United States
Environmental Protection
Agency
Office of Mobile Sources
Emission Control Technology Division
2565 Plymouth Road
Ann Arbor, Michigan 48105
EPA 460/3-85-006
August 1985
Air
c/EPA
Supplementary Guidelines for
Lead Implementation Plans
Updated Projections for
Motor Vehicle Lead Emissions
-------
EPA 460/3-85-006
Supplementary Guidelines for
Lead Implementation Plans
Updated Projections for
Motor Vehicle Lead Emissions
by
Energy and Environmental Analysis, Inc.
1655 North Fort Myer Drive
Arlington, Virginia 22209
Contract No. 68-03-1865
Work Assignment I
EPA Project Officer: Mark Wolcott
Technical Representative: Robert I. Bruetsch
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Mobile Sources
Emission Control Technology Division
2565 Plymouth Road
Ann Arbor, Michigan 48105
August 1985
-------
This report was furnished to the Environmental
Protection Agency by Energy and Environmental
Analysis, Inc., 1655 North Fort Myer Drive,
Arlington, Virginia, in fulfillment of Work
Assignment 1 of Contract No. 68-03-1865. The
contents of this report are reproduced herein as
received from Energy and Environmental Analysis,
Inc. The opinions, findings, and conclusions
expressed are those of the authors and not
necessarily those of the Environmental Protection
Agency. Mention of company product names is not to
be considered as an endorsement by the Environmental
Protection Agency.
Publication No. 460/3-85-006
-------
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
-------
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 (ri) 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
-------
LIST OF FIGURES
Figure
No. Page
2-1 Fuel Economy at Various Speeds 2-46
-------
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 Park, 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 MOBILE3 (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).
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 = / .. 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)
n,s
EF. = lead emission factor for vehicle class i in
' ' calendar year n and vehicle speed s (g/mi)
2-1
-------
i = vehicle class designator; 1 = light-duty
vehicles (LDV), 2 = light-duty trucks I (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 = 7 , V(EF. ) (2-2)
n,s r^J 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 f
\"**
EF. = ? (EF- T^FT > (
"
m.
(EFi,j,n,NL)(FNL,i,J)
2-2
-------
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
F. . . = fraction of the vehicle class i fleet designed
' for use on leaded gasoline in model year j
FMT = 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
1>J 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
To compute emission factors for leaded vehicles (EF. . .) use
i,j,n,L
equations (2-4), (2-5), and (2-6). For unleaded vehicles (EF. . _)
i, j,n,NL
use equation (2-7).
LDV (Pre MY 1971) and LOT (Pre MY 1971): Leaded Fuel
For 1=1,2,3 j=n-19,...1970 C =from Table 2-1 a .=0.75
s si, j
EF = [Pb (0.887) + Pb (0.113)] ,- °>7vfc v (2-4)
liJin»L L L,n NL,n * QE . -KC J
c,i,j s
where: a = fraction of lead burned that is exhausted:
- 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, a . = .40
SZ, j
- for catalyst vehicles using leaded gasoline in 1981
and later, a . = .44
sz, j
2-3
-------
C = speed-dependent fuel economy correction factor
based on steady cruise or cyclic driving; avail-
able from Table 2-1 (nondimensional)
PbUT = lead content of unleaded gasoline in calendar
'n year n from Table 2-2 (g/gal)
FbT = average lead content of leaded gasoline in
'" calendar year n from Table 2-2 (g/gal)
E . . = city/highway combined on-road fuel economy for
C>1'^ model year j and vehicle class i from Table 2-9
(miles/gallon)
LDV (MY 1971-1974) and LDT (MY 1971): Leaded Fuel
For i=l,2 j=1971 1974 C =from Table 2-1 a . .=0.75
and For i=3 j-1971,...,1978 S >J
EF. . T=[Pb. (.916) + Pbm (0.084)] , °'7* » (2-5)
i,j,n,L L L,n NL,n J (Ec>i)jMcs'
LDV (MY 1975+) and LDT (MY 1979+): Leaded Fuel
For i=l,2 j=1975,...,n C =from Table 2-1 a . .=0.75
and For i=3 j=1979,...,n S S1'J
EF =[pb (0.724) + Pb (0.276)] ( °'7* . (2-6)
i|J»n|L « L,n NL,n J (E . -)(C )
c, i,j s
LDV (MY 1975+) and LDT (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
EF. .
i,j,n,NL
PbMT (l-r.)(a . .) + Pb. ,,(r..) /F. . MT (2-7)
I NL,n i sl,j L,n i I L,j,NL,NOCAT
2-4
-------
where: r. = misfueling rate for vehicle class i from Table 2-12
P. = fraction of catalyst equipped vehicle in class i
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. . . -.-»_, = fraction of the unleaded vehicle class i fleet
i,J,NL,NOCAT ... . , . . . ,
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. . H/W^T ^rom Ta^le 2-15) have been
1 , J , NL,
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 EFA 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
s
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
2-5
-------
Figure -2-1
FUEL ECONOMY AT VARIOUS SPEEDS*
SPEED, MPH
« Car Fuel Econon>y' EPA and Road, September 1980,
460/3-80-010J.
2-6
-------
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
Li J
last column of Tables 2-3, 2-5, and 2-7 for light-duty vehicles, light-
duty trucks 1, and light-duty trucks II. These values for (m. .) are
li J
EPA's estimates of the national values. Local values should be used
where available. The term, "m. ." accounts for all light-duty vehicles
Li 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.
NL,i,j L,i,j
Values for F... . . and FT . . account for the increasing dieselization
NL,i,j L,i,j 6
of the light-duty vehicle fleet. Diesel-powered vehicles are assumed to
emit quantities of lead that are insignificant compared to 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
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. . rhT) in
1,J,CAT
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 8.4 percent from
1971 to 1974 for the LDV and LOT I categories. The discretionary rate
for the LOT 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. 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.
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
ci 1> 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 (PbMT ) 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 )
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^~S
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 3
vehicles that have been mis fueled, 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
2-9
-------
time frame. These values of a do not vary with speed, since a is more
s r 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 - -fU ^ (2-8)
i.n,s E . . C
HDGV (Post MY 1986): Leaded Fuel
For i=4 j=1987,...,n C =frora Table 2-1 a =from Table 2-13
J ' ' s s
PbMT m. .U-r.)(a . .) Pb. m. .(r.)(a , .)
ur - NL,n i,j 1 sl,j L,n i,j i s2,j ,, _,
i,n,s E ' .* (C ) * E ' .** (C ) (2"9)
' ' 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.
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
PbXTT ; Pb. Table 2-2
NL,n' L,n
m. . Table 2-10
i-tJ
E . . Table 2-9
c,i,J
Rj 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.
2-11
-------
TABLE 2-1
FUEL ECONOMY CORRECTION FACTORS AT VARIOUS SPEEDS, C
(Normalized to 32.7 miles/hour-cyclic driving)
C C
s s
Speed (mph) Cyclic Driving Steady Cruise
5 0.323 0.467
10 0.553 0.709
15 0.692 0.997
20 0.790 1.153
25 0.885 1.248
30 0.963 1.294
32.7 1.000 1.303
35 1.022 1.303
40 1.053 1.288
45 1.073 1.256
50 1.078 1.210
55 1.063 1.159
60 1.023 1.104
2-12
-------
TABLE 2-2
LEAD CONTENT OF GASOLINE
Leaded Gasoline* Unleaded Gasoline
Year (g/gal) PbL (g/gal) Pbm
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).
2-13
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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
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
(a)(b)
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
[(a)(b)/(SUM)]
Fraction of
LDV Travel by
Model Year, m.
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.
2-14
-------
TABLE 2-4
FLEET SALES FRACTIONS
Light-Duty Vehicles*
Nonleaded Gasoline Leaded Gasoline
Fraction of LDV Fraction of LDV
5 Fleet, FXII . ... Fleet, F, . .
Years NL.l.j** L.l.j
Pre-1975 0.000 1.000
1975 0.869 0.128
1976 0.863 0.134
1977 0.838 0.158
1978 0.865 0.126
1979 0.875 0.097
1980 0.966 0.000
1981 0.939 0.000
1982 0.954 0.000
1983 0.947 0.000
1984 0.940 0.000
1985 0.934 0.000
1986 0.927 0.000
1987 0.920 0.000
1988 0.910 0.000
1989 0.900 0.000
1990 0.887 0.000
1991 0.887 0.000
1992 0.886 0.000
1993 0.886 0.000
1994 0.885 0.000
1995+ 0.885 0.000
Where F . = Estimated fraction of the LDV model year fleet which use
' nonleaded gasoline
F . = 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 MOBILES.
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
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
(a)(b)
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
[(a)(b)/(SUM)]
Fraction of
LDV Travel by
Model Year, m, .
' J
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 (GVW) rating of 6,000
pounds or less.
2-16
-------
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
FNL.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
Leaded Gasoline
Fraction of LDT1
Fleet, F.
L,2
1,
0.
0.
.000
.188
.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,
NL,2
FL,2
Estimated fraction of the LDT1 model year fleet which use
nonleaded gasoline.
Estimated fraction of the LDT1 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.
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
314.6
262.8
217.1
171.0
136.2
105.6
78.9
107.2
[(a)(b)/(SUM)]
Fraction of
LDT2 Travel by
Model Year, m
lii
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.
2-18
-------
TABLE 2-8
FLEET SALES FRACTIONS
Light-Duty Trucks II*
Unleaded Gasoline Leaded Gasoline
, . Fraction of LDT2 Fraction of LDT2
v Fleet, FMT ^ Fleet, FT ,
Years NL,3** L,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 MOBILE3.
2-19
-------
TABLE 2-9
CITY/HIGHWAY COMBINED ON-ROAD FUEL ECONOMY
(miles/gallon)
Fuel Economy, E
LDV*
LDT1** LDT2
HDGV1+
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
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
S.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 LDVs from MOBILE3 data based on EPA memo from
Karl H. Hellman to Ralph C. Stahman regarding Light-Duty MFC, 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.
++Pre-1986 fuel economies are composites of HDGV1 and HDGV2.
2-20
-------
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
TABLE 2-10
TRAVEL WEIGHTING FACTOR CALCULATION*
Heavy-Duty Gasoline Vehicle (HDGV)**
(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
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
[(a)(b)/(SUM)]
Fraction of
HDGT Travel by
(a)(b) Model Year, m^.
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.
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.
2-22
-------
TABLE 2-12
RATES OF MISFUELING (rj
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 (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 raisfueling 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.
2-23
-------
TABLE 2-12a
RATES OF MISFUELING (r.) FOR DIFFERENT VEHICLE AGES AND CLASSES*
Vehicle LDV LDTI LDTII HDGV1 **
Age NoI/M I/M Non-I/M I/M Non-I/M I/M Non-I/M I/M
1 .04 .04 .22 .13 .23 .13 .18 .12
2 .07 .05 .27 .14 .27 .15 .23 .13
3 .10 .06 .31 .16 .32 .16 .28 .15
4 .13 .07 .35 .17 .36 .17 .32 .16
5 .16 .08 .38 .18 .39 .18 .36 .17
6 .18 .09 .42 .19 .43 .19 .39 .18
7 .21 .09 .45 .20 .46 .20 .42 .19
8 .23 .10 .47 .21 .49 .21 .45 .20
9 .25 .11 .50 .21 .51 .22 .48 .21
10 .27 .11 .52 .22 .54 .23 .50 .22
11 .29 .12 .55 .23 .56 .23 .52 .22
12 .31 .12 .57 .24 .58 .24 .54 .23
13 .33 .13 .59 .24 .60 .25 .56 .23
14 .34 .13 .60 .25 .62 .25 .57 .24
15 .36 .14 .62 .25 .63 .26 .59 .24
16 .37 .14 .64 .26 .65 .26 .60 .25
17 .39 .15 .65 .26 .66 .26 .61 .25
18 .40 .15 .66 .26 .68 .27 .62 .25
19 .41 .15 .68 .27 .69 .27 .63 .25
20+ .42 .16 .69 .27 .70 .28 .64 .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
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 MOBILES.
2-24
-------
TABLE 2-13
FRACTION OF LEAD BURNED THAT IS EXHAUSTED, a
asl.j* 8s2.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.
"i J
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.
2-26
-------
TABLE 2-15
FRACTION OF CATALYST AND NON-CATALYST VEHICLES BUILT TO USE UNLEADED FUEL
LDV
LOT I
LDTII
N}
I
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988+
Fl,i,CAT
0.919
0.980
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
FL,i,NL,NOCAT
0.081
0.020
-
-
-
-
-
-
-
-
-
-
-
-
F2,i,CAT
0.877
0.775
0.917
0.930
0.966
0.973
0.989
1.000
1.000
1.000
1.000
1.000
1.000
1.000
F2,i,NL,NOCAT
O.L23
0.225
0.083
0.069
0.034
0.027
0.011
-
-
-
-
-
-
-
3,i,CAT
S.i.NL.NOCAT
0.992
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
0.008
Sources: U.S. EPA Federa] Register: Federal Certification Test Results 1975-78 and 1982-84.
EEA Estimates of Emission Control Systems Projections.
-------
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.
T1.1985 = 1.0
n = 1985
i = 1 = LDV
s = 19.6 mph
asl
as2
as2
PbL,1985 =
PbNL,1985 =
,1966-1985 =
,1975-1980 =
,1981-1985 =
C =
s
Pl =
r,
1.1 g/gal
0.014 g/gal
0.75
0.40
0.44
0.79
0.017
0.09
(Table 2-2)
(Table 2-2)
(Table 2-13)
(Table 2-13)
(Table 2-13)
(Table 2-1)
(Table 2-14)
(Table 2-12)
3-1
-------
EF = > T (EF. ) (3-1)
n,s Z_-rf i>n,s
1985
PC » I ^FF ^ v ^F ^ fl9^
1,1985,19.6" Z-r l,j,1985,L; v L,l,j' V
j=1966 L
IL' x(FNL,i,j)]xn'i,j
Use the following equations to plug into equation (3-2) and sum over the
appropriate model years.
For j=1966-1970
EFi loo* i " [l.KO.887) + 0.014(0.113)) (3-3)
i,j,iyo},L i i
.75 = .928
EC 1 i(0'79) Ec 1 i
C| -1 I J cf * I J
For j-1971-1974
EFi iooc , " fl.K0.916) + 0.014(0.084M (3-4)
1 , J, iyOD,L » I
x .75 = .958
EC i(°'79) E
c»1 Lc,i
For j=1975-1985
EFi IQQ^ t /!KO.724) + 0.014(0.276)) (3-5)
1 , J, 1503,L t I
x ^ .75 = .776
E
3-2
-------
EF
l,j,1985,NL
For j=1975-1985
0.014(0.91X0.75) + 1.1(0.09) (3-6)
^Fl,j,NL,NOCAT + (0-017>
-------
TABLE 3-1
EXAMPLE CALCULATIONS
LIGHT-DUTY VEHICLE PARTICIPATE EMISSION RATE
LESS THAN 10 MICRONS FOR THE YEAR 1985
A. Emission Factor Component Calculation Inputs
I
4>
Model
Year.
1985
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966-
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
"I.J
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
FNL,l,j
0.934
0.940
0.947
0.954
0.939
0.966
0.875
0.865
0.838
0.863
0.869
-
-
-
-
-
-
-
-
-
FT..1.J
_
-
-
-
-
0.000
0.097
0.126
0.158
0.134
0.128
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1,000
Ec,l,j
24.6
23.8
23.2
22.9
21.5
19.6
17.8
16.6
15.5
14.8
13.8
12.6
12.9
13.1
13.2
13.9
13.9
13.9
13.9
13.9
Fl,j,CAT
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
0.980
0.919
-
-
-
-
-
-
-
-
-
l.j.NL.NOCAT
0.020
0.081
cl.1
.00144
.00561
.00510
.00462
.00428
.00414
.00369
.00339
.00297
.00274
.00252
cl.1
.00041
.00049
.00056
.00043
.00037
.00254
.00202
.00160
.00114
.00079
.00050
.00022
.00022
.00029
-------
TABLE 3-1
EXAMPLE CALCULATIONS
LIGHT-DUTY VEHICLE PART1CULATE EMISSION RATE
LESS THAN 10 MICRONS FOR THE YEAR 1985 (cont'd)
B. Emission Factor Summation Description
Summation (1) calculates Lhe emission factor component in Equations (3-2), (3-3), and (3-4) that
are used in Equation (3-1).
Summation (2) calculates the emission factor component in Equation (3-5) that is used in
Equation (3-1).
-------
TABLE 3-1
EXAMPLE CALCULATIONS
LIGHT-DUTY VEHICLE PARTICULATE EMISSION RATE
LESS THAN 10 MICRONS FOR THE YEAR 1985 (cont'd)
C. Emission Factor Calculations
Year,
(EFl,j,1985,L) (EFl,j,1985,NL)
1985 - 0.0001
1984 - 0.0004
1983 - 0.0003
1982 - 0.0003
w 1981 - 0.0003
<* 1980 - 0.0003
1979 0.0003 0.0002
1978 0.0004 0.0002
1977 0.0004 0.0002
1976 0.0003 0.0002
1975 0.0003 0.0002
1974 0.0024
1973 0.0019
1972 0.0015
1971 0.0011
1970 0.0007
1969 0.0005
1968 0.0002
1967 0.0002
1966- 0.0003 -
SUM: 0.0105 0.0027
EF1.1985.19.6 =°-°132
------- |