For 1=1,2,3 j=n-19,...,1980:
EFi,j,D = 0-8°0 MD (g/mile) (2-17)
LPT (1981-1986); Diesel Fuel
For 1=1,2,3 j-1981,...,1986:
EFi,j,D * 0-300 MD (g/mile) (2-18)
LPT (1987 + ) ; Diesel Fuel
For i=2,3 j=1987,...,n:
EFi,j,D = °-260 MD (g/mile) (2-19)
2.3 HEAVY-DUTY VEHICLES
This section presents the lead, sulfate and organic emission factor
component equations for gasoline-fueled heavy-duty vehicles. Composite
particulate emission factor components for heavy-duty diesel vehicles
also are provided. These emission factor components are then used in
conjunction with estimates of sales fractions of heavy-duty vehicles by
model year and fuel type (Table 2-15) and travel fractions by vintage
(Tables 2-16 and 2-17) to calculate total emission factors. As shown in
Table 2-15, heavy-duty gasoline vehicles use leaded gasoline prior to
1987. The fraction of unleaded vehicles from 1987 on represents the
L2-17
-------
8,501-14,000 Ibs percentage of heavy-duty gasoline vehicles, and is based
on the assumption that the more stringent emission standards currently
proposed for 1987 and later heavy-duty gasoline vehicles in the 8,501 to
14,000 Ibs range will require the use of oxidation catalysts and air
injection. Heavy-duty gasoline vehicles above 14,000 Ibs are assumed to
consist entirely of leaded gasoline vehicles for all model years. The
reader also should note that the travel fractions for heavy-duty diesel
trucks in Table 2-17 are specific to calendar year 1987 and are therefore
presented for example only. These fractions shift from one calendar
year to the next due to the increasing penetration of diesels in the
lower mileage, lighter weight categories of heavy-duty trucks (which
consists of all vehicles over 8,500 Ibs. GVW). To calculate heavy-duty
diesel travel fractions in a particular year of interest other than 1987,
the reader needs to use the projections of diesel heavy-duty vehicles
in-use by GVW category and the estimates of diesel heavy-duty vehicle
mileage accumulation by GVW category which are contained in Appendix A.
Table 2-6 presents data on heavy-duty truck fuel economy. Estimates of
misfueling for heavy-duty gas vehicles under 14,000 Ibs GVW (after model
year 1986) are contained in Tables 2-19 and 2-19a. The effect of
discretionary fuel switching ha*s not been incorporated in the heavy-duty
vehicle emission factor equations due to the lack of data on the current
fuel purchase behavior of owners of heavy-duty vehicles. However, as
new data become available these equations will be revised accordingly.
2.3.1 Lead Emission Factor Components
The following equations are used to derive lead emission factor components
for heavy-duty gas vehicles operated on leaded and unleaded gasoline:
L 2-18
-------
HDGV (Pre-1987); Leaded Fuel
For i=4 j-n-19,...,1986 k=l ag = from Table 2-22:
(ML) (2-20)
HDGV (1987->-): Unleaded Fuel
For i=4 j=1987,...,n k=l ag = from Table 2-2 r^ = from Table 2-19:
En.j.M.n.ttL ' ""*>C.1.1""'»L.;)(1.»57) (M^,, (2-21,
^c^a, j'
* (r4)Us2tj)(PbLtn)(1.557)
Ec,4a, j
HDGV (1987 + ) ; Leaded Fuel
For i=4 j=1987,...,n k=l as = from Table 2-22:
*4a represents the fuel economy for HDGV1 after 1986.
**4b represents the fuel economy for HDGV2 after 1986.
2.3.2 Organic Emission Factor Components
Organic emission factors for heavy-duty gasoline vehicles are listed in
Table 2-1 in g/mile. These factors are used in the equations below to
calculate the total HDG organic emission factor component. The reader
should note that the HDG organic emission factors listed in Table 2-1
were derived assuming a constant 5.0 rapg for HDG vehicles of all model
years. Therefore, the equations below have been adjusted by the factor
(5.0/EC>4 :) to account for the HDG fuel economy values currently used
in MOBILE3.
L 2-19
-------
HDGV (Pre-1987); Leaded Fuel
For i=4 j»n-19,...,1986 k=2:
EFi,j,k2,L " 0.370 (HI.) (2"23)
— — ____. _______ — —-*——. — — — — — — —. — — __ — -. — — —. — —— — — — — --— — — — ^. — —. — _-—.»— _-—_-._— _ --.- — — — __—._
HDGV (1987+); Unleaded Fuel
For i=4 j«1987,...,n k=2 r4 * from Table 2-19:
En,i,k,,NL= [° ) (2-25)
•" "-c^b.j
2.3.3 Sulfate Emission Factor Components
Sulfate emission factors for HDG vehicles also are listed in Table 2-1
and are used in the following equations to produce HDG sulfate emission
factor components. As with the HDG organic emisison factor components,
the equations below contain the adjustment factor (5.0/EC 4 j) to
reflect the HDG fuel economy values currently used in MOBILES.
HDGV (Pre-1987); Leaded Fuel
For i=4 j-n-19,...,1986 k=3:
EFi,j,k3,L • 0-006 (ML) (E5>° .) (2-26)
HDGV (1987-O; Unleaded Fuel
For i*4 j«1987,...,n k=3 r4 » from Table 2-19:
EFi i k-> L f (l-r4)(0.048) (\,i r> + (r4) (0.006) (ML)| L—^—) (2-27)
J' L ' -1 Ec,4a,j
L 2-20
-------
HDGV (1987+) ; Leaded Fuel
For i=4 j-1987,...,n k=3:
EFifj,k3,L- 0.006 (ML) <-i^;* (2-28)
2.3,4 Diesel Particulate Emission Factors
Diesel particulate emission factors (measured in g/mile) for heavy-duty
diesel vehicles are derived with the following equations:
HDDV (All Model Years): Diesel Fuel
For i-5 j=n-19,...,n:
EF5,j,D " 0-7 MD (CFDjj) (2-29)
where CFjj : = factor for converting gm/bhp-hr to gm/mi,
' from Table 2-21
2.4 MOTORCYCLE EMISSION FACTORS
This section presents the emission factors for motorcycles. Table 2-18
contains travel fractions for the motor vehicle fleet. Motorcycle sales
are assumed to consist entirely of leaded gasoline vehicles for all model
years. Therefore, misfueling rates for motorcycles are zero.
Discretionary fuel switching rates are not incorporated into the
equations due to the lack of data on the fuel purchasing habits of
motorcycle owners.
Motorcycle fractions are based on 2-stroke versus 4-stroke emission
factor estimates (see Table 2-1). Before 1978, most on-road motorcycle
travel was done by 2-stroke vehicles (53.4 percent) and slightly less
(46.6 percent) by 4-stroke vehicles according to sales figures in the
1983 Motorcycle Statistical Annual published by the Motorcycle Industry
L2-21
-------
Council, Inc. In 1978, more stringent control of motorcycle emis-
sions caused nearly all motorcycle manufacturers to build 4-stroke vehicles
for on-road usage. Therefore, it is assumed that all motorcycles from
1978 on are 4-stroke vehicles since nearly all 2-stroke mileage is
accumulated off-road.
The equations below present the lead emission factor component calcu-
lations for motorcycles. Due to the absence of catalyst emission controls
on motorcycles, organic and sulfate emission factor components are not
calculated.
MC (Pre-1978); Leaded Fuel
For i=6 j=n-19,...,1977:
EF6,j,L = [(0.466X0.046) + (0.534) (0.330)J (ML) (2-30)
= 0.198 ML (g/mile)
MC (1978+) ; Leaded Fuel
For i=6 j=1978,...,n:
EF6,j,L = 0.046 ML (g/mile) (2-31)
2.5 BRAKE AND TIRE WEAR PARTICIPATE EMISSION FACTOR COMPONENTS
Additional sources of motor vehicle particulate emissions include brake
and tire wear emission components. Limited testing has been performed
to estimate the contributions of brake and tire wear emissions to the
total light-duty vehicle particulate emission rate. No data exist on
the rate at which light-duty trucks, heavy-duty vehicles, or motorcycles
emit brake and tire wear emissions. The user should be aware that brake
and tire wear particulates are emitted from these vehicle classes at
different rates than the light-duty vehicle rate, but since no data exists,
the light-duty vehicle rate is used to estimate their contribution to
total particulate emission rates.
L 2-22
-------
Brake, wear emissions from light-duty vehicles have been measured in a
recent study and have been found to consist of significant quantities of
particulate in the airborne particle size range. Airborne particulate
emission rates for brake wear particles as measured on braking cycles
representative of urban driving averaged 0.0128 grams per mile for light-
40/
duty gasoline vehicles. Particle size distribution for brake wear
particulate (M_) is included in this reference and is summarized in Table
2-20. The rate of 0.0128 g/mile times the appropriate fraction of VL
for the particle size cutoff of interest should be added to any calculation
of particulate emissions less than 10 microns for all classes of vehicles.
In the example calculation in Section 3-0 of this report, for example,
M_ » 0.98, the brake wear particulate emission rate is therefore 0.0125
g/raile and the total light-duty vehicle particulate emission rate is
0.0726 g/mile. In this particular example, therefore, brake wear emissions
account for 17 percent of the total particulate emission rate.
Tire wear particulate is generally larger in size than brake wear particulate
and therefore consists of fewer particles in the airborne size range.
Emission rates for airborne tire wear particulate for light-duty vehicles
has been estimated at 0.002 g/mile. This rate should be added to
calculations of particulate emissions less than 10 microns for all classes
of vehicles. The addition of 0.002 g/mile in the example calculation in
Section 3-0 indicates that airborne tire wear particulate accounts for
about 3 percent of the total light-duty particulate emission rate.
No data on airborne particle size distribution are available for analyses
of tire wear particulate emission rates at smaller particle size cutoffs
(i.e., 2.5 microns or 7 microns). The user should either interpolate
between zero and 10 microns to determine the appropriate emission rate
for the distribution of tire wear particles below the desired size cutoff
(e.g., at 7 microns tire wear emissions = 0.0014 g/mile and at 2.5 microns
tire wear emissions = 0.0005 g/mile) or simply neglect tire wear particulate
since it is likely to be negligible in these smaller particle size ranges.
L2-23
-------
Another source of particulate emissions for which emission factors could
be developed is reentrained particulate from particles that have been
deposited on road surfaces or possibly road material itself. While
467 477
information is available on these reentrained particulates, they
are not considered to be directly emitted by mobile sources and
therefore are not included in this report.
L 2-24
-------
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L 2-26
-------
TABLE 2-2
LEAD CONTENT OF GASOLINE
Leaded Gasoline* Unleaded Gasoline
Year (g/gal) (g/gal)
1974 1.79 0.014
1975 1.82 0.014
1976 2.02 0.014
1977 2.03 0.014
1978 1.94 0.014
1979 1.85 0.014
1980 1.38 0.014
1981 1.15 0.014
1982 1.24 0.014
1983 1.14 0.014
1984 1.10 0.014
1985 0.50 0.014
1986 0.10 0.014
1987 0.10 0.014
1988 0.10 0.014
1989 0.10 0.014
1990 0.10 0.014
*1974-1982: Lead content based upon data submitted to EPA on historical
sales data for leaded gasoline and data indicating the actual pooled
average lead content. The value for unleaded gasoline is based on
recent MVMA fuel surveys.
1983-1990: Lead content based upon requirements for average lead
content of leaded gasoline. During the first half of 1983, small
refineries were subject to a pooled average lead standard. Recent EPA
regulations require refiners to reduce the lead content of leaded
gasoline to 0.5 g/gal by July 31, 1985 and to 0.1 g/gal by January 1,
1986 and thereafter. (See Federal Register, Vol. 50, No. 45, March 7,
1985.)
L2-27
-------
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L 2-28
-------
TABLE 2-4
FLEET SALES FRACTIONS
Light-Duty Vehicles
Model
Years
Pre-1975
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995+
Nonleaded Gasoline
Fraction of LDV
Leaded Gasoline
Fraction of LDV
Fleet, F,
NL,l,j*
0.000
0.869
0.863
0.838
0.865
0.875
0.966
0.939
0.954
0.947
0.940
0.934
0.927
0.920
0.910
0.900
0.887
0.887
0.886
0.886
0.885
0.885
1.000
0.128
0.134
0.158
0.126
0.097
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Diesel Fraction
of LDV Fleet,
FD>1.J**
0.000
0.003
0.003
0.004
0.009
0.028
0.034
0.061
0.046
0.053
0.060
0.066
0.073
0.080
0.090
0.100
0.113
0.113
0.114
0.114
0.115
0.115
Where F,IT , = Estimated fraction of the LDV model year fleet which use
NL, 1 , , , .. ,
nonleaded gasoline
F = Estimated fraction of the LDV model year fleet which use
' leaded gasoline
F = Estimated fraction of the LDV model year fleet which use
' diesel fuel
*Percentages of gasoline vehicles requiring leaded and nonleaded fuel
obtained from Energy and Environmental Analysis, Inc., "The Highway
Fuel Consumption Model: Tenth Quarterly Report," November 1983.
**Diesel and gasoline sales projections were made by EPA based on data
obtained from Energy and Environmental Analysis, Inc., "The Highway
Fuel Consumption Model: Tenth Quarterly Report," November 1983.
L 2-28
-------
TABLE 2-5
TRAVEL WEIGHTING FACTOR CALCULATION*
Light-Duty Vehicles
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
(a)
January 1
Fraction
Total
Registration
0.028
0.107
0.100
0.094
0.088
0.080
0.075
0.069
0.062
0.056
0.050
0.043
0.037
0.031
0.024
0.018
0.012
0.008
0.006
0.008
(b)
Annual
Mileage
Accumulation
Rate
t(a)(b)/(SUM)]
Fraction of LDV
Travel by Model Year
m, . „ and m.
l.j.G
,j,D**
12,818
12,639
11,933
11,268
10,639
10,045
9,485
8,955
8,455
7,983
7,538
7,117
6,720
6,345
5,991
5,657
5,341
4,043
4,762
4,496
358.9
1,352.4
1,193.3
1,059.2
936.2
803.6
711.4
617.9
524.2
447.0
376.9
306.0
248.6
196.7
143.8
101.8
64.1
32.3
28.6
36.0
0.038
0.142
0.125
0.111
0.098
0.084
0.075
0.065
0.055
0.047
0.040
0.032
0.026
0.021
0.015
0.011
0.007
0.003
0.003
0.004
SUM: 9,538.9
*Data derived from MOBILE3.
**Travel fractions are the same for diesel and gasoline fueled LDVs.
L2-30
-------
TABLE 2-6
CITY/HIGHWAY COMBINED ON-ROAD FUEL ECONOMY
(miles/gallon)
Fuel Economy, Ec £ j
Model
Year
Pre-1970
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995 +
LDV*
13.9
13.9
13.2
13.1
12.9
12.6
13.5
14.8
15.5
16.8
17.2
20.0
21.4
22.2
22.2
22.8
23.2
23.8
24.3
24.8
25.2
25.7
26.2
26.6
27.2
27.6
29.0
LDTl**
10.6
10.6
10.4
10.2
9.9
9.6
11.6
12.3
13.0
13.4
14.2
16.1
17.7
18.6
19.2
19.9
20.7
21.4
23.0
23.3
23.1
24.0
24.5
24.4
25.3
25.8
26.2
LDT2
7.9
7.9
7.7
7.4
7.0
6.9
8.8
9.7
9.4
9.6
9.8
11.5
13.3
13.6
13.7
13.9
14.0
14.3
14.5
14.7
14.9
15.2
15.4
15.7
15.9
16.2
16.4
HDGVU
_
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
9.5
9.5
9.6
9.7
9.7
9.8
9.8
9.9
10.1
HDGV2
.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
5.6
5.6
5.6
5.6
5.7
5.7
5.7
5.7
5.8
HDGV++
6.5
6.4
6.4
6.4
6.5
6.7
6.8
7.3
7.7
8.0
8.2
8.4
8.6
8.8
8.9
8.9
9.0
9.0
9.0
9.1
9.2
9.2
9.3
9.4
9.4
9.5
9.6
*Fuel economies for LDV's based on EPA memo from Karl H. Helltnan Co
Ralph C. Stahman regarding Light-Duty MPG, June 15, 1984.
**Fuel economies for LDT's drawn from the input data used to generate
"The Highway Fuel Consumption Model: Tenth Quarterly Report,"
prepared by Energy and Environmental Analysis, Inc.
•••Fuel economies for Heavy-duty gasoline vehicles (HDGV) were derived
from figure presented in an EPA memo to Mark Wolcott from Cooper
Smith, dated July 2, 1984.
•n-Pre-1986 fuel economies are composites of HDGV1 and HDGV2.
L2-31
-------
TABLE 2-7
FUEL ECONOOT CORRECTION FACTORS AT VARIOUS SPEEDS, C
(Normalized to 32.7 miles/hour-cyclic driving)
Speed (mph)
5
10
15
f TTTP'\ 70——— ——— -._ —
25
30
32.7
40
45
50
55
60
C
s
Cyclic Driving
0.323
0.553
0.692
0.885
0.963
1.000
- - 1 09?
1.053
1.073
1.078
1.063
1.023
C
s
Steady Cruise
0.467
0.709
0.997
1 1 C-l
1.248
1.294
1.303
1.288
1.256
1.210
1.159
1.104
L 2-32
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-------
TABLE 2-9
FLEET SALES FRACTIONS
Light-Duty Trucks I
Unleaded Gasoline
Years ' NL,2,j*
Pre-1975
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995 +
Where F.TT 0
NT /
nL- , z.
V
L,2
0.000
0.810
0.909
0.957
0.964
0.942
0.945
0.914
0.899
0.878
0.870
0.840
0.820
0.790
0.760
0.730
0.706
0.697
0.688
0.679
0.670
0.661
= Estimated frac
nonleaded gaso
= Estimated frac
1 £» ft d ^ rl r* i f ^\ 1 -IT-I
Leaded Gasoline
Fraction of LDTl
Fleet, F „ .
J-> j *-»J
1.000
0.188
0.088
0.038
0.027
0.030
0.021
0.026
0.021
0.022
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Diesel Fraction of
LDTl Fleet. F
0.000
0.002
0.003
0.005
0.009
0.028
0.034
0.060
0.080
0.100
0.130
0.160
0.180
0.210
0.240
0.270
0.294
0.303
0.312
0.321
0.330
0.339
Estimated fraction of the LDTl model year fleet which use
nonleaded gasoline.
Estimated fraction of the LDTl model year fleet which use
leaded gasoline.
Estimated fraction of the LDTl model year fleet which use
diesel fuel.
*Percentages of gasoline vehicles requiring leaded and unleaded fuel
obtained from Energy and Environmental Analysis, Inc., "The Highway
Fuel Consumption Model: Tenth Quarterly Report," November 1983.
**Diesel and gasoline sales projections were derived from MOBILE3.
L 2-34
-------
TABLE 2-10
TRAVEL WEIGHTING FACTOR CALCULATION*
Light-Duty Gas Trucks I**
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
(a)
January 1
Fraction
Total
Registration
0.023
0.089
0.085
0.081
0.076
0.072
0.068
0.064
0.060
0.055
0.050
0.046
0.042
0.038
0.034
0.029
0.025
0.021
0.017
0.025
(b)
Annual
Mileage
Accumulation
Rate
Ua)(b)/(SUM)]
Fraction of
LDV Travel by
Model Year, m
2,j,G
17,394
17,079
15,839
14,690
13,624
12,636
11,719
10,868
10,080
9,348
8,670
8,041
7,457
6,916
6,415
5,949
5,517
5,117
4,746
4,402
400.1
1,520.0
1,346.3
1,189.9
1,035.4
909.8
796.9
695.6
604.8
514.1
433.5
369.9
313.2
262.8
218.1
172.5
137.9
107.5
80.7
110.1
0.036
0.135
0.120
0.106
0.092
0.081
0.071
0.062
0.054
0.046
0.039
0.033
0.028
0.023
0.019
0.015
0.012
0.009
0.007
0.010
SUM:
11,219.1
*Data derived from MOBILES.
**Light-duty trucks I have a gross vehicle weight (GVW) rating of 6,000
pounds or less.
L 2-
-------
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C/3 C/5
-------
TABLE 2-12
FLEET SALES FRACTIONS
Light-Duty Trucks II
Unleaded Gasoline
Model
Years
Pre-1975
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995+
WHERE F.IT ,
NL,3
F
L,3
.LUV~t.-A.V^LJ \S A. UV JL *-
Fleet« FNL,3,j*
0.000
0.000
0.000
0.000
0.000
0.972
0.966
0.940
0.920
0.900
0.870
0.840
0.820
0.790
0.760
0.730
0.706
0.697
0.688
0.679
0.670
0.661
= Estimated frac
nonleaded gaso
= Estimated frac
1 « »* *•! A /^ r» <•» e> ^ 1 •! «
Leaded Gasoline
Fraction of LDT2
1.000
0.998
0.997
0.995
0.991
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Diesel Fraction of
LDT2 Fleet, F _ .
u,j,j
**
0.000
0.002
0.003
0.005
0.009
0.028
0.034
0.060
0.080
0.100
0.130
0.160
0.180
0.210
0.240
0.270
0.294
0.303
0.312
0.321
0.330
0.339
Estimated fraction of the LDT2 model year fleet which use
nonleaded gasoline.
Estimated fraction of the LDT2 model year fleet which use
leaded gasoline.
Estimated fraction of the LDT2 model year fleet which use
diesel fuel.
*Percentages of gasoline vehicles requiring leaded and nonleaded fuel
obtained from Energy and Environmental Analysis, Inc., "The Highway
Fuel Consumption Model: Tenth Quarterly Report," November 1983.
**Diesel and gasoline sales projections were derived from MOBILES.
L2-37
-------
TABLE 2-13
TRAVEL WEIGHTING FACTOR CALCULATION*
Light-Duty Gas Trucks II**
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20 +
(a)
January 1
Fraction
Total
Registration
0.023
0.089
0.085
0.081
0.076
0.072
0.068
0.064
0.060
0.055
0.050
0.046
0.042
0.038
0.034
0.029
0.025
0.021
0.017
0.025
(b)
Annual
Mileage
Accumulation
Rate
18,352
18,001
16,622
15,348
14,172
13,087
12,084
11,158
10,303
9,514
8,785
8,112
7,491
6,917
6,386
5,897
5,446
5,028
4,643
4,287
SUM:
(a)(b)
422.1
1,602.1
1,412.9
1,243.2
1,077.1
942.3
821.7
714.1
618.2
523.3
439.3
373.2
314.6
262.8
217.1
171.0
136.2
105.6
78.9
107.2
11,582.9
[(a)(b)/(SUM)]
Fraction of
LDT2 Travel by
Model Year, m
3.J.G
0.036
0.138
0.122
0.107
0.093
0.081
0.071
0.062
0.053
0.045
0.038
0.032
0.027
0.023
0.019
0.015
0.012
0.009
0.007
0.009
*Data derived from MOBILE3.
**Light-duty trucks II have a gross vehicle weight (GVW) rating of 6,001
to 8,500 pounds.
L, 2-38
-------
TABLE 2-14
TRAVEL WEIGHTING FACTOR CALCULATION*
Light-Duty Diesel Trucks I and II**
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
(a)
January 1
Fraction
Total
Registration
0.023
0.087
0.083
0.079
0.075
0.071
0.066
0.062
0.058
0.054
0.049
0.045
0.041
0.037
0.033
0.029
0.025
0.020
0.016
0.025
(b)
Annual
Mileage
Accumulation
Rate
[(a)(b)/(SUM)l
Fraction of
LDDT I & II Travel by
Model Year, m.
» j t
17,552
17,230
15,964
14,791
13,705
12,699
11,766
10,901
10,101
9,359
8,671
8,035
7,444
6,897
6,391
5,921
5,487
5,084
4,710
4,364
403.7
1,499.0
1,325.0
1,168.5
1,027.9
901.6
776.6
675.9
585.9
505.4
424.9
361. A
305.2
255.2
210.9
171.7
137.2
101.7
75.4
109.1
0.035
0.129
0.114
0.101
0.088
0.078
0.067
0.058
0.050
0.043
0.037
0.031
0.026
0.022
0.018
0.015
0.012
0.009
0.006
0.009
SUM:
11,622.4
*Data derived from MOBILE3.
**Light-duty trucks I and II have a gross vehicle weight (GVW) rating of
0-8,500 pounds.
L 2-39
-------
TABLE 2-15
FLEET SALES FRACTIONS
Aeavy-Duty Gasoline Vehicles (HDGV)*
Model Unleaded Fraction of Leaded Fraction of
Years HDGV Fleet FNL>4tj** HDGV Fleet FL>4>j
Pre-1977 0.000 1.000
1977 0.000 1.000
1978 0.000 1.000
1979 0.000 1.000
1980 0.000 1.000
1981 0.000 1.000
1982 0.000 1.000
1983 0.000 1.000
1984 0.000 1.000
1985 0.000 1.000
1986 0.000 1.000
1987 0.823 0.177
1988 0.824 0.176
1989 0.825 0.175
1990 0.826 0.174
1991 0.828 0.172
1992 0.829 0.171
1993 0.833 0.167
1994 0.837 0.163
1995 0.840 0.160
*Heavy-duty gasoline vehicles have a gross vehicle weight (GVW) rating
greater than 8,501 pounds.
*The estimated fractions of the HDGV model year fleets which are gasoline-
powered are consistent with figures from M.C. Smith, "Heavy-Duty Vehicle
Emission Conversion Factors: 1962-1997," EPA-AA/SDSB-84-1, Office of
Mobile Sources, August 1984.
L2-40
-------
TABLE 2-16
TRAVEL WEIGHTING FACTOR CALCULATION*
Heavy-Duty Gasoline Vehicle (HDGV)**
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
(a)
January 1
Fraction
Total
Registration
0.000
0.148
0.126
0.107
0.092
0.078
0.067
0.058
0.049
0.041
0.036
0.030
0.026
0.022
0.020
0.016
0.014
0.012
0.010
0.049
(b)
Annual
Mileage
Accumulation
Rate
[(a)(b)/(SUM)]
Fraction of
HDGT Travel by
Model Yeqr, m
4.J.G
0
19,967
18,077
16,365
14,815
13,413
12,143
10,993
9,952
9,010
8,156
7,384
6,685
6,052
5,479
4,960
4,490
4,065
3,680
3,332
0.0
2,955.1
2,277.7
1,751.1
1,363.0
1,046.2
813.6
637.6
487.6
369.4
293.6
221.5
173.8
133.1
121.0
79.4
62.9
48.8
36.8
163.3
0.000
0.227
0.175
0.134
0.105
0.080
0.062
0.049
0.037
0.028
0.023
0.017
0.013
0.010
0.009
0.006
0.005
0.004
0.003
0.013
SUM:
13,035.5
*Data derived from MOBILE3.
**Heavy-duty gasoline vehicles have a gross vehicle weight (GVW) rating
greater than 8,500 pounds.
L 2-41
-------
TABLE 2-17
TRAVEL WEIGHTING FACTOR CALCULATION*
For Heavy-Duty Diesel Vehicles in Calendar Year 1987
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
(a)
January 1
Fraction
Total
Registration
0.000
0.166
0.13
0.115
0.097
0.080
0.067
0.056
0.047
0.040
0.033
0.027
0.023
0.019
0.015
0.013
0.011
0.009
0.008
0.034
(b)**
Annual
Mileage
Accumulation
Rate
0
67,910
61,749
56,155
51,073
46,457
42,260
38,447
34,982
31,832
28,968
26,363
23,995
21,43
19,883
18,101
16,41
15,007
13,665
12,444
0.0
11,273.1
8,521.4
6,457.8
4,954.1
3,716.6
2,831.4
2,153.0
1,644.2
1,273.3
955.9
711.8
551.9
415.0
298.2
235.3
181.3
135.1
109.3
423.1
SUM: 46,841.8
Fraction of
HDTT 1 Travel by
Model Year, mj ; j
0.000
0.241
0.182
0.138
0.106
0.079
0.060
0.046
0.035
0.027
0.020
0.015
0.012
0.009
0.006
0.005
0.004
0.003
0.002
0.009
*Data derived from MOBILE3.
**The tabulated annual mileage accumulation rate is specific to CY 1987
only. The rate shifts from one year to the next due to the increasing
penetration of diesels in the lower mileage, lighter weight classes of
the heavy-duty truck category (which contains all vehicles with a GVW
ra.ting over 8,500 pounds).
L 2-42
-------
TABLE 2-18
TRAVEL WEIGHTING FACTOR CALCULATION*
Motorcycles
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
(a)
January 1
Fraction
Total
Registration
0.000
0.167
0.159
0.134
0.142
0.131
0.080
0.051
0.028
0.010
0.098
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
(b)
Annual
Mileage
Accumulation
Rate
0
4,100
2,800
2,100
1,600
1,200
800
600
400
200
200
200
0
0
0
0
0
0
0
0
t(a)(b)/(SUM)]
Fraction of
MC Travel by
Model Year, m, .
6 , j , G
0.0
685.7
445.7
281.0
227.0
157.8
63.7
30.4
11.1
2.1
19.6
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
-• ' .I..-I- - - w -
0.000
0.356
0.232
0.146
0.118
0.082
0.033
0.016
0.001
0.010
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
SUM:
1,924.0
*Data derived from MOBILES.
L 2-43
-------
TABLE 2-19
RATES OF MISFUELING (r^
FOR DIFFERENT VEHICLE CLASSES*
I/M Non-I/M
Light-Duty Vehicles (i=l) 0.09 0.20
Light-Duty Trucks I (i=2) 0.20 0.46
Light-Duty Trucks II (i=3) 0.21 0.47
Heavy-Duty Gasoline Vehicles (i=4)** 0.19 0.40
Motorcycles (i=6) 0 0
*Values in this table are expressed as fractions of the total number
of vehicles in each class. Misfueling rates are determined for the
weighted average mileage accumulated for each vehicle class.
**Misfueling rates for Heavy-Duty Gasoline Vehicles pertain only to
heavy-duty gasoline vehicles 1 made after model year 1986.
SOURCES: The equations used to estimate misfueling as a function of
mileage for I/M and non-I/M areas are drawn from "Anti-
Tampering and Anti-Misfueling Programs to Reduce In-Use
Emissions from Motor Vehicles," EPA-AA-TSS-83-10, Office of
Mobile Sources, December 31, 1983.
Weighted average mileages by vehicle category are calculated
from data contained in MOBILE3.
L 2-44
-------
TABLE 2-19a
RATES OF MISFUELING (r ) FOR DIFFERENT VEHICLE AGES AND CLASSES*
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
LDV
Non-I/M
.-04
.07
.10
.13
.16
.18
.21
.23
.25
.27
.29
.31
.33
.34
.36
.37
.39
.40
.41
.42
I/M
.04
.05
.06
.07
.08
.09
.09
.10
.11
.11
.12
.12
.13
.13
.14
.14
.15
.15
.15
.16
LDTI
Non-I/M
.22
.27
.31
.35
.38
.42
.45
.47
.50
.52
.55
.57
.59
.60
.62
.64
.65
.66
.68
.69
I/M
.13
.14
.16
.17
.18
.19
.20
.21
.21
.22
.23
.24
.24
.25
.25
.26
.26
.26
.27
.27
LOT 1 1
Non-I/M
.23
.27
.32
.36
.39
.43
.46
.49
.51
.54
.56
.58
.60
.62
.63
.65
.66
.68
.69
.70
I/M
.13
.15
.16
.17
.18
.19
.20
.21
.22
.23
.23
.24
.25
.25
.26
.26
.26
.27
.27
.28
HDGV1
Non-I/M
.18
.23
.28
.32
.36
.39
.42
.45
.48
.50
.52
.54
.56
.57
.59
.60
.61
.62
.63
.64
I/M
.12
.13
.15
.16
.17
.18
.19
.20
.21
.22
.22
.23
.23
.24
.24
.25
.25
.25
.25
.26
*Values in this table are expressed as fractions of the total number of
vehicles in each class. Misfueling rates are determined for the
average mileage in each class. Misfueling rates are determined for
the average mileage accumulated by each vehicle class of each vehicle
age group.
**Misfueling rates for Heavy-Duty Gasoline Vehicles I (HDGV1) are
estimates for 1987 and later calendar years. Currently all HDGVls use
leaded fuel. (For example, for the year 1990, use the first three
values in either the non-I/M or I/M HDGV1 column. All HDGVls greater
than 3 years old in this case (i.e., pre-1987 vehicles) would have a
misfueling rate of zero since they do not require use of unleaded
fuel.
SOURCES: The equations used to estimate misfueling as a function of
mileage for I/M and non-I/M areas are drawn from "Anti-
Tampering and Anti-Misfueling Programs to Reduce In-Use
Emissions from Motor Vehicles," EPA-AA-TSS-83-10, Office of
Mobile Sources, December 31, 1983.
Weighted average mileages by vehicle category are calculated
from data contained in MOBILE3.
L 2-45
-------
TABLE 2-20
AVERAGE DATA ON PARTICLE SIZE DISTRIBUTION
Cumulative Fraction of Particulate
Mass Smaller Than Diameter
Leaded Fuel, M.^
Median Particle Fractions,
Ranges of M Values*
0.2 V
0.23
0.18-0.28
10 u
0.43 0.64
0.28-0.58 0.45-0.84
References: (author summary of) Ninotniya et al, 1970; Moran et al,
1971; Cental et al, 1973; Cantwell et al, 1972; Boyer and Laitiner,
1975; Habibi et al, 1970; Hirschler and Gilbert, 1964.
Cumulative Fraction of Particulate
Mass Smaller Than Diameter
Unleaded Fuel,
Ranges of M^ Valves**
Ranges of M^ Valves
0.2 u
0.87
0.86-0.88
0.42
0.29-0.55
2 y
0.89
0.84-0.94
0.66
0.52-0.80
10 y
0.97
0.84-1.00
0.90
0.63-1.00
References: (author summary of) Foster et al, 1976; Trayser et al,
1976; Foster et al, 1974; Melton et al, 1973; Habibi, 1973; Cental et
al, 1973.
*95 percent confidence intervals on mean of data.
**95 percent confidence intervals by "t" statistics,
2-46
-------
TABLE 2-20
AVERAGE DATA ON PARTICLE SIZE DISTRIBUTION (cont'd)
Cumulative Fraction of Particulate
Mass Smaller Than Diameter
Diesel Fuel, M^
«D
Ranges of M^
Values
0.2 y
0.73
0.69-0.75
1.0 y
0.86
0.76-0.93
2.0 y
0.90
0.86-0.95
2.5 y
0.92
0.88-0.95
10 y
1.00
0.97-1.
00
References: Breslin, et al, 1976; Hare, 1979, Bykowski, 1981; Bykowski,
1983; McCain and Faulkner, 1979; Vuk, et al, 1976; Begeman, 1979;
Carpenter and Johnson, 1979; Verrant and Kittelson, 1977.
Cumulative Fraction of Particulate
Mass Smaller Than Diameter
Brake Wear
Particulate, t'L n . _ . . . _ 7 ,n
__B 0.43 u 1.1 y 4.7 u 7 u 10 u
Median Particle+
Fractions, Kg"1"*" 0.09 0.16 0.82 0.90 0.98
Ranges of M^
Values Not available
Reference: Cha et al, 1983.
Intermediate speed, no load, prechamber engine, 2D fuel.
Samples for determining particle size distribution were collected by
running about 20 braking cycles weighted to be representative of urban
driving conditions.
L 2-47
-------
TABLE 2-21
LOW ALTITUDE HDDV CONVERSTION FACTORS*
Model Year
1951-1962
1963-1965
1966-1968
1969-1971
1972-1974
1975-1979
1980-1981
1982-1984
1985
1986
1987-1992
1993-1996
1997-2000
Conversion Factor (CF;)
2.7420
2.7307
2.8267
3.0080
3.1917
3.1420
2.7780
2.5580
2.4700
2.4260
2.3600
2.3175
2.3100
*These factors are used to convert emissions in g/Bhp-hr to g/mile.
They are consistent with those contained in M.C. Smith, "Heavy-Duty
Vehicle Emission Conversion Factors: 1962-1977," EPA-AA-SDSB-84-1,
Office of Mobile Sourcs, August 1984.
L 2-48
-------
TABLE 2-22
FRACTION OF LEAD BURNED THAT IS EMITTED, a.s
asl,j* as2,j**
All years .75 1975-1980 .40
1981+ .44
*asi j is used for all vehicles using unleaded gasoline and for
vehicles without catalysts using leaded gasoline.
**as2>j is used for catalyst equipped vehicles using leaded gasoline,
L 2-49
-------
TABLE 2-23
FRACTION OF CATALYST EQUIPPED VEHICLES WITH CATALYST REMOVED, P.*
and
I/M .017 .050
Non-I/M .045 .195
*Fractions obtained from "Anti-Tampering and Antl-Misfueling Programs to
Reduce In-Use Emissions From Motor Vehicles," U.S. EPA, December 1983.
L 2-50
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3. EXAMPLE CALCULATION OF AUTOMOBILE PARTICULATE
EMISSIONS LESS THAN 10 MICRONS
PROBLEM
For an area characterized by light-duty vehicles driving under cyclic
conditions with an average speed of 19,6 miles per hour, calculate the
particulate emission rate of particles less than 10 U in diameter for
the year 1985. Assume an inspection and maintenance program has been
implemented in this area. The simplified misfueling rates from Table
2-19 will be used.
SOLUTION
Use equations (2-1), (2-2), (2-3), (2-4), (2-5), (2-6), (2-7), (2-8),
(2-9), (2-10), (2-12), (2-14), and (2-15).
Particulate Matter Size Cutoff = 10 M
n=1985 i=l=LDV s=19.6 mph M^=0.98
r- (from Table 2-19) - 0.09
Base Equation (2-1); Total Particulate Emission Factors
Vehicle Exhaust Particulate 'Component and Airborne Brake
Wear Component and Airborne Tire Wear Component
EFPM10,1985,19.6 " <1-0> + (0.0128)(0.98) + (0.002)
-------
Total Vehicle Exhaust Particulate Emission Component (2-2)*;
,1985,19.6 ' .TT [ + EFl,j,k2,L + EF1,j,k3,L>
,l,j) Mi>:j,G * CEFljj>D)(FD>1>j) m1>j)
where Pb^igss = 1-1 (g/gal)
pbNL,1985 = °-014 (g/gal)
ML, 10 = 0.64
%L,C,10 = °-97
MNL,C,10 = °-90
MD = 1.00
as = from Table 2-22
Cs = 0.79
?l * 0.017
Using the following equations to plug into Equation (2-2) and sum over
the appropriate model years:
Lead Emission Factor Component (2-3a) ; Leaded Fuel
For j=1966-1970 k=l
EFl,j,klf1985,L = [(l.D(. 887X0.64) + (0.014) (0. 113) (0.90) J
(0.75)(1.557) = .925
X (Ecl>jX0.79) Ec>i>j
*The numbers in ( ) in equation titles refer to the equations presented
in Section 2.
L 3-2
-------
Lead Emission Factor Component (2-3b); Leaded Fuel
For j=1971-1974 k=l
EFi,jfklf1985,L = [(1.IX.916X0.64) + (0.014) (0.084) (0. 90)]
(0.75X1.557) .955
Lead Emission Factor Component (2-4); Leaded Fuel
For j=1975-1985 k-1
EFlfj,klf1985tL 3 [(1.1X0.724X0.64) + (0.014) (0.276) (0.90)j
(0.75)(1.557) .7586
CECfi,j)(0.79)
Lead Emission Factor Component (2-5); Unleaded Fuel
For j=1975-1985 k-1
NL ' [(0.014)(0.91)(0.97)(0.75)
* (1.1)(0.09)(0.64) (FI)J?NL)NOCAT * (0.17)
(Fi,j,HLfCAT)) (0-75)
* (1.1X0.09X0.64X.983XFifj>HIj|cAT> J
L Er.i;(0.79) J
Ec>1>j(0.79)
L 3-3
-------
1985 .0731
1984 .0731
1983 .0731
1982 .0731
1981 .0731
1980 .0682
1979 .0682
1978 .0682
1977 .0682
1976 .0694
1975 .0717
Organic Emission Factor Component (2-6); Leaded Fuel
For j-1966-1969 k=2
EFl,j,k2,L = CO.193)(0.64) - 0.124 (g/mile)
Organic Emission Factor Components (2-7); Leaded Fuel
For j=1970-1974 k=2
EFl,j,k2,L = (0.068)(0.64) = 0.044 (g/mile)
Organic Emission Factor Component (2-8): Leaded Fuel
For j=1975-1985 k=2
EFl,j,k2L = (0.030X0.64) - 0.019 (g/mile)
L 3-4
-------
Organic Emission Factor Component (2-9); Unleaded Fuel
For j=1975-1985 k=2
EFl,J,k2,NL - (0.91)(Fifj,cAT><0. 017X0. 97)
+ (0.09)(F1> j>CAT)(0.068)(0.64)
+ (FI,J,NL,NOCATXO. 030X0. 90)
= (0.019)(F1>j)CAT) + <0.027)(FitjfHL|HOCAT>
Sulfate Emission Factor Component (2-10); Leaded Fuel
For j=1966-1985 k»3
EFl,j,k3,L = (0.002X0.64) = 0.001 (g/mile)
Sulfate Emission Factor Component (2-12): Unleaded Fuel
For j=1975-1985 k=3
"l,j,k3,NL " (0.91) [(Fijj)CAT/NOAIRXO. 005X0. 97)
* (n,j,CAT/AIR)(0.016)(0.97)
* (F1, j,NL,NOCATX°-002X0.90) J + (0.09) (0.002) (0.64)
* )Fi, j,CATMiR>Co.oi6)
Diesel Particulate Emission Factor Component (2-14)
For j=1966-1980
EFl,j,D = (0.700)(1.00) = 0.700 (g/mile)
L 3-5
-------
Diesel Particulate Emission Factor Component (2-15)
For j=1981-1985
EFl,j,D • (0.300X1.00) = 0.300 (g/mile)
Table 3-1 presents the inputs and the sequence of calculations necessary
to derive the LDV exhaust particulate emission factor components (using
the above equations) and the total LDV exhaust particulate emission rate,
EF1 1985 19.6' This estimate is then combined with the airborne brake
wear and airborne tire wear particulate components to obtain the total
LDV particulate emission rate:
EFPM10,1985,19.6 = (1.0X0.0581) + 0.0125 + 0.002 =» 0.0726 (g/mile)
This example is an estimate of particulate emissions from light-duty
vehicles only. Therefore, the total emission rate from all vehicle
classes for an area in calendar year 1985 can be expected to be
considerably higher.
3-6
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REFERENCES
1. Carey, Penny M., Supplementary Guidelines for Lead Implementation
Plans — Updated Projections for Motor Vehicle Lead Emissions,
EPA-450/2-3-002, OAR, QMS, ECTD, TSS for OAQPS, March 1983.
2. Compilation of Air Pollutant Emission Factors: Highway Mobile
Sources, EPA 460/3-81-005, OAR, QMS, ECTD, TEB, March 1981.
3.- Anti-Tamper ing and Anti-Mis fueling Programs to Reduce In-Use
Emissions From Motor Vehicles, EPA/AA/TSS-83-10, December 193.
4. Diesel Particulate Study (Draft), U.S. EPA, OAR, QMS, ECTD, SDSB,
i October 1983.
5. Lorang, Philip A., White, John T., and Brzezinski, David J., In-Use
Emissions of 190 and 1981 Passenger Cars; Results of EPA Testing,
SAE Paper No. 820975, U.S. Environmental Protection Agency, presented
at West Coast International Meeting, San Francisco, CA, August 1982.
6. The Impact of Light-Duty Diesel Particulate Standards on the Level
of Diesel Penetration in the Light-Duty Vehicle^ and Light-Duty Truck
Markets, Jack Faucett Associates report for EPA, January 1983.
7. Assessment of Current and Projected Future Trends in Light-Duty
Vehicle Fuel-Switching, Energy and Environmental Analysis, Inc.,
report for EPA, June 1984.
8. Draft Study of Particulate Emissions from Motor Vehicles, by the
Environmental Sciences Research Laboratory (for Section 214 of the
Clean Air Act), U.S. EPA, Office of Research and Development, Mobile!
Source Emissions Research Branch, July 1983.
9. "Control of Air Pollution from New Motor Vehicles and New Motor
Vehicle Engines: Federal Certification Test Results for 1975 Model
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10. "Control of Air Pollution from New Motor Vehicles and New Motor
Vehicle Engines: Federal Certification Test Results for 1976 Model
Year," Federal Register, Vol. 41, No. 46, March 8, 1976.
11. "Control of Air Pollution from New Motor Vehicles and New Motor
Vehicle Engines: Federal Certification Test Results for 1977 Model
Year," Federal Register, Vol. 42, No. 110, June 8, 1977.
R-l
-------
12. "Control of Air Pollution from New Motor Vehicles and New Motor
Vehicle Engines: Federal Certification Test Results for 1978 Model
Year," Federal Register, Vol. 43, No. 181, September 18, 1978.
13. 1983 Motorcycle Statistical Annual, Motorcycle Industry Council,
Inc., Research and Statistics Department, Governmental Relations
Office, Arlington, VA, June 1983.
14. Hare, Charles T., Characterization of Gaseous and Particulate Emissions
from Light-Duty Diesels Operated on Various Fuels, EPA-460/3-79-008,
Southwest Research Institute, report prepared for Office of Mobile
Sources, June 1979.
15. Bykowski, Bruce B., Characterization of Diesel Emissions from Operation
of a Light-Duty Diesel Vehicle on Alternate Source Diesel Fuels.
EPA-460/3-82-002, Southwest Research Institute, report prepared for
Office of-Mobile Sources, November 1981.
16. Bykowski, Bruce B., Petroleum Versus Alternate-Source Fuel Effects
on Light-Duty Diesel Emissions, EPA 460/3-83-007, Southwest Research
Institute, report prepared for Office of Mobile Sources, August
1983.
17. Bykowski, Bruce B., Characterization of Diesel Emissions as a Function
of Fuel Variables, EPA-460/3-81-015, Southwest Research Institute,
report prepared for Office of Mobile Sources, April 1981.
18. McCain, Joseph D., and M. Gregory Faulkner, Assessment of Diesel
Particulate Control: Particle Size Measurements, EPA-600/7-79-232c,
Southern Research Institute, report prepared for Office of Research
and Development, December 1979.
19. Begeman, C.R., and P.J. Groblicki, Particle Size Variation in Diesel
Car Exhaust, SAE Paper No. 790421, presented in Detroit, MI, February
26-March 2, 1979.
20. Carpenter, Kenneth, and John H. Johnson, Analysis of the Physical
Characteristics of Diesel Particulate Matter Using Transmission
Electron Microscope Techniques, SAE Paper No. 790815, presented in
Milwaukee, WI, September 10-13, 1979.
21. Verrant, John A., and David A. Kittelson, Sampling and Physical
Characterization of Diesel Exhaust Aerosols, SAE Paper No. 770720,
presented in Detroit, MI, February 1977.
22. Ter Haar, G.L., D.L. Lanane, J.N. Hu, and M. Brandt, Composition,
Size, and Control of Automotive Exhaust Particulates, Ethyl Corpora-
tion, report presented at the 64th Annual APCA Meeting, Atlantic
City, NJ, June 27-July 1, 1971.
R-2
-------
23. Breselin, J.A., A.J. Strazisar, and R.L. Stein, Size Distribution
and Mass Output of Particulates From Diesel Engine Exhausts, report
prepared by Pittsburg Mining and Safety Research Center, Pittsburgh,
PA, U.S. Department of the Interior, Report of Investigation 8141.
24. Boyer, K.W., and H.A. Laitinen, "Automobile Exhaust Particulates,"
Environ. Sci. Technol., S>( 5) :457-469, 1975.
25. Cantwell, E.N., E.S. Jacobs, W.G. Kunz, Jr., V.E. Liberi, Control
of Particulate Lead Emissions from Automobiles, SAE Paper No. 720672,
Detroit, MI, May 1972.
26. Foster, J.F., D.A. Trayser, C.W. Melton, and R.I. Mitchell, Chemical
and Physical Characterization of Automotive Exhaust Particulate
Matter in the Atmosphere, Fourth Annual Summary Report, prepared by
Battelle Columbus Laboratories, Columbus, OH, to Coordinating Research
Council (CRC-APRAC Project No. CAPE-19-70) and U.S. Environmental
Protection Agency (Contract No. 68-01-0279), July 1974.
i
27. Foster, J.F., D.A. Trayser, E.R. Blosser, F.A. Creswick, and D.F.
Miller, Chemical and Physical Characterization of Automotive Exhaust
Particulate Matter in the Atmosphere, Fifth Annual Summary Reported
prepared by Battelle Columbus Laboratories, Columbus, OH, to
Coordinating Research Council (CRC-APRAC Project No. CAPE-19-80),
March 1974.
28. Gentel, J.E., O.J. Manary, and J.C. Valenta, Characterization of
Particulates and Other Non-regulated Emissions from Mobile Sources
and the Effects of Exhaust Emissions Control Devices on these
Emissions, report prepared by The Dow Chemical Company, Midland,
MI, under Contract No. EHA-70-101 to the U.S. Environmental
Protection Agency, Ann Arbor, MI, March 1973.
29. Habibi, K., "Characterization of Particulate Matter in Vehicle
Exhaust," Environ. Sci. Technolo., 7_(3) :223-234, 1973.
30. Habibi, K., E.S. Jacobs, W.G. Kunz, Jr., and D.L. Pastell,
Characterization and Control of Gaseous and Particulate Exhaust
Emission from Vehicles, paper presented to the Air Pollution
Control Assn., San Francisco, CA, October 1970.
31. Hirschler, D.A., and L.F. Gilbert, "Nature of Lead in Automobile
Exhaust Gas," Arch. Environ. Health, 9_:297-3l3, 1964.
32. Kittelson, D.B., D.F. Dolan, and J.A. Verrant, Investigation of a
Diesel Exhaust Aerosol, SAE Paper No. 780109, Detroit, MI, February
1978.
R-3
-------
33. Melton, C.W., R. Mitchell, D. Trayser, and J. Foster, Chemical and
Physical Characterization of Automotive Exhaust Particulate Matter
in the Atmosphere, Final Summary Report, prepared by Battelle Columbus
Lab, Columbus, OH, to CRC (CRC-APRAC Project No. CAPE-19-70) and
EPA (Contract No. 68-02-0205), June 1973.
34. Moran, J.B., 0. Manary, R. Fay, and M. Baldwin, Development of
Particulate Emission Control Techniques for Spark-Ignition Engines,
Final Report, prepared by Organic Chemicals Department, The Dow
Chemical Company, Midland, MI, under Contract EHS70-101, EPA, Ann
Arbor, MI, July 1971.
35. Ninomiya, J.S., W. Bergman, and B.H. Simpson, Automotive Particulate
Emissions, paper presented to the Second Int'1 Clean Air Congress
of the Int'l Union of Air Pollution Prevention Assn., Washington,
D.C., December 1970.
36. Trayser, D.A., F.A. Creswick, E.R. Blosser, and D.F. Miller, Chemical
and Physical Characterization of Automotive Exhaust Particulate
Matter in the Atmosphere, Sixth and Final Summary Report, prepared
by Battelle Columbus Laboratories, Cblumbus, OH, to Coordinating
Research Council (CAPE-19-70), September 1976.
37. Vuk, C.T., M.A. Jones, and J.H. Johnson, The Measurement and Analysis
of the Physical Character of Diesel Particulate Emissions, SAE Paper
No. 760131, Detroit, MI, February 1976.
38. Duleep, K.G., Forecasts of Emission Control Technology 1983-1990,
Task 5 of EPA Contract No. 68-01-6558 (Work Assignment No. 35), by
Energy and Environmental Analysis, Inc., November 28, 1983.
39. Schneider, Eric W., "Detection of Leaded-Gasoline Usage in Catalyst-
Equipped Vehicles: A Gamma-Ray Transmission Gauge for Measuring
Catalytic Converter Lead Contamination," APCA Journal, Vol. 32,
No. 5, May 1982.
40. Cha, Soyoung, Philip Carter, and Ronald L. Bradow, Simulation of
Automobile Brake Wear Dynamics and Estimate of Emissions, SAE Paper
No. 831036, Dearborn, MI, June 1983.
41. Cadle, S.H., and R.L. Williams, "Gas and Particle Emissions from
Automobile Tires in Laboratory and Field Studies," J. Air Poll.
Control Assoc. , 2_8( 5) :502-507, 1978.
42. Pierson, W.R., and W.W. Brachaczek, "Airborne Particulate Debris
from Rubber Tires," Rubber Chem. Technol., 47_( 5)-.1275-1229, 1974.
43. The Highway Fuel Consumption Model; Tenth Quarterly Report, prepared
for the U.S. Department of Energy, by Energy and Environmental Analysis,
Inc., Arlington, VA, November 1983.
R-4
-------
44. User's Guide to MOBILE3 (Mobile Source Emissions Model), EPA
46013-84-002, June 1984,
45. Energy and Environmental Analysis, Inc., "Supplementary Guidelines
for Lead Implementation Plans," prepared for the U.S. Environmental
Protection Agency, August 1985.
46. Size Specific Particulate Emission Factors for Industrial and Rural
Roads, draft report prepared for the Industrial Environmental
Research Laboratory, U.S. EPA, EPA Contract No. 68-02-3158, by
Midwest Research Institute, Kansas City, MO, June 7, 1984.
47. Paved Road Particulate Emissions — Source Category Report, draft
report prepared for the Industrial Environmental Research Laboratory,
U.S. EPA, EPA Contract No. 68-02-3158, by Midwest Research Institute,
Kansas City, MO, May 7, 1984.
R-5
-------
APPENDIX A
A-i
-------
TABLE A-l
AVERAGE ANNUAL MILEAGE BY VINTAGE FOR HEAVY-DUTY TRUCKS
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
Class
2-B
18,352
16,946
15,648
14,449
13,342
12,320
11,376
10,504
9,700
8,956
8,270
7,637
7,052
6,511
6,012
5,552
5,126
4,734
4,371
4,036
Light
HDDV
45,544
39,671
34,558
30,092
26,213
22,834
19,898
17,332
15,098
13,152
11,456
9,979
8,693
7,572
6,596
5,746
5,005
4,360
3,798
3,308
Medium
HDDV
53,370
46,901
41,190
36,206
31,812
27,948
24,556
21,575
18,956
16,655
14,632
12,856
11,296
9,925
8,719
7,661
6,728
5,913
5,196
4,565
Heavy
HDDV
82,288
74,984
68,328
62,263
56,737
51,700
47,111
42,930
39,119
35,647
32,483
29,599
26,972
24,578
22,396
20,408
18,597
16,946
15,442
14,071
Source: MOBILES.
A-l
-------
TABLE A-2
PROJECTIONS OF HEAVY-DUTY VEHICLES IN OPERATION
Year
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Class
2-B
0.000
0.000
0.049
0.014
0.185
0.274
0.370
0.475
0.588
0.707
0.831
0.960
1.092
1.225
1.354
1.480
1.600
1.712
1.816
1.912
1.999
Light
HDDV
0.006
0.006
0.009
0.013
0.022
0.037
0.053
0.071
0.089
0.106
0.122
0.137
0.151
0.165
0.178
0.190
0.202
0.212
0.222
0.230
0.238
Medium
HDDV
0.112
0.124
0.135
0.141
0.153
0.166
0.177
0.185
0.193
0.201
0.208
0.215
0.222
0.229
0.237
0.245
0.253
0.261
0.269
0.276
0.283
Heavy
HDDV
1.521
1.581
1.599
1.592
1.641
1.719
1.816
1.927
2.041
2.151
2.258
2.362
2.471
2.581
2.693
2.807
2.914
3.015
3.108
3.194
3.273
Source: MOBILE3.
A-2
-------
APPENDIX M
SUPPLEMENTARY GUIDELINES FOR
LEAD IMPLEMENTATION PLANS
Updated Projections for Motor Vehicle
Lead Emissions
Final Report
EPA Contract No. 68-03-1865
Work Assignment No. 1
DRAFT
Prepared for:
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Mobile Source Air Pollution Control
Ann Arbor, Michigan 48105
Prepared by:
ENERGY AND ENVIRONMENTAL ANALYSIS, INC.
1655 North Fort Myer Drive, Suite 600
Arlington, Virginia 22209
August 1985
-------
TABLE OF CONTENTS
Page
1. INTRODUCTION 1-1
2. PROJECTING MOTOR VEHICLE LEAD EMISSIONS 2-1
2.1 Overview of Lead Emission Calculations 2-1
2.2 Emission Factors for Light-Duty Vehicles and
Light-Duty Trucks I and II 2-3
2.3 Lead Emissions from Other
Gasoline-Powered Vehicles 2-10
3. EXAMPLE CALCULATION OF LIGHT-DUTY VEHICLE
LEAD EMISSIONS 3-1
M i
-------
LIST OF TABLES
Table
No. Page
2-1 Fuel Economy Correction Factors at
Various Speeds, Cs 2-12
2-2 Lead Content of Gasoline 2-13
2-3 Travel Weighting Factor Calculation
Light-Duty Vehicles 2-14
2-4 Fleet Sales fractions Light-Duty Vehicles • 2-15
2-5 Travel Weighting Factor Calculation
Light-Duty Gas Trucks I 2-16
2-6 Fleet Sales Fractions Light-Duty Trucks I 2-17
2-7 Travel Weighting Factor Calculation
Light-Duty Gas Trucks II 1-28
2-8 Fleet Sales Fractions Light-Duty Trucks II 2-19
2-9 City/Highway Combined On-Road Fuel Economy 2-20
2-10 Travel Weighting Factor Calculation 2-21
2-11 Fleet Sales Fractions
Heavy-Duty Gasoline Vehicles (HDGV) 2-22
2-12 Rates of Misfueling (r^) for Different
Vehicle Classes 2-23
2-13 Fraction of Lead Burned that is Exhausted, as 2-25
2-14 Fraction of Catalyst Equipped Vehicles with
Catalyst Removed, P^ 2-26
2-15 Fraction of Catalyst and Non-Catalyst Vehicles
Built to Use Unleaded Fuel 2-27
3-1 Example Calculations Light-Duty Vehicle
Particulate Emission Rate Less than 10 Microns
for the Year 1985 3-4
M ±±
-------
LIST OF FIGURES
Figure
No. Page
2-1 Fuel Economy at Various Speeds 2-46
M ill
-------
1. INTRODUCTION
The following material was developed to predict lead emission factors
for gasoline fueled on-road vehicles and trucks at various vehicle speeds.
User inputs to the equations to determine these emission factors include
area travel fractions by vehicle class, vehicle miles traveled and vehicle
speed. Fleet sales fractions and travel fractions by model year are
included for each vehicle class. The fractions within each vehicle class
that are equipped with catalysts also are provided. For the benefit of
the user, an example calculation of lead emissions from light-duty ve-
hicles is provided.
This document is an update to "Supplementary Guidelines for Lead Imple-
mentation Plans Updated Projections For Motor Vehicle Lead Emissions,"
U.S. EPA, EPA-450/2-83-002, Research Triangle Par'<, North Carolina,
March 1983. This document provides updated projections for automotive
lead emissions to be used by those agencies developing State Implementa-
tion Plans for lead. It has been revised to include estimates of travel
fractions and fleet characterizations from the June 1984 EPA report,
"User's Guide to MOBILES (Mobile Source Emissions Model)," EPA 460/3-84-
002. It also reflects the final rulemaking recently issued by EPA which
requires refiners to lower the lead content of leaded gasoline to 0.5
g/gallon on July 1, 1985 and 0.1 g/gallon by January 1, 1986 (Federal
Register. Vol. 50, No. 45, March 7, 1985).
M 1-1
-------
2. PROJECTING MOTOR VEHICLE LEAD EMISSIONS
Lead emissions from mobile sources are calculated based on the percent-
age of burned lead exhausted at different speeds, the lead content of
gasoline, vehicle fuel economy and the model year mix of vehicles on the
road. The lead content of gasoline and the model year vehicle mix are a
function of the calendar year of interest. Fuel economy is averaged for
all vehicles of the same model year in a given vehicle category.
2.1 OVERVIEW OF LEAD EMISSION CALCULATIONS
2.1.1 Individual Roadways or Areawide
For any given year subsequent to 1974, the total population of automo-
biles on the road consists of vehicles using either leaded or "non-
leaded" (i.e., required to contain less than 0.050 gram/gallon lead)
gasoline or diesel fuel. Diesel fuel is assumed to contain quantities
of lead that are insignificant compared to gasoline fuel; therefore,
only emissions from gasoline-powered vehicles are considered. The
emission rate from automotive sources from an individual roadway (line
source) is calculated by the following equation:
EF = I . T(EF. ) (2-1)
n,s rr i,n,s
where: EF = total lead emission factor for calendar year
' n and speed s (g/road mile-day)
EF. = lead emission factor for vehicle class i in
calendar year n and vehicle speed s (g/mi)
i,n,s
M 2-1
-------
i = vehicle class designator; 1 = light-duty
vehicles (LDV), 2 = light-duty trucks 1 (LDT1),
3 = light-duty trucks II (LDT2), and 4 = heavy-
duty gas vehicles (HDGV)
s = vehicle speed; avg. Federal Test Procedure (FTP)
= 19.6, avg. Sulfate Emissions Test (SET) = 34.8
(miles/hr); (Note: The FTP and SET are driving
cycles used for the determination of emission
factors.)
T = average daily traffic (vehicles/day)
To calculate the emission rate in units of grams/meter-second, EF can
8 ' n,s
be corrected by dividing by 1.39 x 10 .
Equation (2-1) can be modified to calculate light-duty vehicle emissions
as an area source rather than as specific line sources. The emission
rate from automotive sources from an area source is calculated by the
following equation:
EF =
n,s T^1. ' i,n,s
In equation (2-2), the term "T" was replaced by the term "V", the
vehicle miles traveled in the area on a daily, monthly, or greater time
basis. When VMT data are used, the emission rate, EF . will be ex-
n, s
pressed in grams per day, month, etc.
For both roadway and areawide emission calculations, the following
generalized equation is used to compute emission factors for individual
vehicle classes.
n
EF.
i,n,s
j=n-19
(EF. . T)(F. . .) (2-3)
. . .
L,L,J
(EFifj,n,NL)(Vi,J)
m.
M 2-2
-------
where: j " model year j - n-19, n-18,...,n-2, n-1, n
L « vehicles designed for use on leaded fuel
ML = vehicles designed for use on unleaded fuel
FT . . z fraction of the vehicle class i fleet designed
*lfJ for use on leaded gasoline in model year j
F . . = fraction of the vehicle class i fleet designed
' for use on unleaded gasoline in model year j
m. . " travel fraction for all gasoline vehicles in
class i in model year j
In the discussion which follows, specific emission component (EF. .
i, j,n,L
and EF. . ._ ) factor equations are presented for each vehicle cate-
i,j,n,NL
gory.
2.2 EMISSION FACTORS FOR LIGHT-DUTY VEHICLES AND LIGHT-DUTY
TRUCKS I AND II
equations (2-4), (2-5), and (2-6). For unleaded vehicles (EF. . )
i,j,n,NL
To compute emission factors for leaded vehicles (EF4 . n T) use
equations (2-4), (2-
use equation (2-7).
LDV (Pre MY 1971) and LOT (Pre MY 1971): Leaded Fuel
For i-1,2,3 j=n-19,...1970 C =from Table 2-1 a .=0.75
s si, j
EF. . - [Pb. (0.887) + PbMT (0.113)] ,, °'7x,r x (2-4)
i, j , n, L LL,n NL,n J(E ..;(C;
c,i,j s
where: a = fraction of lead burned that is exhausted:
s
- for all non-catalyst vehicles and for catalyst
vehicles using unleaded gasoline a = 0.75
s
- for catalyst vehicles using leaded gasoline in
1975-1980, ag2 . = .40
- for catalyst vehicles using leaded gasoline in 1981
and later, a . = .44
M2-3
-------
C = speed-dependent fuel economy correction factor
8 based on steady cruise or cyclic driving; avail-
able from Table 2-1 (nondiraensional)
Pb = lead content of unleaded gasoline in calendar
>n year n from Table 2-2 (g/gal)
PbT * average lead content of leaded gasoline in
'n calendar year n from Table 2-2 (g/gal)
E . . = city/highway combined on-road fuel economy for
' model year j and vehicle class i from Table 2-9
(miles/gallon)
LDV (MY 1971-1974) and LOT (MY 1971): Leaded Fuel
For i-1,2 j=1971,...,1974 C =from Table 2-1 a .=0.75
and For i=3 j-1971,...,1978 S 'J
EF T=OT (-916) + Pbm (0.084)] , °'7wr N (2-5)
i,j,n,L *- L,n NL,n J \& . .)\C )
c,i,j s
LDV (MY 1975+) and LOT (MY 1979+): Leaded Fuel
For i=l,2 j=1975,...,n C =from Table 2-1 a .=0.75
and For i=3 j- S S >J
EF. . T =[PbT (0.724) •*• Pb-_ (0.276)] 7- — °'7^^ . (2-6)
i,j,n,L L L,n NL,n J (E . .)(C )
c, i, j s
LDV (MY 1975+) and LOT (MY 1979+) : Unleaded Fuel
For i"l,2 j«1975,...,n C =from Table 2-1 a =from Table 2-13
and For i=3 j-1979,...,n S S
U-r.Ka J + Pb_ (r.) F. . MT „„._
.,, n x sl,j L,n i \ i,j,NL,NOCAT
(a , .)
l.J:
1
M 2-4
-------
where: r. = misfueling rate for vehicle class i from Table 2-12
P. = fraction of catalyst equipped vehicle in class i
1 with their catalysts removed, from Table 2-14
F. . = fraction of the unleaded vehicle class i fleet
'-^' equipped with a catalyst in model year j
F. . , ,.«^.m = fraction of the unleaded vehicle class i fleet
i,j,NL,NOCAT ...... _ i .. • j ,
' •" without a catalyst in model year j
Equations (2-4), (2-5), and (2-6) collectively give the g lead/vehicle-
road mile emitted by light-duty non-catalyst-equipped vehicles whereas
equation (2-7) gives the g lead/vehicle-road mile emitted by catalyst-
equipped vehicles. It should be noted that since 1975 a small number of
non-catalyst-equipped vehicles (F. . Mr>rAT from Table 2-15) have been
1, j J j NL* j NUC/Ax
certified for use on unleaded gasoline. Since these vehicles constitute
such a small percentage of the total non-catalyst fleet, it will be
assumed that the misfueling rate for these vehicles will be the same as
that for catalyst equipped vehicles. Further discussion of selected
variables used in the equations follows.
2.2.1 Speed Correction Factor
Figure 2-1 compares steady cruise fuel economy and generalized cyclic
driving fuel economy to vehicle speed. Figure 2-1 was generated using
data from 1973, 1974, and 1975 model year vehicles. Using the cyclic
driving fuel economy at 32.7 miles per hour as the basis for comparison
(since this speed is the average speed for the EPA combined city/highway
fuel economy), fuel economy correction factors (C ) for both steady
cruise and cyclic driving can be calculated at various speeds. These
calculations have been made and are presented in Table 2-1. Table 2-1
should be used to interpolate C for those speeds not listed in
Table 2-1. The fuel economy correction factor for cyclic driving should
be used for roadways that do not have steady speed. (The determination
of how much variation in speed constitutes cyclic driving is judgmental.
Questionable cases should be analyzed both ways.) Likewise, the fuel
economy correction factor for steady cruise driving should be used if
M 2-5
-------
Figure -2-1
FUEL ECONOMY AT VARIOUS SPEEDS*
SPEED/ MPH
" Passenger Car Fuel Economy: EPA and Road, September 1980
:S?A-460/3-80-010].
M2-6
-------
free-flow, steady speed driving is indicated (e.g., along a highway at a
relatively constant speed). The correction factors for cyclic and
steady cruise driving become similar at high speeds as the number of
stops, accelerations, and decelerations during cyclic driving decrease.
2.2.2 Fleet Travel and Fleet Sales Fractions
The fraction of annual travel by model year j (m. .) can be found in the
1f J
last column of Tables 2-3, 2-5, and 2-7 for light-duty vehicles, light-
duty trucks I, and light-duty trucks II. These values for (m. .) are
L> J
EPA's estimates of the national values. Local values should be used
where available. The term, "m. ." accounts for all light-duty vehicles
1> J
in a given model year. The travel weighting fractions were taken from
EPA's Mobile Sources Inventory Model, MOBILES. (It should be noted that
the travel weighting fractions reflect a January 1 evaluation date.)
The fractions of the model year j fleet using unleaded and leaded
gasoline, F . . and F . ., respectively, are given in Table 2-4.
ML,1,J L,1,J
Values for F.TT . . and FT . . account for the increasing dieselization
NL,i,j L,i,j 5
of the light-duty vehicle fleet. Diesel-powered vehicles are assumed to
emit quantities of lead that are insignificant compared Co gasoline-
powered vehicles; therefore, sales fractions for diesel-powered vehicles
are not included. Latest sales projections for diesel-powered vehicles
were derived from MOBILE3 data. Estimates of the percentages of gaso-
line vehicles requiring leaded and unleaded fuel were obtained from
Energy and Environmental Analysis, Inc., "The Highway Fuel Consumption
Model: Tenth Quarterly Report," November 1983.
2.2.3 Misfueling and Fuel Switching
EPA has observed that misfueling rates (i.e., percentage of vehicles
designed for use on unleaded gasoline that use leaded gasoline) are
dependent on vehicle mileage and increase with vehicle mileage accumu-
lation. Strictly speaking, this dependence on mileage should be
M 2_7
-------
reflected in the calculation of lead emissions, with each model year
receiving its own misfueling rate. However, this further complicates an
already complex calculation. To give the user a choice, this report
offers both the option of using a single average misfueling rate for all
model years of a given vehicle class and exact misfueling rates for each
vehicle class by vehicle age. The single average rates are determined
for the weighted average mileage accumulated for each vehicle class and
are listed in Table 2-12 for inspection and maintenance (I/M) and non-
I/M areas. In other words, in the calculation of emission factors from
1975 on, the misfueling rate (r.) depends only on which vehicle class
(i) is being considered and whether the area of interest has an I/M
program. As a result, misfueling rates and lead emissions will be
slightly overestimated, with the degree of overestimation declining with
later evaluation years and essentially disappearing in 1995. For users
who desire more accuracy, Table 2-12a gives exact misfueling rates for
different vehicle ages and classes affected by misfueling. For mis-
fueled vehicles with their catalysts removed, the fraction (P.) in Table
2-14 is applied to the fraction of vehicles with catalysts (F. . -,.„) in
l,j,LAT
Table 2-15. These misfueling rates have been derived from the December
1983 EPA Report, Anti-Tampering and Anti-Misfueling Programs to Reduce
In-Use Emissions From Motor-Vehicles, EPA-AA-TSS-83-10.
Discretionary fuel switching (i.e., percentage of vehicles designed for
use on leaded gasoline that use unleaded gasoline) is assumed to equal
11.3 percent of the leaded fleet prior to 1971, and 3.4 percent from
1971 to 1974 for the LDV and LOT I categories. The discretionary rate
for the LOT II class is 3.4 percent from 1971 to 1978, and 27.6 percent
thereafter. For the LDV and LDT1 classes, discretionary switching is
assumed to be 27.6 percent after 1974. The discretionary fuel switching
rates were obtained from Energy and Environmental Analysis, Inc.,
Assessment of Current and Projected Trends in Light-Duty Vehicle Fuel
Switching, June 1984.
M 2-8
-------
The effect of discretionary fuel switching for vehicles designed for use
on leaded fuel has been incorporated into equations (2-4), (2-5), and
(2-6).
2.2.4 Fuel Economy and Fuel Lead Content
Fuel economy is yet another factor affecting lead emission levels. The
city/highway combined on-road fuel economies, E . . for model years
c> L» J
1970 to 1988 are given in Table 2-9. LDV fuel economy estimates were
taken from an internal EPA. memorandum by Karl Hellman to Ralph Stahman
dated June 5, 1984. LDT fuel economies were obtained from Energy and
Environmental Analysis, (EEA) Inc., "The Highway Fuel Consumption Model
- Tenth Quarterly Report," November 1983. HDGV mpg estimates were drawn
from an EPA memo to Mark Wolcott from Cooper Smith dated July 2, 1984.
Area lead particulate emissions also are dependent upon the lead content
of gasoline in a given calendar year. Values for the lead content of
leaded (Pb. ) and unleaded gasoline (Pb._ ) are contained in Table
L,n NL,n
2-2. Values for future years will be updated as new information becomes
available.
2.2.5 Percent of Fuel Burned That is Exhausted (a )_
A value for a of 0.75 (i.e., 75 percent of the lead burned is ex-
s
hausted) should be used for non-catalyst-equipped, gasoline-powered
vehicles operating on leaded fuel, and for all vehicles using unleaded
fuel. For gasoline powered vehicles equipped with catalysts, a value of
a - 0.40 for 1975 to 1980 and a == 0.44 for 1981 and later model year
s s
vehicles that have been misfueled, should be used. The value of a was
computed from lead retention of monolithic and pelleted catalysts,
respectively, and weighted for the sales mix of these catalysts in each
M 2-9
-------
time frame. These values of a do not vary with speed, since a is more
3 S
correlated with driving mode, e.g., acceleration, cruise or decelera-
tion, rather than speed alone.
2.3 LEAD EMISSIONS FROM OTHER GASOLINE-POWERED VEHICLES
In addition to light-duty gasoline-powered vehicles, other vehicles to
consider include heavy-duty gasoline-powered trucks. (Motorcycles are
assumed to emit quantities of lead that are insignificant compared to
other gasoline-powered vehicles.)
Heavy-duty gasoline-powered trucks are assumed to burn leaded gasoline
until 1987. It is assumed that emission standards effective in 1987
will require all new heavy-duty gasoline-powered trucks under 14,001
Ibs GVW to use catalytic converters and thereby burn unleaded fuel. The
emission rate for heavy-duty gasoline powered trucks prior to 1987 is
calculated by using the following modification of equation (2-4):
HDGV (Pre MY 1987): Leaded Fuel
For i=4 j=n-19,...,1986 C =from Table 2-1 a .=0.75
s si, j
a . . Pb.
EF. - -fliJ ±± (2-8)
l'n'8 E °
HDGV (Post MY 1986): Leaded Fuel
For i=4 j=1987,...,n C =frora Table 2-1 a =from Table 2-13
s s
Pb._ m. .(l-r.)(a .) PbT m. .(r.)(a , .
? - NL,n i,j i sl,j L,n i, j i s2, j
i,n,s " E , .* (C ) E .. .** (C )
' ' c,4a,i s c,4b,i s
*4a represents the fuel economy for HDGV1 after 1986.
**4b represents the fuel economy for HDGV2 after 1986.
M 2-10
-------
Values for the variables used in equations (2-8) and (2-9) are given in
the following tables/figures:
Variable HDGV
a Table 2-13
s
C Table 2-1
s
Pb._ ; PbT Table 2-2
NL,n L,n
m. . Table 2-10
if J
E . . Table 2-9
c,t,J
R. Table 2-12
Fleet sales fractions for heavy-duty gasoline vehicles projected to
1995, are given in Table 2-11. Heavy-duty gasoline vehicles have a
gross vehicle weight (GVW) rating of greater than 8,500 Ibs GVW. The
fleet sales fractions are decreasing with model year, reflecting the
increasing dieselization of the heavy-duty fleet. These estimated fleet
sales fractions can be used when projecting T, the average daily traffic
(heavy-duty gasoline trucks/day), for future years.
M2-11
-------
TABLE 2-1
FUEL ECONOMY CORRECTION FACTORS AT VARIOUS SPEEDS, C(
(Normalized to 32.7 miles/hour-cyclic driving)
Speed (tnph)
5
10
15
25
30
32.7
oc _
J J— — — — — —
40
45
50
55
60
C
Cyclic Driving
0.323
0.553
0.692
0.885
0.963
1.000
1 09?
1.053
1.073
1.078
1.063
1.023
C
s
Steady Cruise
0.467
0.709
0.997
i i si
1.248
1.294
1.303
_ i -irn
1.288
1.256
1.210
1.159
1.104
M 2-12
-------
TABLE 2-2
LEAD CONTENT OF GASOLINE
Leaded Gasoline* Unleaded Gasoline
Year (g/gal) PbL (g/gal) Pb^
1974 1.79 0.014
1975 1.82 0.014
1976 2.02 0.014
1977 2.03 0.014
1978 1.94 0.014
1979 1.85 0.014
1980 1.38 0.014
1981 1.15 0.014
1982 1.24 0.014
1983 1.14 0.014
1984 1.10 0.014
1985 0.50 0.014
1986 0.10 0.014
1987 0.10 0.014
1988 0.10 0.014
1989 0.10 0.014
1990 0.10 0.014
*1974-1982: Lead content based upon data submitted to EPA on historical
sales data for leaded gasoline and data indicating the actual pooled
average lead content. The value for unleaded gasoline is based on
recent MVMA fuel surveys.
1983-1990: Lead content based upon requirements for average lead
content of leaded gasoline which were recently revised by EPA for 1985
and beyond and published in the Federal Register (Federal Register,
Vol. 50, No. 45, March 7, 1985).
M2-13
-------
TABLE 2-3
TRAVEL WEIGHTING FACTOR CALCULATION*
Light-Duty Vehicles
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
(a)
January 1
Fraction
Total
Registration
0.028
0.107
0.100
0.094
0.088
0.080
0.075
0.069
0.062
0.056
0.050
0.043
0.037
0.031
0.024
0.018
0.012
0.008
0.006
0.008
(b)
Annual
Mileage
Accumulation
Rate
[(a)(b)/(SUM)]
Fraction of
LDV Travel by
Model Year, m
ill
12,818
12,639
11,933
11,268
10,639
10,045
9,485
8,955
8,455
7,983
7,538
7,117
6,720
6,345
5,991
5,657
5,341
4,043
4,762
4,496
358.9
1,352.4
1,193.3
1,059.2
936.2
803.6
711.4
617.9
524.2
447.0
376.9
306.0
248.6
196.7
143.8
101.8
64.1
32.3
28.6
36.0
0.038
0.142
0.125
0.111
0.098
0.084
0.075
0.065
0.055
0.047
0.040
0.032
0.026
0.021
0.015
0.011
0.007
0.003
0.003
0.004
SUM: 9,538.9
*Data derived from MOBILE3.
M2-14
-------
TABLE 2-4
FLEET SALES FRACTIONS
Light-Duty Vehicles*
Model
Years
Pre-1975
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995 +
Nonleaded Gasoline
Fraction of LDV
FNL.l.j**
0.000
0.869
0.863
0.838
0.865
0.875
0.966
0.939
0.954
0.947
0.940
0.934
0.927
0.920
0.910
0.900
0.887
0.887
0.886
0.886
0.885
0.885
Leaded Gasoline
Fraction of LDV
1.000
0.128
0.134
0.158
0.126
0.097
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Where F.
NL.l
FL,1
Estimated fraction of the LDV model year fleet which use
nonleaded gasoline
Estimated fraction of the LDV model year fleet which use
leaded gasoline
*Percentages of gasoline vehicles requiring leaded and nonleaded fuel
obtained from EPA Certification Data Base.
**Diesel and gasoline sales projections were derived from MOBILE3.
M 2-15
-------
TABLE 2-5
TRAVEL WEIGHTING FACTOR CALCULATION*
Light-Duty Gas Trucks I**
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
(a)
January 1
Fraction
Total
Registration
0.023
0.089
0.085
0.081
0.076
0.072
0.068
0.064
0.060
0.055
0.050
0.046
0.042
0.038
0.034
0.029
0.025
0.021
0.017
0.025
(b)
Annual
Mileage
Accumulation
Rate
[(a)(b)/(SUM)]
Fraction of
LDV Travel by
Model Year, m
2.J
17,394
17,079
15,839
14,690
13,624
12,636
11,719
10,868
10,080
9,348
8,670
8,041
7,457
6,916
6,415
5,949
5,517
5,117
4,746
4,402
400.1
1,520.0
1,346.3
1,189.9
1,035.4
909.8
796.9
695.6
604.8
514.1
433.5
369.9
313.2
262. 6
218.1
172.5
137.9
107.5
80.7
110.1
0.036
0.135
0.120
0.106
0.092
0.081
0.071
0.062
0.054
0.046
0.039
0.033
0.028
0.023
0.019
0.015
0.012
0.009
0.007
0.010
SUM:
11,219.1
*Data derived from MOBILE3.
**Light-duty trucks I have a gross vehicle weight (GW) rating of 6,000
pounds or less.
M2-16
-------
TABLE 2-6
FLEET SALES FRACTIONS
Light-Duty Trucks I*
Model
Years
Pre-1975
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995 +
Unleaded Gasoline
Fraction of LDT1
0.000
0.810
0.909
0.957
0.964
0.942
0.945
0.914
0.899
0.878
0.870
0.840
0.820
0.790
0.760
0.730
0.706
0.697
0.688
0.679
0.670
0.661
Leaded Gasoline
Fraction of LDT1
FL,2
1.000
0.188
0.088
0.038
0.027
0.030
0.021
0.026
0.021
0.022
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Where F
ML, 2
Estimated fraction of the LDT1 model year fleet which use
nonleaded gasoline.
Estimated fraction of the LDTl model year fleet which use
leaded gasoline.
*Percentages of gasoline vehicles requiring leaded and unleaded fuel
obtained from Energy and Environmental Analysis, Inc., "The Highway
Fuel Consumption Model: Tenth Quarterly Report," November 1983.
**Diesel and gasoline sales projections were derived from MOBILE3.
M 2-17
-------
TABLE 2-7
TRAVEL WEIGHTING FACTOR CALCULATION*
Light-Duty Gas Trucks II**
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
(a)
January 1
Fraction
Total
Registration
0.023
0.089
0.085
0.081
0.076
0.072
0.068
0.064
0.060
0.055
0.050
0.046
0.042
0.038
0.034
0.029
0.025
0.021
0.017
0.025
(b)
Annual
Mileage
Accumulation
Rate
18,352
18,001
16,622
15,348
14,172
13,087
12,084
11,158
10,303
9,514
8,785
8,112
7,491
6,917
6,386
5,897
5,446
5,028
4,643
4,287
(a)(b)
422.1
1,602.1
1,412.9
1,243.2
1,077.1
942.3
821.7
714.1
618.2
523.3
439.3
373.2
314. e
262. S
217.1
171.0
136.2
105.6
78.9
107.2
[(a)(b)/(SUM)]
Fraction of
LDT2 Travel by
Model Year, m
'3.1
0.036
0.138
0.122
0.107
0.093
0.081
0.071
0.062
0.053
0.045
0.038
0.032
0.027
0.023
0.019
0.015
0.012
0.009
0.007
0.009
SUM:
11,582.9
*Data derived from MOBILE3.
**Light-duty trucks II have a gross vehicle weight (GVW) rating of 6,001
to 8,500 pounds.
M 2-18
-------
TABLE 2-8
FLEET SALES FRACTIONS
Light-Duty Trucks II*
Unleaded Gasoline Leaded Gasoline
* , Fraction of LDT2 Fraction of LDT2
Year's Fleet' FNL,3** Fleet' FL.3
Pre-1975 0.000 1.000
1975 0.000 0.998
1976 0.000 0.997
1977 0.000 0.995
1978 0.000 0.991
1979 0.972 0.000
1980 0.966 0.000
1981 0.940 0.000
1982 0.920 0.000
1983 0.900 0.000
1984 0.870 0.000
1985 0.840 0.000
1986 0.820 0.000
1987 0.790 0.000
1988 0.760 0.000
1989 0.730 0.000
1990 0.706 0.000
1991 0.697 0.000
1992 0.688 0.000
1993 0.679 0.000
1994 0.670 0.000
1995+ 0.661 0.000
WHERE F _ = Estimated fraction of the LDT2 model year fleet which use
' nonleaded gasoline.
F _ = Estimated fraction of the LDT2 model year fleet which use
' leaded gasoline.
*Percentages of gasoline vehicles requiring leaded and nonleaded fuel
obtained from Energy and Environmental Analysis, Inc., "The Highway
Fuel Consumption Model: Tenth Quarterly Report," November 1983.
**Diesel and gasoline sales projections were derived from MOBILES.
M2-19
-------
TABLE 2-9
CITY/HIGHWAY COMBINED ON-ROAD FUEL ECONOMY
(miles/gallon)
Fuel Economy, E
c>
LDV*
LDT1** LDT2
HDGV1+
HDGV2
HDGV++
Pre-1970
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
and later
13.9
13.9
13.2
13.1
12.9
12.6
13.5
14.8
15.5
16.8
17.2
20.0
21.4
22.2
22.2
22.8
23.2
23.8
24.3
24.8
25.2
25.7
26.2
26.6
27.2
27.6
29.0
10.6
10.6
10.4
10.2
9.9
9.6
11.6
12.3
13.0
13.4
14.2
16.1
17.7
18.6
19.2
19.9
20.7
21.4
23.0
23.3
23.1
24.0
24.5
24.4
25.3
25.8
26.2
7.9
7.9
7.7
7.4
7.0
6.9
8.8
9.7
9.4
9.6
9.8
11.5
13.3
13.6
13.7
13.9
14.0
14.3
14.5
14.7
14.9
15.2
15.4
15.7
15.9
16.2
16.4
9.5
9.5
9.6
9.7
9.7
9.8
9.8
9.9
10.1
5.6
5.6
5.6
5.6
5.7
5.7
5.7
5.7
5.8
6.5
6.4
6.4
6.4
6.5
6.7
6.8
7.3
7.7
8.0
8.2
8.4
8.6
8.8
8.9
3.9
9.0
9.0
9.0
9.1
9.2
9.2
9.3
9.4
9.4
9.5
9.6
*Fuel economies for LDV's from MOBILE3 data based on EPA memo from
Karl H. Hellman to Ralph C. Stahman regarding Light-Duty MPG, June 15,
1984.
**Fuel economies for LDT's drawn from the input data used to generate
"The Highway Fuel Consumption Model: Tenth Quarterly Report,"
prepared by Energy and Environmental Analysis, Inc.
+Fuel economies for Heavy-duty gasoline vehicles (HDGV) were derived
from figure presented in an EPA memo to Mark Wolcott from Cooper
Smith, dated July 2, 1984.
•n-Pre-1986 fuel economies are composites of HDGV1 and HDGV2.
M2-20
-------
TABLE 2-10
TRAVEL WEIGHTING FACTOR CALCULATION*
Heavy-Duty Gasoline Vehicle (HDGV)**
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
(a)
January 1
Fraction
Total
Registration
0.000
0.148
0.126
0.107
0.092
0.078
0.067
0.058
0.049
0.041
0.036
0.030
0.026
0.022
0.020
0.016
0.014
0.012
0.010
0.049
(b)
Annual
Mileage
Accumulation
Rate
I(a)(b)/(SUM)]
Fraction of
HDGT Travel by
Model Year, m. ,
0
19,967
18,077
16,365
14,815
13,413
12,143
10,993
9,952
9,010
8,156
7,384
6,685
6,052
5,479
4,960
4,490
4,065
3,680
3,332
0.0
2,955.1
2,277.7
1,751.1
1,363.0
1,046.2
813.6
637.6
487.6
369.4
293.6
221.5
173.8
133.1
121.0
79.4
62.9
48.8
36.8
163.3
---,_ f.Trf_
0.000
0.227
0.175
0.134
0.105
0.080
0.062
0.049
0.037
0.028
0.023
0.017
0.013
0.010
0.009
0.006
0.005
0.004
0.003
0.013
SUM:
13,035.5
*Data derived from MOBILE3.
**Heavy-duty gasoline vehicles have a gross vehicle weight (GVW) rating
greater than 8,500 pounds.
M 2-21
-------
TABLE 2-11
FLEET SALES FRACTIONS
Heavy-Duty Gasoline Vehicles (HDGV)*
Model Unleaded Fraction of Leaded Fraction of
Years HDGV Fleet F. , .** HDGV Fleet F. . .**
L,4,j L,4, j
Pre-1977 0.000 1.000
1977 0.000 1.000
1978 0.000 1.000
1979 0.000 1.000
1980 0.000 1.000
1981 0.000 1.000
1982 0.000 1.000
1983 0.000 1.000
1984 0.000 1.000
1985 0.000 1.000
1986 0.000 1.000
1987 0.823 0.177
1988 0.824 0.176
1989 0.825 0.175
1990 0.826 0.174
1991 0.828 0.172
1992 0.829 0.171
1993 0.833 0.167
1994 0.837 0.163
1995 0.840 0.159
*Heavy-duty gasoline vehicles have a gross vehicle weight (GVW) rating
greater than 8,500 pounds.
**The estimated fractions of the HDGV model year fleets which are
unleaded are based on figures from "Historical and Projected
Emissions Conversion Factor and Fuel Economy for Heavy-Duty Trucks
1962-2002," prepared for MVMA by Energy and Environmental Analysis,
Inc., December 1983. These estimates are consistent with the data
presented in "Heavy-Duty Vehicle Emission Conversion Factors:
1962-1997 prepared by M.C. Smith IV, U.S. Environmental Protection
Agency, August, 1984.
M 2-22
-------
TABLE 2-12
3F MISFUELIb
FOR DIFFERENT VEHICLE CLASSES*
RATES OF MISFUELING (r )
I/M Non-I/M
Light-Duty Vehicles (i=l) 0.09 0.20
Light-Duty Trucks I (i=2) 0.20 0.46
Light-Duty Trucks II (i=3) 0.21 0.47
Heavy-Duty Gasoline Vehicles I (i=4)** 0.19 0.40
*Values in this table are expressed as fractions of the total number
of vehicles in each class. Misfueling rates are determined for the
weighted average mileage accumulated for each vehicle class.
**Misfueling rates for Heavy-Duty Gasoline Vehicles pertain only to
those trucks made after model year 1986.
SOURCES: The equations used to estimate misfueling as a function of
mileage for I/M and non-I/M areas are drawn from "Anti-
Tampering and Anti-Misfueling Programs to Reduce In-Use
Emissions from Motor Vehicles," EPA-AA-TSS-83-10, Office of
Mobile Sources, December 31, 1983.
Weighted average mileages by vehicle category are calculated
from data contained in MOBILE3.
M 2-23
-------
TABLE 2-12a
RATES OF MISFUELING (r.) FOR DIFFERENT VEHICLE AGES AND CLASSES*
HDGV1 **
TT — U i «-* 1 a
VG ulC LG
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
LDV
NO--I/M
.04
.07
.10
.13
.16
.18
.21
.23
.25
.27
.29
.31
.33
.34
.36
.37
.39
.40
.41
.42
I/M
.04
.05
.06
.07
.08
.09
.09
.10
.11
.11
.12
.12
.13
.13
.14
.14
.15
.15
.15
.16
LOT I
Non-I/M
.22
.27
.31
.35
.38
.42
.45
.47
.50
.52
.55
.57
.59
.60
.62
.64
.65
.66
.68
.69
I/M
.13
.14
.16
.17
.18
.19
.20
.21
.21
.22
.23
.24
.24
,25
.25
.26
.26
.26
.27
.27
LDTII
Non-I/M
.23
.27
.32
.36
.39
.43
.46
.49
.51
.54
.56
.58
.60
.62
.63
.65
.66
.68
.69
.70
I/M
.13
.15
.16
.17
.18
.19
.20
.21
.22
.23
.23
.24
.25
.25
.26
.26
.26
.27
.27
.28
Non-I/M I/M
.18
.23
.28
.32
.36
.39
.42
.45
.48
.50
.52
.54
.56
.57
.59
.60
.61
.62
.63
.64
.12
.13
.15
.16
.17
.18
.19
.20
.21
.22
.22
.23
.23
.24
.24
.25
.25
.25
.25
.26
*Values in this table are expressed as fractions of the total number of
vehicles in each class. Misfueling rates are determined for the
average mileage in each class. Misfueling rates are determined for
the average mileage accumulated by each vehicle class of each vehicle
age group.
**Misfueling rates for Heavy-Duty Gasoline Vehicles 1 (HDGV1) are
estimates for 1987 and later calendar years. Currently all HDGVls use
leaded fuel. (For example, for the year 1990, use the first three
values in either the non-I/M or I/M HDGV1 column. All HDGVls greater
than 3 years old in this case (i.e., pre-1987 vehicles) would have a
misfueli \g rate of zero since they do not require use of unleaded
fuel.
SOURCES: The equations used to estimate misfueling as a function of
mileage for I/M and non-I/M areas are drawn from "Anti-
Tampering and Anti-Mis fueling Programs to Reduce In-Use
Emissions from Motor Vehicles," EPA-AA-TSS-83-10, Office of
Mobile Sources, December 31, 1983.
Weighted average mileages by vehicle category are calculated
from data contained in MOBILE3.
M 2-24
-------
TABLE 2-13
FRACTION OF LEAD BURNED THAT IS EXHAUSTED,
3sl.j*
All years .75 1975-1980 .40
1981+ .44
*a . is used for all vehicles using unleaded gasoline and for
'^ vehicles without catalysts using leaded gasoline.
**a ? . is used for catalyst equipped vehicles using leaded gasoline,
s^> J
M 2-25
-------
TABLE 2-14
FRACTION OF CATALYST EQUIPPED VEHICLES WITH CATALYST REMOVED, P *
and
I/M .017 .050
Non-I/M .045 .195
*Fractions obtained from "Anti-Tampering and Anti-Misfueling Programs to
Reduce In-Use Emissions From Motor Vehicles," U.S. EPA, December 1983.
M2-26
-------
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M2-27
-------
3. EXAMPLE CALCULATION OF LIGHT-DUTY VEHICLE LEAD EMISSIONS
PROBLEM
For an area characterized by light-duty vehicles driving under cyclic
conditions with an average speed of 19.6 miles per hour, calculate the
areawide lead emission rate for the year 1985. Assume an inspection and
maintenance program has been implemented in this area. The simplified
misfueling rates from Table 2-12 will be used.
SOLUTION
Use equations (2-4), (2-5), (2-6), and (2-7) to plug into equation (2-3)
to get emission factors by vehicle class. Use individual class factors
to plug into equation (2-2) for total areawide lead emissions in 1985.
Tl,1985 - 1.0
n = 1985
i = 1 = LDV
s = 19.6 mph
PbL 1985 * l>l g/gal (Table 2-2)
PbNL,1985 = 0>°14 g/gal (Table 2-2)
Si, 1966-1985 = °-75 (Table 2-13)
as2,1975-1980 =°-4° (Table 2-13)
3s2,1981-1985 ' °'44 CTable 2'13)
C - 0.79 (Table 2-1)
?l - 0.017 (Table 2-14)
t = 0.09 (Table 2-12)
M3-1
-------
EF = > T (EF. )
n, s / ^ i»n,s
(3-1)
1985
EF
"
1,1985,19.6
j=1966
(EF, .
^^1 ; i Q«S T ^ x ^T i ;)
i,j,iyoj,L L,i,j
(F.
x m, .
(3-2)
Use the following equations to plug into equation (3-2) and sum over the
appropriate model years.
For j=1966-1970
EF
l,j,1985,L
1.1(0.887) -i- 0.014(0.113)
V /
.75 - .928
EC 1 ;(0'79) Ec , :
c» *• t J c, i, j
(3-3)
EF
l,j,1985,L
For j-1971-1974
'l.1(0.916) + 0.014(0.084)\
.75 = .958
r .(0.79)
c, i
-c, i
(3-4)
EFl,j,1985,L
For j=1975-1985
N .75 - .776
;
J
c i ;
c > 1 ? J
(3-5)
M3-2
-------
For j=1975-1985
EFi • IQOC MT "0.014(0.91X0.75) + 1.1(0.09) (3-6)
1 > J»19oj 9 NL I
<*i • MT MOPAT + (0.017XF. • r._)(0.75)
1,j,NL,NOCAT 1,J,CAT
+ 1.1(0.09X0.983XF . r,T)U . .)
i, J,LAI S j1j J 1
1 = xl
EC l .(0.79) EC
x^
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
?.i
l,j
jj.
.0665
.06389
.06303
.06303
.06303
.06303
.06795
.06795
.06795
.06795
.06795
Plugging the appropriate values into equation (3-1), we arrive at the
values shown in Section C of Table 3-1. Adding summation (1) and
summation (2) we get: EF = 0.0132 (g/mi).
i(oj jiy.o
Note: This example is an estimate of lead emissions from light-duty
vehicles only. Therefore, the total emission rate from all vehicle
classes for an area in calendar year 1985 can be expected to be con-
siderably higher.
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-------
APPENDIX N
DIESEL POWERED TRANSIT BUSES
INTRODUCTION
This appendix presents an alternative methodology for calculating
emission factors for full-size diesel powered transit buses. Because of
the similarities between buses and trucks in terms of inertia weight and
engine type, EPA combines buses and trucks in the heavy duty vehicle
class. Chapter 7 describes the standard procedure for determining
emission factors for diesel powered heavy duty vehicles. Both the
certification and emission factor test procedures for bus engines involve
the use of the EPA engine transient test which is described in Chapter
7. The resultant engine emission data can then be converted to gram per
mile values through the use of conversion factors as discussed in the EPA
report "Heavy Duty Vehicle Emission Conversion Factors, 1962-1997,"
EPA-AA-SDSB-84-1. This has been the standard methodology for calculating
transit bus emission factors in previous AP-42 documents and can continue
to be used if desired.
Based on recent research and analysis, EPA believes that the application
of the standard heavy-duty vehicle emission factor methodology for diesel
powered transit buses is not completely accurate. Because transit buses
operate exclusively in urban areas, typically on the most populated
corridors, and emit pollution at ground level, public exposure to transit
bus emissions is relatively high and EPA has begun to analyze the issue
in greater depth. EPA has recently completed two test programs to
identify the actual emissions from in-use transit buses. These programs
involved buses which were temporarily removed from operating service and
which were tested as-is (i.e., without additional maintenance) in their
chassis configurations over test cycles designed specifically to simulate
transit bus operation. The gram per mile emission factors obtained
directly from these chassis test programs differ significantly from the
emission factors which would be calculated indirectly from engine test
data and conversion factors.
It must be stressed that EPA's analysis of transit bus emissions is
ongoing. The data base currently includes just 2 bus engine designs and
a total of 7 transit buses. Transit bus emissions can be affected by
many parameters such as engine type, design, age, and state of
maintenance; vehicle size and transmission; type of test cycle utilized;
whether No. 1 diesel fuel or No. 2 diesel fuel is used; etc. EPA is not
now able to identify the exact contributions of the various parameters to
the overall emission factor offsets, but is continuing to investigate
these relationships. Despite the limited data base, EPA believes that,
for buses, in-use chassis emissions data provide a more accurate estimate
of actual emission factors than does the general heavy-duty methodology
based on engine emission data and conversion factors. EPA will update
AP-42 as more information becomes available on this issue.
-------
N-2
TEST PROCEDURES
The EPA heavy-duty engine transient test procedure is used for
certification purposes as well as for general emissions testing. This
involves operating an engine over a test cycle that consists of engine
speed and load transients. There are two primary issues with respect to
the representativeness of the EPA engine transient test in characterizing
transit bus emissions. One, recent analysis shows that generating
emission factors from engine data and conversion factors is not as
straightforward for transit buses as it is for heavy-duty trucks. This
has encouraged EPA to utilize bus chassis emission testing which
generates gram per mile values directly. Two, since the design of the
EPA engine transient test was based on truck operation, it does not
represent typical transit bus operation. Transit buses are known for
their low average speed, stop-and-go operation and high acceleration and
deceleration rates.
Accordingly, in recent transit bus test programs EPA has utilized two
chassis test cycles which simulate transit bus operation: 1) an EPA bus
driving cycle generated at the same time and from a similar data base as
the official certification engine test, and 2) the central business
district phase of the SAE Type II Fuel Consumption Test Procedure for
buses. Both of these are chassis transient cycles with low average
speeds and high acceleration rates. Both cycles have yielded dynamometer
fuel economies which are very near to in-use fuel economies, and EPA
believes that these cycles yield emissions which are representative of
actual emissions.
EMISSIONS
There are many different diesel engines which have been utilized in
transit buses, but two engines designed and built by Detroit Diesel
Allison (DDA) Division of General Motors have dominated the transit bus
market. Until recently the standard bus engine was the DDA 71-series
engine, typified by the DDA 6V-71N, a naturally-aspirated, two-stroke,
six-cylinder diesel engine, and its eight-cylinder counterpart, the DDA
8V-71N. It has been estimated that the 71-series engines are installed
in over 80 percent of the transit buses currently operating in the U.S.
Recently, the 71-series engines have been replaced in most new bus
applications by the DDA 6V-92TA, a turbocharged, two-stroke, six-cylinder
diesel with lower fuel consumption and emissions. EPA bus testing
programs have focused on these two engine designs and the first two
subsections will give emission factors for exhaust hydrocarbons, carbon
monoxide, nitrogen oxide, and particulate matter from buses equipped with
these two engines. The third subsection will give guidance for buses
with engines other than DDA designs.
-------
N-3
As discussed in Chapter 7, diesel powered heavy duty vehicles are
considered to have insignificant crankcase and evaporative hydrocarbon
emissions and thus no such emission factors are given. It is not
possible at this time to disaggregate transit bus emission factors into
zero mile emission levels and emission deterioration rates as is done
throughout the rest of AP-42. This is because of the limited transit bus
data base as well as the complications due to the fact that transit bus
engines are typically rebuilt 2 or 3 times during the lifetime of the
bus. The best indicator of expected emissions deterioration is engine
mileage since the last rebuild rather than total bus mileage.
Accordingly, aggregate emission factors are given below, for each major
pollutant from individual engine designs, which EPA believes are
representative of the average emissions from transit buses over their
lifetimes. Finally, there are no speed or temperature correction factors
available at this time for transit bus emissions.
Buses with PDA 71-Series Engines
EPA's Office of Research and Development has performed emission testing
of four buses with 71-series engines as part of a larger overall test
program described in the EPA report "Characterization of Heavy-Duty Motor
Vehicle Emissions Under Transient Driving Conditions," (full report,
dated October 1984, available as NTIS PB85-124154; project summary, dated
December 1984, EPA-600/S3-84-104) . All four buses are CMC RTS II buses
and are part of the San Antonio, Texas transit fleet. Three of the
engines were sold in 1980 and the fourth was sold in 1978. The engines
had accumulated between 137,000 and 247,000 miles prior to testing. Each
of the buses was tested two times over the EPA bus cycle as received,
without maintenance being performed, with No. 1 diesel fuel. No idle
testing was performed. Table N-l gives the average emissions for these
four buses equipped with DDA 71-series engines.
Buses with PDA 6V-92TA Engines
EPA's Office of Mobile Sources has tested three buses with 6V-92TA
engines as one task of a contract described in the EPA report "Emissions
Characterization of Heavy-Duty Diesel and Gasoline Engines and Vehicles"
(EPA 460/3-85-001, March 1985). All three buses are CMC RTS II buses and
were tested as received from the Houston, Texas bus fleet. Two of the
engines were sold in 1983 while the third had been produced in 1982.
Engine mileage ranged from 55,000 to 139,000 miles. Two of the buses
were tested with No. 1 diesel fuel, while the third bus utilized No. 2
diesel fuel. One bus was tested twice over the EPA bus cycle only, the
second bus was tested twice over both the EPA bus cycle and the SAE
central business district cycle, and the third bus was tested once over
both cycles. Emissions data for both the EPA and SAE cycles were similar
and have been aggregated for the latter two buses, while only EPA bus
cycle data are available for the first bus. Hot stabilized idle tests
-------
N-4
were performed on each bus with the transmission in drive and the air
conditioning off. It should be noted that both the EPA bus and SAE
central business district cycles include a fraction of time at idle.
Thus, the idle emission factors need only be used in situations where
idle is the only operating mode. Table N-l gives the average emissions
for these three buses equipped with DDA 6V-92TA engines.
Buses with Other Engines
EPA has no bus chassis data on full-size buses with engines other than
the DDA 71-series and 6V-92TA engines. The EPA recommendation is to use
an average of the emission factors for the 71-series and 6V-92TA
engines. These average values are also shown in Table N-l.
SAMPLE CALCULATION
Given the transit bus emission factors in Table N-l, the only other data
needed to calculate aggregate annual transit bus emissions are a
breakdown of the engines used in a particular transit fleet and
associated annual mileage accumulation. According to the American Public
Transit Association, there were 62,000 transit buses in the U.S. in 1982
which traveled approximately 1.67 billion miles. Thus, on average,
transit buses accumulate 27,000 miles per year. In reality, newer buses
typically have higher annual mileages while older buses, some of which
are only used as substitutes, usually accumulate fewer miles. Annual
vehicle miles traveled data are available from individual transit
authorities.
As an example, assume that an urban area has a transit fleet of 500 buses
and that 300 of the buses utilize DDA 71-series engines and accumulate on
average 25,000 miles per year, 100 of the buses utilize DDA 6V-92TA
engines and average 35,000 miles per year, and the remaining 100 buses
utilize other engines and average 28,000 miles per year. The total
annual particulate emission loading from these buses, based on the
emission factors in Table N-l, would be (300 x 25,000 x 6.27) + (100 x
35,000 x 4.77) + (100 x 28,000 x 5.52) = 79,200,000 grams per year or
87.2 standard tons per year.
-------
N-5
Table N-l
Diesel Powered Transit Bus Emission Factors
(grams per mile, except for idle)
Bus Engines HC CO NOx PM
DDA 6V-71N, 8V-71N 3.59 77.5 24.4 6.27
DDA 6V-92TA 3.10 26.2 27.7 4.77
Other engines(average) 3.35 51.9 26.1 5.52
All engines at idle 0.46 0.40 2.84 0.10
(grams per minute)
-------
Part II - OFF-HIGHWAY MOBILE SOURCES
INTRODUCTION
This section contains emission rates for eight types of off-highway
mobile sources. The emissions of six of these types of sources are
unchanged from the previous edition and supplements. Changes have been
made inboard powered vessels and diesel powered heavy-duty construction
equipment. The changes for these two sources are summarized below.
Inboard Powered Vessels - Only one item has been changed since the
previous edition. This change was the deletion of the 1550 horsepower
diesel emission factors from Table II-3.3 because they were for a 1550
horsepower steam engine and not a diesel engine.
Construction Equipment - The emission factors for heavy-duty diesel
construction equipment are based on a recent study by Environmental
Research and Technology, Inc. Some of the categories of construction
equipment have changed. The emission factors for heavy-duty gas powered
construction equipment are the same as in the previous edition.
Comments on Other Studies - Recently there have been two studies
undertaken for off-highway mobile sources. The first one deals strictly
with inboard powered vessels, and is entitled "Emission Factor
Documentation for AP-42: Section 3.2.3 Inboard Powered Vessels" (EPA
450/4-84-001). The second report discusses locomotives, construction
equipment and inboard powered vessels, and is entitled "Recommended
Revisions to Gaseous Emission Factors for Several Classes of Off-Highway
Vehicles - Final Report" (EPA 460/3-85-004, March 1985). The following
are EPA's comments on material presented in these reports relative to
AP-42.
Locomotives - The current emission factors for locomotives are based on
tests of three in-use locomotives. The second report located data on at
least fifteen new locomotives, and recommended updating the emissions to
this new data set. The report also suggested that the duty cycle for
locomotives include some engine shut-down in place of some engine idle,
mostly based on the fact that fuel costs are higher and companies would
encourage engine shut-down as a cost saving measure. The previous
emission factors do not assume any engine shut-down during the duty
cycle. EPA has not adopted the new emission factors, and instead has
retained the previous emission factors for two reasons. First, there
does not appear to be any verifiable basis for picking the percent of
engine shut-down time during the duty cycle. Second, EPA has become
aware of a larger data set of in-use locomotives with emission data. EPA
intends to analyze these data in the near future, and feels it would be
inappropriate to update the locomotive emission factors with the fifteen
locomotives on an interim basis, only to change them at a later date.
Inboard Powered Vessels - The first report compiled available data on
inboard powered vessels and attempted to estimate the emission factors.
Il-i
-------
The second report critiqued the first report, and found some
inconsistencies in the manner in which the emission factors were
estimated. The second report recommended only two changes to the
existing emission factors — one was the removal of the 1550 horsepower
emission rates from Table II-3.3. (This engine was a steam boiler, and
not diesel powered as presented.) This we have done. The second was
the addition of some new emission rates for diesel engines above 3000
horsepower, but at only one load setting and in units which were
inconsistent with those in Table II-3.2. EPA investigated the
possibility of converting the new data into the old units but had no
basis for estimating the appropriate conversion factor. Therefore, the
previous emission factors (at 3600 horsepower) are retained.
Future Work - Beside locomotives, EPA may also soon undertake a study of
emissions from new aircraft. Emission standards for new aircraft took
effect in 1984; therefore, all 1984 and newer aircraft should have lower
emissions than the rates presented herein. However, the present emission
rates for aircraft are sufficient for now, since the majority of aircraft
in use are pre-1984 uncontrolled technology.
-------
II- 1 AIRCRAFT
II- 1.1 General
Aircraft engines are of two major categories, reciprocating piston
and gas turbine.
In the piston engine, the basic element is the combustion chamber,
or cylinder, in which mixtures of fuel and air are burned and from which
energy is extracted by a piston and crank mechanism driving a propeller.
The majority of aircraft piston engines have two or more cylinders and
are generally classified according to their cylinder arrangement -
either "opposed" or "radial". Opposed engines are installed in most
light or utility aircraft, and radial engines are used mainly in large
transport aircraft. Almost no singlerow inline or V-engines are used in
current aircraft.
The gas turbine engine usually consists of a compressor, a combus-
tion chamber and a turbine. Air entering the forward end of the engine
is compressed and then heated by burning fuel in the combustion chamber.
The major portion of the energy in the heated air stream is used for
aircraft propulsion. Part of the energy is expended in driving the
turbine, which in turn drives the compressor. Turbofan and turboprop
(or turboshaft) engines use energy from the turbine for propulsion, and
turbojet engines use only the expanding exhaust stream for propulsion.
The terms "propjet" and "fanjet" are sometimes used for turboprop and
turbofan, respectively.
The aircraft in the following tables include only those believed to
be significant at present or over the next few years.
Few piston engine aircraft data appear here. Military fixed wing
piston aircraft, even trainers, are being phased out. One piston
engine helicopter, the TH-55A "Osage", sees extensive use at one train-
ing base at Ft. Rucker, AL (EPA Region IV), but engine emissions data
are not available. Most civil piston engine aircraft are in general
aviation service.
The fact that a particular aircraft brand is not listed in the
following tables does not mean the emission factors cannot be calculated.
It is the engine emissions and the time-in-mode (TIM) category which
2/80 Internal ConihiiMion Ei^int* Sou «•«•!• II-I-1
-------
determine emissions. If these are known, emission factors can be
calculated in the same way that the following tables are developed.
The civil and military aircraft classification system used is shown
in Tables II- 1-1 and II- 1-2. Aircraft have been classified by kind of
aircraft and the most commonly used engine for that kind. Jumbo jets
normally have a miximum of about 40,000 pounds thrust per engine, and
medium range jets about 14,000 pounds thrust per engine. Small piston
engines develop less than 500 horsepower.
II- 1.2 The Landing/Takeoff Cycle and Times-in-Mode
A landing/takeoff (LTO) cycle incorporates all of the normal
flight and ground operation modes (at their respective times-in-mode),
including: descent/approach from approximately 3000 feet (915 m) above
ground level (AGL), touchdown, landing run, taxi in, idle and shutdown,
startup and idle, checkout, taxi out, takeoff, and climbout to 3000 feet
(915m) AGL.
In order to make the available data manageable, and to facilitate
comparisons, all of these operations are conventionally grouped into
five standard modes: approach, taxi/idle in, taxi/idle out, takeoff and
climbout. There are exceptions. The supersonic transport (SST) has a
descent mode preceding approach. Helicopters omit the takeoff mode.
Training exercises involve "touch and go" practice. These omit the
taxi/idle modes, and the maximum altitude reached is much lower. Hence,
the duration (TIM) of the approach and climbout modes will be shorter.
Each class of aircraft has its own typical LTO cycle (set of TIMs).
For major classes of aircraft, these are shown in Tables II- 1-3 and
II-1-4. The TIM data appearing in these tables should be used for
guidance only and in the absence of specific observations. The military
data are inappropriate to primary training. The civil data apply to
large, congested fields at times of heavy activity.
All of the data assume a 3000 foot AGL inversion height and an
average U.S. mixing depth. This may be inappropriate at specific
localities and times, for which specific site and time inversion height
data should be sought. Aircraft emissions of concern here are those
released to the atmosphere below the inversion. If local conditions
suggest higher or lower inversions, the duration (TIM) of the approach
and climbout modes must be adjusted correspondingly.
A more detailed discussion of the assumptions and limitations
implicit in these data appears in Reference 1.
Emission factors in Tables II- 1-9 and II- 1-10 were determined
using the times-in-mode presented in Tables II- 1-3 and II- 1-4, and
generally for the engine power settings given in Tables II- 1-5 and
II- 1-6.
II-1-2 EMISSION FVCTORS 2/80
-------
Table II- 1-1. CIVIL AIRCRAFT CLASSIFICATION*1
Aircraft
Engine
No.
Mfg.
Type
Model/Series
Supersonic transport
BAC/Aerospatiale Concorde 4
Short, medium, long range
and jumbo jets
BAG 111-400
Boeing 707-320B
Boeing 727-200
Boeing 737-200
Boeing 747-200B
Boeing 747-200B
Boeing 747-200B
Lockheed L1011-200
Lockheed L1011-100
McDonnell-Douglas DC8-63
McDonnell-Douglas DC9-50
McDonnell-Douglas DC10-30
Air carrier turboprops -
commuter, feeder line and
freighters
Beech 99
GD/Convair 580
DeHavilland Twin Otter
Fairchild F27 and FH227
Grumman Goose
Lockheed L188 Electra
Lockhead L100 Hercules
Swearingen Metro-2
Business jets
Cessna Citation
Dassault Falcon 20
Gates Learjet 24D
Gates Learjet 35, 36
Rockwell International
Shoreliner 75A
RR
P&W
GE
GE
GE
GE
TF
TF
TF
TJ
TF
TF
Olymp. 593-610
2
4
3
2
4
4
4
3
3
4
2
3
RR
P&W
P&W
P&W
P&W
P&W
RR
RR
RR
P&W
P&W
GE
TF
TF
TF
TF
TF
TF
TF
TF
TF
TF
TF
TF
Spey 511
JT3D-7
JT8"D-17
JT8D-17
JT9D-7
JT9D-70
RB211-524
RB211-524
RB211-22B
JT3D-7
JT8D-17
CF6-50C
2
2
2
2
2
4
4
2
PWC
All
PWC
RR
PWC
All
All
GA
TP
TP
TP
TP
TP
TP
TP
TP
PT6A-28
501
PT6A-27
R. Da. 7
PT6A-27
501
501
TPE 331-3
JT15D-1
CF700-2D
CJ610-6
TPE 731-2
CF 700
Business turboprops
(EPA Class P2)
Beech B99 Airliner 2
DeHavilland Twin Otter 2
Shorts Skyvan-3 2
Swearingen Merlin IIIA 2
General aviation piston
(EPA Class PI)
Cessna 150 1
Piper Warrior 1
Cessna Pressurized
Skymaster 2
Piper Navajo Chieftain 2
PWC
fWC
GA
GA
Con
Lye
Con
Lyn
TP
TP
TP
TP
PT6A-27
PT6A-27
TPE-331-2
TPE-331-3
0-200
0-320
TS10-360C
T10-540
References 1 and 2.
Abbreviations: TJ - tubojet, TF - turbofan, TP - turboprop, R -
reciprocating piston, 0 - opposed piston. All - Detroit Diesel Allison
Division of General Motors, Con - Teledyne/Continental, GA - Garrett
AiResearch, GE - General Electric, Lye - Avco/Lycoming, P&W - Pratt &
Whitney, PWC - Pratt & Whitney Aircraft of Canada, RR - Rolls Royce.
2/80
Interim! <'oml>u>lion En Sonnet-
II- 1.3
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II- 1-4
EMISSION FACTORS
2/80
-------
Table II-1-3. TYPICAL DURATION FOR CIVIL LTD CYCLES
AT LARGE CONGESTED METROPOLITAN AIRPORTS*
Aircraft
Commercial
carrier
Jumbo, long
and medium
range jet*3
Turboprop
Transport-
piston
General
aviation
Business jet
Turboprop
Piston
Helicopter
Taxi/
Idle out
19.0
19.0
6.5
6.5
19.0
12.0
3.5
Takeoff
0.7
0.5
0.6
0.4
0.5
0.3
-
Mode
Climbout
2.2
2.5
5.0
0.5
2.5
5.0
6.5
Approach
4.0
4.5
4.6
1.6
4.5
6.0
6.5
Taxi/
Idle in
7.0
7.0
6.5
6.5
7.0
4.0
3.5
Total
32.9
33.5
23.2
15.5
33.5
27.3
20.0
, Reference 3. Data given in minutes.
Same times as EPA Classes T2, T3 and T4 (Note b, Table II-1-5) .
^Same times as EPA Classes Tl and P2 (Note b, Table II-1-5) .
Same times as EPA Class PI (Note b, Table II- 1-5).
2/80
Internal ("oml>u>tion Ermine Sourre*
II- 1-5
-------
Table II-1-4. TYPICAL DURATION FOR MILITARY LTO CYCLES'
Aircraft
Q
Combat
USAF
USNd
Trainer -
Turbine
USAF T-38
USAF general
USNd
Transport -
Turbine6
USAF general
USNf
USAF B-52
and KC-135
Military -
Piston
Military -
Helicopter
TIMb
Code
1
2
3
4
2
5
6
7
8
9
Taxi/ Takeoff
Idle out
18.5 0.4
6.5 0.4
12.8 0.4
6.8 0.5
6.5 0.4
9.2 0.4
19.0 0.5
32.8 0.7
6.5 0.6
8.0
Mode
Climbout
0.8
0.5
0.9
1.4
0.5
1.2
2.5
1.6
5.0
6.8
Approach
3.5 •
1.6
3.8
4.0
1.6
5.1
4.5
5.2
4.6
6.8
Taxi/
Idle in
11.3
6.5
6.4
4.4
6.5
6.7
7.0
14.9
6.5
7.0
Total
34.5
15.5
24.3
17.1
15.5
22.6
33.5
55.2
23.2
28.6
Reference 1. Data given in minutes. USAF - U.S. Air Force, USN - U.S.
Navy.
TIM Code defined in Table II-1-5.
Q
.Fighters and attack craft only.
Time-in-mode is highly variable. Taxi/idle out and in times as high as
25 and 17 minutes, respectively, have been noted. Use local data base if
possible.
Includes all turbine craft not specified elsewhere (i.e., transport,
fcargo, observation, patrol, antisubmarine, early warning, and utility).
Same as EPA Class P2 for civil turboprops.
11-I-6
EMISSION FACTORS
2/80
-------
Table II-1-5. ENGINE POWER SETTINGS FOR TYPICAL EPA
LTO COMMERCIAL CYCLES3
Mode
Taxi/Idle (out)
Takeoff
Climbout
Approach
Taxi/Idle (in)
Power
Class Tl,
Idle
100
90
30
Idle
setting (% thrust
P2b Class T2,T3
Idle
100
85
30
Idle
or horsepower)
, T4b Class Plb
Idle
100
75 - 100
40
Idle
Helicopter
Undefined
References 1 and 3.
DAs defined by EPA (Reference 3):
Class Tl is all aircraft turbofan or turbojet engines except Class T5
of rated power less than 8000 Ibs thrust.
Class T2 is all turbofan or turbojet aircraft engines except Classes
T3, T4 and T5 of rated power of 8000 Ibs thrust or greater.
Class T3 is all aircraft gas turbine engines of the JT3D model family.
Class T4 is all aircraft gas turbine engines of the JT8D model family.
Class T5 is all aircraft gas turbine engines on aircraft designed to
operate at supersonic speeds.
Class PI is all aircraft piston engines, except radial.
Class P2 is all aircraft turboprop engines.
Table II- 1-6. ENGINE.POWER SETTINGS FOR A TYPICAL LTO
MILITARY CYCLE3
Mode
Taxi/Idle (out)
Takeoff
Climbout
Approach
Taxi/Idle (in)
Power setting
Military
transport
Idle
Military
90 - 100
30
Idle
(% thrust or
Military
jet
horsepower)
Military
piston
Idle 5-10
Military or
Afterburner 100
Military 75
84 - 86 30
Idle 5-10
Military
helicopter
Idle
60 - 75
45 - 50
Idle
Reference 1.
2/80
Internal ('omlui-tinn En^iin- Sourco
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II- 1.3 Modal Emission Rates and Emission Factors per LTO Cycle
The first step in the calculation of aircraft emission factors is
the development of a set of modal emission rates. These represent the
quantity of pollutant released per unit time in each of the standard
modes. Each mode is characterized by an engine power setting (given in
Tables II- 1-5 and II- 1-6) and a fuel rate (the quantity of fuel
consumed per unit time).
The following procedure is for calculation of aircraft emission
factors per LTO cycle, starting with engine modal emission rates:
1) For a specific aircraft, determine the number and model of
engines, using for example, Tables II- 1-1 or II-1-2.
2) Using Table II-1-7 or II- 1-8, locate the appropriate engine
data, and prepare a list of modal emission rates -for each mode
m and pollutant p:
(—)
vAt'
m,p
3) Using known military assignment and mission, or civil aircraft
type and application, use Table II-1-3 or II-1-4 to select
an appropriate set of times-in-mode (TIM) .
m
4) For each mode m and pollutant p, multiply the modal emission
rate and TIM data for each mode and the sum over all modes.
This will yield an emission factor per engine, which must be
multiplied by the number of engines, N, to produce the emission
factor per LTO cycle, E , for an aircraft:
V N Z (f|) ' (TIM)m
m,p
On a conveniently laid out work sheet, this calculation can be set up
easily on a hand calculator with one storage location.
Emission factors calculated in exactly this way are presented in
Tables II-1-9 and II-1-10.
References for Section II— 1
I. D. R. Sears, Air Pollutant Emission Factors for Military and Civil
Aircraft, EPA-450/3-78-117, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina, October 1978.
2. R. G. Pace, "Technical Support Report - Aircraft Emission Factors",
Office of Mobile Source Air Pollution Control, U.S. Environmental
Protection Agency, Ann Arbor, MI, March 1977.
2/8() Interim! (.omhiiMion En
-------
3. Control of Air Pollution for Aircraft and Aircraft Engines,
38 FR 19088, July 17, 1973.
4. M. Platt, et al., The Potential Impact of Aircraft Emissions upon Air
Quality. APTD-1085, U.S. Environmental Protection Agency, Research
Triangle Park, NC, December 1971.
II-1-18 EMISSION FACTORS 2, KO
-------
II- 2 Locomotives
II- 2.1 General - Railroad locomotives generally follow one of two use patterns: railyard switching or road-haul
service. Locomotives can be classified on the basis of engine configuration and use pattern into five categories:
2-stroke switch locomotive (supercharged), 4-stroke switch locomotive, 2-stroke road service locomotive
(supercharged), 2-stroke road service locomotive (turbocharged), and 4-stroke road service locomotive.
The engine duty cycle of locomotives is much simpler than many other applications involving diesel internal
combustion engines because locomotives usually have only eight throttle positions in addition to idle and
dynamic brake. Emission testing is made easier and the results are probably quite accurate because of the
simplicity of the locomotive duty cycle.
II-2.2 Emissions - Emissions from railroad locomotives are presented two ways in this section. Table EI-2-1
contains average factors based on the nationwide locomotive population breakdown by category. TableII-J-2
gives emission factors by locomotive category on the basis of fuel consumption and on the basis of \vork output
(horsepower hour).
The calculation of emissions using fuel-based emission factors is straightforward. Emissions are simply the
product of the fuel usage and the emission factor. In order to apply the work output emission factor, however, an
TableII-2-1. AVERAGE LOCOMOTIVE
EMISSION FACTORS BASED
ON NATIONWIDE STATISTICS3
Pollutant
Particulatesc
Sulfur oxidesd
(SOX as SC>2)
Carbon monoxide
Hydrocarbons
Nitrogen oxides
(NOxasNO2)
Aldehydes
(as HCHO)
Organic acids0
Average emissions6
lb/103gal
25
57
130
94
370
5.5
7
kg/103 liter
3.0
6.8
16
11
44
0.66
0.84
Reference 1.
Based on emission data contained m Table n- 2-2
and the breakdown of locomotive use by engine
category in the United States in Reference 1
Data based on highway diesel data from Reference
2 No actual locomotive paniculate test data are
available.
Based on a fueJ sulfur content of 0.4 percent from
Reference 3.
4/73
Internal Combustion Engine Sources
II-2-1
-------
TableII-2-2. EMISSION FACTORS BY LOCOMOTIVE ENGINE
CATEGORY8
EMISSION FACTOR RATING: B
Pollutant
Carbon monoxide
lb/103gal
kg/103 liter
g/hphr
g/metric hphr
Hydrocarbon
Ib/I03gal
kg/103 liter
g/hphr
g/metric hphr
Nitrogen oxides
(NOxasN02>
Ib/ICPgal
kg/103 liter
g/hphr
g/metric hphr
Engine category
2-Stroke
supercharged
switch
84
10
3.9
3.9
190
23
8.9
8.9
250
30
11
11
4-Stroke
switch
380
46
13
13
146
17
5.0
5.0
490
59
17
17
2-Stroke
supercharged
road
66
7.9
1.8
1.8
148
18
4.0
4.0
350
42
9.4
9.4
2-Stroke
turbocharged
road
160
19
4.0
4.0
28
3.4
0.70
0.70
330
40
8.2
8.2
4-Stroke
road
180
22
4.1
4.1
99
12
2.2
2.2
470
56
10
10
a Use average factors (TableII-2-1) for pollutants not listed in this table.
additional calculation is necessary. Horsepower hours can be obtained using the following equation:
w=lph
where: w = Work output (horsepower hour)
1 = Load factor (average power produced during operation divided by available power)
p = Available horsepower
h = Hours of usage at load factor (1)
After the work output has been determined, emissions are simply the product of the work output and the
emission factor. An approximate load factor for a line-haul locomotive (road service) is 0.4: a typical switch
engine load factor is approximately 0 Ob.1
References for Section II- 2
1. Hare, C.T. and K.J. Springer Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Part 1. Locomotive Diesel Engines and Marine Counterparts. Final Report.
Southwest Research Institute. San Antonio, Texas Prepared for the Environmental Protection Agency,
Research Triangle Park, N.C., under Contract Number EHA 70-108. October 1972.
2. Young. T.C. Unpublished Data from the Engine Manufacturers Association. Chicago. 111. May 1970.
3. Hanley. G.P. Exhaust Emission Information on Electro-Motive Railroad Locomotives and Diesel Engines.
General Motors Corp. Warren, Mich. October 1971.
II- 2-2
EMISSION FACTORS
4/73
-------
II-3 Inboard-Powered Vessels
II-3.1 General - Vessels classified on the basis of use will generally fall into one of three categories: commercial,
pleasure, or military. Although usage and population data on vessels are, as a rule, relatively scarce, information on
commercial and military vessels is more readily available than data on pleasure craft. Information on military
vessels is available in several study reports,1"5 but data on pleasure craft are limited to sales-related facts and
figures.6'10
Commercial vessel population and usage data have been further subdivided by a number of industrial and
governmental researchers into waterway classifications11"16 (for example, Great Lakes vessels, river vessels, and
coastal vessels). The vessels operating in each of these waterway classes have similar characteristics such as size,
weight, speed, commodities transported, engine design (external or internal combustion), fuel used, and distance
traveled. The wide variation between classes, however, necessitates the separate assessment of each of the waterway
classes with respect to air pollution.
Information on military vessels is available from both the U.S. Navy and the U.S. Coast Guard as a result of
studies completed recently. The U.S. Navy has released several reports that summarize its air pollution assessment
work.3"5 Emission data have been collected in addition to vessel population and usage information. Extensive
study of the air pollutant emissions from U.S. Coast Guard watercraft has been completed by the U.S. Department
of Transportation. The results of this study are summarized in two reports.1"2 The first report takes an in-depth
look at population/usage of Coast Guard vessels. The second report, dealing with emission test results, forms the
basis for the emission factors presented in this section for Coast Guard vessels as well as for non-military diesel
vessels.
Although a large portion of the pleasure craft in the U.S. are powered by gasoline outboard motors (see section
11-4 of this document), there are numerous larger pleasure craft that use inboard power either with or without
"out-drive" (an outboard-like lower unit). Vessels falling into the inboard pleasure craft category utilize either Otto
cycle (gasoline) or diesel cycle internal combustion engines. Engine horsepower varies appreciably from the small
"auxiliary" engine used in sailboats to the larger diesels used in yachts.
11-3.2 Emissions
Commercial vessels. Commercial vessels may emit air pollutants under two major modes of operation:
underway and at dockside (auxiliary power).
Emissions underway are influenced by a great variety of factors including power source (steam or diesel), engine
size (in kilowatts or horsepower), fuel used (coal, residual oil, or diesel oil), and operating speed and load.
Commercial vessels operating within or near the geographic boundaries of ihe L'ni'cd States fall into one of the
three categories of use discussed above (Great Lakes, rivers, coastline). Table--II-3 ! andII-'3-2 contain emission
information on commercial vessels falling into these three categories. Table 11-3-3 presents emission factors for
diesel marine engines at various operating modes on the basis of horsepower. These dau aie applicable to any vessel
having a similar size engine, not just to commercial vessels.
Unless a ship receives auxiliary steam from dockside facilities, goes immediately into drydock, or is out of
operation after arrival in port, she continues her emissions at dockside. Power must be made available for the ship's
lighting, heating, pumps, refrigeration, ventilation, etc. A few steam ships use auxiliary engines (diesel) to supply
power, but they generally operate one or more main boilers under reduced draft and lowered fuel rates-a very
inefficient process. Motorships (ships powered by internal combustion engines) normally use diesel-powered
generators to furnish auxiliary power.17 Emissions from these diesel-powered generators may also be a source of
underway emissions if they are used away from port. Emissions from auxiliary power systems, in terms of the
1/75 Internal Combustion Engine Sources II- 3-1
-------
TableII-3-1. AVERAGE EMISSION FACTORS FOR
COMMERCIAL MOTORSHIPS BY WATERWAY
CLASSIFICATION
EMISSION FACTOR RATING: C
Emissions3
Sulfur oxidesb
(SOxasS02)
kg/103 liter
lb/103 gal
Carbon monoxide
kg/103 liter
lb/103 gal
Hydrocarbons
kg/103 liter
lb/103 gal
Nitrogen oxides
(NOxasN02>
kg/103 liter
lb/103 gal
ClassC
River
3.2
27
12
100
6.0
50
33
280
Great Lakes
3.2
27
13
110
7.0
59
31
260
Coastal
3.2
27
13
110
6.0
50
32
270
aExpressed as function of fuel consumed (based on emission data from
Reference 2 and popu'ation/usage data from References 11 through 16.
^Calculated, not measured. Based on 0.20 percent sulfur content fuel
and density of 0.854 kg/liter (7.12 Ib/gal) from Reference 17.
cVery approximate particulate emission factors from Reference 2 are
470 g/hr (1.04 Ib/hr). The reference does not contain sufficient
information to calculate fuel-based factors.
quantity of fuel consumed, are presented in Table II-3-4. In some instances, fuel quantities used may not be
available, so calculation of emissions based on kilowatt hours (kWh ) produced may be necessary. For operating
loads in excess of zero percent, the mass emissions ('.; j) in kilograms per hour (pounds per hour) are given by:
ej = kief
where: k = a constant that relates fuel consumption to kilowatt hours,-
that is. 3.63 xlO'4 1000 liters fuel/kWh
or
9.59 x 10'5 1000 gal fuel/kWh
1 = the load. kW
ef = the fuel-specific emission factor from Table 3.2.3-4, kg/10^ liter (Ib/KP gal)
11-3-2 EMISSION FACTORS
(1)
1/75
-------
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1/75
Internal Combustion Engine Sources
II-3-3
-------
TableII-3-3. DIESEL VESSEL EMISSION FACTORS BY OPERATING MODE3
EMISSION FACTOR RATING: C
Horsepower
200
300
500
600
700
900
1580
2500
3600
Mode
Idle
Slow
Cruise
Full
Slow
Cruise
Full
Idle
Cruise
Full
Idle
Slow
Cruise
Idle
Cruise
Idle
2/3
Cruise
Slow
Cruise
Full
Slow
2/3
Cruise
Full
Slow
2/3
Cruise
Full
Emissions
Carbon monoxide
lb/103
gal
210.3
145.4
126.3
142.1
59.0
47.3
58.5
282.5
99.7
84.2
171.7
50.8
77.6
293.2
36.0
223.7
62.2
80.9
122.4
44.6
237.7
59.8
126.5
78.3
95.9
148.5
28.1
41.4
62.4
kg/10J
liter
25.2
17.4
15.1
17.0
7.1
5.7
7.0
33.8
11.9
10.1
20.6 ^
6.1
9.3
35.1
4.3
26.8
7.5
9.7
14.7
5.3
28.5
7.2
15.2
9.4
11.5
17.8
3.4
5.0
7.5
Hydrocarbons
lb/103
gal
391.2
103.2
170.2
60.0
56.7
51.1
21.0
118.1
44.5
22.8
68.0
16.6
24.1
95.8
8.8
249.1
16.8
17.1
16.8
22.6
14.7
16.8
21.3
60.0
25.4
32.8
29.5
kg/103
liter
46.9
12.4
20.4
7.2
6.8
6.1
2.5
14.1
5.3
2.7
8.2
2.0
2.9
11.5
1.1
29.8
2.0
2.1
2.0
2.7
1.8
2.0
2.6
7.2
3.0
4.0
3.5
Nitrogen oxides
(NOxasN02)
lb/103
gal
6.4
207.8
422.9
255.0
337.5
389.3
275.1
99.4
338.6
269.2
307.1
25-1.5
349.2
246.0
452.8
107.5
167.2
360.0
371.3
623.1
472.0
419.6
326.2
391.7
399.6
367.0
358.6
339.6
307.0
kg/103
liter
0.8
25.0
50.7
30.6
40.4
46.7
33.0
11.9
40.6
32.3
36.8
30.1
41.8
29.5
54.2
12.9
20.0
43.1
44.5
74.6
5.7
50.3
39.1
46.9
47.9
44.0
43.0
40.7
36.8
Reference 2
Participate and sulfur oxides data are not available
11-3-4
EMISSION FACTORS
1/75
-------
TableII-3-4. AVERAGE EMISSION FACTORS FOR DIESEL-POWERED ELECTRICAL
GENERATORS IN VESSELSa
EMISSION FACTOR RATING: C
Rated
output, b
kW
20
40
200
500
Load,0
% rated
output
0
25
50
75
0
25
50
75
0
25
50
75
0
25
50
75
Emissions
Sulfur oxides
(SOxasSO2)d
lb/103
gal
27
27
27
27
27
27
27
27
27
27
27
27
27
27
27
27
kg/103
liter
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
Carbon
monoxide
lb/103
gal
150
79.7
53.4
28.5
153
89.0
67.6
64.1
134
97.9
62.3
26.7
58.4
53.4
48.1
43,7
kg/103
liter
18.0
9.55
6.40
3.42
18.3
10.7
8.10
7.68
16.1
11.7
7.47
3.20
7.00
6.40
5.76
5.24
Hydro-
carbons
lb/103
gal
263
204
144
84.7
584
370
285
231
135
33.5
17.8
17.5
209
109
81.9
59.1
kg/103
liter
31.5
24.4
17.3
10.2
70.0
44.3
34.2
27.7
16.2
4.01
2.13
2.10
25.0
13.0
9.8
7.08
Nitrogen oxides
(NOxasNO2)
lb/103
gal
434
444
477
495
214
219
226
233
142
141
140
137
153
222
293
364
kg/103
liter
52.0
53.2
57.2
59.3
25.6
26.2
27.1
27.9
17.0
16.9
16.8
16.4
18.3
26.6
35.1
43.6
Reference 2.
Maximum rated output of the diesel-powered generator.
""Generator electrical output (for example, a 20 kW generator at 50 percent load equals 10 kW output).
Calculated, not measured, based on 0.20 percent fuel sulfur content and density of 0.854 kg/liter (7.12 Ib/gal) from Reference 17.
At zero load conditions, mass emission rates (ej,) may be approximated in terms of kg/hr (Ib/hr) using the
following relationship:
el - klratedef
where, k = a constant that relates rated output and fuel consumption.
that is. 6.93 x 10"5 1000 liters fuel/kW
(2)
or
1000 gal fuel/kW
1.83x 1CT5
'rated = the rated output. kW
ef = the fuel-specific emission factor from TableII-3-4. kg/10^ liter (lb/10-5 gal)
Pleasure craft. Many of the engine designs used in inboard pleasure craft are also used either in military vessels
(diesel) or in highway vehicles (gasoline). Out of a total of 700,000 inboard pleasure craft registered in the United
States in 1972, nearly 300,000 were inboard/outdrive. According to sales data. 60 to 70 percent of these
1/75
Internal Combustion Engine Sources
II-3-S
-------
inboard/outdrive craft used gasoline-powered automotive engines rated at more than 130 horsepower.6 The
remaining'400,000 pleasure craft used conventional inboard drives that were powered by a variety of powerplants,
both gasoline and diesel. Because emission data are not available for pleasure craft. Coast Guard and automotive
data2'19 are used to characterize emission factors for this class of vessels in Table 11-3-5.
Military vessels. Military vessels are powered by a wide variety of both diesel and steam power plants. Many of the
emission data used in this section are the result of emission testing programs conducted by the U.S. Navy and the
U.S. Coast Guard.'"3'5 A separate table containing data on military vessels is not provided here, but the included
tables should be sufficient to calculate approximate military vessel emissions.
TABLEII-3.-5. AVERAGE EMISSION FACTORS FOR INBOARD PLEASURE CRAFT3
EMISSION FACTOR RATING: D
Pollutant
Sulfur oxides1^
(SOX as SO2>
Carbon monoxide
Hydrocarbons
Nitrogen oxides
(NOX as N02)
Based on fuel consumption
Diesel engine'3
kg/103
liter
3.2
17
22
41
lb/103
gal
27
140
180
340
Gasoline engine0
kg/103
liter
0.77
149
10.3
15.7
lb/103
gal
6.4
1240
86
131
Based on operating time
Diesel engine'3
kg/hr
-
-
-
-
Ib/hr
-
-
-
Gasoline enginec
kg/hr
0.008
1.69
0.117
0.179
Ib/hr
0.019
3.73
0.258
0.394
aAverage emission factors are based on the duty cycle developed for large outboards (> 48 kilowatts or > 65 horsepower) from Refer-
ence 7. The above factors take into account the impact of water scrubbing of underwater gasoline engine exhaust, also from Reference
7. All values given are for single engine craft and must be modified for multiple engine vessels.
"Based on tests of diesel engines in Coast Guard vessels, Reference 2.
C8ased on tests of automotive engines. Reference 19. Fuel consumption of 11.4 hter/hr (3 gal/hr) assumed The resulting factors are
only rough estimates.
^Based on fuel sulfur content of 0.20 percent for diesel fuel and 0.043 percent for gasoline from References 7 and 17 Calculated using
fuel density of 0.740 kg/liter (6.17 Ib/gal) for gasoline and 0 854 kg/liter (7.12 Ib/gal) for diesel fuel
References for Section II-3
1. Walter. R. A.. A. J. Broderick, J. C. Sturm, and E. C. Klaubert. USCG Pollution Abatement Program: A
Preliminary Study of Vessel and Boat Exhaust Emissions. U.S. Department of Transportation, Transportation
Systems Center. Cambridge. Mass. Prepared for the United States Coast Guard. Washington, D.C. Report No.
DOT-TSC-USCG-72-3. November 1971. 119 p.
11-3-6
EMISSION FACTORS
1/75
-------
2. Souza, A. F. A Study of Emissions from Coast Guard Cutters. Final Report. Scott Research Laboratories, Inc.
Plumsteadville, Pa. Prepared for the Department of Transportation, Transportation Systems Center,
Cambridge, Mass., under Contract No. DOT-TSC-429. February 1973.
3. Wallace, B. L. Evaluation of Developed Methodology for Shipboard Steam Generator Systems. Department of
the Navy. Naval Ship Research and Development Center. Materials Department. Annapolis, Md. Report No.
28-463. March 1973. 18 p.
4. Waldron, A. L. Sampling of Emission Products from Ships' Boiler Stacks. Department of the Navy. Naval Ship
Research and Development Center. Annapolis, Md. Report No. 28-169. April 1972. 7 p.
5. Foernsler, R. 0. Naval Ship Systems Air Contamination Control and Environmental Data Base Programs;
Progress Report. Department of the Navy. Naval Ship Research and Development Center. Annapolis, Md.
Report No. 28-443. February 1973. 9 p.
6. The Boating Business 1972. The Boating Industry Magazine. Chicago, 111. 1973.
7. Hare. C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Final Report Part 2. Outboard Motors. Southwest Research Institute. San
Antonio, Tex. Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under
Contract No. EHS 70-108. January 1973. 57 p.
8. Hurst, J. W. 1974 Chrysler Gasoline Marine Engines. Chrysler Corporation. Detroit, Mich.
9. Mercruiser Sterndrives/ Inboards 73. Mercury Marine, Division of the Brunswick Corporation. Fond du Lac,
Wise. 1972.
10. Boating 1972. Marex. Chicago, Illinois, and the National Association of Engine and Boat Manufacturers.
Greenwich, Conn. 1972. 8 p.
11. Transportation Lines on the Great Lakes System 1970. Transportation Series 3. Corps of Engineers, United
States Army, Waterborne Commerce Statistics Center. New Orleans, La. 1970. 26 p.
12. Transportation Lines on the Mississippi and the Gulf Intracoastal Waterway 1970. Transportation Series 4.
Corps of Engineers, United States Army, Waterborne Commerce Statistics Center. New Orleans, La. 1970. 232
P-
13. Transportation Lines on the Atlantic, Gulf and Pacific Coasts 1970. Transportation Series 5. Corps of
Engineers. United States Army. Waterborne Commerce Statistics Center. New Orleans, La. 1970. 201 p.
14. Schueneman. J. J. Some Aspects of Marine Air Pollution Problems on the Great Lakes. J. Air Pol. Control
Assoc. 74:23-29, September 1964.
15. 1971 Inland Waterborne Commerce Statistics. The American Waterways Operations, Inc. Washington, D.C.
October 1972. 38 p.
16. Horsepower on the Inland Waterways. List No. 23. The Waterways Journal. St. Louis, Mo. 1972. 2 p.
17. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Part 1. Locomotive Diesel Engines and Marine Counterparts. Southwest
Research Institute. San Antonio, Tex. Prepared for the Environmental Protection Agency, Research Triangle
Park. N.C., under Contract No. EHS 70-108. October 1972. 39 p.
18. Pearson, J. R. Ships as Sources of Emissions. Puget Sound Air Pollution Control Agency. Seattle, Wash.
(Presented at the Annual Meeting of the Pacific Northwest International Section of the Air Pollution Control
Association. Portland. Ore. November 1969.)
19. Study of Emissions from Light-Duty Vehicles in Six Cities. Automotive Environmental Systems, Inc. San
Bernardino. Calif. Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under
Contract No. 68-04-0042. June 1971.
1/75 Internal Combustion Engine Sources II- 3-7
-------
II- 4 Outboard-Powered Vessels
II-4.1 General - Most of the approximately 7 million outboard motors in use in the United States are 2-stroke
engines with an average available horsepower of about 25. Because of the predominately leisure-time use of
outboard motors, emissions related to their operation occur primarily during nonworking hours, in rural areas,
and during the three summer months. Nearly 40 percent of the outboards are operated in the states of New York,
Texas, Florida, Michigan, California, and Minnesota. This distribution results in the concentration of a large
portion of total nationwide outboard emissions in these states.1
II- 4.2 Emissions — Because the vast majority of outboards h'ave underwater exhaust, emission measurement is
very difficult. The values presented in TableII-4-1 are the approximate atmospheric emissions from outboards.
These data are based on tests of four outboard motors ranging from 4 to 65 horsepower.1 The emission results
from these motors are a composite based on the nationwide breakdown of outboards by horsepower. Emission
factors are presented two ways in this section: in terms of fuel use and in terms of work output (horsepower
hour). The selection of the factor used depends on the source inventory data available. Work output factors are
used when the number of outboards in use is available. Fuel-specific emission factors are used when fuel
consumption data are obtainable.
TableII-4-1. AVERAGE EMISSION FACTORS FOR OUTBOARD MOTORS8
EMISSION FACTOR RATING: B
Pollutant6
Sulfur oxidesd
(SOxasS02)
Carbon monoxide
Hydrocarbons8
Nitrogen oxides
(NOxasNO2)
Based on fuel consumption
lb/103gal
6.4
3300
1100
6.6
kg/103 liter
0.77
400
130
0.79
Based on work output0
g/|iphr
0.49
250
85
0.50
g/metric hphr
0.49
250
85
0.50
a Reference 1. Data m this table are emissions to the atmosphere. A portion of the exhaust remains behind in
the water.
Paniculate emission factors are not available because of the problems involved with measurement from an
underwater exhaust system but are considered negligible.
c Horsepower hours are calculated by multiplying the average power produced during the hours of usage by
the population of outboards in a given area. In the absence of data specific to a given geographic area, the
hphr value can be estimated using average nationwide values from Reference 1. Reference 1 reports the
average power produced (not the available power) as 9.1 hp and the average annual usage per engine as 50
hours. Thus, hphr = (number of outboards) (9.1 hp) (50 hours/outboard-year) Metric hphr = 0.9863 hphr.
d Based on fuel sulfur content of 0.043 percent from Reference 2 and on a density of 6.17 Ib/gal.
e Includes exhaust hydrocarbons only. (VJo crankcase emissions occur because the majority of outboards are
2-stroke engines that use crankcase induction. Evaporative emissions are limited by the widespread use of
unvented tanks.
4/73
Internal Combustion Engine Sources
II- 4-1
-------
References for sections 11-4
1. Hare, C.T. and K.J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Part II, Outboard Motors. Final Report. Southwest Research Institute. San
Antonio, Texas. Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under
Contract Number EHS 70-108. January 1973.
2. Hare, C.T. and K.J. Springer. Study of Exhaust Emissions from Uncontrolled Vehicles and Related Equipment
Using Internal Combustion Engines. Emission Factors and Impact Estimates for Light-Duty Air-Cooled Utility
Engines and Motorcycles. Southwest Research Institute. San Antonio, Texas. Prepared for the Environmental
Protection Agency, Research Triangle Park, N.C., under Contract Number EHS 70-108. January 1972.
11-4-2 EMISSION FACTORS 4/73
-------
II-5 Small, General Utility Engines
ll—5.1 General—This category of engines comprises small 2-stroke and 4-stroke, air-cooled, gasoline-powered
motors. Examples of the uses of these engines are: lawnmowers, small electric generators, compressors, pumps,
minibikes, snowthrowers, and garden tractors. This category does not include motorcycles, outboard motors, chain
saws, and snowmobiles, which are either included in other parts of this chapter or are not included because of the
lack of emission data.
Approximately 89 percent of the more than 44 million engines of this category in service in the United States
are used in lawn and garden applications.1
II-5.2 Emissions-Emissions from these engines are reported in Table II-5-1. For the purpose of emission
estimation, engines in this category have been divided into lawn and garden (2-stroke), lawn and garden (4-stroke),
and miscellaneous (4-stroke). Emission factors are presented in terms of horsepower hours, annual usage, and fuel
consumption.
References for Section II- 5
1. Donohue, J. A., G. C. Hardwick, H. K. Newhall, K. S. Sanvordenker, and N. C. Woelffer. Small Engine Exhaust
Emissions and Air Quality in the United States. (Presented at the Automotive Engineering Congress, Society of
Automotive Engineers, Detroit. January 1972.)
2. Hare. C. T. and K. -J. Springer. Study of Exhaust Emissions from Uncontrolled Vehicles and Related
Equipment Using Internal Combustion Engines. Part IV, Small Air-Cooled Spark Ignition Utility Engines.
Final Report. Southwest Research Institute. San Antonio, Tex. Prepared for the Environmental Protection
Agency, Research Triangle Park, N.C., under Contract No. EHS 70-108. May 1973.
1/75 Internal Combustion Engine Sources II-5-1
-------
TableII-5-1. EMISSION FACTORS FOR SMALL, GENERAL UTILITY ENGINESa>b
EMISSION FACTOR RATING: B
Engine
2-Stroke, lawn
and garden
g/hphr
g/metric
hphr
g/gal of
fuel
g/unit-
year
4-Stroke, lawn
and garden
g/hphr
g/metric
hphr
g/gal of
fuel
g/umt-
year
4-Stroke
miscellaneous
g/hphr
g/metric
hphr
g/gal of
fuel
g/u nit-
Sulfur
oxidesc
(SOX as S02)
0.54
0.54
1.80
38
0.37
0.37
2.37
26
0.39
0.39
2.45
30
year
Particulate
7.1
7.1
23.6
470
0.44
0.44
2.82
31
0.44
0.44
2.77
34
Carbon
monoxide
486
486
1,618
33,400
279
279
1,790
19,100
250
250
1,571
19,300
Hydrocarbons
Exhaust
214
214
713
14,700
23.2
23.2
149
1,590
15.2
15.2
95.5
1,170
Evaporative
—
-
-
113
—
-
—
113
—
—
—
290
Nitrogen
oxides
(NOX as NO2)
1.58
1.58
5.26
108
3.17
3.17
20.3
217
4.97
4.97
31.2
384
Alde-
hydes
(HCHO)
2.04
2.04
6.79
140
0.49
0.49
3.14
34
0.47
0.47
2.95
36
Reference 2.
Values for g/unit-year were calculated assuming an annual usage of 50 hours and a 40 percent load factor. Factors for g/hphr can
be used in instances where annual usages, load factors, and rated horsepower are known Horsepower hours are the product of the
usage in hours, the load factor, and the rated horsepower.
cValues calculated, not measured, based on the use of 0.043 percent sulfur content fuel.
Values calculated from annual fuel consumption. Evaporative losses from storage and filling operations are not included (see
Chapter 4).
II- 5-2
EMISSION FACTORS
1/75
-------
II-6 Agricultural Equipment
II-6.1 General — Farm equipment can be separated into two major categories: wheeled tractors and other farm
machinery. In 1972, the wheeled tractor population on farms consisted of 4.5 million units with an average power
of approximately 34 kilowatts (45 horsepower). Approximately 30 percent of the total population of these
tractors is powered by diesel engines. The average diesel tractor is more powerful than the average gasoline tractor,
that is, 52 kW (70 hp) versus 27 kW (36 hp).1 A considerable amount of population and usage data is available
for farm tractors. For example, the Census of Agriculture reports the number of tractors in use for each county in
the U.S.- Few data are available on the usage and numbers of non-tractor farm equipment, however. Self-propelled
combines, forage harvesters, irrigation pumps, and auxiliary engines on pull-type combines and balers are examples
of non-tractor agricultural uses of internal combustion engines. 'Table II-6-1 presents data on this equipment for
the U.S.
II- 6.2 Emissions — Emission factors for wheeled tractors and other farm machinery are presented in Table
IL-b-2. Estimating emissions from the time-based emission factors—grams per hour (g/hr) and pounds per hour
(lb''hr)—requires an average usage value in hours. An approximate figure of 550 hours per year may be used or, on
the basis of power, the relationship, usage in hours = 450 + 5.24 (kW - 37.2) or usage in hours = 450 + 3.89 (hp -
50) may be employed.1
The best emissions estimates result from the use of "brake specific" emission factors (g/kWh or g/hphr).
Emissions are the product of the brake specific emission factor, the usage in hours, the power available, and the
load factor (power used divided by power available). Emissions are also reported in terms of fuel consumed.
TableII-6-1. SERVICE CHARACTERISTICS OF FARM EQUIPMENT
(OTHER THAN TRACTORS)3
Machine
Combine, self-
propelled
Combine, pull
type
Corn pickers
and picker-
shellers
Pick-up balers
Forage
harvesters
Miscellaneous
Units in
service, x103
434
289
687
655
295
1205
Typical
size
4.3m
(14ft)
2.4m
(8ft)
2-row
5400 kg/hr
(6 ton/hr)
3.7m
(12ft) or
3-row
-
Typical power
kW
82
19
_b
30
104
22
hp
110
25
40
140
30
Percent
gasoline
50
100
100
0
50
Percent
diesel
50
0
0
100
50
Reference 1.
Unpowered.
1/75
Internal Combustion Engine Sources
II-6-1
-------
TableII-6-2. EMISSION FACTORS FOR WHEELED FARM TRACTORS AND
NON-TRACTOR AGRICULTURAL EQUIPMENT*
EMISSION FACTOR RATING: C
Pollutant
Carbon monoxide
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Exhaust
hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Crankcase
hydrocarbons'3
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Evaporative
hydrocarbons^
g/u nit-year
Ib/unit-year
Nitrogen oxides
(NOxasNO2)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Aldehydes
(RCHOasHCHO)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Sulfur oxides0
(SOX as S02)
g/hr
Ib/hr
Diesel farm
tractor
161
0.355
4.48
3.34
14.3
119
77.8
0.172
2.28
1.70
7.28
60.7
-
—
-
_
—
—
-
—
452
0.996
12.6
9.39
40.2
335
16.3
0.036
0.456
0.340
1.45
12.1
42.2
0.093
Gasoline farm
tractor
3,380
7.46
192
143
391
3,260
128
0.282
7.36
5.49
15.0
125
26.0
0.057
1.47
1.10
3.01
25.1
15,600
34.4
157
0.346
8.88
6.62
18.1
151
7.07
0.016
0.402
0.300
0.821
6.84
5.56
0.012
Diesel farm
equipment
(non-tractor)
95.2
0.210
5.47
4.08
16.7
139
38.6
0.085
2.25
1.68
6.85
57.1
-
—
-
_
—
— '
-
— •
210
0.463
12.11
9.03
36.8
307
7.23
0.016
0.402
0.30
1.22
10.2
21.7
0.048
Gasoline farm
equipment
(non-tractor)
4,360
9.62
292
218
492
4,100
143
0.315
9.63
7.18
16.2
135
28.6
0.063
1.93
1.44
3.25
27.1
1,600
3.53
105
0.231
7.03
5.24
11.8
98.5
4.76
0.010
0.295
0.220
0.497
4.14
6.34
0.014
II-6-2
EMISSION FACTORS
1/75
-------
TableII-6-2. (continued). EMISSION FACTORS FOR WHEELED FARM TRACTORS AND
NON-TRACTOR AGRICULTURAL EQUIPMENT3
EMISSION FACTOR RATING: C
Pollutant
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Paniculate
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Diesel farm
tractor
1.17
0.874
3.74
31.2
61.8
0.136
1.72
1.28
5.48
45.7
Gasoline farm
tractor
0.312
0.233
0.637
5.31
8.33
0.018
0.471
0.361
0.960
8.00
Diesel farm
equipment
(non-tractor)
1.23
0.916
3.73
31.1
34.9
0.077
2.02
1.51
6.16
51.3
Gasoline farm
equipment
(non- tractor)
0.377
0.281
0.634
5.28
7.94
0.017
0.489
0.365
0.823
6.86
Reference 1.
Crankcase and evaporative emissions from diesel engines are considered negligible.
Not measured. Calculated from fuel sulfur content of 0.043 percent and 0.22 percent for gasoline-powered and diesel-
powered equipment, respectively.
References for Section 11-6
1. Hare. C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Final Report. Part 5: Heavy-Duty Farm, Construction and Industrial Engines.
Southwest Research Institute, San Antonio. Tex. Prepared for Environmental Protection Agency, Research
Triangle Park, N.C., under Contract No. EHS 70-108. August 1973. 97 p.
2. County Farm Reports. U.S. Census of Agriculture. U.S. Department of Agriculture. Washington, D.C.
1/75
Internal Combustion Engine Sources
11-6-3
-------
II-7 Heavy-Duty Construction Equipment
II-7.1 General - The useful life of construction equipment is fairly
short because of the frequent and severe usage it must endure. The
annual usage of tha various categories of equipment considered here
ranges from 740 hours (wheeled tractors and rollers) to 2000 hours
(scrapers and off-highway trucks). This high level of use results in
average vehicle lifetimes of only 6 to 16 years. The equipment
categories in this section include: track type tractors/ track type
loaders, motor graders, wheel tractor scrapers, off-highway trucks
(includes pavement cold planers and wheel dozers), wheeled loaders,
wheeled tractors, rollers (static and vibratory), and miscellaneous
machines. The latter category contains an array of less numerous mobile
and semi-mobile machines used in construction such as log skidders,
hydraulic excavatorg/crawlers, trenchers, concrete pavers, compact
loaders, crane lattice booms, cranes, hydraulic excavator wheels, and
bituminous pavers. Some of these categories are different from the Third
Edition.
II-7.2 Emissions - Recently, Environmental Research and Technology, Inc.
prepared a report under the sponsorship of a consortium of industry
groups. This report, referred to as the CAL/ERT report, provided a very
comprehensive investigation of farm construction and industrial equipment
emissions. The emissions of twenty different types of construction
equipments are grouped roughly according to the categories in the Third
Edition by their populations in California (based on a report prepared by
the California Air Resources Board4). The updated emission factors on
HC/CO/NOx for heavy-duty construction equipment for diesel engines are
reported in Table II-7.1. No update has been done on other emissions
(aldehydes, sulfur oxides, and particulates), and their values are
carried over from the Third Edition. Less than five percent of the sales
use gasoline engines, and the trend is toward complete dieselization. No
update has been done oh the gasoline engine construction equipment
emissions. Therefore, the emission factors for gasoline engines from
the Third Edition are reprinted in Table II-7.2. The factors are
reported in three different forms-on the basis of running time, fuel
consumed, and power consumed.
In order to estimate emissions from time-based emission factors, annual
equipment usage in hours must be estimated. The following estimates of
use for the equipment listed in the tables should permit reasonable
emission calculations.
II-7-1
-------
Category Annual operation, hours/year
Tracklaying tractors 1050
Tracklaying shovel loaders 1100
Motor graders 830
Scrapers 2000
Off-highway trucks 4000
(including wheeled dozers) 2000
Wheeled loaders 1140
Wheeled tractors 740
Rollers 740
Miscellaneous 1000
The best method for calculating emissions, however, is on the basis of
"brake specific" emission factors (g/kWh or g/hphr). Emissions are
calculated by taking the product of the brake specific emission factor,
the usage in hours, the power available (that is, rated power), and the
load factor (the power actually used divided by the power available).
II-7-2
-------
References for Section II-7
1. Hare, C.T. and K.J. Springer. Exhaust Emissions from Uncontrolled
Vehicles and Related Equipment Using Internal Combustion
Engines-Final Report. Part 5: Heavy-Duty Farm, Construction, and
Industrial Engines. Southwest Research Institute, San Antonio, Tex.
Prepared for Environmental Protection Agency, Research Triangle Park,
N.C., under Contract No. EHS 70-108. October 1973. 105p.
2. Hare, C.T. Letter to C.C. Masser of Environmental Protection Agency,
Research Triangle Park, N.C., concerning fuel-based emission rates
for farm, construction, and industrial engines. San Antonio, Tex.
January 14, 1974. 4p.
3. Ingalls, Melvin N. Recommended Revisions to Gaseous Emission Factors
from Several Classes of Off-Highway Mobile Sources—Final Report.
Southwest Research Institute, San Antonio, Texas. Prepared for
Environmental Protection Agency, Office of Mobile Source Air
Pollution Control, Ann Arbor, MI., under Contract NO. 68-03-3162
September 1984.
4. State of California Air Resources Board. Status Report: Emissions
Inventory on Non-Farm (MS-1), Farm (MS-2), and Lawn and Garden
(Utility) (MS-3) Equipment. July 1983. 87p.
II-7-3
-------
Table II-7.1 Emission Factors for Heavy-Duty, Diesel-Powered
Construction Equipment3
Emission Factor Rating: C
Pollutant
CARBON MONOXIDE
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
EXHAUST HYDROCARBONS
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
NITROGEN OXIDES
(NOx as N02)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
ALDEHYDES
(RCHO as HCHO)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
SULFUR OXIDES
(SOX as SO2)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
PARTICULATE
g/hr
Ib/hr
g/kWh
g/hphr
kg/10"
Track-type
tractor
157.01
0.346
2.88
2.15
9.4
78.5
55.06
0.121
1.01
0.75
3.31
27.6
570.70
1.26
10.47
7.81
34.16
284.92
12.4
0.027
0.228
0.170
0.745
6.22
62.3
0.137
1.14
0.851
3.73
31.1
50.7
0.112
0.928
0.692
3.03
25.3
Wheeled
tractor
1622.77
3.59
9.84
7.34
32.19
268.5
85.26
0.188
2.36
1.76
7.74
64.6
575.84
1.269
15.96
11.91
52.35
436.67
13.5
0.030
0.378
0.282
1.23
10.3
40.9
0.090
1.14
0.851
3.73
31.1
61.5
0.136
1.70
1.27
5.57
46.5
Wheeled
dozer
29.5
0.065
0.215
0.160
0.690
5.76
158.
0.348
1.16
0.867
3.74
31.2
75.
0.165
0.551
0.411
1.77
14.8
Scraper
568.19
1.257
3.28
2.45
10.16
84.6
128.15
0.282
0.74
0.55
2.28
19.0
1740.74
3.840
10.00
7.46
30.99
258.6
65.
0.143
0.375
0.280
1.16
9.69
210.
0.463
1.21
0.901
3.74
31.2
184.
0.406
1.06
0.789
3.27
27.3
Motor
grader
68.46
0.151
2.06
1.54
6.55
54.65
18.07
0.040
0.48
0.36
1.53
12.73
324.43
0.713
9.57
7.14
30.41
253.84
5.54
0.012
0.162
0.121
0.517
4.31
39.0
0.086
1.17
0.874
3.73
31.1
27.7
0.061
0.838
0.625
2.66
22.2
References 3 and 4 for the HC/CO/NOX emissions, and
references 1 and 2 for other emissions.
The wheeled dozer HC/CO/NOX emissions are included in the
off-highway truck category.
II-7-4
-------
Table II-7.1 (cont'd) Emission Factors for Heavy-Duty
Diesel-Powered
Construction Equipment
Emission Factor Rating: C
Off-
Pollutant
CARBON MONOXIDE
g/hr
Ib/hr
g/kWh
g/hphr
kg/103
lb/103
EXHAUST HYDROCARBONS
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/10- gal
NITROGEN OXIDES
(NOX as NO2)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
ALDEHYDES
(RCHO as HCHO)
g/hr
Ib/hr
g/kWh
g/hphr
kg/10~
SULFUR OXIDES
(SOX as S02)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
PARTICULATE
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 qal
Wheeled
loader
259.58
0.572
3.63
2.71
11.79
98.66
113.17
0.25
1.59
0.97
5.17
43.16
858.19
1.89
11.81
8.81
38.5
321.23
18.8
0.041
0.264
0.197
0.859
7.17
82.5
0.182
1.15
0.857
3.74
31.2
77.9
0.172
1.08
0.805
3.51
29.3
Tracktype
loader
91.15
0.201
3.03
2.26
9.93
82.85
44.55
0.098
1.49
1.11
4.85
40.55
375.22
0.827
12.46
9.30
40.78
339.82
4.00
0.009
0.134
0.100
0.439
3.66
34.4
0.076
1.14
0.853
3.74
31.2
26.4
0.058
0.878
0.655
2.88
24.0
Highway
truck
816.81
1.794
4.70
2.28
14.73
123.46
86.84
0.192
0.50
0.37
1.58
13.16
1889.16
4.166
10.92
8.15
34.29
286.10
51.0
0.112
0.295
0.220
0.928
7.74
206.
0.454
1.19
0.887
3.74
31.2
116.
0.256
0.673
0.502
2.12
17.7
Roller
137.97
0.304
8.08
6.03
22.64
188.37
30.58
0.067
1.30
0.97
3.60
30.09
392.90
0.862
17.49
13.05
48.49
404.51
7.43
0.016
0.263
0.196
0.731
6.10
30.5
0.067
1.34
1.00
3.73
31.1
22.7
0.050
1.04
0.778
2.90
24.2
Miscel-
laneous
306.37
0.675
6.16
4.60
18.41
153.51
69.35
0.152
1.35
1.01
4.04
33.70
767.30
1.691
14.75
11.01
44.10
368.01
13.9
0.031
0.272
0.203
0.813
6.78
64.7
0.143
1.25
0.932
3.73
31.1
63.2
0.139
1.21
0.902
3.61
30.1
References 3 and 4 for the HC/CO/NO
references 1 and 2 for other emissions.
The off-highway truck category incudes
emissions from the wheeled dozer.
emissions and
HC/CO/NO,
II-7-5
-------
Table II-7.2 Emission Factors for Heavy-Duty, Gasoline-Powered
Construction Equipment3
Emission Factor Rating: C
Pollutant
CARBON MONOXIDE
g/hr
Ib/hr
g/kWh
EXHAUST HYDROCARBONS
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
EVAPORATIVE
HYDROCARBONS b
g/hr
Ib/hr
CRANKCASE
HYDROCARBONS"
g/hr
Ib/hr
NITROGEN OXIDES
(NOX as NO2)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103
lb/10:
ALDEHYDES
(RCHO as HCHO)
g/hr
Ib/hr
0.0198
g/kWh
g/hphr
kg/103 liter
lb/103 gal
SULFUR OXIDES
(SOX as S02)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/10- gal
Wheeled
tractor
4320.
9.52
190.
142.
389.
3250.
164.
0.362
7.16
5.34
14.6
122.
30.9
0.0681
32.6
0.0719
195.
0.430
8.54
6.37
17.5
146.
7.97
0.0176
0.341
0.254
0.697
5.82
7.03
0.0155
0.304
0.227
0.623
5.20
Motor
grader
5490.
12.1
251.
187.
469.
3910.
186.
0.410
8.48
6.32
15.8
132.
30.0
0.0661
37.1
0.0818
145.
0.320
6.57
4.90
12.2
102.
8.80
0.0194
0.386
0.288
0.721
6.02
7.59
0.0167
0.341
0.254
0.636
5.31
Wheeled
loader
7060.
15.6
219.
163.
435.
3630.
241.
0.531
7.46
5.56
14.9
124.
29.7
0.0655
48.2
0.106
235.
0.518
7.27
5.42
14.5
121.
9.65
0.0213
0.298
0.222
0.593
4.95
10.6
0.0234
0.319
0.238
0.636
5.31
Roller
6080.
13.4
271.
202
460.
3840.
277.
0.611
12.40
9.25
21.1
176.
28.2
0.0622
55.5
0.122
164.
0.362
7.08
5.28
12.0
100.
7.57
0.0167
0.343
0.256
0.582
4.86
8.38
0.0185
0.373
0.278
0.633
5.28
Miscel-
laneous
7720.
17.0
266.
198.
475.
3960.
254.
0.560
8.70
6.49
15.6
130.
25.4
0.0560
50.7
0.112
187.
0.412
6.48
4.79
11.5
95.8
9.00
0.0198
0.298
0.222
0.532
4.44
10.6
0.0234
0.354
0.264
0.633
5.28
II-7-6
-------
Table II-7.2 (cont'd) Emission Factors for Heavy-Duty,
Gasoline-Powered
Construction Equipment3
Emission Factor Rating: C
Wheeled
tractor
Motor
grader
Wheeled
loader
Roller
Miscel-
laneous
Pollutant
PARTICULATE
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
References 1 and 2.
Evaporative and crankcase hydrocarbons based on operating
time only (Reference 1).
10.9
0.0240
0.484
0.361
0.991
8.27
9.40
0.0207
0.440
0.328
0.822
6.86
13.5
0.0298
0.421
0.314
0.839
7.00
11.8
0.0260
0.527
0.393
0.895
7.47
11.7
0.0258
0.406
0.303
0.726
6.06
ir-7-7
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11-8 Snowmobiles
II-8.1 General — In order to develop emission factors for snowmobiles, mass emission rates must be known, and
operating cycles representative of usage in the field must be either known or assumed. Extending the applicability
of data from tests of a few vehicles to the total snowmobile population requires additional information on the
composition of the vehicle population by engine size and type. In addition, data on annual usage and total machine
population are necessary when the effect of this source on national emission levels is estimated.
An accurate determination of the number of snowmobiles in use is quite easily obtained because most states
require registration of the vehicles. The most notable features of these registration data are that almost 1.5 million
sleds are operated in the United States, that more than 70 percent of the snowmobiles are registered in just four
states (Michigan, Minnesota, Wisconsin, and New York), and that only about 12 percent of all snowmobiles are
found in areas outside the northeast and northern midwest.
II-8.2 Emissions - Operating data on snowmobiles are somewhat limited, but enough are available so that an
attempt can be made to construct a representative operating cycle. The required end products of this effort are
time-based weighting factors for the speed/load conditions at which the test engines were operated; use of these
factors will permit computation of "cycle composite" mass emissions, power consumption, fuel consumption, and
specific pollutant emissions.
Emission factors for snowmobiles were obtained through an EPA-contracted study1 in which a variety of
snowmobile engines were tested to obtain exhaust emissions data. These emissions data along with annual usage
data were used by the contractor to estimate emission factors and the nationwide emission impact of this pollutant
source.
To arrive at average emission factors for snowmobiles, a reasonable estimate of average engine size was
necessary. Weighting the size of the engine to the degree to which each engine is assumed to be representative of
the total population of engines in service resulted in an estimated average displacement of 362 cubic centimeters
(cm3).
The speed/load conditions at which the test engines were operated represented, as closely as possible, the
normal operation of snowmobiles in the field. Calculations using the fuel consumption data obtained during the
tests and the previously approximated average displacement of 362 cm-5 resulted in an estimated average fuel
consumption of 0.94 gal/hr.
To compute snowmobile emission factors on a gram per unit year basis, it is necessary to know not only the
emission factors but also the annual operating time. Estimates of this usage are discussed in Reference 1. On a
national basis, however, average snowmobile usage can be assumed to be 60 hours per year. Emission factors for
snowmobiles are presented m Table 11-6-1.
References for Section 11-8
1. Hare, C. T. and K. J. Springer. Study of Exhaust Emissions from Uncontrolled Vehicles and Related
Equipment Using Internal Combustion Engines. Final Report. Part 7: Snowmobiles. Southwest Research
Institute. San Antonio, Tex. Prepared for Environmental Protection Agency. Research Triangle Park. N.C..
under Contract No. EHS 70-108. April 1974.
1/75 Internal Combustion Engine Sources II-8-1
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TableII-8-1. EMISSION FACTORS FOR
SNOWMOBILES
EMISSION FACTOR RATING: B
Pollutant
Carbon monoxide
Hydrocarbons
Nitrogen oxides
Sulfur oxides0
Solid particulate
Aldehydes (RCHO)
Emissions
g/unit-yeara
58,700
37,800
600
51
1,670
552
g/gaib
1,040.
670.
10.6
0.90
29.7
9.8
g/literb
275.
177,
2.8
0.24
7.85
2.6
g/hrb
978.
630.
10.0
0.85
27.9
9.2
aBased on 60 hours of operation per year and 362 cm3 displacement.
Based on 362 cm displacement and average fuel consumption of 0.94 gal/hr.
cBased on sulfur content of 0.043 percent by weight.
II-8-2
EMISSION FACTORS
1/75
•U.S. GOVERNMENT PRINTING OFFICEi 1985-641-346
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