EPA-AA-TSS-PA-84-4
Technical Report
Size Specific Total Particulate
Emission Factors for Mobile Sources
By
Robert I. Bruetsch
June 1984
NOTICE
Technical Reports do not necessarily represent final EPA
decisions or positions. They are intended to present
technical analysis of issues using data which are
currently available. The purpose in the release of such
reports is to facilitate the exchange of technical
information and to inform the public of technical
developments which may form the basis for a final EPA
decision, position or regulatory action.
Technical Support Staff
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
Office of Air, Noise and Radiation
U. S. Environmental Protection Agency
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Table of Contents
Page
List of Tables 3
List of Figures 5
1.0 Introduction 6
2.0 Projecting Size Specific Total
Particulate Emission Factors 9
2.1 Lead Emission Factors 14
2.2 Misfueling and Fuel Switching 18
2.3 Particle Size Distribution 20
2.4 Control System Fractions 21
2.5 Organic, Sulfate, Heavy-Duty Truck
and Motorcycle Emission Factors 23
2.5.1 Organic Emission Factor Components 23
2.5.2 Sulfate Emission Factor Components 23
2.5.3 Diesel Emission Factors 27
2.5.4 Heavy-Duty Truck Emission
Factor Components . 28
2.5.5 Motorcycle Emission Factors 32
2.6 Brake and Tire Wear Particulate Emission
Factor Components 33
3.0 Example Calculation of Automobile
Particulate Emissions Less than 10 Microns 57
4.0 References 66
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List of Tables
Number Title Page
1 Emission Factors of Motor Vehicle Engine
Total Particulate Emissions 35,36
2 Lead Content of Gasoline , 37
3 Fraction of Light-Duty Vehicle Model Year
Sales Equipped with Different Emission
Control Systems (Low-Altitude Non-California) 38
4 Fleet Sales Fractions: Light-Duty Vehicles 39
5 Travel Weighting Factor Calculation: Light-
Duty Vehicles - 40
6 City/Highway Combined On-Road Fuel Economy 41
7 Fuel Economy Correction Factors at Various
Speeds, Cs 42
8 Fraction of Light-Duty Truck I Model Year
Sales Equipped with Different Emission
Control Systems (Low-Altitude Non-California) 43
9 Fleet Sales Fractions: Light-Duty Trucks I 44
10 Travel Weighting Factor Calculation: Light-
Duty Trucks I 45
11 Fraction of Model Year Sales of Light-Duty
Trucks II by Emission Control Systems 46
12 Fleet Sales Fractions: Light-Duty Trucks II 47
13 Travel Weighting Factor Calculation: Light-
Duty Trucks II 48
14 Fleet Sales Fractions: Heavy-Duty Gasoline-
. . Powered Trucks I and II ... 49
15 Travel Weighting Factor Calculation: Heavy-
Duty Trucks I and Heavy-Duty Gasoline Trucks
II 50
16 Travel Weighting Factor Calculation: Heavy-
Duty Diesel Trucks II 51
17 Travel Weighting Factor Calculation:
Motorcycles 52
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List of Tables (cont'd)
Number Title Page
18 Rates of Misfueling (r^) for Different
Vehicle Classes (Simplified Rates) 53
18a Rates of Misfueling (r^) for Different
Vehicle Ages and Classes (Exact Rates) 54
19 Average Data on Particle Size Distribution 55,56
20 Example Calculations: Light-Duty Vehicle
Particulate Emission Rate Under 10 Microns
for the Year 1985 61
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List of Figures
Number Title Page
1 Leaded Gasoline Particulate Size Distribution 62
2 Unleaded Gasoline Particulate Size Distribution 63
3 Diesel Particulate Size Distribution 64
4 Brake Wear Particulate Size Distribution 65
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1.0 INTRODUCTION
The following material was developed to predict total
particulate emission factors of on-road vehicles, trucks and
motorcycles, both gasoline and diesel fueled, at various
vehicle speeds for particles in the respirable 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 developed for this emission
factor determination include area travel fractions by vehicle
class, vehicle miles traveled, vehicle speed, particle size
limits of interest and calendar year.
This report is arranged to present total particulate emission
factor equations, as the sum of individual masses of lead
salt, organic and sulfate components for leaded and unleaded
gasoline fueled vehicles and compositely (i.e., total
particulate mass) 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 are also 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.
The procedure herein can be used to project automotive
particulate emissions by those agencies developing State
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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 was prepared by the Office of Mobile Sources in
response to a request from the Office of Air Quality Planning
and Standards. It has been designed to be consistent with
the methodology developed in the April 15, 1983 EPA report,
Supplementary Guidelines for Lead Implementation Plans—
Updated Projections for Motor Vehicle Lead Emissions, by
Penny M. Carey, and uses this methodology for the projection
of the lead component of total particulate emissions for
vehicles using leaded and unleaded gasoline (1)*. In
addition to the lead document, from which the methodology for
the projection of area lead emission factors is used, this
report uses three other sources of particulate emission
factor estimates. Emission factors for organics, sulfates on
the Federal Test Procedure (FTP) cycle, and heavy-duty
gasoline trucks came from the Draft Study of Particulate
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 1983
(10). Sulfates on the Sulfate Emission Test (SET) cycle and
motorcycle emission factors came from the March 1981 EPA
report, Compilation of Air Pollutant Emission Factors:
Highway Mobile Sources, EPA-460-3-81-005 (2). Light- and
heavy-duty diesel particulate emission factors are referenced
from the Draft Diesel Particulate Study, Emission Control
Technology Division, Office of Mobile Sources, Office of Air
and Radiation, U.S. EPA, October 1983 (4). Emission
* Numbers in parentheses represent references which are given
at the end of this report in Section 4.0.
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factor estimate updating is an ongoing process and, in many
cases, these values are based on testing of only a few
vehicles.
Further revisions will be made to this document as needed as
new information becomes available. In particular, new
information on fleet characteristics and on the incidence of
fuel switching has recently been prepared in connection with
the preparation of MOBILES, the latest computer program for
calcu-
lation of motor vehicle emissions of hydrocarbons, carbon
monoxide, and oxides of nitrogen. This document will be
revised to reflect this new information as promptly as
possible. In the meantime, the calculations described here
will give acceptable results.
This document may also have to be revised in the future to
reflect changes in the use of unleaded fuel. EPA is
currently considering banning the use of leaded fuel because
of the health hazards associated with lead and to discourage
the practice of misfueling which deteriorates the efficiency
of vehicle emission control systems. Since EPA has not at
this time proposed these regulations, this report assumes
that use of leaded gasoline will continue with only the lead
phasedown in effect restricting the lead level to 1 g/gallon
in leaded gasoline.
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2.0 PROJECTING SIZE SPECIFIC TOTAL PARTICULATE EMISSION
FACTORS
The purpose of this report is to provide a methodology with
which 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 PbClBr. Therefore estimates of
the mass of lead particulate will be considerably larger than
those predicted by the lead document. 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, are also important contributors to total vehicular
particulate emissions.
Areawide particulate emissions, as is shown in Equation 1.0,
are a function of calendar year, average vehicle speed,
vehicle class travel fractions, the particle size range of
interest and the vehicle class emissions associated with the
calendar year and vehicle speed. With the exceptions 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 from the area of interest.
Equation 1.0
EF
Pm,n,s
EF
brakes
EF
tires
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where:
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EF
' pm,n,s
size specific all-vehicle class total
particulate emission factor on January 1 of
calendar year n at vehicle speed s (g/mile);
vehicle class designator 1 = light-duty
vehicles (LDV), 2 = light-duty trucks I
(LDT1), 3 = light-duty trucks II (LDT2), 4 =
heavy-duty trucks I (HDT1), 5 = heavy-duty
trucks II (HDT2), 6 = motorcycles (MC);
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.)
area travel fraction of vehicle class i in
calendar year n;
EF.
exhaust particulate emission
vehicle class i in calendar
vehicle speed s (g/mile).
factor for
year n at
EF.
brakes
airborne brake wear particulate emission
factor 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;
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EF.. = airborne tire wear particulate emission
tires
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;
M-. = fraction of airborne particles less than a
hi
user specified size cutoff (0.1-10 urn) that
are attributable to vehicle brake wear, from
Table 19 or Figure 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
trucks I (8501-14000 Ibs. GVWR), 5) heavy-duty trucks II
(greater than 14001 Ibs. GVWR), and 6) motorcycles.
The exhaust emission factors for each vehicle class for a
given calendar year (EF. ) are broken down into compo-
i, n, s
nent emission factors in Equation 1.1. The components repre-
sent 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 attributable to that
model year (m. .) in the calendar year of interest. For
1» J
example, the component (EF. . ) represents the
i, j , K , n, LI
emissions in grams per mile of lead salts (k=l) from vehicle
class i emitted from model year j vehicles that are on the
road in calendar year n and are designed for use on leaded
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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.
The travel fractions for the six vehicle classes from model
years n to n-19 are provided in Tables 5, 10, 13, 15, 16, and
17. These tables are entitled "Travel Weighting Factor
Calculation" and there is one for each of the six vehicle
classes. (Table 15, however, should be used for all vehicles
in the heavy-duty truck I category and all gasoline heavy-
duty trucks II. Table 16 should be used for all diesels in
the heavy-duty truck II category only. For an explanation of
how to compute emissions from heavy-duty trucks II, see
Section 2.5.4 on p. 23.) The fraction of vehicles from each
class and model year of vehicles designed to use leaded
gasoline (F, . .), unleaded gasoline (FNTT . .), and
J-i , 1 , J JN.LJ, 1 , J
diesel fuel (F . .) are contained in Tables 4, 9, 12, and
LJ , 1 , J
14. These tables are entitled "Fleet Sales Fractions".
Separate tables are provided for light-duty vehicles and
light-duty trucks I and II. Table 14 contains fleet sales
fractions of gasoline fueled versus diesel heavy-duty trucks
I and II. Gasoline-fueled heavy-duty trucks I are assumed to
use leaded gasoline prior to 1987 and unleaded gasoline from
1987 on. Gasoline-fueled heavy-duty truck II and motorcycle
fleet sales are assumed to consist entirely of leaded
gasoline vehicles for all model years.
Equation 1.1
n
EFi „ = = Y! C(EF< -i v „ T + EF. . . T + EF. . . T)(F_ . .)
inc 71 Lvi-iV r.T±JJ-i-ilr T^^^-i-iV T'^^T-i
l,n,S ^J l,J/K1,n,Li l,J,K_,JLi l,3,K0,Li Li>l»
j=n-19
2
(EFi,j,k1,n,NL + EFi,j,k2,NL + EFi,j,k3,NL)(FNL,i,j}
(EF )(F . .)]m. .
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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;
FL . . = fraction of the vehicle class i fleet
designed for use on leaded gasoline in model
year j;
FXT, . . = fraction of the vehicle class i fleet
NL,i,j
designed for use on unleaded gasoline in
model year j;
Fn . = fraction of the vehicle class i fleet
Ut 1 / J
designed for use on diesel fuel in model
year j ;
m. ." = travel fraction for vehicle class i in model
1» J
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
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Test Procedure) and 34.8 mph (cruising conditions comparable
to the average speed of the Sulfate Emissions Test) beginning
with Equation 1.1.1 and ending 'with Equation 1.1.47.
Emission factors for speeds between 19.6 and 34.8 should be
interpolated linearly.
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, hereinafter referred to as the "lead
document" (1). These lead emission estimates are multiplied
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
from 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 on FTP results of
16 test vehicles (24).
For i = 1,2,3 j = n-19,...,1974 k=l C = from Table 7 a = 0.75
s s
Equation 1.1.1
EFi -i k n T = CPbT n(0.929)(MT)+
11 J / K. , n, LI LI, n LI
(aWl1^?}
TV\_ / ^ A *» "I \ / »• \ T \ ^^ / V ^ • «J «^ / /
PbXTT _ (0.071) (MXTT „-)] s/v
where:
(E . . )(C )
c,i,3 s'
fraction of lead burned that is exhausted;
for non-catalyst vehicles use a = 0.75
S
(i.e., 75%); for catalyst vehicles use a
= 0.30 (i.e. 30%);
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C = speed-dependent fuel economy correction
s
factor based on steady cruise or cyclic
driving; available from Table 7
(nondimensional);
Pb.TT = lead content of unleaded gasoline in
NL,n ^
calendar year n from Table 2 (g/gal);
n
PbT n = average lead content of leaded gasoline in
calendar year n from Table 2 (g/gal);
= city/highway combined on-road fuel economy
for model year j and vehicle class i from
Table 6 (miles/gallon);
M = fraction of particles less than a user
specified size cutoff (0.1-10 urn) that are
emitted from vehicles that are fueled with
leaded gasoline, from Table 19 or Figure 1;
^NL C = fraction of particles less than a user
specified size cutoff (0.1-10 urn) that are
emitted from catalyst vehicles that are
fueled with unleaded gasoline, from Table 19
or Figure 2;
MNL NC = fraction of particles less than a user
specified size cutoff (0.1-10 urn) .that are
emitted from non-catalyst vehicles that are
fueled with unleaded gasoline, from Table 19
or Figure 2.
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For i = 1,2,3 j = 1975,. ..,n k=l C = from Table 7 a = 0.75
-* O *3
Equation 1,1*2
EPifjfkrn,L
' (£„ . ,)(C'
c, i, 3 s
For i = 1,2,3 j = 1975,...,n k=l GS = from Table 7 ag = 0.30
Equation 1.1.3
EPi, j.k^n.NL
where:
r. = misfueling rate for vehicle class i from
Table 18.
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
. S . S * ' .
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% of the
lead is retained by the engine (in the oil and combustion
chamber) and 8% is retained by the muffler and exhaust pipes
(33). For gasoline-powered vehicles with catalysts a value
of 0.30 for a should be used. The 0.30 value accounts for
S
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lead retention by the catalyst (approximately 45% based on
some tests run by GM (41) on pelleted catalyst-equipped
vehicles), the oil, the combustion chamber and the rest of
the exhaust system (approximately 25%). The appropriate
values for a have been included above the appropriate
s
equations for convenience.
Combined city/highway fuel economy (E . .) is yet another
c /11 D
factor affecting area lead particulate emissions. Fuel
economy versus model year is provided for each vehicle class
(except motorcycles) in Table 6. Fuel economy of gasoline-
fueled heavy-duty trucks was assumed to equal 5.0 mpg in all
model years in the lead document since this is the value used
in MOBILE2. Values for heavy-duty and future model year fuel
economy for other vehicle classes were updated for this
report since newer information is now available. The heavy-
duty fuel economy values in this report are expected to be
changed in a future version to make them consistent with
MOBILES. The values in Table 6 are closer to the MOBILES
values than was the 5.0 mpg figure used in MOBILE2.
Lead particulate emissions can be determined at any speed by
using Equations 1.1.1, 1.1.2 and 1.1.3 (for light-duty
vehicles and trucks) and 1.1.18, 1.1.19, and 1.1.20 (for
heavy-duty trucks) and the appropriate value of the speed
dependent fuel economy correction factor (C ) for the
S
vehicle speed of interest. Values of C at various speeds
• S
are provided in Table 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
S
the average vehicle speed for the area of concern. The
average area vehicle speed should be a weighted 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
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determine C and area emissions separately for each roadway
s
classification (and average speed).
Area lead particulate emissions are also dependent upon the
lead content of gasoline in a given calendar year. Values
for the lead content of leaded (Pb_ ) and unleaded
L, n
gasoline (Pb,TT ) are contained in Table 2. Values for
NL,n
future years will be updated as new information becomes
available.
Emission factors for organic sulfates and diesels have been
derived and are listed in Table 1 for speeds of 19.6 and 34.8
mph. However, if emission estimates for these particulate
components are desired at other speeds, linear interpolation
of emission factors is possible and appropriate. In fact,
some of the emission factor.s in Table 1 (particularly for
organic and diesel particulate masses) can be used at "all"
vehicle speeds.
2.2 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 accumulation. 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 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 18 for inspection
and maintenance (I/M) and non-I/M areas. In other words, in
the calculation of emission factors from 1975 on, the
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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 overestimation declining with later evaluation
years and essentially disappearing in 1995. For users who
desire more accuracy, Table 18a 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.
Discretionary fuel switching (i.e., percentage of vehicles
designed for use on leaded gasoline that use unleaded
gasoline) is assumed to equal 7.1% of the leaded fleet prior
to 1974 and 27.5% in 1975 and later years and only applies to
the lead salt component of light-duty vehicle and light-duty
truck I and II emissions. Misfueling and fuel switching
rates for all heavy-duty trucks II (over 14000 Ibs. GVWR) and
motorcycles are assumed to be zero. 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 (3). The
discretionary fuel switching were obtained from Energy and
Environmental Analysis, Inc., Assessment of_ Current and
Projected Future Trends in Light-Duty Vehicle Fuel Switching,
June 1982 (8).
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2.3 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 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 19 and also in Figures 1, 2, 3, and 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
particles 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 19.
Values for ML, MNL c, MNL NC/ MD, and M_ should be
expressed as dimensionless fractions of total particulate by
weight emitted below a given size cutoff. Values may be read
directly from Table 19 for the data points listed therein, or
may be read off the graphs of continuous cumulative particle
size distributions in Figures 1, 2, 3, and 4 for interpolated
size cutoffs (e.g., 6.5 urn, 2.5 urn).
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2.4 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 3, 8, and
ll for light-duty vehicles, light-duty trucks I and II,
respectively. These are the vehicle classes that 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 since 1975 a small number of non-catalyst equipped
vehicles have been certified for use on unleaded gasoline.
These vehicles constitute a very small percentage of the total
non-catalyst fleet. However, unlike the lead document, these
are considered in this report and have been given their own
control system fraction category (Fi,j/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 mixes 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 model
years are determined from recent projections by Energy and
Environmental Analysis, Inc. in a report entitled, Forecasts
Oj£ Emission Control Technology 1982-1990 (40). For 1987 and
later, light-duty trucks I and II which are assumed to convert
largely to three-way catalyst technology to meet the proposed
1987 standards.
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Air injection fractions were obtained for light-duty vehicles
and trucks from the Anti-Tampering and Anti-Misfueling
Programs to Reduce In-Use Emissions from Motor Vehicles
(EPA/AA/83-10) report and include all types of air injection
(e.g., pulse-air) in addition to conventional air pump
control systems (3).
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, Vol. 40, No. 48, March 11, 1975 (11); Vol.
41, No. 46, March 8, 1976 (12); Vol. 42, No. 110, June 8,
1977 (13); and Vol. 43, No. 181, Sept. 18, 1978 (14). The
certification data provided emission control systems by model
type and engine displacement which were matched with fuel
economy sales fractions.
Heavy-duty vehicles are either leaded gasoline or diesel
fueled (Table 14) vehicles through 1986. In 1987, more
stringent standards have been promulgated. Therefore, it is
assumed, for the purposes of this report, that all 1987 and
later gasoline fueled trucks in the heavy-duty trucks I
category (less than 14,001 Ibs.) will be equipped with
oxidation catalysts and air injection and will use unleaded
gasoline. All 1987 and later gasoline-fueled trucks in the
heavy-duty truck II category (greater than 14,000 Ibs.) are
assumed in this report to still use leaded gasoline. It
should be noted that other EPA publications may use different
definitions of HDTI and HDTII.
The effect of discretionary fuel switching has not been
incorporated in heavy-duty vehicle emission factor equations
due to the lack of data on the current fuel purchase behavior
of owners of heavy-duty vehicles. Also, as new estimates for
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-23-
heavy-duty fuel economy and new emission standards scenarios
become available, these equations will be revised accordingly.
Motorcycle fractions are based on 2-stroke versus 4-stroke
emission factor estimates. Before 1978, most on-road
motorcycle travel was done by 2-stroke vehicles (53.4%) and
slightly less (46.6%) by 4-stroke vehicles according to sales
figures in the 1983 Motorcycle Statistical Annual published
by the Motorcycle Industry Council, Inc (15). In 1978, more
stringent control of motorcycle emissions 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.
2.5 Organic, Sulfate, Diesel, Heavy-Duty Truck and
Motorcycle Emission Factors
Emission factors for organics, sulfates and diesel
particulates for different model years, control systems, fuel
types and vehicle speeds are listed in Table 1. This' table
also refers the user to the proper equation(s) to which each
emission factor should be applied. All emission factors in
Table 1 are expressed in grams per mile. The following
equations should be used for the calculation of organic,
sulfate, diesel, heavy-duty truck and motorcycle emission
factor components.
i
2.5.1 Organic Emission Factor Components
For i = 1,2,3 j = ri-19,...,1969 k=2
Equation 1.1.4
EF. . = 0.193 MT (g/mile)
_
-------
-24-
For i = 1,2,3 j = 1970,...,1974 k=2
Equati on 1.1.5
EF. . . , 0.068 MT (g/mile)
1 » J , K_ , Li J-i
For i = 1,2,3 j = 1975,...,n k=2 TCi = from Table 18
Equation 1.1.6
EF. . = 0.030 MT (g/mile)
i» D » Ko '
Equation 1.1.7
EFi,j,k0,NL
where:
F. . _.,._ = fraction of the unleaded vehicle class i
n "i [^ A rp
J. , J , \~t\ i
fleet equipped with a catalyst in model
year j;
*"i -i MT Mor-AT- = fraction of the unleaded vehicle class i
1 / J / JN .LJ g IN vJv^f\ X
fleet without a catalyst in model year j.
2.5.2 Sulfate Emission Factor Components
For i = 1,2,3 j = n-19,...,n k=3 s = 19.6
Equation 1.1.8
EF = 0.002 M (g/mile)
1 » J / K-3 » •" -I-1
-------
-25-
For i = 1,2,3 j = n-19,...,n k=3 s = 34.8
Equat ion 1.1.9
EF. . , _ = 0.001 M_ (g/mile)
i,u,k_,L L
For i = 1,2,3 j = 1975,...,n k=3 s = 19.6
Equation 1.1.10
EFi,j,k3,NL
'i)[(Fi,j,CAT/NOAIR}(°-005)(MNL,C)+(Fi,j,CAT/AIR)
where:
i,j,CAT/NOAIR
fraction of the unleaded vehicle class i
fleet equipped with a catalyst but no air
pump in model year j; this includes
oxidation catalyst (F.. ) and
three-way catalyst
with no air pump;
(F..^ j/OXCAT)
i f j , 3WCAT
^ vehicles
Fi,j,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 (F. ^ . ^ OXCAT/AIR) and
three-way plus oxidation catalyst
(Fi, j,3WCAT/OXCAT) -vehicles with air
pumps .
-------
-26-
For i = 1,2,3 j = 1975,. ..,n k =3 s = 34.8 ri = from Table 18
Equation 1.1.11
EF = (
i,j,k3,NL
where :
Fi,j,OXCAT
fraction of the unleaded vehicle class i
equipped with an oxidation catalyst but
no air pump in model year j.
i,j,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.)
i,j,OXCAT/AIR
fraction of the unleaded vehicle class i
equipped with an oxidation catalyst and
an air pump in model year j.
Fi,j,3WCAT/OXCAT
fraction of the unleaded vehicle class i
equipped with both an oxidation and a
three-way catalyst in model year j.
-------
-27-
2.5.3 Diesel Emission Factors (Light-Duty)
For i = 1 j = n-19,...,1980
Equation 1.1.12
EF. = 0.700 M (g/mile)
i / j , JJ JJ
Mn = fraction of particles less than a user specified
size cutoff (0.1-10 urn) that are emitted from
vehicles that are fueled with diesel fuel, from
Table 19 or Figure 3 ;
For i = 1 j = 1981,...,1986
Equation 1.1.13
EF. • n = 0.320 Mn (g/mile)
i, j , u u
For i = 1 j = 1987, . .. ,n
Equation 1.1.14
EF.. . = 0.200 M_ (g/mile)
i» J , L) . D .
For i = 2,3 j = n-19,...,1980
Equation 1.1.15
EF = 0.800 Mn (g/mile)
i i j i U U
-------
-28-
For i = 2,3 j = 1981,...,1986
Equation 1.1.16
EF. . n = 0.280 Mn (g/mile)
1 , J , U LJ
For i = 2,3 j = 1987,...,n
Equation 1.1.17
EF. . = 0.260 M (g/mile)
2.5.4 Heavy-Duty Truck Emission Factor Components
In this report, heavy-duty trucks are divided into two groups;
those less than or equal to 14,000 Ibs. GVW are classified as
heavy-duty trucks I (i=4) and those greater than 14,000 Ibs.
GVW are classified as heavy-duty trucks II (i=5). Calculation
of heavy-duty truck I emissions is accomplished by the same
procedure as light-duty emissions by use of Equation 1.1 (page
7) and the appropriate emission factor component equations
discussed on the following pages. Heavy-duty truck II
emissions are calculated by a slightly different procedure to
distinguish between heavy-duty truck II gasoline and diesel
mileage accumulation rates and vehicle age distribution, which
together determine •travel fraction by vehicle age. Because
gasoline and diesel vehicles in the HDT II weight class are
characterized by different travel fractions by vehicle age, a
single travel fraction itu . does not exist, and it is
necessary to keep the two vehicle types disaggregated.
Gasoline fueled heavy-duty trucks II are assumed to use only
leaded fuel for all model years (i.e., FMT . = 0 for all
'i 3 i j
-------
-29-
j). Therefore, equation 1.1 for heavy-duty trucks II (i=5)
is used as modified below.
Equation 1.1 (for i=5)
EF5,n,s = S t(EF5/jf L + EF5/j/ + EP5f jf k L)
j=n-19 .
(F ,)(m,r ,) + (EF )(F i)U5D J3
L,5,j =>G,3 b , ] , L) U,D,J DU, j
where:
FT c . = fraction of the heavy-duty truck II fleet designed
ij i -> » 3
for use on leaded gasoline in model year j, from
Table 14.
Fn ,. . = fraction of the heavy-duty truck II fleet designed
\J i D , J
for use on diesel fuel in model year j, from Table 14.
m5G . = travel fraction for gasoline fueled heavy-duty
trucks II in model year j, from Table 15 (Note:
mr:p -; = m/i -;as explained in Table 15);
-)Vj i j *» / j
nun . = travel fraction for diesel fueled heavy-duty trucks
DL), J
II in model year j , from Table 16.
The emission factor component equations for both heavy-duty
trucks I and II are listed below in equations 1.1.18 through
For i = 4,5 j = n-19,...,1986 k = 1 a = 0.75
s
Equation 1.1.18
vv (* )(pbr ) (1.557) ,M .
kr • • i, T s L,n (M)
i,3»k,,n,L — L
c, i, j
-------
-30-
For i = 4 j = 1987,..., n k = 1 a = 0.30 r = from Table 18
"
Equation 1.1.19
U-r4)(as)(PbNL>n)(1.557) (
:,j,k,,n,NL 5 NL,C
c,4, j
+ (r4)(as)(PbL/n)(1.557)
Ec,4,j
For i = 5 j = 1987,...,n k = 1 a = 0.75
s
Equation 1.1.20
(a )(Pb )(1.557)
t- . . T = s L,n (MT
D , j , K , n, LJ = i
1 c,5,j
For i = 4,5 j = n-19,...,1986 k = 2
Equation 1.1.21
EF. = 0.370 MT (g/mile)
1»D'^/
For i = 4 j = 1987, ,n k = 2 r4 = from Table 18
r-
Equation 1.1.22
EF4,j,k ,NL = d-r4)(0.054)(MNLfC)+(r4)(0.370)(ML) (g/mile)
-------
-31-
For i = 5 j = 1987,...,n k = 2
Equation 1.1.23
EF_ . , _ = 0.370 MT (g/mile)
5 , ] , K9 ,Li J-.
For i = 4,5 j = n-19,...,1986 k = 3
Equation 1.1.24
EF^^ . k L = 0.006 ML (g/mile)
For i = 4 j = 1987,..., n k = 3 r. = from Table 18
Equation 1.1.25
EF4,j,k ,NL = d-r4)(0.048)(MNLjC)+(r4)(0.006)(ML) (g/mile)
For i = 5 j = 1987,.. .,n k = 3
Equation 1.1.26
EF. . = 0.006 MT (g/mile)
3 / J , K^ , J-i J-i
-------
-32-
For i = 4 j = n-19,...,1982
Equation 1.1.27
EF4,j,D = 1-423 MD
For i = 4 j = 1983,..., n
Equation 1.1.28
EF4,j,D = 1-188 MD
For i = 5 j = n-19,...,n
Equation 1.1.29
EF5jj>D = 1.954 MD (g/mile)
2.5.5 Motorcycle Emission Factors
For i = 6 j = n-19, ... ,1977
Equation 1.1.30
EF6,j,L = r(0.466).(0.046) + (0.534)(0.330)](ML)
= 0.198 M_ (g/mile)
-------
-33-
For i = 6 j = 1978,...,n
Equation 1.1.31
EF,_ . T = 0.046 MT (g/mile)
D , ] , J-i L,
2.6 Brake and Tire Wear Particulate 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.
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-duty gasoline vehicles (42). Particle size
distribution for brake wear particulate (MB) is included in
this reference and is summarized in Table 19. The rate of
0.0128 g/mile times the appropriate fraction of M_, for the
o
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
-------
-34-
Section 3.0 of this report, for example, M_ = 0.98, the
D
brake wear particulate emission rate is therefore 0.0125
g/mile and the total light-duty vehicle particulate emission
rate is 0.0731 g/mile. In this particular example,
therefore, brake wear emissions account for 17% 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 (43,44). 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% 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.
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 information is
available on these reentrained particulates (46, 47), they
are not considered to be directly emitted by mobile sources
and therefore are not included in this report.
-------
Table 1
Emission Factors of Motor
Vehicle Engine Total Particulate Emissions
Applicable Participate Cbntrol
MDdel Year(s) Component System
Light-Duty
Pre-1970
1970-1974
1975+
1975+
1975+
1975+
All
1975+
Pre-1975
1975+
1975+
1975+
1975+
1975+
1975+
1975+
1975+
1975+
1975+
Light-Duty
Pre-1981
1981-1986
1987+
Pre-1981
1981-1986
1987+
Heavy-Duty
Pre-1987
1987+
Type of
FXiel Used
Vehicle
Speed
(MPH)
Emission
Factor
(grama/mile)
Emission
Equation Factor Source
Used In Reference No.
Gasoline Vehicles and Trucks:
Organic
Organic
Organic
Organic
Organic
Organic
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Diesel Vehicles
All LDDV
All LDDV
All LDDV
All LDDT
All LDDT
All LDDT
Gasoline Trucks:
Organic
Organic
NOCAT
NOCAT
NOCAT
CAT
CAT
NOCAT
NOCAT
CAT
NOCAT
CAT/NOAIR(f)
CAT/AIR(g)
NOCAT
NOCAT
NOCAT
OXCAT/NOAIR
3WCAT
OXCAT/AIR
3WCAT/QXCAT
CAT
and Trucks:
—
_
_
_
-
NOCAT
CAT/AIR
Leaded
Leaded
Leaded
Unleaded
Leaded
Uhleaded
Leaded
Leaded
Leaded
Unleaded
Unleaded
Unleaded
Leaded
Unleaded
Unleaded
Unleaded
Unleaded
Unleaded
Leaded
Diesel
Diesel
Diesel
Diesel
Diesel
Diesel
Leaded
Unleaded
All
All
All
All
All
All
19.6
19.6
34.8
19.6
19.6
19.6
34.8
34.8
34.8
34.8
34.8
34.8
34.8
All
All
All
All
All
All
All
All
0.193
0.068
0.030
0.017
0.068
0.030
0.002
0.002
0.001
0.005
0.016
0.002
0.001
0.001
0.005
0.001
0.020
0.025
0.001
0.700
0.320
0.200
0.800
0.280
0.260
0.370
0.054
1.1.4
1.1.5
1.1.6,7
1.1.7
1.1.7
1.1.7
1.1.8,10
1.1.8,10
1.1.9
1.1.10
1.1.10
1.1.10
1.1.9
1.1.11
1.1.11
1.1.11
1.1.11
1.1.11
1.1.11
1.1.12
1.1.13
1.1.14
1.1.15
1.1.16
1.1.17
1.1.21,23
1.1.22
10
10
10(a)
10(b)
10(c)
10(a)(h)
10
10 (d)
2
10
10
10(e)
2
2
2
2
2
2
2(d)
4
4(i)
4
4
4
4
10
10
Ul
I
-------
Table 1 (cont'd)
Bnission Factors of Mator
Vehicle Efrgine Total Participate Emissions
Applicable
ttxJel Year(s)
Pre-1987
1987+
Participate
Component
Sulfate
Sulfate
Control
System
NOCAT
CAT/AIR
"type of
Fuel Used
Leaded
Unleaded
Vehicle
Speed
(MPH)
All
All
Emission
Factor
(grains /mile)
0.006
0.048
Equation
Used In
1.1.24,26
1.1.25
Bnission
Factor Source
Reference No.
10
10
Heavy-duty Diesel Trucks;
Pre-1983
1983+
All
Motorcycles;
All
All
All HDDT1
All HDDT1
All HDDT2
4-Stroke
2-Stroke
Diesel
Diesel
Diesel
Leaded
Leaded
All
All
All
All
All
1.423
1.188
1.954
0.046
0.330
1.1.27
1.1.28
1.1.29
1.1.30,31
1.1.30
10
10
10
2
2
o\
I
(a)Ratio 1.5/3.4 of 1970-74 organic value.
(b) Combined value of organic from catalyst/no air and catalyst/air vehicles.
(c) Same as 1970-74 no catalyst leaded organic value.
(d) Misfueled vehicles.
(e) Same as no catalyst leaded value.
(f) Includes oxidation catalyst vehicles and three-way catalyst vehicles without air pumps.
(g) Includes oxidation catalyst vehicles and three-way plus oxidation catalyst vehicles with air pumps.
(h) Value should actually be higher for the light-duty truck II class (much like the 1970-74 organic
value) but no data exist.
(i) The average LDCV emission factor for 1981 through 1986 is 0.320 g/mile. "Hiis emission factor was
obtained by averaging the factor of 0.270 g/mile for 1981 through 1984 (appropriate for a 1.5
g/mile NOx standard) and 0.420 g/mile for 1985 and 1986 (appropriate for a 1.0 g/mile NQx
standard). Both factors are used in reference 4.
-------
-37-
Table 2
Lead Content of Gasoline
Leaded Gasoline* Unleaded Gasoline
Year (g/gal) (g/gal)
1974 1.79
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 1.1 0.014
1985 1.1 0.014
1986 1.1 0.014
1987 1.1 0.014
1988 1.1 0.014
1989 1.1 0.014
1990 1.1 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.
-------
Table 3
Fraction of Light-Duty Vehicle Model
Year Sales Equipped with Different
Control
System
FL,I,J
Fl,j,NL,NOCAT
Fl, j,aXCAT/NOAIR
Fl.j,OXCAT/AIR
Fl,j.3WCAT
pl. J.3WCAT/CIXCAT
FD,l.j
Fl,j.CAT
Fl,j,CAT/NOAIR
pl. CAT/AIR
Pre-
1975
1.000
o
0
0
0
o
0
0
0
0
1975
.127
.081
.597
.322
. 0
0
0
.919
.597
.322
1976
.132
.020
.637
.343
0
0
0
.980
.637
.343
1977
.157
0
.650
.350
0
0
0
1.000
.650
.350
Emission
Systems (Low-Altitude Non-California)
1978
.131
0
.650
.350
0
0
.030
1.000
.650
.350
1979
.090
0
.640
.345
.015
0
.040
1.000
.655
.345
1980
.041
0
.421
.514
.053
.012
.050
l.OOO
.474
.526
1981
0
0
.033
.099
.263
.605
.061
1.000
.296
.704
1982
0
0
0
.140
.320
.540
.047
1.000
.140
.860
1983
0
0
0
.120
.220
.660
.024
1.000
.180
.820
1984
0
0
0
0
.400
.600
.030
1.000
.240
.760
1985
0
0
0
0
.530
.470
.054
1.000
.370
.630
1986
0
0
0
0 '
.550
.450
.063
1.000
.440
.560
1987
0
0
0
0
.570
.430
.072
1.000
.520
.480
1988+
0
0
0
0
.600
.400
.082
1.000
.530
.470
Sources: U.S. EPA Emission Factor In-Use Test Vehicle Data Dase.
EEA Forecasts of Emission Control Technology 1983-1990.
U.S. EPA Fuel Economy Data Dase.
Anti-Tampering and Anti-Misfueling Programs to Reduce In-Use Emissions from Motor Vehicles.
Mote: Model year columns don't add up to 1.000. Only FL, 1, j and FD,1, j are fractions of all IXVs. All other
systems are fractions of all unleaded LDVs.
-------
-39-
Table 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+
WHERE:
FNL,I,j
FL,I,J
FD,I,J
Unleaded Gasoline
Fraction of LDV
Fleet, FNL>lyj*
0.000
0.873
0.868
0.843
0.839
0.870
0.909
0.939
0.953
0.976
0.970
0.946
0.937
0.928
0.918
Leaded Gasoline
Fraction of LDV
Fleet, FL,I,J*
1.000
0.127
0.132
0.157
0.131
0.090
0.041
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
0.000
0.000
0.000
0.030
0.040
0.050
0.061
0.047
0.024
0.030
0.054
0.063
0.072
0.082
Estimated fraction of the LDV fleet which use unleaded
gasoline in model year j;
Estimated fraction of the LDV fleet which use leaded
gasoline in model year j ;
Estimated fraction of the LDV fleet which use diesel
fuel in model year j.
*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.
Percentages of gasoline vehicles requiring leaded and nonleaded
fuel obtained from Energy and Environmental Analysis, Inc.
"Documentation for the New Highway Fuel Consumption Model", January
1982.
-------
-40-
Table 5
TRAVEL WEIGHTING FACTOR CALCULATION*
Light-Duty Vehicles
(a)
January 1
Fraction
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
Total
Registration**
0.025
0.106
0.096
0.074
0.096
0.108
0.093
0.074
0.069
0.062
0.050
0.037
0.031
0.024
0.016
0.010
0.005
0.003
0.002
0.016
(b)
Annual
Mileage
Accumulation
Rate
(a) (b)
C(a)(b)/(SUM)]
Fraction of
LDV Travel by
Model Year,
14400
14275
13775
13250
12675
12175
11650
11075
10575
10050
9475
8975
8450
7875
7375
6850
6275
5775
5275
4750
360.0
1513.2
1322.4
980.5
1216.8
1314.9
1083.5
819.6
729.7
623.1
473.8
332.1
262.0
189.0
118.0
68.5
31.4
17.3
10.6
76.0
0.031
0.131
0.115
0.085
0.106
0.114
0.094
0.071
0.063
0.054
0.041
0.028
0.023
0.016
0.010
0.006
0.003
0.002
0.001
0.006
SUM:
11542.4
Compilationof Air Pollutant Emission Factors: Highway Mobile
Sources, March 1981, [EPA-460/3-81-005]. The travel weighting
fractions reflect a January 1 evaluation date.
**January 1 fractions of total registration differ from those in
the cited source because they have been normalized to add up to
1.000. The cited source performed on equivalent normalization
at a later stage in its calculation.
-------
-41-
Table 6
Ci
Model Year
Pre-1970
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988+
ty/Highway
Fuel
LDV
13.9
13.9
13.2
13.1
12.9
12.6
13.9
14.9
15.6
16.7
18.5
19.6
21.8
23.3
24.6
26.0
27.4
28.8
30.2
31.6
Combined
On-Road
Fuel Economy*
(miles/gallon)
Economy,
LDT1
10.6
10.6
10.4
10.2
9.9
9.6
12.0
12.6
13.8
14.3
15.2
16.3
18.1
18.4
18.9
19.5
20.2
21.1
22.0
22.9
Ec , i , j
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
13.8
14.3
14.9
15.4
16.0
16.6
17.2
HDT1 HDT2
7.6
8.0
8.0
8.0
8.4
8.7
9.1
9.2
9.4
9.2
9.7
10.2
10.7
11.3
11.5
11.8
12.0
12.4
12.7
13.1
5.5
5.1
5.0
5.0
5.0
5.0
5.0
5.1
5.1
5.2
5.1
5.1
6.0
6.3
6.5
6.7
6.9
7.1
7.3
7.5
*Fuel economies for model years 1980-1988 were obtained from
Energy and Environmental Analysis, Inc., "The Highway Fuel
Consumption Model - Tenth Quarterly Report" (U.S. DOE
Contract Number DE-AC01-80IE-11972, Task No. 8, November
1983). Fuel economies for model years 1970-1979 were
obtained from Robert Dulla, EEA.
-------
-42-
Table 7
Fuel Economy Correction Factors at Various Speeds, Cs
(Normalized to 32.7 miles/hour-cyclic driving)
Cs Cs
Speed (mph) Cyclic Driving Steady Cruise
(-FTP)
(-SET)
5
10
15
9 O,
25
30
32.7
0 C
40
45
50
55
60
0.323
0.553
0.692
07 an
0.885
0.963
1.000
i H99 —
1.053
1.073
1.078
1.063
1.023
0.467
0.709
0.997
1 1 C 0
1.248
1.294
1.303
i on^
1.288
1.256
1.210
1.159
1.104
-------
Table 8
Fraction of Light-Duty Truck I
Year Sales Equipped with Different
Control
System
FL.2,j
F2,j,NL,NCCAT
F2,j.OXCAT/NCAIR
F2.j,OXCAT/AIR
F2.j.3WCAT
F2,j,3WCAT/OXCAT
FD.2,j
P2,j,CAT
F2,j,CAT/NCAIR
F2, CAT/AIR
Pre-
1975
1.000
0
0
0
0
0
0
0
0
0
1975
.188
.123
.570
.307
0
0
0
.877
.570
.307
1976
.088
.225
.504
.271
0
0
0
.775
.504
.271
1977
.038
.083
.596
.321
0
0
0
.917
.596
.321
Model
Emission
Systems (Low-Altitude Non-California)
1978
.027
.069
.605
.325
0
0
.005
.930
.605
.325
1979
.032
.034
.561
.405
0
0
.011
.966
.561
.405
1980
.023
.027
.564
.409
0
0
.021
.973
.564
.409
1981
0
.011
.574
.415
0
0
.084
.989
.574
.415
1982
0
0
.400
.500
.100
0
.067
1.000
.500
.500
1983
0
0
.300
.500
.200
0
.061
1.000
.500
.500
1984
0
0
.150
.450
.400
0
.056
1.000
.250
.750
1985
0
0
.150
.450
.400
0
.050
1.000
.250
.750
1986
0
0
.150
.450
.400
0
.075
1.000
.250
.750
1987
0
0
0
.150
.850
0
.100
1.000
.250
.750
1988+
0
0
0
.150
.850
0
.125
1.000
.250
.750
OJ
I
Sources: U.S. EPA Emission Factor In-Use Test Vehicle Dbta Base.
U.S. EPA Fuel Economy Eata Base.
U.S. EPA Federal Register: Federal Certification Test Results 1975-78.
Anti-Tampering and Anti-Misfueling Programs to Reduce In-Use Emissions from Motor Vehicles.
tbte: Model year columns don't add up to 1.000. Only FLf2,j and
systems are fractions of all unleaded LOTls.
^, j are fractions of all LDTls. All other
-------
-44-
Table 9
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+
WHERE:
FL,2,j
FD,2,j
Unleaded Gasoline
Fraction of LDT1
Fleet, FNL,2,j*
0.000
0.812
0.912
0.962
0.968
0.957
0.956
0.916
0.933
0.939
0.944
0.950
0.925
0.900
0.875
Leaded Gasoline
Fraction of LDT1
Fleet, FL>2,j*
1.000
0.188
0.088
0.038
0.027
0.032
0.023
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Diesel Fraction of
LDT1 Fleet, FD>2,j*
0.000
0.000
0.000
0.000
0.005
0.011
0.021
0.084
0.067
0.061
0.056
0.050
0.075
0.100
0.125
FNL,2,j = Estimated fraction of the LDT1 fleet which use unleaded
gasoline in model year j;
Estimated fraction of the LDT1 fleet which use leaded
gasoline in model year j;
Estimated fraction of the LDT1 fleet which use diesel
fuel in model year j.
*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.
Percentages of gasoline vehicles requiring leaded and unleaded fuel
obtained from Energy and Environmental Analysis, Inc. "Documentation
for the New Highway Fuel Consumption Model", January 1982.
-------
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
-45-
Table 10
TRAVEL WEIGHTING FACTOR CALCULATION*
Light-Duty Trucks I**
(a)
January 1
Fraction
of Total
Registration***
0.034
0.101
0.091
0.065
0.098
0.106
0.081
0.064
0.047
0.051
0.049
0.035
0.038
0.035
0.028
0.023
0.016
0.012
0.011
0.014
(b)
Annual
Mileage
Accumulation
Rate
15600
15200
13625
12175
10925
9925
9200
8450
7875
7375
6900
6500
6125
5800
5425
5150
4925
4625
4400
4400
SUM:
530.4
1535.2
1239.9
791.4
1070.7
1052.1
745.2
540.8
1
1
1
,5
370,
376,
338,
227 ,
232.8
203.0
151.9
118.5
78.8
55.5
48.4
61.6
9768.0
[(a)(b)/(SUM)]
Fraction of
LDT1 Travel by
Model Year, n^j
0.054
0.157
0.127
0.081
0.110
0.108
0.076
0.055
0.038
0.039
0.035
0.023
0.024
0.021
0.016
0.012
0.008
0.006
0.005
0.006
Compilation of Air Pollutant Emission Factors: Highway Mobile
Sources, March 1981, [EPA-460/3-81-005]. The travel weighting
fractions reflect a January 1 evaluation date.
**Light-duty trucks I have a gross vehicle weight (GVW) rating
of 6000 pounds or less.
***January 1 fractions of total registration differ from those
in the cited source because they have been normalized to add up
to 1.000. The cited source performed an equivalent
normalization at a later stage in its calculation.
-------
Table 11
Fraction of Model Year Sale of
Light-Duty Trucks II by Emission Control Systems
System
FL,3,j
F3, j.NL.NOCAT
F3,j,OXCAT
F3, j.OXCAT/AIR
F3,j,3VKAT
F3 , j . 3WCAT/OXCAT
FD,3.j
F3,j,CAT
F3,j,CAT/NOAIR
F3, CAT/AIR
Pre-
1975
1.000
0
0
0
0
0
0
0
0
0
1975
1.000
0
0
0
0
0
0
0
0
0
1976
1.000
0
0
0
0
0
0
0
0
0
1977
1.000
0
0
0
0
0
0
0
0
0
1978
.988
0
0
0
0
0
.012
0
0
0
1979
0
.008
.496
.496
0
0
.025
.992
.496
.496
1980
0
0
.500
.500
0
0
.050
1.000
.500
.500
1981
0
0
.500
.500
0
0
.050
1.000
.500
.500
1982
0
0
.500
.500
0
0
.080
1.000
.500
.500
1983
0
0
.500
.500
0
0
.113
1.000
.500
.500
1984
0
0
.150
.450
.400
0
.147
1.000
.250
.750
1985
0
0
.150
.450
.400
0
.180
1.000
.250
.750
1986
0
0
.150
.450
.400
0
.194
1.000
.250
.750
1987
0
0
0
0
.850
0
.208
1.000
.250
.750
1988+
0
0
0
0
.850
0
.222
1.000
.250
.750
Source:. U.S. EPA Emission Factor In-Use Itest Vehicle Data Base.
Anti-Tampering and Anti-Misfueling Programs to Reduce In-Use Emissions from Motor Vehicles.
Note: Model year columns don't add up to 1.000. Only FL(3 j and ^,3, j are fractions of all LDT2s. All other
systems are fractions of all unleaded LDT2s. '
-------
-47-
Table 12
FLEET SALES FRACTIONS
Light-Duty Trucks II
Unleaded Gasoline
Model Fraction of LDT2
Years Fleet, FNL,3,j*
Pre-1975 0.000
1975 0.000
1976 0.000
1977 0.000
1978 0.000
1979 0.975
1980 0.950
1981 0.950
1982 0.920
1983 0.887
1984 0.853
1985 0.820
1986 0.806
1987 0.792
1988+ 0.778
Leaded Gasoline
Fraction of LDT2
Fleet, FL>3,j*
1.000
1.000
1.000
1.000
0.988
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Diesel Fraction of
LPT2 Fleet, FD>3,j*
0.000
0.000
0.000
0.000
0.012
0.025
0.050
0.050
0.080
0.113
0.147
0.180
0.194
0.208
0.222
WHERE:
FNL,3,j
FL,3,j
FD,3,j
= Estimated fraction of the LDT2 fleet which use unleaded
gasoline in model year j ;
= Estimated fraction of the LDT2 fleet which use leaded
gasoline in model year j;
= Estimated fraction of the LDT2 fleet which use diesel
fuel in model year j.
*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.
Percentages of gasoline vehicles requiring leaded and nonleaded fuel
obtained from Energy and Environmental Analysis, Inc.,
"Documentation for the New Highway Fuel Consumption Model", January
1982. '
-------
-48-
Table 13
TRAVEL WEIGHTING FACTOR CALCULATION*
Light-Duty Trucks II**
(a)
January 1
Fraction
Vehicle of Total
Age Registration***
1 0.098
2 0.247
3 0.185
4 0.116
5 0.068
6 0.067
7 0.047
8 0.036
9 0.027
10 0.024
11 0.020
12 0.013
13 0.012
14 0.010
15 0.006
16 0.007
17 0.005
18 0.004
19 0.004
20+ 0.005
(b)
Annual
Mileage
Accumulation
Rate
15800
15400
13800
12300
11125
10100
9300
8550
7975
7475
6975
6525
6225
5875
5425
5175
5000
4625
4400
4400
SUM:
C(a)(b)/(SUM)]
Fraction of
LDT2 Travel by
(a)(b) Model Year, m3/
1548.4 0.125
3803.8 0.306
2553.0 0.206
1426.8 0.115
756.5 0.061
676.7 0.055
437.1 0.035
307.8 0.025
215.3 0.017
179.4 0.014
139.5 0.011
84.8 0.007
74.7 0.006
58.8 0.005
32.6 0.003
36.2 0.003
25.0 0.002
18.5 0.001
17.6 0.001
22.0 0.002
12414.5
Compilation of Air Pollutant Emission Factors: Highway Mobile
Sources, March 1981, [EPA-460/3-81-005]. The travel weighting
fractions reflect a January 1 evaluation date.
**Light-duty trucks II have a gross vehicle weight (GVW) rating
of 6001 to 8500 pounds.
***January 1 fractions of total registration differ from those
in the cited source because they are normalized to add up to
1.000. The cited source performed an equivalent normalization
at a later stage of its calculation.
-------
-49-
Table 14
FLEET SALES FRACTIONS
Heavy-Duty Trucks I and II*
Model
Years
-
Pre-1977
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
Gasoline
Fraction of
HDT1 Fleet,
. .or F.. . .
L'4O NL,4,]
1.000 (LEADED)
1.000
1.000
1.000
1.000
1.000
0.838
0.820
0.803
0.785
0.772
0.759 (UNLEADED)
0.746
0.733
0.720
0.716
0.712
0.708
0.704
0.700
Diesel
Fraction of
HDT1 Fleet,
FD.4,j
0.000
0.000
0.000
0.000
0.000
0.000
0.162
0.180
0.197
0.215
0.228
0.241
0.254
0.267
0.280
0.284
0.288
0.292
0.296
0.300
Gasoline
Fraction of
HDT2 Fleet,
p **
L,5, j
0.623
0.468
0.440
0.412
0.472
0.330
0.360
0.344
0.327
0.311
0.303
0.295
0.288
0.280
0.272
0.264
0.256
0.248
0.240
0.232
(LEADED)
n
n
it
ti
it
H
n
ii
M
II
II
II
II
11
II
II
II
II
II
Diesel
Fraction of
HDT2 Fleet,
FD,5,j
0.
0.
.377
.532
0.560
0.588
0.528
0.670
0.640
0.656
0.673
0.689
0.697
0.705
0.712
0.720
0.728
0.736
0.744
0.752
0.760
0.768
*Heavy-dutytrucks I are assumed to have a gross vehicle weight (GVW)
rating of 8,501 to 14,000 pounds for this report. The reason for the
14,000 pound cutpoint is that it is projected that catalysts will be used
in 1987 and beyond on gasoline HDTs with a GVW of 14,000 pounds or under.
Heavy-duty trucks II are assumed to have a gross vehicle weight (GVW)
rating greater than 14,000 pounds for this report.
**The estimated fractions of the HDT1 and HDT2 model year fleets which are
gasoline-powered are based on sales projections by Energy and Environmental
Analysis, Inc., "The Highway Fuel Consumption Model: Tenth Quarterly
Report," November 1983. Gasoline HDTls use leaded fuel through the 1986
model year and are all unleaded from 1987 on. All gasoline HDT2s use
leaded fuel for all model years.
-------
-50-
Table 15
TRAVEL WEIGHTING FACTOR CALCULATION*
Heavy-Duty Trucks I**
and Heavy-Duty Gasoline 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
of Total
Registration***
0.0
0.131
0.112
0.084
0.098
0.101
0.081
0.061
0.047
0.050
0.045
0.035
0.034
0.030
0.024
0.020
0.015
0.011
0.009
0.011
(b)
Annual
Mileage
Accumulation
Rate
0
21000
18900
17200
15500
14100
12600
11300
10300
9400
8600
8000
7300
6700
6300
5900
5500
5200
5000
5000
SUM:
0.0
2741.7
2110.1
1449.1
1524.4
1425.5
1018.2
691.7
487.6
473.0
390.4
280.6
250.2
200.4
. 148.8
119.7
81.3
54.8
47.0
55.6
13550.2
[(a)(b)/(SUM)]
Fraction of
HDT1 Travel by
Model Year,
m4> j and m5G> j
0.000
0.202
0.156
0.107
0.113
0.105
0.075
0.051
0.036
0.035
0.029
0.021
0.019
0.015
0.011
0.009
0.006
0.004
0.003
0.004
Compilation of Air Pollutant Emission Factors: Highway Mobile
Sources, -March 1981, [EPA-460/3-81-005]. These are MOBILE2
heavy-duty gasoline travel fractions (for gasoline-fueled trucks
over 8,501 pounds) which are used in this report for all HDTls
(trucks greater than 8,501 pounds and less than 14,000 pounds)
and all HDGT2s (gasoline-fueled trucks over 14,001 pounds). The
travel weighting fractions reflect a January 1 evaluation date.
**Heavy-duty trucks I are assumed in this report to have a gross
vehicle weight (GVW) rating greater than 8,501 pounds and less
than 14,000 pounds.
***January 1 fractions of total registration differ from those
in the cited source because they are normalized to add up to
1.000. The cited source performed an equivalent normalization
in a later stage of its calculation.
-------
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
-51-
Table 16
TRAVEL WEIGHTING FACTOR CALCULATION*
Heavy-Duty Diesel Trucks II**
(a) (b)
January 1 Annual
Fraction Mileage
of Total Accumulation
Registration*** Rate
C(a)(b)/(SUM)]
0.0
0.172
0.104
0.065
0.120
0.113
0.088
0.063
0.051
0.051
0.038
0.029
0.031
0.023
0.016
0.012
0.009
0.005
0.005
0.008
0
70400
66900
60600
54200
47900
43700
39400
36600
34500
33100
32400
31700
31000
29600
27500
24600
20400
17600
17600
SUM:
Fraction of
HDT2 Travel by
(a)(b) Model Year,
0.0
12135,6
6937.2
3948.7
6483.4
5432.9
3824.9
2466.7
1873.2
1748.2
1243.4
925.6
975.0
727.3
464.2
317.6
209.3
94.2
81.3
147.6
50037.0
0.0
0.243
0.139
0.079
0.130
0.109
0.076
0.049
0.037
0.035
0.025
0.018
0.019
0.015
0.009
0.006
0.004
0.002
0.002
0.003
*Compilation of Air Pollutant Emission Factors: Highway Mobile
Sources, March 1981, [EPA-460/3-81-005]. These are MOBILE2
heavy-duty diesel travel fractions (for diesel-fueled trucks over
8,501 pounds) which are used in this report for all HDDT2s
.(diesel-f ueled trucks over 14,001 pounds). The travel weighting
fractions reflect a January 1 evaluation date.
**Heavy-duty trucks II are assumed in this report to have a gross
vehicle weight (GVW) rating greater than 14,001 pounds.
***January 1 fractions of total registration differ from those in
the cited source because they are normalized to add up to 1.000.
The cited source performed an equivalent normalization in a later
stage of its calculation.
-------
-52-
Table 17
TRAVEL WEIGHTING FACTOR CALCULATION*
(a)
January 1
Fraction
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
of Total
Registration**
0.0
0.167
0.159
0.134
0.142
0.131
0.080
0.051
0.028
0.010
0.098
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Motorcycles
(b)
Annual
Mileage
Accumulation
Rate
0
4100
2800
2100
1600
1200
800
600
400
200
200
200
0
0
0
0
0
0
0
0
SUM:
1924.0
[(a)(b)/(SUMj
Fraction of
MC Travel by
Model Year, m<
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
0.0
0.356
0.232
0.146
0.118
0.082
0.033
0.016
0.001
0.010
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Compilation of Air Pollutant Emission Factors: Highway Mobile
Sources, March 1981, [EPA-460/3-81-005]. The travel weighting
fractions reflect a January 1 evaluation date.'
**January 1 fractions of total registration differ from those in
the cited source because they are normalized to add up to
1.000. The cited source performed an equivalent normalization
in a later stage of its calculation.
-------
-53-
Table 18
Rates of Misfueling (r^)
for Different Vehicle Classes*
I/M Non-I/M
Light-Duty Vehicles (i=l) 0.08 0.17
Light-Duty Trucks I (i=2) 0.16 0.32
Light-Duty Trucks II (i=3) 0.14 0.26
Heavy-Duty Trucks I (i=4)** 0.17 0.35
Heavy-Duty Trucks II (i=5) 0 0
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 Trucks I (HDT1) pertain
only to gasoline-fueled HDTls made after model year 1986.
Source: "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.
-------
-54-
Table 18a
Rates of Misfueling (rj) 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+
Light-Duty
Vehicles
Non-I/M
0.04
0.08
0.11
0.15
0.18
0.21
0.24
0.27
0.30
0.32
0.35
0.37
0.39
0.41
0.43
0.45
0.46
0.48
0.49
0.51
I/M
0.04
0.05
0.06
0.07
0.08
0.09
0.10
0.11
0.12
0.13
0.14
0.14
0.15
0.16
0.16
0.17
0.17
0.18
0.18
0.18
Light-Duty
Trucks I
Non-I/M
0.22
0.26
0.29
0.33
0.35
0.38
0.40
0.43
0.45
0.46
0.48
0.50
0.51
0.53
0.54
0.56
0.57
0.58
0.59
0.60
I/M
0.13
0.14
0.15
0.16
0.17
0.18
0.19
0.19
0.20
0.20
0.21
0.21
0.22
0.22
0.23
0.23
0.24
0.24
0.24
0.25
Light-Duty
Trucks II
Non-I/M
0.22
0.26
0.30
0.33
0.36
0.38
0.41
0.43
0.45
0.47
0.49
0.50
0.52
0.53
0.55
0.56
0.57
0.59
0.60
0.61
I/M
0.13
0.14
0.15
0.16
0.17
0.18
0.19
0.19
0.20
0.21
0.21
0.22
0.22
0.23
0.23
0.23
0.24
0.24
0.24
0.25
Heavy-Duty
Gas Vehicles I**
Non-I/M
0.18
0.23
^ 0.28
0.33
0.37
0.40
0.44
0.47
0.49
0.52
0.54
0.56
0.58
0.59
0.61
0.63
0.64
0.65
0.67
0.68
I/M
0.12
0.13
0.15
0.16
0.17
0.19
0.20
0.20
0.21
0.22
0.23
0.23
0.24
0.24
0.25
0.25
0.26
0.26
0.27
0.27
*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 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.)
Source: "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.
-------
-55-
Table 19
Average Data on Particle Size Distribution
Cumulative Fraction of Particulate
Mass Smaller Than Diameter
Leaded Fuel,-ML 0.2 urn 2 urn 10 urn
Median Particle
Fractions, ML 0.23 0.43 0.64
Ranges of ML Valuesa 0.18-0.28 0.28-0.58 0.45-0.84
a95% confidence intervals on mean of data.
References: (author summary of) Ninomiya 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, MNL 0.2 urn 2 urn 10 urn
MNL,c 0.87 0.89 0.97
Ranges of MNL,C Valves0 0.86-0.88 0.84-0.94 0.84-1.00
MNL/NC 0.42 0.66 0.90
Ranges .of MNL.C Valves 0.29-0.55 0.52-0.80 0.63-1.00
D95% confidence intervals by "t" statistics.
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.
Cumulative Fraction of Particulate
Mass Smaller Than Diameter
Diesel Fuel, MQ 0.2 urn 1.0 urn 2.0 urn 2.5 urn 10 urn
MD 0.73 0.86 0.90 0.92 1.00
Ranges of MD 0.69-0.75 0.76-0.93 0.86-0.95 0.88-0.95 0.97-1.00
Values0
clntermediate speed, no load, prechamber engine, 2D fuel. (Also, limited
data cited below indicate this is appropriate for direct injection engines.)
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.
-------
-56-
Table 19 (cont'd)
Average Data on Particle Size Distribution
Cumulative Fraction of Particulate
Brake Wear . Mass Smaller Than Diameter
Particulate, M 0.43 urn 1.1 urn 4.7 urn 7 urn 10 urn
B
Median Particle
Fractions, MBd 0.09 0.16 0.82 0.90 0.98
Ranges of Mg Values Not available
QSamplesfordetermining particle size distribution were collected by
running about 20 braking cycles weighted to be representative of urban
driving conditions.
Reference: Cha et. al., 1983.
-------
-57- .
3.0 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 urn in diameter for
the year 1985. Assume an inspection and maintenance program
has been implemented in this area. The simplified misfueling
rates from Table 18 will be used.
Solution: Use equations 1.0, 1.1., 1.1.1, 1.1.2,
1.1.3, 1.1.4, 1.1.5, 1.1.6, 1.1.7, 1.1.8, 1.1.10, 1.1.12, and
1.1.13.
Particulate Matter Size Cutoff = 10 urn
n = 1985 i = 1 = LDV s = 19.6 mph M0 = 0.98
B
fcl,1985 = 1'° ri (from Table 18) = 0.08
Equation 1.0
EFPM10,1985,19.6 = (1.0)(EF1
Equation 1.1
1985
EF1,1985,19.6 V S ^EFl,j,lclf1985fL + EPl,j,k,,L + EF1, j^,
j=1966 1 2 3
X (FL,l,j} + (EF1, 3fklf1985fNL + EPl,j,k2,NL + EF1, j.kg.NL*
-------
-58-
PbL,1985 = 1'1 "
PbNL,1985 = °-014
MT 1A = 0.64;
L,10 um
M.TT _ .. = 0.97;
NL,C,10 um
"NL.NCMO um = °-90;
M^ = 1.00;
a = 0.75;
s
C = 0.79.
s
Use the following equations -to plug into Equation 1.1 and sum
over the appropriate model years:
Equation 1.1.1
EF, . . -.QOC T = [(1.1)(0.929)(0.64) + (0.014)(0.071)(0.90)]
1 1 D / K-\ i -LyoD, LJ
• (0.751(1.557) = 0.968 , = 1966.74
Equation 1.1.2
EF . = C(l.l)(0.725)(0.64) + (0.014) (0. 275) (0. 90) ]
-L / D ' Ki '
0 (0.75) (1.557) _ 0.760 . • . _ _
(Eo ' for D - 1975-85
c, 1,
Equation . 1.1.3
(Eo .)(0.79) o . .
c, 1, 3 c, 1, 3
T . v C: r = C(0.014)(0.92)(0.97) + (l.l)(0.08)(0.64)
J- » D » K- /
° (0.75X1.557) m 0.102 . _
IE .0.79 E : : for 3 ~
-------
-59-
Equation 1.1.4
EFn _. ,. T = (0.193) (0.64) = 0.124 (g/mile)
for j = 1966-69
1,j/k2'L
Equation 1.1.5
EF, . . _ = (0.068)(0.64) = 0.044 (g/mile)
for j = 1970-74
Equation 1.1.6
EF, . . T = (0.030)(0.64) = 0.019 (g/mile)
J-1 3 i KO '
for j = 1975-85
Equation 1.1.7
EPl.j.k2,NL = (0.92)(Fif jfCAT)(0.017)(0.97)+
(0.068) (0.64)4-
for j = 1975-85
= (0.019)(FlfjfCAT)
for j = 1975-85
Equation 1.1.8
EFn . . _ = (0.002)(0.64) = 0.001 (g/mile)
J-1 D / K., / J-<
for j = 1966-85
Equation 1.1.10
EFl,j,k3,NL ' <
(Fl,j,NL,NOCAT)(0'002)(0-90)]+(0'08)(0-002)(0-64)
= C(Fl,j,CAT/NOAIR)(0-004)+(Fl,j/CAT/AIR)(0-°16)
for j = 1975-85
-------
-60-
Equation 1.1.12
EF, . _ = (0.700)(1.00)
-L , J l *->
= 0.700 (g/mile) for j = 1966-80
Equation 1.1.13
EF. . = (0.320)(1.00)
J-» D » ^
= 0.320 (g/mile) for j = 1981-85
After calculating EF. ,ooc , Q .- in Table 20, substitute in
.L, J.7OO, J_y.o
Equation 1.0 and obtain the total LDV particulate emission
rate:
Equation 1.0
EF = (1.0)(0.0586) + 0.0125 + 0.002
PM10,1985,19.6
= 0.0731 (g/mile)
Note: 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.
-------
LIGHT-OUT* vtnicn
......... .
O.IMIMI
moan ro> tin m» n>»
Mission nCKM COHNMDR CALCULATION IWUtS
ttMMf"" "CIO* <
19*5
19*4
1*81
1*82
1*81
1*80
1*7*
1*78
1*77
1*7* U
1*75 11
1*74 L
1*71 L
1*72 11
1*71 L
1*70 U
i»c» 11
UM 11
on u
Utt- X
0.011
0.111
0.115
0.085
0.10*
0.114
0.0*4
o.on
0.0(1
0.054
L 0.041
1 0.02*
1 0.013
1 0.01*
1 0.010
i 0.00*
r o.ooi
1 0.002
I 0.001
K 0.00*
0.94*
O.*70
0.(7(
O.»51
0.»M
o.to*
0.870
0.81*
0.841
0.86*
0.871
.
•
.
_
_
_
*
.
-
.
_
..
_
_
0.041
0.0*0
0.111
0.157
0.112
0.127
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
27.
26.
. 24.
21.
21.
1*.
1*.
16.
15.
14.
11.
12.
12.
11.
11.
11.
11.
11.
11.
11.
0.054
0.010
0.024
0.047
0.0*1
0.050
0.040
O.OM
_
_
.
_
_
_
.
.
_
-
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
O.»80
o.u*
_
.
_
.
.
.
.
.
-
0.020
0.0*1
0.170
0.240
0.180
0.140
0.29*
0.474
0.655
0.6M
O.CSO
0.637
0.5*7
0.610
0.760
0.820
0.8*0
0.704
0.526
O.MS
0.150
0.150
O.J41
0.122
111
1.1.
121
1.1.
Ill
UM! In lv»tlan 1,1.
141
1.1.
HI
1.1.
|6|
1.1.
171
tn> mimian Itctoc
in
in
in
in
In
In
in
«t U UMi In
1.1.4. 1.1.1, ml 1.1.6
1.1.7 ttet U un4 In
1.1.8 Omt U UMI! In
1.1.10 th«t U iwd In
1.1.12 ml 1.1.11 that
I
ill
1*85
1*84
1*81
1*82
1*81
1*7*
1*78
1*77
1*7*
1*75
1*74
1*71
1*72
1*71
1*70"
IX*
1***
1M7
1*M-
10
11
U
11
14
15
1*
17
U
1*
20*
0.0001
0.0004
0.8005
0.0001
0.0022
0.0017
0.0012
0.0007
O.OOM
0.0002
0.0001
0.0001
0.0004
121
0.0001
0.0005
0.0005
0.0004
0.0005
0.0005
0.0005
0.0004
0.0001
0.0001
0.0001
C. (MISSION MCTCW COMOKMT
111 141
0.0043
0.0002
0.0002
0.0002
0.0001
0.0001
0.0012
0.0010
0.0007
0.0004
0.0001
0.0004
0.0002
0.0001
0.0007
A.UU
0.000*
0.0024
0.0021
0.0013
0.001*
0.0020
0.001*
0.0011
0.0010
0.0001
0.0007
0.4151
CUCUUtTIOMB
151
1*1
0.0003
0.0017
0.001*
0.0012
0.0012
0.0011
0.0007
0.0005
0.0004
0.0004
0.0001
0.0005
0.0011
0.0004
0.0011
0.0021
0.0040
0.002*
0.0015
O.OM4
A.U41 - 0.0586 -
-------
FIGURE 1. LEADED GASOLINE PARTICULATE SIZE DISTRIBUTION
o
to
I
PARTICLE DIAMETER microns
-------
FIGURE 2. UNLEADED GASOLINE PARTJCULATE SIZE DISTRIBUTION
100
0
i
(Tl
OJ
Legend
O Catalyst
A Noncololyst
PARTICLE DIAMETER microns
-------
FIGURE 3. DIESEL PARTICULATE SIZE DISTRIBUTION
a I0°
u
u
I*
U BO
a.
w
W
I-
ui
W
^1
O
ao
70
60
50
3
30
20
10-
u o
~T
3
T
4
nr
5
~r
7
070
PARTICLE DIAMETER microns
~r
9
10
-------
FIGURE 4. BRAKE WEAR PARTICULATE SIZE DISTRIBUTION
100
I
CTl
•m
I
PARTICLE DIAMETER microns
-------
-66-
4.0 REFERENCES
1. Carey, Penny M., Supplementary Guidelines for Lead
Implementation Plans—Updated Projections for Motor
Vehicle Lead Emissions, EPA Report 450/2-83=Ol5"2, OAR,
QMS, ECTD, TSS for OAQPS, March 1983.
2. Compliation o_f_ Air Pollutant Emission Factors: Highway
Mobile Sources, EPA Report 460/3-81-005, OAR, QMS, ECTD,
TEB, March 1981.
3. Anti-Tampering and Anti-Misfueling Programs to Reduce
In-Use Emissions From Motor Vehicles" (Draft Report for
Public CommentTT EPA/AA Report 83-3, OAR, QMS, ECTD,
TSS, May 25, 1983.
4. Diesel Particulate Study (Draft), U.S. EPA, OAR, QMS,
ECTD, SDSB, October 1983.
5. Lorang, Philip A., White, John T. and Brzezinski, David
J. , In-Use Emissions of 1980 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 ~ofDieselPenetrationTntheLight-Duty
Vehicle andLight-Duty Truck Markets, Jack Faucett
Associates Report for EPA, January 1983.
7. Documentation for the New Highway Fuel Consumption
Model, Energy and Environmental Analysis, Inc. Report
for EPA, January 1982.
8. Assessment of Current and Projected Future Trends in
Light-Duty VehicleFuel-Switching, Energy and
Environmental Analysis, Inc. Report for EPA, June 1982.
9. The Highway Fuel Consumption Model - Eighth Quarterly
Report, Energy and Environmental Analysis,Inc. Report
for EPA, July 1982.
10. 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.
-------
-67-
References (cont'd)
11. "Control of Air Pollution from New Motor Vehicles and
New Motor Vehicle Engines: Federal Certification Test
Results for 1975 Model Year," Federal Register, Vol. 40,
No. 48, March 11, 1975.
12. "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.
13. "Control of Air Pollution from New Motor Vehicles and
New Motor Vehicle Engines: Federal Certfication Test
Results for 1977 Model Year," Federal Register, Vol. 42,
No. 110, June 8, 1977.
14. "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.
15. 1983 Motorcycle Statistical Annual, Motorcycle Industry
Council, Inc., Research and Statistics Dept.,
Governmental Relations Office, Arlington, VA, June 1983.
16. 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.
17. Bykowski, Bruce B., Characterization gjE Diesel Emissions
from Operation of a_ Light-Duty Diesel Vehicle on
Alternate Source Diesel Fuels, EPA-460/3-82-OU2",
Southwest Research Institute Report prepared for Office
of Mobile Sources, November 1981.
18. 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.
19. 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.
20. McCain, Joseph D., and M. Gregory Faulkner, Assessment
of Diesel Particulate Control; Particle Size
Measurements, EPA-600/7-79-232c, Southern Research
-------
-68-
References (cont'd)
Institute report prepared for Office of Research and
Development, December 1979.
21. 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.
22. 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.
23. 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.
24. Ter Haar, G.L., D.L. Lanane, J.N. Hu, and M. Brandt,
Composition, Size, and Control o_f Automotive Exhaust
Particulates, Ethyl Corporation report presented atthe
64th Annual APCA Meeting, Atlantic City, NJ, June 27 -
July 1, 1971.
25. Breslin, J.A., A.J. Strazisar, and R.L. Stein, Size
Distribution and Mass Output of Particulates From Diesel
Engine Exhausts, report preparedbyPittsburgh Mining
and Safety Research Center, Pittsburgh, PA, U.S.
Department of the Interior, Report of Investigation 8141.
26. Boyer, K.W., and H.A. Laitinen, "Automobile Exhaust
Particulates," Environ. Sci. Techno1., 9_( 5):457-469,
1975.
27. 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, May 1972.
28. Foster, J.F., D.A. Trayser, C.W. Melton, and R.I.
Mitchell, Chemical and Physical Characterization p_f
Automotive Exhaust Particulate Matter in. the Atmosphere,
Fourth Annual Summary Report prepared byBattelle
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.
-------
-69-
References (cont'd)
29. Foster, J.F., D.A. Trayser, E.R. Blosser, F.A. Creswick,
and D.F. Miller, Chemical and Physical Characterization
o_f Automotive Exhaust Particulate Matter in the
Atmosphere, Fifth Annual Summary Report prepared by
BattelleColumbus Laboratories, Columbus, OH, to
Coordinating Research Council (CRC-APRAC Project No.
CAPE-19-70), March 1974.
30. 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.
31. Habibi, K. , "Characterization of Particulate Matter in
Vehicle Exhaust," Environ. Sci . Techno 1. , 1_ ( 3 ): 223-234,
1973.
32,
33,
34,
35
36,
Habibi, K., E.S. Jacobs, W.G. Kunz, Jr., and D.L.
Pastell, Characterization and Control of Gaseous and
Particulate Exhaust
"to
Emission from Vehicles,
presented to the Air
Francisco, October 1970.
paper
PollutionControlAssn., San
Hirschler, D.A., and L.F. Gilbert, "Nature of Lead in
Automobile Exhaust Gas," Arch. Environ. Health,
9_:297-313, 1964.
Kittelson, D.B., D.F. Dolan, and J.A. Verrant,
Investigation of a. Diesel Exhaust Aerosol, SAE Paper No.
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