EXAMPLE INDEX

The following files are included with electronic copies of PARTS (either on disk or via the bulletin
board system). A brief description accompanies each filename to help the user find specific

examples.

Figure.
1
2

Filename:
VMT2.IN
VMT3.IN
MY.IN

FMS5.IN
PRT2.IN

PRT1.IN

BUS2.IN

MANY.IN

TRAP.IN

Description:
VMFLAG=2 showing altemate VMT mixes for each scenario.
VMFLAG=3 showing altemate VMT mix once per run.

MYMRFG=4 showing input for altemate mileage accumulation rates
and registration distributions.

OUTFMTS=S showing by-model-year input for LDGV.

PRTFLG=2 showing only Exhaust PM and components printed in
output.

PRTFLG=1 showing Exhaust PM and components, Indirect
Sulfate, Sulfate PM, Brake; Fire; Total Particulate and Fugitive Dust
emissions factors pinted in output.

BUSFLG=2 showing Transit and CBD bus usage categories.

VMFLAG=3, MYMRFG=4, RFGFLG=2, OUTFMTSS, showir'g
order of one-time data inputs.

BUSFLG=2, TRAPFLG=2 showing different scenarios of traps on
buses for model years 1992 and 1993.

17


Figure 8a (continued)

PARTS Revised 02-24-95
Sample Input File Using Many User Optional Inputs
scenel
Emission Factors (Gm/Mile)
Light Duty Gas Vehicles
January 1, 1994
Model 1 Exhaust PM: | Braker | Tire:
Yoar TF Miles | Emiss Rate | Emiss Rate | Emiss Rate

1994 9.02 1799. 0.012 0.013 0,008
1993 0.11 1076! 0.022 0.013 0.008
1992 0.21 24876. 0,012 0,013 0,008
1991 0.11 37637. 0,012 0,013 0.008
1990 0,10 49991. 0,012 0,013 0.008
1989 0.09 61679, 0,012 0.013 0.008
1988 0,08 72738. 0.012 0,013 0.008
1987 0,06 93193. 0.012 0.013 0.008
1986 0.05 93085, 0,016 0,013 0.008
1985 0.08 102442. 0,016 0,013 0,008
1984 0.04 111294, 0,016 0,013 0.008
1983 0,04 119667. 0.015 0.013 0.008
1982 0.03 127586, 0,016 0,013 0,008
1981 0,03 135078, 0,017 0,013 0,008
1980 0.02 142168, 0,026 0,013 0,008
1979 0.02 149869. 0.019 0.023 0.008
1978 0.01 155210, 0,019 0,013 0,008
1977 0,02 161201 0.018 0,013 0,008
1976 0,01 166882. 0,019 0,013 0,008
1978 0.00 172249, 0.019 0,013 0,008
1974 0,00 177326. 0.043 0.013 0.008
1973 0,00 182129. 0,043 0,013 0,008
1972 0.00 186672. 0,043 0,013 0,008
1971 0.00 190970. 0.043 0,013 0.008
1970 0,00 198034, 0,043 0.013 0.008
Composite: 0.014 0,013 0.008

PARTS February 24, 1995
38


Figure 7

PARTS Revised 02-24-95
Sample with OUTFMT = 3 and BUSFLG=2

scenel
Particle Size Cutoff 10.00 Microns Altitude: 300. Ft. Driving: Transient RFG:No
al. Year: 1994 1/M Program: No Region: Low ALL Transit CBD

Veh. Type: LDGV LOGTL LOGT2 MDGvV MC LOOV = LDDT = 2BHDDV LHDDV =MHDDV HHDDV BUSES Veh. Suses** Buses*

Veh. Speeds: 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 18.5 10.6
VME Mix: 0.6337 0.1760 0.0831 0.0307 0.0072 0.0045 0.0017 0.0102 0.0012 0.0137 0.0346 0.0038

Composite Emission Factora (g/mt)

Exhaust PM: 0.014 0.018 0,040 0.154 0.020

Brake: 0.013 0.013 0.013 0.013 0.013

Tire: 0.008 0.008 0,008 0.012 0,004

Total PM: 0.058 0,070 0,092 0.237 0,046

0.346 0.324 0.921 1,156 1.380 1,260 0.094 1.477 3,536
0.013 0.013 0.013 0.013 0.013 0.013 0.013 9.013 0.013
0.008 0.008 0.012 0,012 0,036 0.008 0.009 0.008 0.908
0.405 0.409 1.042 1.306 1,883 1,430 0.149 2.723 3,830

Fugitive Dust: Unpaved Roads Fleet Average 139.04 g/ml (as calculated in AP42 Vol 1 9/88)*
Paved Roads Fleet Average 13.42 g/ai (as calculated in draft AP42 Vol 1 3/93)¢
Unpaved Roads Fleet Average 136.83 g/ai (as calculated in AP42 Vol 1 9/68, minus tailpipe and
tire-wear emissions) **
Paved Roads Fleet Average 13.21 g/ai (as calculated in draft AP42 Vol 1 3/93, minus tailpipe
and tire-wear emissions) **

* Includes fleet average tailpipe, tire-weer and brake-weer emissions.
** Includes fleet average brake-wear emissions.

Paved Road Silt: $.10 (g/m*2) Fleet average vehicle weight: 6000
Unpaved Silt: 4.38 Floet average number of wheels: 4
Precipitation Days: 140 >0.01 in. (per year)

** Not Included in All Veh.

PARTS February 24, 1995
34


Figure 9a (continued)

8 trap ef's, 1008 no trap ef's

Partizle Size Cutoff 10.00 Microns Altitude: 500. Fe. Driving: Transient RFG:No

Cal. Year: 1998 1/M Program: No Region: Low All Transit cep
Veh. Types LOGY LDGT1 LDGT2 HDGV MC LDDV LDDT 2BHDDV LHDOV MHDDV HHDDV BUSES Veh. Buses** Buses*

Veh. Speeds: 19.6 19.6 19.6 19,6 19,6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 18.5 10.6

WMT Mix: 0.6203 0.1864 0.0849 0.0309 0.0066 0.0019 0.0011 0.0123 0.0013 0.0187 0.0384 0.0032

Composite Emission Factors (3/mi)

Exhaust PM: 0.013 0.017 0,026 0.122 0.020 0.238 0.274 0.206 0.894 0.796 0.928 0.788 0.070 0.934 2.237
Brake: 0.013 0.013 0,013 0,013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013
Tire: 0.008 0.008 0.008 0.012 0.004 0.008 0.008 0.008 0.012 0.012 0.036 0.008 0.009 9.008 9.008
Total PM: 0.056 0.067 9.077 0,200 0.066 0.290 0.333 0.289 «1.017 0.942 1.125 0.983 0.124 1.180 2.530

Fugitive. Dust: Unpaved Roads Fleet Average
Paved Roads Fleet Average
Unpaved Roads Fleet Average

Paved Roads Fleet Average

139.04 g/mi (as calculated in AP42 Vol 1 9/88)*
13.41 g/mi (as calculated in draft AP42 Vol 1 3/93)*
138.63 g/mi (as calculated in AP42 Vol 1 9/88, minus tailpipe and

tire-wear emissions) **

and tire-wear emissions) **

* Includes fleet average tailpipe, tire-wear and brake-wear emissions.
** Includes fleet average brake-wear emissions.

Paved Road Silt: 5.10 (g/m*2)
Unpaved silt: 4.38

Fleet averege vehicle weight:

6000

Fleet average number of wheeler 4

Precipitation Days: 140 >0.01 in. (per year)

13,21 g/mi (as calculated in draft AP42 Vol 1 3/93, minus tailpipe

** Not Included in All Veh.

PARTS February 24, 1995

43


Ranges of unpaved road silt percents are (see references page 67, EPA 1988a):

Copper smelting: 15.9% - 19.1%
Iron and steel production: 4.0% - 16.0%
Sand and gravel processing: 4.1% - 6.0%
Stone quarrying and processing: 10.5% - 15.6%
Taconite mining and processing: 3.7% - 9.7% for a haul road, 2.4% - 7.1% for
a service road
Westem surface coal mining: 4.9% - 5.3% for an access road, 2.8% - 18% fora
hanl road, 7. -2% - 25.0% for a scraper road, and 18.0% - 29.0% for a freshly graded
Rural roads: 5.8% - 68% for dirt, and 7.7% - 13.0% for crushed limestone.

Ranges of different paved road silt loadings are (in g/m”):

Copper smelting: 188 - 400
Iron and steel production: 0.09 - 79
Asphalt batching: 76 - 193

Concrete batching: 11-12 3

Sand and gravel processing: 53 - 95
Municipal solid waste landfill: 1.1 - 32
Quarry: 2.4- 14

When WHEELFLG is set to blank or "1", the model will not require any additional user input and
the model will assume the default values for average number of wheels in each vehicle class to be
as listed in the sample of line 7 on page 12. When WHEELFLG is set to "2", the model will
expect a seventh line of output at the end of that scenario. The format for line 2 is:

F4.1,1X,F6.2,1X,11

A sample input line specifying 4.3 % unpaved silt, and 5.1 g/m* paved silt, is:
04.3 05.1 2 sunpaved silt%, paved silt (g/m?), WHEELFLG

The iapus The third input line also has information for the fugitive dust emission factor calculations.
of precipitation days with more than 0.01 inches of rain per year. The

pe cm ea emission factors for the entire year, and thus are
affected by pattems: the more the annual precipitation days, the lower the
fugitive dust factors will be, and conversely.
The format for this input line is:

13 .
A sample input line specifying 140 annual days of precipitation, is:

140 :number of precipitation days

An optional input for this line (after number of precipitation days) is a value for TRAPFLG, where
a blank or 1 = no trap emission control technology for buses for model years 1992 and 1993. If

11


FRAC,,/,i, = the fraction of vehicles which are oxidation catalyst equipped with air pump, for
vehicles of class v and model year m :

FRAC,,,,i- = the fraction of vehicles which are 3-way catalyst equipped with air pump, for
vehicles of class v and model year m

The direct sulfate from all gasoline-fueled vehicles is computed as:

DSULF,,, = CTLFRC,,,* DSULFC,,, + (1.-CTLFRC,,,) * DSULFN (26)
where
CTLFRC,,, = CATFCT,,, (1 - RMIS,, ,), the fraction of the vehicle class that lias an
. effective catalyst

The model assumes that all the sulfur in the fuel is exhausted as either sulfate or gaseous sulfur
dioxide, so once the direct sulfate emission factor is calculated, the remaining sulfur in the fuel is
considered to be exhausted as SO,. To calculate the amount of sulfur exhausted as SO, in g/mi,
the amount of sulfur remaining in the fuel after the direct sulfate emission factor has been found

must be calculated.
The following equation is used to derive the fraction of sulfur in the fuel that has been directly
converted to sulfate (DSULF,, , calculated in equation 26 above). This equation calculates direct
sulfate as a function of the fuel sulfur content, DCNVRT (which is the fraction of sulfur in the fuel
that is converted to direct sulfate), and the fuel economy.

DSULF,, , = 13.6078 * (1. + WATER) * FDNSTY * SWGHT * DCNVRT /FE,,, (27)
where

DSULF,,,, = the direct sulfate emission factor of a vehicle in class v and of model-year m

(ghmi)
weight ratio of seven water molecules to sulfate, 7. 18 / 98 = 1.2857 (this

WATER =
ratio comes from the estimate that, at 50% humidity, seven water
molecules bond with each sulfuric acid molecule; EPA 1990, p.6-25)
FDNSTY = fuel density in lb/gal (6.09 Ib/gal, EPA 1988).
FE,,, = fuel economy for vehicles of class v and model year m (mi/gal)

SWGHT = Fe ee i alee ne 138, NAN cept reformulated fuel phase
DCNVRT I and later calendar years .0138, AAMA 1993)

=

Percent of sulfur in the fuel that is directly converted into sulfate (2%, EPA
)
13.6078 = unit conversion factor = (453.592 * 3.)/100., where 453.592 = number of

grams in a pound, 3. = weight ratio of SO, to sulfur, and the division by 100 is
to correct for the weight percent of sulfur, SWGHT (EPA 1990)

53


Note that catalyst equipped vehicles burning unleaded fuel have a different fraction of lead bumed
exhausted (ABURN) than the other categories and that it depends on the model year of the vehicle.

For the case of catalyst-equipped vehicles using leaded fuel, the amount of lead particulates comes
from the remaining terms of equation 2-5 of reference EPA 1985b. The correction to the
fuel economy is handled later in the program by the factor FEC, and ‘ore can be ignored here.
The terms for misfueling and for catalyst removal can also be ignored here, since these will be used
later to determine the fraction of vehicles which are catalyst equipped and what fraction of catalyst-
equipped vehicles use leaded and unleaded fuel. The final form is:

PLYSCT»,y = (ABURN(1) * 1.5571 FE») * PBL * PSL (14)

There are four different combinations of catalyst and misfueling which will each have a separate
estimate of particulate emissions. They are:

Catalyst-equipped vehicles using unleaded fuel

Catalyst-equipped vehicles using leaded fuel

Non-catalyst vehicles using unleaded fuel

Non-catalyst vehicles using leaded fuel

First the number of catalyst equipped vehicles must be determined. CATFCT,, , is the fraction of
all vehicles which are originally catalyst equipped and TAMFRC,,, , is the fraction of originally

catalyst equi vehicles which have had their catalyst removed for model year m and vehicle
class v. re, the remaining catalyst equipped vehicles are:
CATS,,, = CATFCT,,,* (1.-TAMFRC,,,) (15)

The fraction of non-catalyst vehicles using leaded gasoline, then, would be:

VLNOCT,,, = (1.-CATS,,,) * (1.-DFS,,)) (16)
Where DFS,, , is discretionary fuel switching (use of unleaded fuel by non-catalyst vehicles) for
model year m and vehicle class v. The fraction of non-catalyst vehicles using unleaded gasoline is
then:

VUNOCT,,, = (1.-CATS,,,) * DFS, (17)

The fraction of all vehicles equipped with catalysts, but using leaded fuel, would be:

VLYSCT,,,. = CATFCT,,,* ( RMIS,,,- TAMFRC,,,,) : (18)

This assumes that all vehicles with removed catalysts are a subset of RMIS,, ,. the misfueling rate
for model year m and vehicle class v. The catalyst removed vehicles are treated as non-catalyst
vehicles in the equations above. The remaining vehicles will all be catalyst-equipped vehicles
using unleaded fuel. That fraction is:

VUYSCT,,, = (1.-VLNOCT,,,- VUNOCT,,,- VLYSCT,,,) (19)

51


DIESEL-FUELED VEHICLES

LEAD EMISSION FACTORS

No lead emission factors for diesel-fueled vehicles are calculated in the model. The lead emissions
result almost exclusively from the lead content of the fuel; and since the lead content of diesel fuel
is negligible, it is assumed that the lead emissions from diesel-fueled vehicles are also negligible.
SULFATE EMISSION FACTORS

The sulfate emission factors are calculated assuming all sulfur in the fuel is exhausted as either
sulfuric acid or gaseous sulfur dioxide (EPA 1990).

The direct sulfate emission factor (g/mi) is calculated as follows:
DSULF,,, = 13.6078 * (1.0 + WATER) * FDNSTY * SWGHTD * DCNVRT | FE,,,, (38)

where

DSULF,,, = the direct sulfate emission factor for a vehicle of class v and model year m
(g/m)

DCNVRT = _ the fraction of sulfur in the fuel that is converted directly to sulfate (2.0

EPA 1990, 3-4)
FDNSTY = density of diesel (7.11 Ib/gal, EPA 1988b)
FE,,, = the fuel economy for a vehicle of class v and model year m (mi/gal, EPA

1990, Table 6-A-1; note that the same fuel economies are used for both
2BHDDV and LHDDV for all model years)

SWGHTD = the weight percent of sulfur in diesel fuel ( 0.25 for high sulfur fuel, .05 for

low sulfur fuel used for calendar years 1993 and later)

WATER = weight ratio si seven water molecules to sulfate, 7.18 / 98 = 1.2857 (EPA
1990, p.

13.6078 = units conversion factor = (453.592 * 3.)/100., where 453.592 = number of
grams in a pound, 3 = weight ratio of SO, to sulfur, and the division by
100 is to correct for the weight percent of sulfur, SWGHTD

‘The gaseous sulfur emission factor is calculated as follows:
502 = 9.072 * FDNSTY * SWGHTD * (1. - DCNVRT) / FE,,., (39)

ae
where the new tems are ’

502,., the sulfur emission factor (g/mi) of a vehicle in class v and of model-year m
9.072 units conversion factor = (453.592 * 2)/100., where 453.592 = number of
grams in a pound, 2 = weight ratio of SO, to sulfur, and the division by
100 is to correct for the weight percent of sulfur, SWGHTD.

57


TABLE 2 (cont'd)

Exhaust Particulate Emission Factors for Diesel

Vehicles
Vehicle Type/ Exhaust Particulate
Model Year Group Emission Factor (EFDPM,, ,)
Medium Heavy Duty Diesel Vehicles (g/BHp-hr):
pre-1987 6946
1988-1990 4790
1991-1993 .2747
1994+ 0948
Heavy Heavy Duty Diesel Vehicles (g/BHp-hr):
pre-1987 6444
1988-1990 .4360
1991-1993 .2709
1994+ 0836
Buses (g/BHp-hr): :
pre-1987 693 L--
1988-1990 4790
1991 .2772
1992 without traps 1716
1992 with traps 0257
1993 without traps .1457
1993 with traps 0240
1994+ 0591

61


CLEAD yy

FEC * LEAD,, , (4)
where

CLEAD,,, = the lead emissions for a vehicle of model year m and vehicle class v, which

has been adjusted for the speed effect (g/mi)
FEC = 1/SCF, (5)
SCF, = the speed correction factor, based on either transient driving cycle (c=1) or
steady cruise driving cycle (c=2):

SCF, = 0.17930 + (0.038561 * SPEED,) - (0.00041067 * SPEED,*) (6)
SCF, = 0.26929 + (0.054607 * SPEED,) - (0.00069818 * SPEED,*) (7)

SPEED, = the average speed for vehicle class v, user input (mph)

Motorcycles _
Due to the absence of catalyst emission controls on motorcycles, organic emission factors are not
calculated and sulfate emission factors are negligible. The exhaust particulate printed in the output
is almost exclusively lead. The lead particulate emission factor for 2-stroke engines is 0.33 g/mi
and for 4-stroke engines is 0.046 g/mi. For pre-1978 model years there were 51% 4-stroke
engines and 49% 2-stroke engines (see references page 67, EPA 1985a):

LEAD, motorcycle = ( (0.49 * 0.33) + (0.51 * 0.046) ] * PSL (8)
For 1978 and later motorcycles are assumed to consist of 100% 4-stroke engines:

LEAD,,, motorcycie = 9-046 * PSL (9)
where

PSL = _ the fraction of all particles that are emitted based on user input of the particle
size cutoff :

49


Figure 2a

PARTS Revised 02-24-95

Sample Using Alternate VT Mixes once per run

User supplied veh miles traveled mixture  .

scene

Particle Size Cutoff 10.00 Microns Altitude: 500. Fe. Driving: Transient RFG:No

Cal. Year: 1994
Veh. Type: LOGY LoGTt

1/M Program: No Region: Low ALL
WeT2 HDGV «MC LDV. LODT «© 2BHDOV LHDOV MHDOV HHDDV BUSES Veh.

Veh. Speads: 19.6 19.6
Vr Mix: 0.6340 0.1760

19.6 19,6 19.6 19.6 19.6 19,6 19.6 19.6 19.6 19.6 19.6
0.0830 0.0310 0.0070 0.0040 0.0020 0.0100 0.0010 0.0140 0.0340 0.0040

Composite Emission Factors (g/mi)

Exhaust PM: 0.014 0,018
Brake: 0,013 0.013
Tire: 9.008 0.008
Total PM: 0.058 0.070

0.040 0.184 0,020 0.288 0.346 0.324 0.921 1,156 1.380 1.260 0.096
0,013 0.013 0,013 0.013 0.013. 0.013 0.013 0,013 0.013 0,013 0.013
0.008 0.012 0.004 0,008 0,008 0.008 0.012 0.012 0.036 0.008 0.009
0.092 0.237 0,046 0.342 0,408 0.409 «1.042 1,306 1.583 1.430 0.149

Fugitive Dust: Unpaved Roads
Paved Roads
Unpaved Roads

Paved Roads

Fleet Average 139.04 g/mi (ae calculated in AP42 Vol 1 9/68)*

Fleet Average 13.41 g/m (aa calculated in draft AP42 Vol 1 3/93)*

Fleet Average 138.83 g/mi (as calculated-tr-RPtZ-V61 1 9/88, minus tailpipe and
tire-wear emissions) **

Fleet Average 13.21 g/mi (as calculated in draft AP42 Vol 1 3/93, minus tailpipe
and tire-wear emissions) **

* Includes fleet average tailpipe, tire-wear and brake-wear emissions.
** Includes fleet average brake-wear eaissions.

Paved Road Silt: 5.10 (g/m*2) Fleet average vehicle weight: 6000

Unpaved Silt: 4.3%

Precipitation Days: 140 >0.

Fleet average number of wheels: 4
01 in, (per year)

PARTS February 24, 1995

21


Figure 8a

++-Continued
PARTS Revised 02-24-98

Sample Input File Using Many User Optional Inputs
scenel

Emission Factors (Gm/Mile)

Model
Year
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
igen
1980
1979
1978
1977
1976
1975
1974
1973
1972
1971,
1970

Tr

0,02
0,11
O.2L
oO.
9.10
0.09
0.08
0.06
0,08
0.08
0,06
0.08
0.03
0.03
0.02
0.02
0.02
0.0L
0.01
9.00
0.00
0.00
0,00
0.00
0.00

Composites

Miles

1799,

10768,
24576,
37637,
49991,
61679,
72735.
93193.
93088.
102442.
1294.
119667.
127586.
135078.
142165.
148869,
1ssz210.
161208.
166
172249.
177326.
182129.
186672.
190970,
198034.

(continued)

| Total PM:
| Emiss Rate

0,055
0.055
0.085
0,088
0.085
0.083
9.085
0.055
0,087
0.059
0.060
0,060
0.061
0.062
0.073
0.070
0.072
0.073
0,076
0,080
0,108
0.108
0,107
0.108
0.105

0.058

Light Duty Gas Vehicles
January 1, 1994

PARTS February 24, 1995
39


The first four lines of the driver file (PARTS.IN, when running non-interactively) instruct the
particulate model how to run. The first line is a single character "N” or "Y" for no or yes to the
question "Do you want to run interactively?” If the first line was "N", then the second line is the
name of the input file. The next line of the driver file contains the name of the report file, which
will contain all the computed emission factors. The last line is the name of the error output file,
which will contain all the error and waming messages from the program. If there are no errors the
error output file will be empty.

An example driver file, PARTS.IN is:

N
BUS2.IN
BUS2.0UT
ERR.OUT

If the user wishes to run PARTS interactively, the driver file (PARTS.IN) must still be used. "Y"
is entered in the first Line, the remaining lines in the driver file (PARTS IN) are not used. mfle

ogram will require line of the i interactively, starting wi name of the report file and
The name of the error input file. The user will not be prompted for those file names. This is not the
preferred method of running the model due to the complexity of the input. It is recommended that
the non-interactive approach be used, which will provide.a recerd of the input file that can be used
in review and in detecting and correcting any errors.

INPUTS

pedis sete orien nanciaepe Senn PARTS ‘od tan ers The
examples provi ions use options input requirements.

sample input files contain default data, showing the actual values which are intemal to the model.
The corresponding output files echo the input with the emission factors in the chosen formats.
However, reference to the examples in 5 cannot substitute for a thorough reading of
chapters 2 and 3. PARTS utilizes an input file that provides program control information and the
data describing the scenarios for which emission factors are to be estimated. The input information
consists of three distinct sections: the Control section, the One-time Data section, and the Scenario
section.

The Control section is the portion of the input file that controls the input, ou and execution of
the program. For example, the Control section indicates whether PARTS il require the user 10
Meee ee cmap Tec coininn fan tac fortes susable for visual ee

emission factors in a format suitable for visual inspection or in a format
fuitable as inpetes another program.

Some parameters used in the emission factor calculations have intemal values built into PARTS.
The One-time Data section is the portion of the input that allows the user to define parameter values
different from those internal to PARTS, which will be used in the calculations for all of the
scenarios within a given run. For example, in the One-time Data section the user can speci
alternate annual mileage accumulation rates or registration distributions by age for each vehicle
type.

‘The Scenario section is the portion of the PARTS input that details the individual scenarios for
which emission factors are to be calculated. For example, in the Scenario section the user specifies


Figure 6a

PARTS Revised 02-24-95
Sample with PRIFLG = 1

scenel
Particle Size Cutoff 10.00 Microns Altitude: 500. Ft. Driving: Transient RFG:No
Cal. Year: 1994 1/M Program: No Region: Low AL

Veh. Type: LOGV LDGT1 LOGT2 HDGV “ ‘LoDV = -LDDT- = 2BHDDV LHDOV =MHDDV HHDDV BUSES = Veh.

Veh. Speeds: 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6
VM Mix: 0.6337 0.1760 0.0832 0.0307 0.0072 0.0048 0.0017 0.0202 0.0012 0.0137 0.0344 0.0035

Composite Emission Factors (g/mi) .

Lead: 0.000 0,000 0.000 0.000 0.000 0.000 0.000 9.000 0.000 9.000 0,000 0.000 9.000

SOF: - - - - - 0.062 0,200 0.187 0.457 0,495 0.322 «0.539
RCP: - - - - - 0.220 0.139 0.181 0.440 0,630 «1.022 0,685 =

Direct S04: 0.009 0.010 0.009 0,008 0,002 0.006 0,007 0.016 0.024 0,030 0.037 0.036 0.010
Exhaust PM: 0.014 0,018 0,040 0.184 0,020 0.288 0.346 0.324 0.921 1.156 1.380 1.260 0,094

0,128 0.184 0.149 0,033
0.186 0,291 0.186 0.043

Indir. $04: 0.023 0.031 0.032 0.089 0,009 0.032 0.039 0.066
Sulfate PM: 0.032 0.040 0.041 0.067 0.011 0.038 0.046 0.080
Brake: 0.013 0.013 0.023 0.013 0,013 0.013 0.013 0.013" 0,019 0,013 0.013 0.013
Tire: 0,008 0.008 0.008 0.012 0,004 0.008 0.008 0.008 0,012 0.036 0,008 0.009
Total PM: 0.058 0.070 0,092 0.237 0,046 0.341 (0.408 0.409 1.042 1.306 1.583 1.430 0.149

Fugitive Dust: Unpaved Roads Fleet Average 139.04 g/mi (as calculated in AP42 Vol 1 9/88)*
Paved Roads Fleet Average 13.41 g/ml (as calculated in draft AP42 Vol 1 3/93)*
Unpaved Roads Fleet Average 139.83 g/mt (as calculated in AP42 Vol 1 9/88, minus tailpipe and
tire-wear emissions) **
Paved Roads Fleet Average 13.21 g/m (as calculated in draft AP42 Vol 1 3/93, minus tailpipe
and tire-wear emissions) **

* Includes fleet average tailpipe, tire-wear and brake-wear omissions.
+* Includes fleet average brake-wear emissions.

Paved Road Silt: 5.10 (g/m*2) Fleet average vebicle weight: 6000
Unpaved Silt: 4.3% ” Fleet average number of wheels: 4
Precipitation Dayss 140 >0.01 in. (per year)

PARTS February 24, 1995

32


Figure 1

Sample Using Alternate VMT Mixes for each scenario

2 iVMFLAG (alternate VMT mixes)

1 i:MYMRFG (alternate mileage accumulation rates & registration)
1 :IMFLAG (Inspection and maintenance)

1 i:RFGFLG (2 to apply reformulated gasoline effects, 1 not to)
3 :OUTFMT (indicates type of output format)

1 :IDLFLG (2 to print, 1 not to print idle emission factors)

1 :SO2FLG (2 to print Gaseous SO2 emissions, 1 not to print them)
3 :PRTFLG (determines which pollutants to print out)

1 :BUSFLG (determines which alternative bus cycle to print out)
11994 1 19.6 : region, year, speed cycle, speed

04.3 05.1 2 : unpaved silt%, ind. silt g/m*2, WHEELFLG

140 : number of precip. days

scenel :scene name

10.  <-- Particle size cutoff

6000

04

0.6340 0.1760 0.0830 0.0310 0.0070 0.0040

0.0020 0.0100 0.0010 0.0140 0.0340 0.0040

1 2000 1 19.6 2: region, year, speed cycle, speed

04.3 05.1 2 : unpaved silt%, ind. silt g/m*2, WHEELFLG

140 number of precip. days
scene2 scene name
10. -- Particle size cutoff

6000

04

0.6150 0.1900 0.0860 0.0310 0.0060 0.0010
0.0010 0.0130 0.0010 0.0170 0.0360 0.0030

PARTS February 24, 1995
18


Figure 3a

WARNING: According to historical records
there are no Clase 28 Heavy Duty Diesel vehicles
for model years before 1981 or Light Heavy Duty
Diesel vehicles after 1976. PARTS will always
assume 0.0 registration for these vehicle:
during those periods.

PARTS Revised 02-24-95
Sample Input File Using Alternate Mil. Accum, Rates & Reg. Dist,

User supplied mileage accrual distributions , veh registration distributions,
scenel

Particle Size Cutoff 10.00 Hicrons Altitude: $00, Fe. Driving: Transient RFG:No
Cal. Year: 1994 I/M Program: No Region: Low aL
Veh. Type: LOGV LDGTL [DGT2 HDGvV MC = LODV. ss LODT-««2BHDDV LHDOV GIDDY HHDOV BUSES = Veh.
Von, Speeds: 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19%6 19.6 196 19.6 1%6
VME Mix: 0.6337 0.1760 0.0831 0.0307 0.0072 0.0045 0.0017 0.0102 0.0012 0.0137 0.0346 0.0035
Composite Emission Factors (g/m)
Exhaust PM: 0.014 0.018 0.040 0.154 0,020 0.288 0.346 0.324 0.921 1.156 1.380 1.260 0.094
Brake: 0.013 0,013 0.023 0,013 0.013 0,013 0.013 07013" "0.013 0.013 0.013 0.013 0.023
Tire: 0,008 0,008 0,008 0,012 0.004 0,008 0.008 0.008 0,012 0.012 0.036 0.008 0.009
Total PM: 0.058 0.070 0,092 0.237 0.046 0.342 0.405 0.409 1.042 1.306 1.583 1.430 0.149

Fugitive Dust: Unpaved Roads Fleet Average 139.04 g/mi (as calculated in AP42 Vol 1 9/68)*

Paved Roads Fleet Average 13.41 g/mi (as calculated in draft AP42 Vol 1 3/93)*
Unpaved Roads Fleet Average 138.83 g/mi (as calculated in AP42 Vol 1 9/88, minus tailpipe and

tire-wear emissions) **

Paved Roads Fleet Average 13.21 g/mi (as calculated in draft AP42 Vol 1 3/93, minus tailpipe

and tire-wear eaissions)**

* Includes fleet average tailpipe, tire-wear and brake-wear emissions.
** Includes fleet average brake-wear emissions.

Paved Road Silt: 5.10 (g/m*2) Fleet average vehicle weight:

6000

Unpaved Silt: 4.38 Fleet average number of wheels: 4

Precipitation Daye: 140 >0.01 in. (per year)

PARTS February 24, 1995

24


Figure 2

Sample Using Alternate VMT Mixes once per run

(alternate VMT mixes)

(alternate mileage accumulation rates & registration)
(Inspection and maintenance)

(2 to apply reformulated gasoline effects, 1 not to)
(indicates type of output format)

(2 to print, 1 not to print idle emission factors)

(2 to print Gaseous S02 emissions, 1 not to print them)
(determines which pollutants to print out)

:BUSFLG (determines which alternative bus cycles to print out)
0.6340 0.1760 0.0830 0.0310 0.0070 0.0040

0.0020 0.0100 0.0010 0.0140 0.0340 0.0040

1 :1994 1 19.6 2: region, year, speed cycle, speed

04.3 05.1 2 2? unpaved silt%, ind. silt g/m*2, WHEELFLG

PWRP WP Pew

140 number of precip. days
scenel scene name
10. -- Particle size cutoff

6000

04

PARTS February 24, 1995
20


Figure 7

Sample with OUTFMT = 3 and BUSFLG=2

1 :VMFLAG
1 :MYMRFG
1 2: IMFLAG
1 :RFGFLG
3 :OUTFMT
1 :IDLFLG
1 :SO2FLG
3 :PRTFLG
2 :BUSFLG
11994 1 19.6
04.3 05.1 2

{alternate VMT mixes)
(alternate mileage accumulation rates & registration)
(Inspection and maintenance)
(2 to apply reformulated gasoline effects, 1 not to)
(indicates type of output format)
(2 to print idle emissions, 1 not to print them)
(2 to print Gaseous SO2 emissions, 1 not to print them)
(determines which pollutants to print out)
(determines which alternative bus cycles to print out)
: region, year, speed cycle, speed
2: unpaved silt%, ind. silt g/m*2, WHEELFLG

140 number of precip. days
scenel scene name

10. -- Particle size cutoff

6000 : fleet average vehicle weight
04 : fleet average vehicle wheels

PARTS February 24, 1995
33


The tire-wear emission factor (printed when PRTFLG = | or 3) varies with the number of wheels
designated for that vehicle class (optional input), and the particle size cutoff. See the discussion on
tire-wear emissions on page 63 of the appendix, and Table 4 for particle size cutoffs, page 66 of

he appendix.

The "Total PM" (printed when PRTFLG = | or 3) is the sum of exhaust PM, brake-wear, tire-
wear, and indirect SQ4.

There are two fugitive dust categories, "Unpaved Dust" and "Paved Dust,” to represent reentrained
road dust emission factors. The formulas used in the model for fugitive dust are based on AP-42
Sections 11.2.1 (EPA 1985b), and 11.2.5 and 11.2.6 (EPA 1993b). See page 62 of appendix for
a discussion of the fugitive dust emission factors in the model. -

18


SOF,,,, = the soluble organic fraction of the exhaust particulate emission factor for a vehicle
in class v and of model-year m (g/mi)
RCP, = the remaining carbon portion (elemental carbon) of the exhaust particulate
-. emission factor for a vehicle in class v and of model-year m (g/mi)
EF, = EFDPM,,, * CF,,,,, exhaust particulate emission factor for a vehicle in class v

my

and of model-year m (g/mi)
EFDPM,,, = exhaust particulate emission factor for a vehicle in class v and of model-year m
(g/BHp-hr)
CF,,,y = conversion factor from g/BHp-hr to g/mi of a vehicle in class v and of model-year
m (BHp-hr/mi)

fraction, 4, = the fraction of the non-sulfate portion (equivalent to the carbon portion) of the
diesel exhaust particulate emission factor which is organic carbon, for vehicle in
class v (BHp-hr/mi)

59


effects of reformulated gasoline are consistent with the reformulated gasoline reductions for total
hydrocarbons as modeled in MOBILES.

OUTFMT specifies the output format of the report file. The output format selections are:

long (235 - 250 column) numerical format

short (204 - 221 column) numerical format

115 - 133 column text format

115 - 133 column text format, plus tables of data by model-year.

AWN
ound

The numerical format is useful when using the output of this program as input for other

The text format has more detailed headers and longer titles. The by model- ryear tables show the
emission factors for vehicles of each model-year in a particular vehicle class, multiplied by the
corresponding travel fractions, as well as the composite emission factors for all vehicle classes.

No additional data are required for any of the OUTFMT selections, with the exception of
OUTFMT = 5. In this case an extra line must be input (at the end of the user-supplied data section,
immediately before the scenario inputs section) with either a 1 or a 2 entered for each vehicle class,
denoting whether or not to a table for that class (1 = do not print, Print, 2 = Pant). ). The format for
this input is 1211 (when BUSFLG = 1), 1411 (when BUSFLG = 2), or 1311 (when BUSFLG =
3). See "BUSFLG" on page 8 of this section. Sample input files using OUTFMT = 5 appear in
Figures 4 and 8. Tassos

IDLFLG specifies whether or not to print the idle emission factors. ‘The legal values are:

1 = donot idle emission factors
2 = print idle emission factors

Currently, idle emission factors are calculated in PARTS only for heavy-duty diesel vehicles.

SO2FLG specifies whether or not to print gaseous SO, emission factors. The legal values are:

1 do not print gaseous SO, emission factors
2 print gaseous SO, emission factors

NOTE: Setting SO2FLG = 2 will not print gaseous SO2 when PRTFLG = 2. Set PRTFLG
to 1 or 3 when gaseous SO2 emission factors are required.

PRTFLG specifies the pollutant information to be reported. The legal values for PRTFLG are:

all particulate emission factors (including dust)
exhaust PM factors only
exhaust PM, brake-wear, tire-wear, total PM and fugitive dust.

nN
uw


Figure 5a

PARTS Revised 02-24-95
Sample with PRTFLG = 2

scenel

Particle Size Cutoff 10,00 Microns Altitude: 500, Ft. Driving: Transient RFG:No
Cal. Year: 1994 T/M Program: No Region: Low AL
Veh. Type: LOGV LDGTL LDGT2 HDGvV «= MC_—sLDDV.«-LDDT = _2BHDOV LHDDV MHDDV HHDDV BUSES Veh.
Veh. Speeds: 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 196 19.6 19.6 19.6 19.6
VMT Mix: 0.6337 0.1760 0.0831 0.0307 0,0072 0.0048 0.0017 0.0102 0.0012 0.0137 0.0344 0.0035
Composite Emission Facters (g/mi)
Lead: 0,000 9.000 0.000 0,000 0.000 0.000 0,000 0.000 9.000 0.000 0.000 0.000 9.000
‘SOF: - - - - - 0.062 0,200 0.157 0.457 0,495 0.322 0,839 -
RCP: - - - - - 0.220 0,139 0.181 0.460 0.630 1.021 0,685 -
Direct S04: 0.009 0.010 0.009 0.008 0.002 0.006 0.007 0.016 0.024 0.030 0.037 0,036 © 0.010
Exhaust PM: 0,014 0.018 0.040 0.154 0.020 0.288 0,346 0,324 0.921 1,156 1.380 1.260 0,094

PARTS February 24, 1995
30


TABLE 4
Fraction of Particles Less than or Equal to the Particle Size Cutoff

Vehicle : Type/ Particle Size Fraction of Particles less than or
Gasoline vehicles using 10.0 0.64
leaded fuel/ Lead, Carbon 2.0 0.43
0.2 0.23
Gasoline vehicles with catalyst, 10.0 0.97
using unleaded fuel/ Lead, Carbon 2.0 0.89
0.2 0.87
Gasoline vehicles without a 10.0 0.90
catalyst, using unleaded fuel/ 2.0 0.66
Lead, Carbon 0.2 0.42
Diesel vehicles/ Exhaust PM 10.0 1.00
2.5 0.92
2.0 0.90
1.0 . 0.86
All vehicles/ Brake-wear 10.0 0.98
7.0 0.90
47 0.82
LL 0.16
0.43 0.09
All vehicles/ Tire-wear 10.0 1.00
0.10 0.01
All vehicles/ Unpaved. 10.0 0.36
Road Dust 5.0 0.20
2.5 095
All vehicles/ Paved Road Dust 10.0 7.3*
- 2.5 3.3*

*Note: Paved Road Dust values are actual emission factors in g/mi.

66


Figure 4a (continued)

PARTS Revised 02-24-95
Sample with OUTFMT = 5
scenel
Emission Factors (Ga/Mile)

Light Duty Gas Vehicles

January 1, 1994

Model | Exhaust PM: | Braker | Tire:
Year TF Miles | Emiss Rate | Emias Rate | 2mise Rate

1994 0,02 1799, 0,012 0,013 0.008
1993 9,11 10768, 0.022 0,013 0,008
1992 0,21 24576. 0.012 0.013 0.008
1992 0,11 37637, 0.012 0.013 0.008
1990 0.10 49992. 0,012 0.013 0,008
1989 0.09 61679. 0,022 0,013 0,008
1988 0,08 72738. 0.012 0.013 0.008
1987 0.06 93193, 0,012 0.013 0,008
1986 0.05 93085. 0.014 0,013 0,008
1985 0.05 102442. 0.016 0,013 0,008
1984 0,06 111294, 0,016 0,013 0.008
1983 0,06 119667. 0.018 0,013 0,008
1982 0,03 127586, 0,016 0.013 0.008
1982 0,03 135076, 0,017 0.013 0.008
1980 0.02 142165. 0.026 0,013 0,008
1979 0,01 148869. 0.019 0.013 0.008
1978 0.01 158210. 0.019 0.013 0.008
1977 0.01 161208. 0.018 0.013 0.008
1976 0.01 166882. 0,019 0.013 0.008
1978 0,00 172249, 0,019 0,013 0.008
1974 0,00 177326. 0.043 0,013 0.008
1973 0,00 182129. 0,043 0,013 0.008
1972 0.00 186672. 0.043 0.013 0.008
1971 0,00 190970. 0,043 0,013 0.008
1970 0.00 198034, 0.043 0.013 0.008
Composite: 0.014 _ 9.033 0.008

PARTS February 24, 1998
27


2 PROGRAM CONTROLS AND USER-SUPPLIED DATA

The program control flags instruct the program whether user-supplied or default values are to be
used for the fraction of the total vehicle miles traveled by each vehicle class (VMT mixes), mileage
accumulation rates, and registration distributions. The flags also control whether or not an
inspection and maintenance (I/M) program is assumed, whether reformulated fuel effects are
required, ne

If any of the above user-specifi data are required, such as a VMT mix, this information will
come Sher al he contol Regs Fane entered and before the scenario inputs are entered. If you
specify user-supplied data for more than one control flag, the data pertaining to each flag shall be
entered in the same order in which the corresponding flags are entered in the control section.

The PARTS control flags are:

Following is a description of each control flag and any user-supplied data required for certain flag
settings.

VMELAG is the first control flag and specifies whether default or user-supplied VMT (vehicle
miles traveled) mixes are used. The VMT "mix" is the fraction of the total of all motor
vehicles contributed by each vehicle class. The fractions from all the vehicle classes must sum to 1.

‘The VMT mix in PARTS is based on national averages and changes over time (calender years).
There are three main trends driving the shifts in VMT. The first is the shift in sales from light duty
passenger cars torlight duty trucks. The next two have to do with the dieselization of trucks in

general. Light diesel tracks are increasing in sales over time as com to light duty
gasoline trucks. same trend can be seen even more noticeably, w: duty diesel trucks
replacing heavy duty gasoline trucks.

The only place in which the program uses VMT is to vreight all the emission factors for each
vehicle class together into the "All Vehicles" emission factor numbers shown in the
output.


the calendar year of evaluation and the particle size cuttoff to be assumed. Each PARTS run can
include many scenarios, and each scenario can have different scenario parameters.

The Control section specifies values for variables termed flags. In Chapter 2 each flag is named,
and the range of possible settings for that flag and the resulting action is noted. The One-time Data
required for certain flags is also described in Chapter 2. In Chapter 3, the Scenario section is
described line by line.

FORTRAN FORMAT SPECIFICATIONS

The descriptors used in Chapters 2 and 3 to define and describe the input field specifications are
FORTRAN format specifications. Following is a brief key for interpretation. Additional detail can
be found in any FORTRAN manual.

Descti Definiti iL .

‘Iw' The next w characters (columns; includes blank }) will be read
in as an integer value. Leading blanks are i , but trailing
blanks are read as zeroes; thus, integer input values should be
“right-justified” within the input field (i.e., if a value of "2" is to be
entered in a field specified as 12, the two columns should be filled in
"blank,2", not "2,blank" which will be interpreted as "20").

‘Fw.d' ‘The next w characters will be read in as a floating int real
number, where d is the number of digits to the right of (following)
Sara eee nee
value wi as speci paanet int speci
in the descriptor will be overridden. The Hecimal point, if present, is
considered a character in the overall field width, w.

‘Aw’ The next w characters will be interpreted and stored as alphanumeric
(ie., labels, text; any keyboard character can be entered).

‘wX' “The next w characters will be ignored; they are not read by PARTS.

Tv The field separator, used to indicate the end of one record (line of

input). Input after the '/ will be read from the next record.


5 EXAMPLES

INTRODUCTION

Inputs and outputs for nine examples (Figures 1-9a) are provided to illustrate various aspects of
PARTS. The user is encouraged to try two or more of these examples to ensure that the model as
compiled is running properly. In addition, the reader is encouraged to run the example input file
MANY-.IN, after reading Chapters 2 and 3, in order to get a global sense of the options and data
input requirements. All files listed in the example index below are available on disk and on the
Technology Transfer Network (TTN) Bulletin Board System (BBS).

Any word processing software or other test editor can be used to modify the example PARTS input
files to match user requirements. This is the easiest way to.insure that the proper formats and
record orders are maintained. However, when using word processing software the user should be
careful to save input files only as DOS text documents (ASCII text). Converting and saving input
files as word-processing documents will add hidden characters to the file which will not be
properly processed by the PARTS model.

You can determine if an input has had hidden characters by using the TYPE command available in
DOS to list the input file to the screen. Any characters shown which were not intended to be in the
file will cause problems when the file is read by PARTS. An example of the TYPE command, with
an option to pause after each screen of characters would be:

TYPE <filename>| MORE
Another problem that may occur when editing PARTS i input files column,
location. When using word-processing software to edit input flea if the B is viewed or

Printed using a proportional Font, some characters in each row will take up more or less column
space than other characters. All PARTS input and output files assume that all characters take up

equal column space (non-proportional spacing). It is helpful then to always use a non-proportional
font (such as Courier) when viewing or printing PARTS input or output files.

16


mileage accumulation rates but use the default registratiori distributions (MYMRFG = 2), you will
be asked to enter 25 mileage accumulation rates for each of the 12 vehicle classes (only the first 12
will be read for motorcycles, but the input must include spaces or zeros to fill out the 25 values, as
in the other vehicle type records). The data must be entered from newest to oldest vehicle. The
format for entering the data is 10F7.5/10F7.5/5F7.5, where "/" indicates end of record. So for
each vehicle class you would enter two lines of 10 rates each and one line of five rates. Once these
25 rates are entered for LDGVs, then the 25 rates for the next vehicle class (LDGT1s) should be
entered. This process should be repeated until the rates for all 12 vehicle classes are entered. The
order of the classes must follow the sequence listed above.

The registration distribution contains the fractions of the total number of vehicles in a particular
class that are of ages | through 25+. Thus the first number in the registration distribution for
LDGVs represents the fraction of all LDGVs that are one year old, and the 25th entry represents
the fraction of all LDGVs that are 25 or more years old. The sum of the 25 fractions must be 1 for
each vehicle class.

If you wish to enter your own registration distributions but use default mileage accumulation rates,
select MYMRFG = 3. In this case you must enter the registration distribution for each vehicle
class. The format for entering the distributions is 10F5.3/10F5.3/5F5.3, so for each vehicle
class you would enter two lines of 10 fractions each and one line of five fractions. The order of
the fractions is newest to oldest vehicle. The order of the classes is as listed on page 4.

If you wish to enter both your own mileage accumulation rates-and registration distributions, select
MYMRFG =4. In this case you must first enter the average mileage accumulation rates, and then
the registration distributions. A sample input file using MYMRFG = 4 is shown with the default
values in Figure 3.

IMFLAG is the third control flag and specifies whether or not an inspection and maintenance
(I/M) program is assumed. The I/M program in the model will only affect emissions from
gasoline-fueled vehicles. I/M programs reduce particulate emissions by having a deterrent effect
on tampering. The reductions in tampering and misfueling rates will have a slight effect on lead
and sulfate particulate emissions. The legal values for IMFLAG are:

1 = nol/M program
2 = WM program.

No user-supplied data is required for this flag.

NOTE: ‘This flag will only affect lead and sulfate particulate emission factors for gasoline
vehicles. Unless you are modeling calendar years in which a substantial fraction of the in-use
fleet is pre-198S model year vehicles, the effects will most likely be very insignificant.

RFGFLG specifies whether reformulated gasoline effects are required. The legal values for
RFGFLG are:

1 no reformulated gasoline
2 reformulated gasoline

The reformulated gasoline effects for particulate emissions are partially based on the sulfur content
of the gasoline used. The average sulfur weight percent is .034 for any gasoline fuel in any

calendar years preceding 2000. When reformulated fuel is used (RFGFLG = 2) and the calendar
year is set to 2000 and later (Federal Phase II), the sulfur weight percent is .0138. The remaining


Figure 3

Sample Input File Using Alternate Mil. Accum. Rates & Reg. Dist.
(alternate VMT mixes)
{alternate mileage accumulation rates & registration)
(Inspection and maintenance)
(2 to apply reformulated gasoline effects, 1 not to)
(indicates type of output format)
(2 to print, 1 not to print idle emission factors)

(2 to print Gaseous SO2 emissions, 1 not to print them)
(determines which pollutants to print out)
(determines which alternative bus

PWPPWHEH ee

14390
08254
04735
15442
08276
04436
14779
10335
07227
17251
09114
04815
04786
01678
00000
17825
08123
03702
20140
06883
03342
22517
06910
02121
24239
16139
10746
26081
18527
13160
62176
34754
19426
25354
10971
04760

3 VMFLAG
:MYMRFG
: IMFLAG
?REGFLG
:OUTEMT
:IDLFLG
:SO2FLG
:PRTFLG
:BUSFLG
-13612
07807
04478
~14508
07776
04168
+14259
09972
«06973
-16185
-08551
04517
04475
.01368
-00000
16478
07509
03422
17572
06405
03080
+20009
-06140
01884
+23273
-15496
10317
25204
+17904
-12718
58663
.32790
-18328
+23317
-10090
-04397

049 .079 .083
050 .054 .047
006 .005 .004
063 .084 .084
030 .053 .047
009 .008 .008

.12875 .12180
-07386 .06987
04237 .04007
+13631 .12807
07306 .06864
03916 .03679
.13758 .13275
09621 .09283
06728 .06492
+15185 .14246
08022 .07526
04238 .03976
04164 .03853
00000 .00000
-00000 .00000
+15233 .14081
-06942 .06417
-03163 .02924
-15432 .13639
05999 .05655
02839 .02616
+17779 .15798
05456 .04848
01675 .01488
22346 .21455
-14878 .14285
09906 .09511
-24387 .23538
+17302 .16720
+12290 .11877
-55348 .52220
«30937 .29189
.17293 .16315
+21443 .19720
09279 .08533
-04074 .03787

+11522
-06608
-03790
-12032
06449
-03456
-12809
08957
06264
+13365
.07061
-03730
-03543
-00000
-00000
+13017
+05932
.02703
-12133
+05365
02411
-14038
-04308
-01322
+20600
13716
09132
22746
«16158
121478
«49269
+27540
+15393
.18135
07847
-03541

-082 .084 .081 .077
+037 .024 .019 .014

+003 .010

084 .084 .069 .059
046 .036 .028 .017

005 .025

-10899
06251

+11305
-06059

«12359
-08642

«12539
+06625

+03232
00000

+12033
05484

- 10863
.05123

212474
+ 03828

+19779
-13169

-21982
215614

46485
+ 25983

-16678
07216

-10310
-05913

-10621
-05693

-11924
-08339

-11764
-06215:

-02921
-00000

211124
-05069

09788
04924

-11084
03402

«18990
-12644

+21243
+15089

~ 43858
+24515

-15338
06637

056 .050 .051
+015 .011 .008

+044 .036 .031
022 .017 .014

cycles to print out)

09751 .09225
05594 .05291

09979 .09376
+05348 .05025

211505 .11101
08046 .07763

+11037 .10355
-0583F .05471

02611 .02300
00000 .00000

+10283 .09506
04686 .04332

-08877 .08103
04763 .04637

09849 .08752
+03023 .02686

«18233 .17507
212140 .11656

+20528 .19838
+14582 .14092

41380 .39042
«23130 .21823

.14106 .12972
-06103 .05613

LDGV

LDGT1

PARTS February 24, 1995

22

08726
+05005
LoGv
-08809
04721
LDGT1
210711
-07490
LDGT2
09715
+05132
HDGV
01989
-00000
Mc
08788
04005
LDDV
07444
204543
LDDT
07777
02387
2BHDDV
+16809
«11192
LHDVM
219171
+13618
MHDVM
-36836
+20590
HHDVM
+11929
05161
BUSES


EPA-AA-AQAB-94-2

DRAFT USER'S GUIDE TO PARTS:
A PROGRAM FOR CALCULATING PARTICLE
EMISSIONS FROM MOTOR VEHICLES

February 1995

Office of Mobile Sources
National Motor Vehicle and Fuels Emission Laboratory
U.S. Environmental Protection Agency

lymouth
Amn Arbor, Michigan 48105


Appendix

PARTICULATE EMISSION FACTORS FOR MOBILE
SOURCES AS CALCULATED IN THE MODEL PARTS

45


The alternative emission factors are calculated using different conversion factors from grams per
brake-horsepower per hour (g/bhp-hr) to grams sper mile that reflect different driving behavior than
the EPA heavy-duty truck transient test cycle. conversion factors developed for the bus usage
Categories are inversely proportionate to fuel consumption. In general, the lower the fuel economy
the more severe the conversion factor.

Figure 7 shows an example of BUSFLG = 2.

NOTE: BUSFLG = 3 is not recommended. The situation this flag represents very rarely
occurs. The cycle was developed to heavy urban bus routes in downtown
Manhatten (NY,NY). Submissions to EPA using this flag will be examined carefully.
Modelers should supply justification for the use of BUSFLG = 3 in any State
Implementation Plan (SIP) - related modeling.


The following are the different pollutant categories (in g/mi) as they are labeled in the output for
OUTFMT = 3:

Lead = . exhausted lead

SOF = soluble organic fraction

RCP =- remaining carbon portion

Direct SO4 = direct sulfate emissions, exhausted as sulfuric acid (H,SO,)
ExhaustPM = lead + SOF +RCP + Direct SO,

IndirectSO4 = = _ estimated indirect sulfate material ((NH,) 2SO,]
Sulfate PM = indirect sulfate + direct sulfate

Brake = brake wear emissions

Tire = tire wear emissions

Total PM = Exhaust PM + brake + tire + indirect SO,
Unpaved dust = road dust from unpaved roads

Paved dust = road dust from paved roads

PRTFLG = 1 will print all pollutants above; PRTFLG = 2 will print Lead, SOF, RCP, Direct SO4
and Exhaust PM; and PRTFLG = 3 will print Exhaust PM, Brake-wear, Tire-wear, Total PM, and
Fugitive Dust (paved and unpaved).

Figures 5 and 6 show examples of PRTFLG = 2 and | respectively.

BUSFLG determines which alternative bus cycle emission factors to print out when using
OUTFMT=3. The legal values for BUSFLG are:

1
2

Do not print alternative bus cycle emission factors.
Print transit and CBD (Central Business District) bus cycle emission factors.

The transit usage category is based on the truck chassis cycle which is
representative of inter-city bus routes. This cycle is intended to represent the same
vehicle operations as the EPA heavy-duty transient engine dynamometer test for
heavy-duty diesel engines which is used to certify bus engines to Federal emissions
standards

The CBD usage category is based on an equal contribution of both the Central
Business District cycle (CBD) and the New York Bus Composite cycle (NYBC).
The CBD. cycle simulates driving in a heavily built up urban environment. It is a
squldistan stope. The NYBC cycle fea "compressed" version of the EPA eo
equidistant stops. The ! The NYBC cycle is a essed” version of the EPA unfiltered
bas test cycle. of the cycle si non-freeway driving with large
amounts of idle time, while the second part simulates freeway driving of a highly

Print heavy urban bus cycle emission factors. Based on the New York City cycle
which is representative of driving in heavily congested inner city areas. A lot of
stop and go with large amounts of acceleration and deceleration, resulting in very
low fuel economy, is represented in the heavy urban usage category.


The indirect sulfate emission factor, which consists mostly of ammonium sulfate and ammonium
bisulfate (EPA 1990, Chapter 6), is calculated as follows:

ISULF,,, = ICNVRT *SO2,,,* (3/2) * AMNWGT (40)
where
ISULF,,,, = the indirect sulfate emission factor of a vehicle in class v and of model-ye
m (g/mi)
ICNVRT = the fraction of SO, that is converted to sulfate (either ammonium sulfate or
ammonium bisulfate) in the atmosphere (12 percent)
3/2 = weight ratio of SO, to SO,,
AMNWGT = the estimated weight ratio of the combination of ammonium bisulfate and

ammonium sulfate in the atmosphere to SO, (1.6)

TOTAL EXHAUST PARTICULATE

eae a aa Orne muasion factors for diesel focted veice Classes (EFDOM, a)
are from reference EPA 1990. The emission factors for heavy-duty vehicles are

g/BHP-hr, which are converted to g/mi in PARTS. The conversion factors (EPA 1' 8b and EPA
1992) and emission factors both vary by model year. The emission factors for light-duty diesel
vehicles and trucks are in units of gir. The total exhaust emission factors given in Table 2 are
based on high sulfur fuel. The sulfur content in diesel fuel is being forced down in 1993 by EPA
regulatory requirements. When the user requests a calendar year of evaluation of 1993 or later, the
program will make the appropriate adjustments to the exhaust emission factors for low sulfur fuel
effects.

The only other adjustment that is made to the total exhaust emission factor is the multiplication by

the particle size cutoff fraction (see page 65). Particulate emission factors for diesel-powered
vehicles are not adjusted for vehicle speed.

SOLUBLE ORGANIC FRACTION AND
REMAINING CARBON PORTION

The soluble organic fraction (SOF) is calculated as a fraction of the remaining mass:

SOF», =(EF,,-DSULF,,,) * (fractionsop,) (41)
The remaining carbon portion (RCP) is defined to be everything else: :
RCP yy = EF _y-DSULFq, -SOF ny ° (42)

The soluble organic fractions (fractionsop ,) for different vehicle classes are as follows: 0.51 for
LHDDVs, 0.44 for MHDDVs, and 0.24 for HHDDVs. The fraction 0.51 is also used for the
2BHDDV vehicle class. The fraction 0.44 is also used for the vehicle class BUSES. The fractions
for LDDVs, LDDT1s, and LDDT72s are 0.18, .5, and .48 respectively (EPA 1990, Table 3-9).

where

58


Figure 9a

PARTS Revised 02-24-98
Sample with TRAPELG=2, showing percentages of bus traps

100% trap ef's, O& no trap ef's

Particle Size Cutoff 10.00 Microns Altitude: 500, Ft, Driving: Transient RFG:No

cal. Year: 1998 1/M Program: No Region: Low All Transit CBD
Veh. Type: LOGY LDGT1 LDGT2 HDGV co LoOV ««LDDT «= 2BHDDV LHDOV MHDDV HHDDV BUSES Veh. Buses** -Buses*

Veh. Speeds: 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 18.5 10.6
VME Mix: 0.6203 0.1864 0.0849 0.0309 0.0066 0.0019 0.0011 0.0123 0.0013 0.0187 0.038¢ 0.0032

Composite Emission Factors (g/mi)

Exhaust PM: 0.013 0.017 0.026 0.121 0.020 0.238 0.274 0.206 0.894 0.796 0.928 0.737 9.069 0.871 2.086

Brake: 0.013 0.013 0.013. 0,013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 9.013 9.013 0.013

Tire: 0,008 0.008 0,008 0.012 0,004 0.008 0.008 0.008 0.012 0.012 0,036 0,008 0.009 0,008 0.008

Total PM: 0.056 0.067 0.077 0.200 0.046 0.290 0,333 0.289 1.017 0.942 2.125 0.902 0.124 1.117 2.380

Fugitive Dust: Unpaved Roads Fleet Average 139.04 g/mi (as calculated in AP42 Vol 1 9/88)*
Paved Roads Fleet Average 13.41 g/ml (as calculated in draft AP42 Vol 1 3/93)*
Unpaved Roads Fleet Average 136.03 g/ml (as calculated in AP42 Vol 1 9/88, minus tailpipe and
tize-wear emisefeds) **—
Paved Roads Fleet Average 13.21 g/mi (ae calculated in draft AP42 Vol 1 3/93, minus tailpipe
and tire-wear emissions) **

* Includes fleet average tailpipe, tire-wear and brake-weer emissions.
** Includes fleet average brake-wear enissions.

Paved Road Silt: 5.10 (g/m*2) Fleet average vehicle weight: 6000
Unpaved Silt: 4.3% Fleet average number of wheels: 4
Precipitation Days: 140 >0.01 in. (per year)

** Not Included in All Veh.

PARTS February 24, 1995

41


Figure 5

Sample with PRIFLG = 2

NPRPWRRPEE

1
1 1994

: VMFLAG
:MYMRFG
: IMFLAG
:RFGFLG
:OUTFMT
:IDLFLG
:SO2FLG
:PRIFLG
:BUSFLG

119.6

04.3 05.1 2

140
scenel
10.
6000
04

{alternate VMT mixes)
(alternate mileage accumulation rates & registration)
(Inspection and maintenance)
(2 to apply reformulated gasoline effects, 1 not to)
(indicates type of output format)
(2 to print, 1 not to print idle emission factors)
(2 to print Gaseous SO2 emissions, 1 not to print them)
(determines which pollutants to print out)
(determines which alternative bus cycles to print out)

: region, year, speed cycle, speed

: unpaved silt%, ind. silt g/m*2, WHEELFLG

3: number of precip. days

rscene name

-- Particle size cutoff

PARTS February 24, 1995
29


1 INTRODUCTION

This appendix describes the methodologies used to calculate particulate emission factors from
motor vehicles in the computer model PARTS. PARTS is designed to estimate particulate emission
factors for a representative vehicle in an average fleet. The model calculates these fleet
characteristics, such as the travel fractions, from data that are representative of national averages.
The user has the option, in many cases, to input data that represents more closely the characteristics
of the region being modeled instead of using the model defaults.

‘The emission factors calculated by PARTS include the particulate pollutant compounds of lead,
sulfate, soluble organic fraction particulate, remaining carbon portion particulate, and total
exhausted particulate. The lead and sulfate are formed from the lead and sulfur contained in the
fuel. The soluble organic fraction consists primarily of hydrocarbons coming from unbumed or
partially bumed fuel and lubricating oil. The remaining carbon portion consists of soot-like carbon
(elemental carbon) and trace amounts of other components from the fuel and lubricating oil. The:
total exhaust particulate is the sum of these four categories... In-addition to these categories of
exhaust emissions, idle exhaust emissions!, brake wear, tire wear, fugitive dust, indirect sulfate,
and gaseous sulfur dioxide are also calculated.

The model calculates the emission factors for 12 vehicle classes and a fleet-wide average (estimated
by vehicle miles traveled (VMT) weighting of the emission factors for all 12 classes). The vehicle
classes include light-duty gasoline vehicles, two classes of light-duty gasoline trucks, heavy-duty
gasoline trucks, motorcycles, light-duty diesel vehicles, light-duty diesel trucks, four classes of
heavy-duty diesel trucks, and buses. To account for older vehicles on the road, the emission
factors reported for each vehicle class are composites of emission factors for vehicles 25+ years
old through the calendar year of evaluation (the calendar year of evaluation is provided by the
user.) The c ite emission factor for each vehicle class is calculated by weighting the emission
factor calculated for each mode! year by the travel fraction for that model year, and then summing
the 25 weighted factors. The travel fraction of a model year is the fraction of miles traveled by a
vehicle of that model year out of the total number of miles traveled by all model years’ vehicles in
that vehicle class:
. 25
EFCOMP,= = EF,,,* TF,,, (1)

mal

where

EFCOMP,
EF,.,
TF,

my

the composite emission factor for vehicle class v,
the emission factor for vehicle class v, model-year m,
the travel fraction for vehicle class v, model-year m.

In tum, the overall travel fraction of a vehicle class represents the fraction of the total number of
vehicle miles traveled (VMT) of that class out of the total highway VMT (from all 12 classes). The

1* Idle emissions are calculated only for beavy-duty diesel vehicles.

46


Figure 4a (continued)

++-Cont inued

PARTS Revised 02-24-95
Sample with OUTEMT = 5
cenel

Emission Factors (Gm/Mile)

Light Duty Gas Vehicles
January 1, 1994

Medel | Total PM:
Year TF Miles | Emiss Rate

1994 0,02 1799, 0.055

1993 0,11 10768, 0.088
1992 0.11 24576, 0.088
1991 0.12 37637, 0.088
1990 0,10 49992, 0.055
1989 0,09 61679. 0,055
1988 0,08 72735. 0,058

1987 0.06 43193. 0.055
1986 0,05 93088, 0.087
1985 0.08 102442. 0.089
1984 0.04 111294, 0,060
1983 0.04 119667, 0,060
1982 0,03 127586, 0,061
1981 0,03 135078, 0,062
1980 0.02 142168. 0.073
1979 0.01 148969. 0.070

1978 0,01 185210, 0,072
1977 0.01 161208, 0,073
1976 0.01 166882. 0,076
1975 0.00 172249. 0.080
1974 0,00 177326. 0.208

1973 0.00 182129. 0.108
1972 0.00 186672. 0.107
1971 0.00 190970. 0.108
1970 0.00 195034. 0,105

Composite: 0.058

PARTS February 24, 1995

28


5 ADJUSTMENTS AND CORRECTION FACTORS

All the emission factors-exhaust PM, direct and indirect sulfate, lead, SOF, RCP, brake-wear, tire-
wear, and fugitive dust-are adjusted for the particle size cutoff (PSC).

PARTICLE SIZE CUTOFF

The user of the PARTS model must enter a particle size cutoff. This cutoff is defined to be the
maximum aerodynamic diameter (between 1.0 and 10.0 tum) of the particles in the emission
factors. Each emission factor is then multiplied by the fraction of particles less than or equal to the
PSC.

The fraction of particles less than or equal to the PSC is determined from the fractions in Table 4
(EPA 1985a). auser inputs a PSC, the program linearly interpolates the appropriate fraction
of mass less than or to that cutoff based on the date im Fable 4 (but not less than the lowest
cutoff listed). PARTS has a lower limit of 1.0 for the PSC.

As can be seen in Table 4, the lowest PSC is 2.5 um for fugitive dust. jhe program will print
note for the user to be aware that the fugitive dust emission factors are on 2.5 jum when the
user inputs values between 1.0 and 2.4 jum as a PSC.

65


_ The legal values for VMFLAG are:

1 use default VMT mix
2 “user supplies a different VMT mix for each scenario
3 user supplies one VMT mix for all scenarios.

muw

If you enter 2, the VMT mix must be entered for each scenario. In this case the data are entered for
each scenario in the scenario section.

If you enter 3, the program requires input of the fraction of VMT contributed by each vehicle class
after all the control flags are entered.

The format for a user-supplied VMT mix is the same for options 2 and 3. This format is
(6(F6.4,1X)). Two lines of data are entered, each consisting of six fractions, for a total of 12
fractions corresponding to the 12 vehicle classes. The data must be entered in the same order as
the vehicle classes. The order of the vehicle classes with the corresponding Federal Highway
Administration (FHA) Class and gross vehicle weight (GVW) is:

Vehicle Class FHA Class GVW (bs)
1 = LDGV (light-duty gasoline vehicle)
2 = LDGTI (light-duty gasoline truck, I) -» L— < 6,000
3 = LDGT2 (light-duty gasoline truck, I) 2A 6,001 - 8,500
4=HDGV (heavy-duty gasoline truck) 2B-8B > 8,500
5 = MC (motor cycle)
6 = LDDV (light-duty diesel vehicle) 1 < 6,000
7 =LDDT (light-duty diesel truck) 2A 6,001 - 8,500
8 = 2BHDDV (class 2B heavy duty diesel vehicle) 2B 8,501 -10,000 _
9 = LHDDV (light heavy-duty diesel vehicle) 3,4,5 10,001 - 19,500
10 = MHDDV (medium heavy-duty diesel vehicle) 6,7,8A 19,501 - 33,000
l= HHDDV (heavy heavy-duty diesel vehicle) 8] 33,000+

12 = BUSES (buses)

Figure 1 (all figures are in Chapter 5, "Examples") shows an example of different VMT mixes
used for two different scenarios (VMFLAG = 2), and Figure 2 shows an example of a single VMT
mix used for both scenarios (VMFLAG = 3). The default values are shown in both figures.

MYMRIG is the second control flag and specifies whether default or user lied mileage
accumulation rates and registration distributions will be used. The legal values for MYMRFG are:

use default registration distributions and mileage accrual rates

user supplies mileage accumulation rates; default registration distributions used
user supplies registration distributions; default mileage accumulation rates used
user supplies both the mileage accumulation rates and the registration distributions

‘The mileage accumulation rate is the expected number of miles a vehicle will travel in one year,
divided by 100,000. The rates are assumed to vary by vehicle class and the age of the vehicle.
For example, if a light-duty gasoline vehicle is expected to accumulate 13,118 miles in its first year
of ownership, the average mileage accumulation rate for this first year would be 0.13118. The
program requires mileage accumulation data for vehicles ages 1 to 25 years for each vehicle class,
with the exception of motorcycles which are 1 to 12 years. Hence, if you wish to enter your own

i

1
2
3
4


Figure la

PARTS Revised 02-24-95

Sample Using Alternate: V4P Mizes for each scenario

User supplied veh miles traveled mixture =.

scenel

Particle Size Cutoff

Cal. Years 1994
Veh. Type: LDGV

Veh. Speeds: 19.6
VME Mix: 0.6340

Composite Emission Factors (g/m!)

Exhaust PM: 0.016
Brake: 0,013
Tire: 0,008
Total PM: 0.088

10.00 Microns Altitude: 500, Fe. Driving: Transient AFG:No

1/M Program: No Regions Low Al
LOGTL «=LOGT2,-HOGV  McsLDOV. LDDT = _2BHDDV LHDOV MHDOV HUDOV BUSES Veh.
19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6
0.1760 0.0830 0.0310 0.0070 0.0040 0,0020 0.0100 0.0010 0.0140 0.0340 0.0040
0.018 0.040 0.154 0,020 0,288 0.346 0.324 0,921 -1.156 1.380 1.260 0.094
0,013 © 0,013 0.013 0.013 0.013 0,013 0,013 0.013 0.013 0.013 0.013 0.013
0.008 0,008 0.012 0.004 0.008 0.008 0.008 0.012 0.012 0.036 0.008 0.009
0.070 0,092 0.237 0.046 0.341 0.405 0.409 1.042 2.306 1.583 1.430 0.149

Fugitive Dust: Unpaved Roads Fleet Average 139.04 g/mi (as calculated in APé2 Vol 1 9/88)*
Paved Roads Fleet Average 13.41 g/mi (as calculated in draft AP42 Vol 1 3/93)*

Unpaved Roads Fleet Average 13!

Paved Roads Fleet Average

tire-weer emissions) **

and tire-waar emissions) **

* Includes fleet average talipipe, tire-wear and brake-wear eaissions.
** Includes fleet average brake-wear emissions.

Paved Road Silt: 5.

Unpaved Silt: 4.3%
Precipitation Daya:

10. (g/m*2) Fleet average vehicle weight: 6000
Fleet average number of wheels: 4
140 >0.01 in. (per year)

g/mi (as calculated-tr RPEE-VOL 1 9/08, minus tailpipe and

13.21 g/mi (as calculated in draft AP42 Vol 1 3/93, minus tailpipe

PARTS February 24, 1995
19


TABLE 1
Carbon Emission Factors for Gasoline Vehicles (g/mi)

Leaded Unleaded
Vehicle Type/ Catalyst Catalyst Non-catalyst
Model Year Group (No-Air) (Air)
Light Duty Gasoline Vehicles:
pre-1970 193 .030
1970-1974 068 0060 0250 030
1975-1980 .030 0060 0250 .030
1981+ 017 0043 0043 017
Light Duty Gasoline Trucks I:
pre-1970 193 030
1970-1974 068 0060 0250 .030
1975-1986 030 0060 0250 .030
1987+ O17 0043 0043 O17
Light Gasoline Trucks II:
en atci4 370 es 054
1979-1986 068 0060 0250 .030
1987+ .030 0043 0043 017
Heavy Duty Gasoline Vehicles:
pre-1987 .370 054 054 054
1987+ 163 054 054 054

Motorcycles: see page 49 for description of motorcycle emission factors in PARTS.

56


BRAKE WEAR

The brake wear emission factor is assumed to be the same for all vehicle classes in the model. It is set
equal to

BRAKE = 0.0128 * PSBRK, (45)
where

PSBRK = the fraction of particles less than or equal to the particle size cutoff.
The emission factor 0.0128 g/mi was measured by Cha, Carter, and Bradow (EPA 1985a).

TIRE WEAR
The tire wear emission factor is calculated as
EFTIRE, = 0.002 * PSTIRE * IVEHWL, (46)
where

EFTIRE, = tire wear emission factor for a vehicle in class v (g/mi)

0.002 = cision rf eure acl fr wen fe ight uy (EPA
1985b)
PSTIRE = the fraction of particles less than or equal to the particle size cutoff
IVEHWL, = the average number of wheels on a vehicle of class v: LDGV = 4, LDGT1, 2 = 4,

HDGV = 6, MC = 2, LDDV = 4, LDDT = 4, 2BHDDV = 4, LHDDV = 6,
MHDDV =6, HHDDV = 18, BUSES = 4

IDLE EMISSIONS

The idle emission factor data in grams per hour was collected from manufacturers. The factors are
reported only for the heavy-duty diesel vehicle classes, and as such, are not factored into the overall
vehicle ("All veh.") emissions category. The vehicle class emission factors are calculated by averaging
together model-year-specific emissions data, where the model-year-specific emissions data are
weighted by the estimated travel fraction of that model year within the vehicle class.

Currently the idle emission rates are model-year-specific but the model year emission rates do not vary
by vehicle class, Hence, the same model year emission factors are used for all the heavy duty diesel
classes, and the differences between the idle emission factors between classes is a reflection only of the
differing travel fractions from model year to model year within that class (where the travel fractions are
the TF,, ,'5 in equation (1)). As a result, the emission factors reported for the smaller of the heavy

duty diesel vehicle classes, such as 2BHDDV and LHDDV, may be over-predicted.

The base idle emission factors in PARTS for all heavy-duty diesel vehicles are shown in Table 3.

63


Figure 8

030
009
054
028
009
023
034
021
144
023
000
049
050
006
. 063
030
009
043
066
000
000
000
125
034
053
011
034
053
011
030
050
008

+053
008
072
+080
-008
047
064
+022
-168
097
-000
079
054
005
-084
+053
008
084
083
000
-000
-000
~102
067
-066
009
067
066
009
-060
049
-007

-047
-008
+072
+084
+009
047
054
+022
2135
000
-000
-083
047
-004
084
047
008
084
069
-000
-000
+000
+080
-067
-055
007
067
055
007
059
047
-006

211111111111
1 1994 1 19.6

04.3 05.1

140

scenel

10.
6000
04

-- Particle size cutoff

2

+046
+005
072
+049
006
047
+058
014
+109
+000
-000
+082
037
-003
-084
046
-005
-084
071
+000
-000
+000
057
067
057
005
067
-057
-005
-058
+046
+005

-036
+025
+072
+039
+026
-047
+052
117
-088
+000
-000
-084
024
-010
084
036
025
-084
000
-000
-000
-000
+182
067
045
-016
-067
+045
+016
-057
045
025

(continued)

028

+052
-030

-038
+038

+070
-000

-081
019

069
028

091
000

-000
-000

+073
019

073
019

-055
044

017

050
.018

+033
+043

056
.000

077
+014

059
017

076
+000

+000
-000

061
.023

.061
1023

054
044

-022

+034
+023

021
.0421

2045
-000

056
-015

2044
+022

-050
-000

-000
+000

040
028

-040
028

+053
+043

: region, year, speed
: unpaved silt%, ind. silt g/m*2, WHEELFLG

017

054
+018

+026
+035

-036
000

-050
O11

-036
017

051
000

+000
+273

041
+024

2041
024

+052
+042

cycle, speed

number of precip. days
: zscene name

-014

+031
-015

+029
029

029
+000

051
008

031
.014

064
-000

LDGT1

LDGT2

Mc

LDDV

LDDT

_ 2BHDDV

-000-—= ===

-182

051
016

051
016

+050
.010

LHDVV

MHDVV

HHDVV

BUSES

PARTS February 24, 1995

36


Figure 8a

WARNING: According to historical records

there are no Class 2B Heavy Duty Diesel vehicles
for model years before 1981 or Light Heavy Duty
Diesel vehicles after 1976. PARTS will always
assume 0.0 registration for these vehicles

‘during those periods.

PARTS Revised 02-24-95

Sample Input File Using Many User Optional Inputs

User supplied veh miles traveled mixture

scenel
Particle Size Cutoff 10.00 Mtcrons
Cal. Year: 1994

Veh. Type: LOGV- LOGTL LOGT2 HDGV

Altitude: 500, Ft. Driving:

IMM Program: Wo Region:
Mc «LOY LDDT«_2BHDOV LHDOV « MDOV

+ mileage accrual distributions , veh registration distributions.

Transient REG:Ho
low AL
HHDDV BUSES = Veh.

Veh. Speeds: 19.6 19.6 19.6 19.6

19.6 19.6 19.6 19.6 19.6 19.6

WMT Miz: 0.6340 0.1760 0.0830 0.0310 0.0070 0.0040 0,0020 0.0100 0.0010 0.0140

Composite Emission Factors (g/mi)
Exhaust PM: 0.014 0.018 0.040 0.154
Braker 9.013 0.013 0.013 0.023
Tire: 0,008 0,008 0.008 0,012
Total PM: 0.088 0.070 0,092 0.237

0.922 1.186

0.020 0.346 0.3247

0,013 9.013 0.013 0,013 0,013
0.004 0.008 0,008 0.012 0.012,
0.066 0.405 0.409 1.042 1.306

19.6 19.6 19.6
0.0340 09,0040

1.380 1.260 0.094
0.013 0.013 0.013
0.036 0.008 0.009
1.583) 1.430 0.149

Fugitive Dust: Unpaved Reads Fleet Average 139.04 g/mt (as calculated in AP42 Vol 1 9/88)*
13.42 g/mi (as calculated in draft APé2 Vol 1 3/93)*
Unpaved Roads Fleet Average 139.83 g/m! (as calculated in AP42 Vol 1 9/88, minus tailpipe and

Paved Roads Fleet Average

Paved Roads Fleet Average

tire-wear emissions)**

13.22 g/mi (ae calculated in draft AP42 Vol 1 3/93, minus tailpipe

and tire-wear emissions) **

* Includes fleet average tailpipe, tire-wear and brake-wear emissions.
** Includes fleet average brake-wear emissions.

Paved Road Silt: 5.10 (g/m*2)
Unpaved Silt: 4.3%

Fleet average vebicle weight:

6000

Fleet average number of wheels: 4

Precipitation Dayst 160-20,02 in. (per year)

PARTS February 24, 1995
37


Finally, all of the terms can be combined to give the composite lead particulate emission rate for
this vehicle/model year (compare to equation 3):

LEAD,,, = PLNOCT,,, * VLNOCT,, , (20)
+ PUNOCT,,, * VUNOCT,,,
+ PLYSCT,, * VLYSCT,,,
+ PUYSCT,, * VUYSCT,.,

This rate is adjusted for speed by the factor FEC so that:
CLEAD,,, = FEC *LEAD,,, (21)

SULFATE EMISSION FACTORS

The particulate sulfate emission factors consist of direct and indirect sulfate material. The direct
sulfate is exhausted as sulfuric acid, and the indirect sulfate is formed later in the atmosphere from
exhausted SO,. The indirect sulfate in the model is calculated based on the assumption that it
consists entirely of ammonium sulfate and ammonium bisulfate. The direct sulfate, indirect
sulfate, and gaseous sulfur are all computed in the model, and the emission factors are reported a8
g/mi (EPA 1990). to inircee .

The direct sulfate from non-catalyst vehicles using leaded fuel (includes catalyst-equipped vehicles
which are misfueled, making the catalyst ineffective) is calculated as:

DSULFN = .002, for speeds at or < 19.6 mph (22)
DSULFN = .0O1, for speeds at or > 34.8 mph (23)
The direct sulfate from catalyst vehicles is calculated as:
DSULFC,,, = [FRAC cating gid 005) + FRAC. ayaiel-016) ], (24)
for speeds at or < 19.6 mph

DSULFC,,, = [FRAC jupoai 005) + FRAC 3yynogid-001) + FRAC, jgief-020) (25)
+ FRAC 3, 4;-{.025) ], for speeds at or > 34.8 mph

For speeds between 19.6 and 34.8 mph, DSULFN and DSULFC are interpolated between
equations 22 and-23; and 24 and 25, respectively (EPA 1985a).

where

’

FRAC, ,inogir = the fraction of vehicles which are catalyst equipped with no air pump, for
vehicles of class v and model year m
FRAC, air = the fraction of vehicles which are catalyst equipped with air pump, for vehicles of
class v and model year m
= the fraction of vehicles which are oxidation catalyst equipped with no air pump,
for vehicles of class v and model year m
FRAC;,/nogir = the fraction of vehicles which are 3-way catalyst equipped with no air pump, for
vehicles of class v and model year m

FRAC,

‘oxlnoaii

52


Figure 4

Sample with OUTFMT = 5

: VMFLAG
:MYMRFG
:IMFLAG
:RFGFLG
:OUTFMT
:IDLFLG
:SO2FLG
:PRTFLG
1 :BUSFLG
211111111111
1 1994 1 19.6
04.3 05.1 2

WrPRPUPEEE

(alternate VMT mixes)

(alternate mileage accumulation rates & registration)
(Inspection and maintenance)

(2 to apply reformulated gasoline effects, 1 not to)
(indicates type of output format)

(2 to print, 1 not to print idle emission factors)

(2 to print Gaseous SO2 emissions, 1 not to print them)
(determines which pollutants to print out)

(determines which alternative bus cycles to print out)

: region, year, speed cycle, speed
: unpaved silt%, ind. silt g/m*2, WHEELFLG

140 : number of precip. days
scenel scene name
10. -- Particle size cutoff

6000

04

PARTS February 24, 1995
25


6-30). Thus, the PARTS model calculates the indirect sulfate emission factors as 12 percent of the
gaseous SO, motor vehicle emissions.

The model uses the following general formula to derive the emission factors for indirect sulfate,
which consists of ammonium sulfate and ammonium bisulfate (EPA 1990, page 6-30):

ISULF = ICNVRT * SO2 * (3 /2) * AMNWGT (34)
where

ISULF the estimated indirect sulfate emission factor (g/mi)

SO2 = the gaseous sulfur emission factor (g/mi)
3/2 = weight ratio of SO, to SO,
AMNWGT = the estimated weight ratio of the combination of ammonium bisulfate and
ammonium sulfate in the atmosphere to SO, (1.6, EPA 1990, p. 6-25)
ICNVRT = the fraction of SO, converted to sulfate (.12 is the national average, EPA 1990,

page 6-29, Table 6-13)
The actual computation is performed in the model for each vehicle type (catalyst and non-catalyst):

ISULFC,,, = ICNVRT *SO2C,,, * (3 /2)* AMNWGT (35) -

ISULFN,,, = ICNVRT * SO2N,,, * (3/2) * AMNWGT (6)
ISULF,,, = (CTLFRC,,, * ISULFC,,,) + [ (1.0 - CTLFRC,,,) * ISULFN ,,,) (37)

where

ISULFC,,, = the estimated indirect sulfate from catalyst vehicles in class v of model-year m

ISULFN,,, = te eatimuted indirect sulfate from non-catalyst vehicles in class v of model-year
ISULF,,, = the Sotnated indirect sulfate emission factor of a vehicle in class v of model-

year m (g/mi)

TOTAL EXHAUST PARTICULATE

The total exhaust i emission factors for light-duty gasoline vehicles are calculated from
the sum of lead,. sulfate, and a carbon emission factor which includes soluble organics and
other remaining carbon. The carbon emission factor has been determined based on reference EPA
1985a and the information in EPA 1993a. Table 1 summarizes the carbon emission
factors by year and technology type. .

55


TABLE 3

Model Years Emission Factor (g/hr)
pre-1988 5.370
1988-1990 3.174
1991-1993 1.860
1994 1.004

64


1 INTRODUCTION

DESCRIPTION OF THE MODEL

PARTS is a Fortran program for use in the analysis of the particulate air pollution impact of in-use
gasoline-fueled and diesel-fueled motor vehicles which supercedes the 1985 particulate emission
factor model. It calculates particle emission factors in grams ara erm (gi) om ond

: automobiles, trucks, and motorcycles, for particle sizes of 1-10 The particulate matter
emission factors include exhaust particulate, exhaust particulate con components, brakewear, tirewear,
and reentrained road dust, all of which are required for PM10 inventories and analyses. The model
is appropriate for comparative analyses, such as comparing the potential impact of one traffic

_ control measure versus another.

PARTS differs from the previous particulate model (released in 1985) in the following ways: It It
reflects the low sulfur diesel fuel regulation of October 1993, it reflects lower particulate standards,

there is an expansion of the heavy- -duty diesel vehicle classification into five sub-categories anda
separation of the light-duty cars and trucks by gasoline and diesel. Additions in the new model
include an option to print gaseous SO2, the calculation of fugitive dust for paved and unpaved
roads based on algorithms developed by the Office of Air Quality Planning and Standards
(Unpaved Roads - AP42, section 11.2.1, 9/88, Paved Roads - draft AP42, section 11.2.x, 3/93),
and an option to calculate idle emissions from manufacturers’ data. The mileage
accumulation rates, vehicle counts, diesel sales ions, registration distributions and catalyst
fractions also were updated to be consistent with MOBILES.

The program contains default values for most data required for the calculation of all the emission
factors, but it also allows for user- pser-supplied data in many cases. All of the required inputs and
optional inputs are described in in this guide. The methodology for the calculation of the
emission factors is described in the appendix.

Questions about this document or the PARTS model can be addressed to:

PARTS User's Guide -- Comments
Air Quality Analysis Branch

2565 Plymouth Road

Ann Arbor, MI 48105

Fax: (313) 668-4368

GETTING STARTED

To run the model the user must change to the directory in which the executable file, PARTS.EXE
and the driver file, PARTS.IN, reside. After editing the driver file PARTS.IN (see the discussion
of how to set up the driver file below), the user can run the model by typing "PARTS" at the DOS
prompt.


Figure 9a (continued)

508 trap ef's, 50% no trap ef's

Particle Size Cutoff 10.00 Microns Altitude: 500. Ft. Driving: Transient REG:No

Cal. Year: 1998 I/M Program: No Region: Low ALL Transit C80
Veh. Type: LOGY LDGTL LOGTZ HDGV = MC) LDDV.)--LDDT = _2BHDDV LHDDV MHDDV HHDDV BUSES Ven. Buses** Bus

Veh. Speeds: 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.5 18.5 10.6
VMT Mix: 0,6203 0.1964 0.0849 0.0309 0,0066 0.0019 0,0011 0.0123 0.0013 0.0187 0.0354 0.0032

Composite Emission Factors (g/ml)

Exhaust PM: 0.013 0.017 0.026 0.121 0,020 0.238 0.274 0.206 0.894 0.796 0,928 0.763 0.070 0.903 2.161

Bral 0.013 0,013 0,013 0,013 0.013 0.013 0.013 0,013 0.013 0,013 0.013 0.013 0.013 9.013 9,013

Tire: 0,008 0,008 0,008 0.012 0.004 0.008 0,008 0.008 0.012 0.012 0.036 0.008 0.009 0.008 0.008

Total PM: 0.056 0.067 0.077 0.200 0.046 0.290 0.333 0.289 «1.027 0,942 1.125 0.927 1.149 2.455

Fugitive Dust: Unpaved Roads Fleet Average 139.04 g/mi (as calculated in AP42 Vol 1 9/88)*
Paved Roads Fleet Average 13.41 g/mi (as calculated in draft AP42 Vol 1 3/93)*
Unpaved Roads Fleet Average 138.83 g/mi (as calculated in AP42 Vol 1 9/89, minus tailpipe and
tire-wear emissions) **
Paved Roads Fleet Average 13.21 g/mi (as calculated in draft AP42 Vol 1 3/93, minus tatlpipe

and tire-wear emissions) **

* Includes fleet average tailpipe, tire-wear and brake-weer emissions,
** Includes fleet average brake-wear enissions.

Paved Road Silt: $5.10 (g/m*2) Fleet average vehicle weight: 6000
Unpaved silt: 4.38 Pleet average number of wheels: 4

Precipitation Days: 140 >0.01 in. (per year)

** Not Included in All Veh.

PARTS February 24, 1998
44


Figure 9a (continued)

100% no traps for buses

Particle Stze Cutoff 10.00 Microns Altitude: 500, Ft. Driving: Transient REG:No

Cal. Year: 1998 1/M Program: No Region: Low ALL Transit cep
Veh. Type: LOGY LDGT! LoGTZ HDGvV MC =—-LODV.««-LODT-««2BHDDV LHDDV mIDDV HHDDV BUSES Van. Busas** Buses*

Veh. Speeds: 19.6 19.6 19.6 19.6 19,6 19.6 19.6 19,6 196 19.6 19.6 19.6 19.6 18.5 10.6

VM Mix: 0.6203 0.1664 0.0849 0.0309 0.0066 9.0019 0.0011 0.0123 0.0013 0.0187 9.0384 0.0032

Composite Emission Factors (g/mi)

Exhaust PM: 0.013 0.017 0.026 0.121 0,020 0,238 0.274 0.206 0.896 0.796 0.928 9.070 0,934 2.237
Brake: 0.013 0.023 0,013 0,013 0,013 0.013 0.013 0,013 0,013 0,013 0.013 0.013 0.013 0.013
Tire: 9.008 0,008 0.008 0.012 0.004 0,008 0.008 0.008 0.012 0.012 0.036 9.009 9,008 0,008
Total PMt 0.056 0.067 0,077 0,200 0,046 0.290 0.333 0,289 «1.017 0.942 1.128 0.124 1.180 2.530

Fugitive Dust: Unpaved Roads Fleet Average
Paved Roads Fleet Average
Unpaved Roads Fleet Average

Paved Roads Fleet Average

139.04 g/mi (as calculated in AP42 Vol 1 9/88)*

13.41 g/m (as calculated in draft AP42 Vol 1 3/93)*

138,83 g/mi (as calculated in AP42 Vol 1 9/88, minus tailpipe and
tire-wear emissions) **

13.21 g/mt (as calculated in draft AP42 Vol 1 3/93, minus tatlpipe

and tire-wear emi:

* Includes floet average tailpipe, tire-wear and brake-wear omissions.
** Includes fleet average brake-wear enissions.

Paved Road Silt: 5.10 (g/m*2)
Unpaved Silt: 4.38

Fleet average vehicle weight:

ions) **

6000

Fleet average number of wheels: 4

Precipitation Days: 140 >0,01 in. (per year)

** Not Included in All Veh.

PARTS February 24, 1995

42


References

AAMA 1993 National Fuel Survey, 1980 - 1993

EPA. 1985a. Size Specific Total Particulate Emission Factors for Mobile Sources. U.S.
Environmental Protection Agency (EPA-460/3-85-005).

EPA. 1985b. Compilation of Air Pollutant Emission Factors, Volume 2: Stationary Point and Area
Sources. U.S. Environmental Protection Agency. (AP-42, 4th edition)

EPA. 1988a. Compilation of Air Pollutant Emission Factors, Volume 1: Stationary Point and Area
Sources. us. Environmental Protection Agency. (AP-42, 4th edition)
ection 11.2.1

EPA. 1988b. Heavy-Duty Vehicle Emission Conversion Factors II 1962-2000. U.S. +
Environmentatal Protections Agency | (EPA- -AA-SDSB-89-01) :

EPA. 1990. Regulatory Impact Analysis. Control of Sulfur and Aromatics Contents-of On-Highway
Diesel Fuel. Office of Mobile Sources, U.S. Environmental Protection
Agency.

EPA. 1992. Development of Conversion Factors for Heavy-Duty Bus Engines GIBHP-HR to
G/Mile. U.S, Environmental Protection Agency (EPA-AA-EVRB-92-01).

EPA. 1993a. Motor Vehicle-Related Air Toxics Study. U.S. Environmental Protection Agency
(EPA-420-R-93-005).

EPA. 1993b. Compilation of Air Pollutant Emission Factors, Volume 1: Stationary Point and Area
Sources. U.S. Environmental Protection Agency. (AP-42, 4th edition)
Sections 11.2.5 and 11.2.6

NAV. 1991. Letter from Ed Sienecki of Navistar International to Dr. Jaroslav Vostal of General

Motors . and Dr. Joe Somers of Environmental Protection Agency dated
June 25, 1991.

67


nothing is entered for TRAPFLG, no trap technology is assumed. Setting TRAPFLG = 2
indicates there is some fraction of buses for model years 1992 and 1993 which are maintaining
traps. TRAPFLG = 2 should only be used when there is a maintenance program enforced, in
which the traps are subject to stringent maintenance procedures. When a "2" is used, the program
will look for a set of two percentages: one for traps maintained on 1992 model year buses and
another percentage for traps maintained on 1993 model year buses.

The format for the third scenario record when the TRAPFLG option is set, is:
13,1X,11,2(1X,F5.1)

A sample line utilizing the optional bus trap emission control technology input, specifying 140
annual days of precipitation, 100% of buses with trap technology for which there is a maintenance
program for model year 1992, and 50% of buses with trap technology for which there is a
maintenance program for model year 1993, is:

140 2 100.0 050.0 :number of precipitation days, TRAPFLG, % 1992 buses
equipped with maintained traps, % 1993 buses equipped
with maintained traps

Line 4. ‘The fourth input line is the scenario name, up to 32 characters. The name should be
different for each scenario and is echoed back as part of the output labeling. The format is:

A32
A sample input line is
Scenario 1 :scenario name
Line 5. The fifth input line is the particle size cutoff (PSC). The emission factors
represent the estimated grams per mile of particles with aerodynamic diameter less than or equal to
the PSC. The maximum PSC allowed is 10.0 jm, the minimum is 1.0 tm. The lower limit for

the PSC for fugitive dust is 2.5 jm. When less than 2.5 jum is entered, the program will reflect
emissions for 2.5 jum PSC for fugitive dust only. The format for this input is:

F5.2
A sample input line specifying 10 microns, is:
10.00 :Particle size cutoff (in xm).

Line 6. The sixtft input line is the fleet average vehicle weights which is used for the calculation
of fugitive dust emissions.

The format for this input is:
16

A sample line specifying a standard fleet average vehicle weight (Ibs), is:
6000

12


Substituting DSULFC,, , and DSULFN (from equations 22 through 25) in equation 27, we can

solve for the fractions of sulfur in the fuel that are converted to sulfate separately for catalyst, and
noncatalyst vehicles:

FCNVRC,,,=DSULFC,,,,* FEp,y / (13.6078 * (1.+WATER) * FDNSTY * SWGHT) (28)
FCNVRN,,,= DSULFN * FE,,,/ (13.6078 * (1.4WATER) * FDNSTY * SWGHT) (29)

where

FCNVRC,,,= the fraction of the percent of fuel that is directly converted into sulfate for
catalyst vehicles of class v and model year m

FCNVRN,, ,= the fraction of the percent of fuel that is directly converted into sulfate for
non-catalyst vehicles of class v and model year m

The gaseous sulfur emission factors, which are dependent on these fractions, are calculated from
equation

5O2,,y= 9.072 * FDNSTY * SWGHT * (1. - DCNVRT) | FE,,, (30)
where the new terms are a
502,,y = the gaseous sulfur emission factor of a vehicle in class v of model-year m

(g/mi)

9.072 = unit conversion factor = (453.592 * 2.)/100., where 453.592 = number of
grams in a pound, 2. = weight ratio of SO, to sulfur, and the division by 100 is
to correct for the weight percent of sulfur, SWGHT.

The gaseous sulfur emission factor is calculated in the model as the combination of the sulfur
emission factor from both catalyst and noncatalyst vehicles as follows:

5S02C,,y= 9.072 * FDNSTY * SWGHT * (1.0-FCNVRC,,)/FEy,y (31)
5O2N,,,= 9.072 * FDNSTY * SWGHT * (1.0-FCNVRN,,)/FEy,y (32)

SO2qy = (CTLFRC,,* SO2C,,,) + (1. -CTLFRCq,)*SO2Nyy} (33)

mh
where

502C,,, = the SO, emission factor from catalyst vehicles in class v of model-year m (g/mi)
5O2N,,, = the SO, emission factor from non-catalyst vehicles in class v of model-year m
(g/mi)
In addition to the direct sulfate emission factors, the model estimates an indirect sulfate emission
factor by assuming that a fraction of the gaseous sulfur dioxide emissions is later converted in the
to sulfate material. Based on ambient sulfur and sulfate measurements in 11 cities,
EPA estimates that 12 percent of all gaseous sulfur is converted to sulfate (EPA 1990, pp. 6-28 to

54


TABLE 2

Exhaust Particulate Emission Factors for Diesel

Vehicles
Vehicle Type/ Exhaust Particulate
Model Year Group Emission Factor (EFDPM, my)
Light Duty Diesel Vehicles (g/mi):
pre-1981 .700
1981 259
1982-1984 256
1985-1986 .255
1987 134
1988-1990 132
1991-1993 131
1994-1995 128
1996+ 100
Light Duty Diesel Trucks (g/mi):
pre-1981 .700
1981 309-
1982-1984 354
1985-1986 358
1987 334
1988-1990 291
1991-1993 .294
1994-1996 -130
1997+ * 109
Class 2B of Heavy Duty Diesel Vehicles (g/BHp-hr):
pre-1988 "5156
1988-1990 5140
1991-1993 .2873
1994+ AOLL
Light Heavy Duty Diesel Vehicles (g/BHp-hr):
pre-1988 5156
1988-1990 5140
1991-1993 .2873
1994+ 1011

60


4 OUTPUT

The output for PARTS is determined by the user-specified combination of the values assigned to
the control flags OUTFMT, PRTFLG, IDLFLG, "SO2FLG, and BUSFLG.

The particulate emission factor "Exhaust PM" (as printed in the output), is a summation of four
components in the model: lead, soluble organic fraction (SOF), remaining carbon portion (RCP),
and direct sulfate (SOx).

Lead particulate emission factors are based on the assumption that virtually all the lead in the fuel is
exhausted. As a result, the emission factors depend principally on the lead content in the fuel and
the fuel economy of the vehicle. The lead content of diesel fuel is negligible, so it is assumed that
the lead emissions from diesel-fueled vehicles are also negligible. The lead content of leaded
gasoline is substantially greater than that of unleaded fuel, so the fraction of vehicles that have had
their catalysts removed (and thus are assumed to be using leaded fuel in most cases) can also be an
factor in determining the lead emission factor from a vehicle that is representative of the
entire fleet. See discussions on lead emission factors and "Lead Derivation” on pages 48-52 of the

appendix.

The carbon portion of particulate emissions is broken down in the output as soluble organic
fraction ("SOF", printed when PRTFLG = | or 2) and remaining carbon portion ("RCP", printed
when PRTFLG = | or 2) for diesel vehicles (see 58 of appendix). Carbon emission

for gasoline vehicles are very small, and it is to distinguish between organic carbon and
remaining carbon based on the available data. Table 1 of tee appendix (pegs 56) shows the carbon
component for gasoline vehicles used in the model. This component is not printed for gasoline
vehicles, but is included in the total "Exhaust PM” in the output.

The direct sulfate ("Direct SO4", printed when PRTFLG = | or 2) is also a of the
exhausted particulate matter. The model assumes that all of the sulfur in the fuel is exhausted as
either direct SO, or gaseous SO. See page 52 of appendix for a discussion of gasoline sulfate
emission factors, and page 57 of the appendix for a discussion of diesel sulfate emission factors.

Gaseous sulfur dioxide (SO2) is an optional output, produced by setting the SO2FLG to "2" and
the PRTFLG to."2* or "3", in the control flag section of the input. The remaining sulfur in the fuel
(which was not exhausted as SO,) is considered to be exhausted as gaseous SO2. Gaseous SO2
acts as a precurses to form additional SO, in the atmosphere.

"Indirect SO4" (printed only when PRTFLG = 1) is calculated in the model based on
measurements of ambient sulfur and sulfate from 11 cities in the United States. The model
assumes that 12 percent of the gaseous SO; reacts in the atmosphere to form SO,.

‘The "Sulfate PM" (printed only when PRTFLG = 1) is the sum of direct and indirect SO,.
The brake-wear emission factor (printed when PRTFLG = | or 3) is assumed to be the same for all
vehicle classes in the model. The only input which will affect brake-wear emissions is the particle

size cutoff. See the discussion on brake-wear emissions on page 63 of the appendix, and Table 4
for particle size cutoffs, page 66 of the appendix.

14


ge ep >

ea - 3 Oo

y¥ -° SF @

Figures

Sample input file with user-defined VMT mixes for each scenario ...........0...0++- 18
Sample output file with user-defined VMT mixes for each scenario. .cscssss. 19
Sample input file with user-defined VMT mix for all scenariog...........:.ssssssees: 20
Sample output file with user-defined VMT mix for all scenarios ..........::.0000000 21
i i 2
Sample input file using QUTFMT 3 5 .....s..sssscsssssssssssecaseesssssssessstecssecess
Sample output file using OUTFMT = 5........sscssssssssecsessesesssecess .
Sample. eupot fle ing PRIFLG =.
Sample input file using PRTFLG = 1........sssscssssssssssccssessesssessssessssecessses 31
Sample output file using PRTFLG = 1 32
Sample input using OUTFMT = 3 and BUSFLG = 33
Sample output using OUTFMT = 3 and BUSFLG = 2 34
38
37
40
4

ii


Figure 8

Sample Input File Using Many User Optional Inputs
(alternate VMT mixes)

(alternate mileage accumulation rates & registration)
(Inspection and maintenance)
(2 to apply reformulated gasoline effects, 1 not to)
(indicates type of output format)
(2 to print, 1 not to print idle emission factors)

(2 to print Gaseous SO2 emissions, 1 not to print them)
(determines which pollutants to print out)
tBUSFLG (determines which alternative bus cycles to print out)
0.6340 0.1760 0.0830 0.0310 0.0070 0.0040
0.0020 0.0100 0.0010 0.0140 0.0340 0.0040

WRPrRUNH AW

1

14390
08254
04735
15442
08276
04436
14779
10335
07227
17251
09114
04815
04786
01678
00000
17825
08123
03702
20140
06883
03342
22517
06910
02121
24239
16139
10746
26081
18527
13160
62176
34754
19426
25354
10971
04760

049 .079
050 .054
006 .005
063 .084

: VMFLAG
s:MYMRFG
: IMFLAG
:REGFLG
:OUTFMT
:IDLFLG
:SO2FLG
i PRIFLG

+13612
07807
-04478
14508
07776
-04168
.14259
09972
-06973
-16185
08551
04517
04475
01368
-00000
16478
-07509
+03422
17572
06405
-03080
+20009
-06140
01884
«23273
-15496
-10317
+25206
-17904
-12718
-58663
«32790
-18328°
+23317
+10090
+04397

+12875
.07386
04237
.13631
+ 07306
-03916
.13758
09621
-06728
~15185
-08022
04238
04164
00000
-00000
«15233
+06942
-03163
-15432
-05999
-02839
217779
05456
01675
~22346
+14878
09906
26357
- E7302
+12290
«55348
-30937
.17293
21443
09279
04074

+12180
+ 06987
04007
-12807
06864
-03679
+13275
-09283
06492
+14246
07526
-03976
+03853
~00000
-00000
14081
«06417
02924
+13639
-05655
-02616
-15798
04848
-01488
+21455

“.14285

09511
«23538
-16720
-11877
-52220
-29189
-16315
~19720
-08533
03787

+11522
-06608
-03790
+12032
06449
+ 03456
-12809
08957
06264
+13365
-07061
+03730
-03543
-00000
-00000
.13017
+05932
-02703
+12133
-05365
02411
+14038
-04308
«01322
«20600
«13716
09132
«22746
-16158
+11478
49269
«27540
+15393
-18135
07847
-03541

-083 .082 .084 .081 .077
047 .037 .024 .019 .014
004 .003 .010
«084 .084 .084 .069 .059

.10899 .10310
06251 .05913

«11305 .10621
06059 .05693

+12359 .11924
08642 .08339

«12539 .11764
06625 .06215

-03232 .02921
00000 .00000

«12033 .11124
05484 .05069

+10863 .09788
05123 .04924

+12474 .11084
-03828 .03402

-19779 .18990
-13169 .12644

+21982 .21243
-15614 .15089

46485 .43858
+25983 .24515

+16678 .15338
-07216 .06637

+056 .050 .051
+015 .011 .008

-044 .036 .031

:VMT MIX
:VMT MIX

09751
-05594

09979
-05348

+11505
-08046
«11037
-05831

02611
+00000

-10283
04686

08877
04763

-09849
+03023

-18233
+12140

+20528
.14582

«41380
+ 23130

-14106
-06103

PARTS February 24, 1995

38

-09225
05291

-09376
-05025

+11101
-07763

+10355
05472

+02300
-00000

-09506
-04332

+08103
-04637

-08752
+02686

«17507
-11656

«19838
«14092
«39042
+21823

.12972
-05613

08726
-05005
LDGV
-08809
04721
LDGT1
210711
«07490
LDGT2
09715
-05132
HDGV
-01989
-00000
MC
08788
+04005
LDDV
07444
04543
LDDT
07777
+02387
2BHDDV
-16809
-11192
LHDVM
«19171
-13618
MHDVM
- 36836
+20590
HHDVM
.11929
-05161
BUSES


Figure 3

054
028
009
023
034
021
144
023
000
049
050
006
063
030
009
043
066
000
000
000
125
034
053
011
034
053
011
030
050
008
119

04.3 05.1

140

2072
-080
008
+047
+064
-022
-168
097
+000
.079
+054
-005
084
+053
-008
084
-083
+000
+000
+000
+102
-067
066
009
067
-066
009
-060
-049
-007
941

scenel

10.
6000
04

-- Particle size cutoff

+072
084
009
047
+054
022
.135
-000
+000
+083
047
004
084
047
008
084
069
-000
-000
-000
+080
067
2055
007
067
2055
007
-059
047
-006
19.6

2

+072 .072
+049 .039
006 .026
+047 .047
-058 .051
-014 .117
+109 .088
000 .000
+000 .000
+082 .084
+037 .024
003 .010
+084 .084
+046 .036
005 .025
084 .084
-071 £000
+000 .000
000 .000
+000 .000
057 .182
067 .067
057 .045
005 .016
-067 .067
057 .045
005 .016
-058 .057
046 .045
+005 .025

(continued)

+052
+030

038
038

070
+000

081
.019

+069
+028

-091

-000.

000
.000

-073
+019

+073
.019

05S
044

+050
+018

+033
+043

-056
+000

077
-014

+059
017

-076
-000

-000
.000

061
+023

061
.023

054
2044

+034
+023

021
041

+045
-000

-056
-015

+044
+022

-050
+000

000
-000

+040
028

.040
+028

-053
2043

region, year, speed
unpaved silt%, ind.
number of precip. days

+054
-018

026
.035

+036
-000

-050
-O1L

+036
017

-051
+000

+000
+273

041
024

041
+024

-052
2042

+031
+015

029
029

029
000

051
+008

+0321
014

064
-000

-000
+182

-051
016

051
.016

-050
+010

LDGT2

LDDV

LpDT

2BHDDV

“+ = LHDVV

MHDVV

HEDVV

BUSES

cycle, speed
silt g/m*2, WHEELFLG

:scene name

PARTS February 24, 1995

23


List of Figures...

1

vA & YW N

Contents

Description ot

Getting Started ..
Inputs...........
FORTRAN Format

PROGRAM CONTROLS AND USER-SUPPLIED DATA....... seeeseeeeeeevensees

EXAMPLES..
Introduction

Appendix: Particle Emission Factors for Mobile Sources as

Calculated in the Model PARTS..........ssscccssssssessssseeeessseesesssnesseserees


VMT fractions for each vehicle class are multiplied by the corresponding composite emission
factors (EFCOMP.,,), then the sum of these adjusted emission factors is reported as the emission
factor for all vehicles:

12
EFALL =X EFCOMP,* TFCLASS, (2)
val
where
EFALL = the weighted emission factor for all vehicles,
TFCLASS, = the vehicle miles traveled of vehicle class v.

The emission factor for all vehicles, EFALL, represents the average g/mi emissions from the entire
fleet, so this emission factor, when multiplied by the total number of vehicle miles traveled in a
particular region, provides an estimate of the total grams of particulate emissions contributed by the
entire on-road motor vehicle fleet.

The rest of this appendix describes in detail the methodologies used to calculate the emission
factors for each pollutant category for gasoline-fueled and diesel-fueled vehicles, as well as the
factors for dust, brake wear, and tire wear emissions. The adjustment factors for different vehicle

47


Figure 6

Sample with PRIFLG = 1

: VMFLAG
:MYMRFG
:IMFLAG
:REGFLG
:OUTFMT
: IDLFLG
:SO2FLG
:PRTFLG
:BUSFLG
1 1994 1 19.6
04.3 05.1 2

PPR PWRHPE

(alternate VMT mixes)
(alternate mileage accumulation rates & registration)
(Inspection and maintenance)
(2 to apply reformulated gasoline effects, 1 not to)
(indicates type of output format)
(2 to print, 1 not to print idle emission factors)
(2 to print Gaseous SO2 emissions, 1 not to print them)
(determines which pollutants to print out)
(determines which alternative bus cycles to print out)
: xvegion, year, speed cycle, speed
t unpaved silt%, ind. silt g/m*2, WHEELFLG

140 number of precip. days
scenel :scene name
10. -- Particle size cutoff

6000

04

PARTS February 24, 1995
31


Figure 9

Sample with TRAPFLG=2, showing percentages of bus traps

:VMFLAG (alternate VMT mixes)

:MYMRFG (alternate mileage accumulation rates & registration)
:IMFLAG (Inspection and maintenance)

<RFGFLG (2 to apply reformulated gasoline effects, 1 not to)
:OUTFMT (indicates type of output format)

:IDLFLG (2 to print, 1 not to print idle emission factors)
:SO2FLG (2 to print, 1 not to print Gaseous SO2 emission factors)
i:PRIFLG (determines which pollutants to print out)

:BUSFLG (determines which alternative bus cycles to print out)
1 1998 1 19.6 : region, year, speed cycle, speed

04.3 05.1 2 unpaved silt%, ind. silt g/m*2, WHEELFLG

140-2 100.0 100.0: number of precip. days, TRAPFLG, 92 TRAP %, 93 TRAP %
100% trap ef's, 0% no trap ef's

10. -- Particle size cutoff

6000

04

1 1998 1 19.6 : region, year, speed cycle, speed

04.3 05.1 2 unpaved silt%, ind. silt g/m*2, WHEELFLG

140 1 : mumber of precip. days, TRAPFLG

100% no traps for buses Tee

10. -~ Particle size cutoff

NWPPORH EE

6000

04

1 1998 1 19.6 : region, year, speed cycle, speed

04.3 05.1 2 : unpaved silt%, ind. silt g/m*2, WHEELFLG

140 2 000.0 000.0: number of precip. days, TRAPFLG, 92 TRAP %, 93 TRAP %
0% trap ef's, 100% no trap ef's

10. -- Particle size cutoff

6000

04

1 1998 1 19.6 : region, year, speed cycle, speed

04.3 05.1 2 : unpaved silt%, ind. silt g/m*2, WHEELFLG

140 2 050.0 050.0: number of precip. days, TRAPFLG, 92 TRAP %, 93 TRAP %
50% trap ef's, 50% no trap ef's

10. -- Particle size cutoff

6000 .

04

PARTS February 24, 1995

40


Figure 4a

PARTS Revised 02-24-95.

Sample with OUTEMT =

scenel

Particle Size Cutoff 10.00 Microns Altitude: 500. Ft. Driving: Transient RFG:No
Cal. Year: 1994 T/M Program: No Region: Low AL
Veh. Type: LOGV  LOGT1 LDGT2 HDGV Ld LoDV LDDT 2BHDDV LHDDV MHDDV HHDDV BUSES Veh.
Veh. Speeds: 19.6 19.6 19.6 19.6 19.6 19.6 19.6 19.6 196 196 19.6 19.6 19.6
VMT Mix: 0.6337 0.1760 0.0831 0.0307 0.0072 0.0045 0.0017 6.0102 0.0012 0.0137 0.0344 0,0035
Composite Emission Factors (g/mi)
Exhaust PM: 0.014 0,018 0,040 0,154 0,020 0.288 0,346 0,324 0.921 1.156 1,380 1.260 0.094
Brake: 0.013 0.013 0,013 0,013 0.013 0.013 0,013 0.013 0.013 0.013 0.013 0.013 0.023
Tire: 0.008 0,008 0,008 0,012 0.004 0,008 0.008 0.008 0.012 0.012 0.036 0,008 0.009
Total PM: 0.058 0.070 0.092 0.237 0,066 «0,342 0,408 0,409 1,042 1.306 1.583 1.430 0,149
Fugitive Dust: Unpaved Roads Fleet Average 139.04 g/mi (as calculated in AP42 Vol 1 9/88)*
Paved Roads Fleet Average 13.41 g/mi (as calculated in draft AP42 Vol 1 3/93)*
Unpaved Roads Fleet Average 136.03 g/mi (as calculated in APA2.Vol 1 9/88, minus tailpipe and
tire-wear emissions) *:
Paved Roads Fleet Average 13.21 g/m (as calculated in draft AP42 Vol 1 3/93, minus tailpipe

and tire-wear emissions)

* Includes fleet average tailpipe, tire-wear and brake-wear emissions.
** Includes fleet average brake-wear omissions.

Paved Road Silt: 5.10 (g/m*2)

Unpaved Silt: 4,38
Precipitation Days:

140 >0,01 in. (per year)

Fleet average vehicle weight:

6000

Fleet average number of wheels: 4

PARTS February 24, 1995

26


3 SCENARIO INPUTS

The scenario section always consists of six input lines for each scenario. Several different
scenarios may be modeled using one set of control flags. The only control flag that affects the
input of the scenario section is VMFLAG: If VMFLAG = 2, a VMT mix must be supplied for each
scenario. The VMT mix data in this case are entered following the six lines of each scenario
section, instead of in the user-defined data input section (see section 2, VMFLAG).

Line 1. The first line of the scenario inputs contains the region, calendar year of evaluation,
speed cycle, and vehicle speed. The value of region must be either | or 2: 1 for low altitude and 2
for high altitude. Currently the program produces the same emission factors for low and high
altitude, but we plan to implement regional effects in the future if data warrants. The calendar year
of evaluation is the year for which emission factors are being modeled. The cycle is either 1
or 2; 1 is for transient (cyclical) driving, and 2 is for steady (cruise). The choice of cycle.
only effects lead emission factors, so there will be no significant effect in current or future calender
years. The average vehicle speed must be between 2.5 and 55.0-miles per hour. Lead and sulfates
are affected by speed in opposing directions, therefore relatively little variation will be seen in total
exhaust PM. The format for this first scenario input line is:

11,1X,14,1X,11,1X,F4.1

A sample line specifying low-altitude (region = 1), calender year of evaluation 1991, steady
(cruise) driving (speed cycle = 2), and an average speed of 19.6 mph, is:

11991 219.6 :region, year, speed cycle, speed

Line 2. The second input line contains three inputs for the calculation of the fugitive

emission factors. The first input is the unpaved road silt percent; the lower and Pounds for
this number are 4.3 and 20.0 ec perree naar cake pir in g/m’; the
lower and upper bounds for the paved road silt loading are 0.02 and 400 g/m? The third input is
an optional flag, WHEELFLG, to tell the program that the user would like to input the fleet average
number of wheels for use in unpaved dust calculations (note that tire-wear emissions
calculations use vehicle class specific average number of wheels which are not affected by this
input).

Fugitive dust emission factors are very sensitive to the silt percent (used in unpaved road
calculations) and silt loading (used in paved road calculations). Due to the large variability i in silt
loadings and percents, it is highly recommended that the user supply loadings from actual

measurements of the roadways to be modeled. If no measurements are readily available, the user is
highly encouraged to study the AP-42 references 1988a and 1993b given on page 67, to determine
appropriate input values to model specific situations based on region, traffic volume, road type,
etc.

10


4 OTHER EMISSION FACTORS

FUGITIVE DUST

Reentrained road dust emission factors are calculated for both unpaved and paved roads. The fugitive
dust emission calculations for unpaved roads are from an empirical formula from the AP-42 Section
11.2.1 (EPA 1988a), and the generic paved road dust calculation formula is from AP-42 Sections
11.2.5 and 11.2.6 (EPA 1993b).

‘The particulate emission factor for unpaved roads is calculated as

UNPVD = PSDUNP * 5.9 * (UNSILT / 12.0) * (SPD / 30.0) * (WEIGHT /3.0)°7 (43)
* (VWHEEL | 4.) * (365 - IPDAYS) / 365 * 453.592

where
UNPVD = the fleet average unpaved road dust emission factor (g/mi)
PSDUNP = the fraction of particles less than or equal to the particle size cutoff
UNSILT = the percent silt content of the surface material (input by the user)
SPD = the average vehicle speed (mph, input by the user)
WEIGHT = the fleet average vehicle weight (ons, input by the user in Ibs)
VWHEEL = the fleet average number of wheels (input by the user)
IPDAYS = the average number of precipitation days per year with greater than 0.01 inches of
rain (input by the user)
453.592 = the number of grams in a pound
The particulate emissions factor for generic paved roads is calculated as.
PAVED = PSDPVD *(PVSILT | 2) * (WEIGHT /3)!5 (44)
where

PAVED = the fleet average paved road dust emission factor (g/mi)
PSDPVD:: =. the base emission factor for the particle size cutoff (input by the user)
the road surface silt loading (g/m?, input by the user)
WEIGH: the fleet average vehicle weight (tons, input by the user in Ibs)

62


2 GASOLINE-FUELED VEHICLES

LEAD EMISSION FACTORS

Lead particulate emission factors are based on the assumption that virtually all the lead in fuel is
exhausted. As a result, the emission factors (in units of grams per mile) depend principally on the
lead content in the fuel and the fuel economy of the vehicle (in miles per gallon). The lead content
of leaded fuel is substantially greater than that of unleaded fuel, so the fraction of vehicles that have
had their catalysts removed (and thus are assumed to be using leaded fuel in most cases) can also
be an important factor in determining the lead emission factor from a vehicle that is representative
of the entire fleet.

The lead emission factors for a vehicle of model year m and vehicle class v (with the exception of
motorcycles; see discussion in the next section) are computed in PARTS using the followmg
formula (see the following section, "Lead Particulate Derivation,” page 50, for the derivation of all
variables and further explanations): -—--

LEAD,,, =  PLNOCT,,,* VLNOCT,, (3)
+ PUNOCT,,,* VUNOCT,,,

+ PLYSCT,,, * VLYSCT,,,
+ PUYSCT,,, * VUYSCT,,,

where
LEAD,,, = the lead particulate emissions for a vehicle of model year m and vehicle class
v (g/mi)
PLNOCT,,, = the emissions for a non-catalyst, leaded fuel vehicle of model year m and
vehicle class v (g/mi)
PUNOCT,,, = the emissions for a non-catalyst, unleaded fuel vehicle of model year m and
vehicle class v (g/mi)
PLYSCT,,, = the emissions for a catalyst, leaded fuel vehicle of model year m and vehicle
class v (g/mi)
PUYSCT,,,... = the emissions for a catalyst, unleaded fuel vehicle of model year m and
. vehicle class v (g/mi)
VLNOCT,,,..= _ the fraction of non-catalyst, leaded fuel vehicles of model year m and
vehicle class v ’
VUNOCT,,, = the fraction of non-catalyst, unleaded fuel vehicles of model year m and
vehicle class v
VLYSCT,,, = the fraction of catalyst, leaded fuel vehicles of model year m and vehicle
class v
VUYSCT,,,, = the fraction of catalyst, unleaded fuel vehicles of model year m and vehicle
class v

This emission rate is adjusted for speed by the factor FEC so that:

48


Lead Particulate Derivation

The original formulae for Jead particulate are found and described in reference EPA 1985a,
equation numbers 2-3, 2-4, and 2-5. All of these equations appropriately combine the amount of
particulates per vehicle of a given category (i.e., model year group, catalyst or non-catalyst, leaded
or unleaded fuel) with the fraction of vehicles in that category. basic form of the portion of the
equation which determines the amount of lead particulate per vehicle is:

LEAD,,, = (ABURN * PWR/ FE,,,)* PB* PS (10)
where
ABURN = _ the fraction of lead bumed that is exhausted (ABURN(1) = 0.75 for non-
catalyst and catalyst vehicles using leaded fuel, ABURN(2) = 0.40 for
catalyst vehicles using unleaded fuel in calender years 1975-1980,
ABURN(3) = 0.44 for catalyst vehicles using unleaded fuel in calender
years 1981 and later)
PWR = _ particle weight ratio (1.557 = PbClBr/Pb)
FE,,y = fuel economy for vehicles of class v and model year m (mi/gal)
PB = __ fuel lead content (g/gal) [ PBL and PBNL in formulae below, National Fuel
Survey, AAMA 1993] peneeyees
PS = _ the fraction of all particles that are emitted (PSL, PSNL and PSNLCT in

formulae below), on user input of the particle size cutoff.

All of the other terms in the equations relate to the fraction of vehicles which exhibit each specific

For the case of non-catalyst vehicles using leaded fuel, the amount of lead parti comes from
the first term of equations 2-3 and 2-4 of reference EPA 1985a. The correction to the fuel
economy is handled later in the program by the factor FEC, and is not discussed here.
We will also drop the discretionary fuel switching term from the equation. This term will be used
later to determine the fraction of non-catalyst vehicles using leaded and unleaded fuel. The final
form is:

PLNOCT,,, = (ABURN(I)* 1.5571 FE,,,)* PBL * PSL (11)

For the case of non-catalyst vehicles using unleaded fuel, the amount of lead particulates comes
from the second term of equation 2-3 and 2-4 of reference EPA 198Sa. Again the discretionary
fuel switching and the speed correction to fuel economy terms are dropped from the equation here
(they are handled Iater in the program). The final form is:

PUNOCT,,, = ( ABURN(1)* 1.5571 FE,,,)* PBNL* PSNL , (12)

For the case of catalyst equi vehicles using unleaded fuel, the amount of lead particulates
comes from the first term of equation 2-5 of reference EPA 1985a. The speed correction to the fuel
economy is handled later in the program by the factor FEC, and therefore can be ignored here. The
term for misfueling can also be removed, since it will be used later to determine the fraction of =~
catalyst equipped vehicles using leaded and unleaded fuel. The final form as:

PUYSCT,,, = ( ABURN(2 or 3)* 1.5571 FE,,,) * PBNL * PSNLCT (13)

50


Line 7. The seventh input line is only required when WHEELFLG = 2 in line 2 of that scenario.
The fleet average number of wheels will be used in calculations for unpaved road dust only.

The format for this input is:

12
A sample line specifying the fleet average number of wheels, is:
04

13