EPA-AA-IMS-81-18
                               Technical Report
             Emissions Reductions From Inspection and Maintenance:
                      Vancouver Versus Portland Snapshot
                                      by

                               R. Bruce Michael
                                 August, 1981
                                    Notice

This Report  does  not necessarily  represent  final EPA decisions  or positions.
It is intended to present technical analysis of  the  issue  using data which are
currently  available.   The  purpose  in  the  release  of   such  reports  is  to
facilitate the exchange  of  technical information and  to  inform  the  public  of
technical  developments  which may  form  the  basis  for a  final  EPA  decision,
position or regulatory action.
                       Inspection and Maintenance Staff
                     Emission Control Technology Division
                 Office of Mobile  Source  Air  Pollution  Control
                      Office  of  Air,  Noise, and  Radiation
                     U.S. Environmental Protection Agency

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                               Table of Contents
Section
  1.0
   Heading

INTRODUCTION
  2.0
SUMMARY AND CONCLUSIONS
  3.0
REPRESENTATIVENESS OF VANCOUVER VEHICLES FOR THIS
COMPARISON
  3.1
  3.2
  3.3
  3.4
  3.5

  3.6
Maintenance Habits
Driving Habits
Amount of Driving
Vehicle Age
Effect of Knowledge of the Portland I/M Program
on Vancouver Vehicle Repairs
Summary of Factors
 5
 6
 8
 3

 8
 9
  4.0

  4.1

  4.2

  4.3
  4.4
RESULTS

Atypically Low Emissions From 1978 Model Year
Vehicles in Both Cities
Federal Test Procedure, Idle Emissions and
Fuel Economy Results
State Inspection Test Failure Rate
Effect of Time Since Last State Inspection Test on
Emissions of Portland Vehicles
10
10

14
16

18
  5.0
COMPARISON OF ACTUAL EMISSIONS VERSUS PREDICTED
EMISSIONS FROM MOBILE2 PROGRAM
                                                                      21
APPENDIX

A.  VEHICLE LIST FOR EACH GROUP
B.  TESTS PERFORMED
C.  BRIEF DESCRIPTION OF TESTS
                                                         22
                                                         23
                                                         24

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1.0 INTRODUCTION

Test Group  No. 9  of EPA  Contract  No.  68-03-2829  with Hamilton  Test Systems
compared  the  emissions  of  similar  cars  in  Portland,  Oregon  and Vancouver,
Washington,  which  are neighboring cities.   The purpose of this  study  was to
compare the  emissions  from vehicles  subject  to Inspection/Maintenance (I/M) in
Portland with  emissions  from non-I/M vehicles  (Vancouver).   EPA reasoned  that
the  proximity of  these   two   cities   would  make   a   suitable  controlled
comparison.  No prior  study had been performed which  would yield a comparison
with as much confidence.

The study design called for  two groups of  100 vehicles each to be tested.  One
hundred vehicles were to be  recruited  from Vancouver and  then one hundred  from
Portland, with vehicle pairs matching  by both  vehicle  type and odometer.  The
vehicles were  of  1976 and  1978 model  years  and  were  similar by  type  to the
national population mix.   These  years were  chosen so that  Portland vehicles
would have been inspected  in the prior  12 months,  thus representing an annual
I/M  program.   This  was   necessary  because  the   Portland  I/M  program  is
biennial.   Portland vehicles  were  also to  be evenly distributed  over  time
since  their  last  I/M inspection, representing a  "snapshot" situation  of an
annual I/M program  in which  the vehicle  fleet  is evenly distributed over  time
since the last inspection.   Testing  was  conducted  in  the  latter part of 1980,
so  the  1976 model  year  vehicles  were between four and   five years  old when
tested and the 1978 vehicles were between two and three years old.

The  Federal  Test   Procedure  (FTP)  and  several  emissions  short  tests  were
performed  on  each  vehicle  in  the  as-received   condition  only.   Vancouver
vehicles which failed  the  State Inspection Test entered  Test Group  No.  10,  a
task to investigate the effect of specific repairs on emissions.*
*  "Effect  of  Specific  Repairs  on Emissions  of  Vehicles  from,  Vancouver,
Washington", EPA-AA-IMS/81-19, R. Bruce Michael, July, 1981.

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2.0 SUMMARY AND  CONCLUSIONS

Results  indicate the  following:

    1.  The comparison  of maintenance, driving  habits,  and  the similarity  of
    the  vehicles  supports  the  use   of  Vancouver  as  a  non-I/M  version  of
    Port land.

    2.  For  the  1976  model  year,  Portland  I/M  vehicles  had  Federal  Test
    Procedure  (FTP) HC  emissions  272  lower  and CO emissions 22% lower  than the
    non-I/M vehicles.*

    3.  Predictions  for  the  emission  levels of the  1976  model  year using
    MOBILE2  agree closely  with  study  results  for  both  the  I/M  and  non-I/M
    cities.  This supports  the accuracy of  the  MOBILE2  I/M emission  reduction
    benefits.

    4.  Vancouver 1978  vehicles  were   unexpectedly  clean,   having   as   low
    emissions  levels as  the  Portland 1978  vehicles.   On the  surface,  this
    would  suggest that there  was no  I/M   effect  on  the  Portland vehicles.
    However, the Vancouver  vehicles were  far cleaner than  similar vehicles  EPA
    has   tested   in  other   cities  and   far  cleaner   than   EPA's   MOBILE2
    predictions.   The  reason  for this  is  unknown  and  we  do  not   try  to
    hypothesize  one.   Whatever  the reason,  one can  presume  that  it  affects
    Vancouver and Portland vehicles equally.

    The important question  to consider is not why  the Vancouver 1978 vehicles
    were so clean,  but  why the Portland  1978 vehicles were  not even cleaner,
    as might be  expected as a result of the  I/M  program.   It is almost  certain
    that  the  Portland  1978  vehicle emissions would  have  been  as  low  as   the
    Vancouver  1978 vehicle  emissions even without  I/M,  due  to  the similarity
    of maintenance,  social habits, mileage,  etc.  (see  Section  3.0).   These
    emissions  averaged  very  close  to  the Federal  standards.    I/M  then would
    not  have  had much  chance  to  reduce the emissions  of the  Portland  1978
    vehicles,   since  I/M  can  only  correct   emissions  which are substantially
    higher than  they should be.   Therefore,  the  negative  finding on the effect
    of I/M on  the 1978 model  year vehicles  can  be  explained in  light  of   the
    low  non-I/M  emission levels  of  these   vehicles.   The  negative   finding
    should  not  be  taken to  mean  I/M cannot be  effective  on  typical   1978
    vehicles or  on  vehicles  of  this  age  (2-3 years  old).  Rather,  it merely
    indicates that emphasis should be placed on the 1976 model year  results.
*  Since  I/M  is not  intended  to  affect  NOx  emissions,  comparisons  of  NOx
emissions are omitted in the text, but do appear in the tables.

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3.0 REPRESENTATIVENESS OF VANCOUVER VEHICLES FOR THIS COMPARISON

EPA believes Chat the comparison  of vehicle  emissions  from these two cities is
valid  for  several  reasons,  and  that  it produces  valuable results  about the
impact of I/M.

3.1 Maintenance Habits

One factor which  can affect  vehicle emissions  is  maintenance.   Cars which have
been well  maintained  and are  in a proper state  of  tune  will  generally have
lower  emissions   than vehicles poorly  maintained.  Several  items  may affect
maintenance  habits,  such   as  social  structure  and   economic  conditions.
Although the cities in this  study are  in two different  states,  the city limits
are only about one mile apart.  Many  residents  of Vancouver commute to work in
Portland.   Therefore,   it is   likely  that  social beliefs and  behavior  are
similar  for  the  cities.  The  economic status  of  the  cities is  also  similar,
which  contributes  to   the   likelihood  that  vehicle  maintenance  habits  are
similar.

Each vehicle  owner was  interviewed  to  find  out  when   the  vehicle had  last
received  a tune-up.   Table  1 shows  the  answer  to   this question  for  the
Portland  and  Vancouver  owners.   The  similarity in  the  owners'  responses
support  the  assumption  that  Vancouver  can be  used as  a non-I/M  control  site
for Portland.
                                    Table  1

                        Recent Maintenance of Vancouver
                             and Portland  Vehicles
Question                                    Number of Responses

                                      Due, But  0-6     6-12    Over    Don't
                             Not Due  Not Done  Months  Months  1 Year  Know

How Long Ago Was
The Last Tune-Up?

    Vancouver                  11       4         55      25      3      2
    Portland                    4       3         50      29     11      3

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3.2 Driving Habits

A  second  factor  affecting  emissions  is  the  type  of  driving  performed.
Vancouver  is  a  smaller  city  with  a  less  congested  downtown  area.    It  is
therefore likely that the average Vancouver  car is  driven a smaller percentage
of the  time  in stop-and-go  city  traffic and a larger percentage  in  suburban
and highway driving than  the average  Portland car.   The  latter type of driving
causes  less   wear and  deposit  accumulation on engines  and  tends  to  keep
emissions  low.    This   factor  would  therefore   tend  to  make  Vancouver  cars
cleaner  than  Portland  vehicles  (and  vehicles  in  other  large  cities)  in  the
absence of I/M.   On  the vehicle owner  questionnaire,  however,  owners  reported
very similar  driving  patterns and  amount  of driving  per year.   For  example,
nearly  all driving was  performed  mostly on major  city  streets,  with  88%  of
Vancouver  owners  and  79% of  Portland  owners  reporting  this  type.   Table  2
shows the owner responses to several questions.

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                                    Table 2

                   Owner Response to Driving Habit Questions
              For Vancouver and Portland (N-100 for both cities)
Questions
               Number of Responses
Thousands of miles
driven per year

   Vancouver
   Portland
  0-5
   3
   3
5-10
 34
 39
10-15
  42
  41
15-20
  19
  11
20-30
  2
  6
Where driving occurs
   Vancouver
   Portland
Mostly Major
City Streets

    88
    79
        Some on
    Other City Streets

           87
           86
                    Some on
                City Expressways

                       92
                       89
How driving is done *
   Vancouver
   Portland
    Mostly
    to Work

      53
      47
         Some for
         Errands

           61
           57
                   Some for
                 Other Reasons

                      90
                      91
*  The  responses do not  add up to  100,  because .owners  could respond  to  each
question with varying answers, such as  "most",  "some",  "little or none".  Only
the major responses are shown in the table.

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3.3 Amount of Driving

A  third  factor  affecting  emissions  is  the   amount  of  driving  performed.
Generally, vehicles with more  mileage have higher emissions than vehicles with
low mileage.   This factor has no affect  on the present  comparison,  however,
due  to  the  design  requirement which  made matched-pair  vehicle mileages  be
similar.  The average mileage  of the  two  city groups,  shown in Table 3 on page
11, is nearly identical.

3.4 Vehicle Age

A  fourth factor  affecting emissions  is  vehicle age.   Because  vehicles  were
matched by age (as well as several other  things) this  possible factor also has
no affect on the comparison.

3.5 Effect  of Knowledge  of   the  Portland  I/M  Program  on Vancouver  Vehicle
    Repairs

A fifth  factor which could affect  the emissions of the Vancouver cars  is that
some of  these cars may  receive I/M-type low emission repairs  despite  the lack
of an  I/M program in Vancouver.   This would be due to  the  proximity  of the
cities.

A few  possibilities  exist  for Vancouver cars receiving  low emissions  repairs.
First, Vancouver  owners may  want to  get  low emission^ repairs having  heard  of
the I/M  program and having  an  interest  in clean  air.   However,  it  is  very
unlikely  that Vancouver mechanics  would have success with  giving low emission
repairs,  because  they  are  unfamiliar  with the  repairs  and,  mainly,  because
very  few facilities  have  the emission  analyzers  to  check   the adjustments.
Only  one  real   possibility   exists   for   their  cars  actually   receiving  low
emission  repairs: • if  they  go  to  Portland  repair  facilities  for  normal
maintenance.   Since  it  is also unlikely  that  Vancouver  residents  would  take
their  vehicles  to  Portland  repair  shops,  this  possibility  should  have  an
insignificant effect.

Second, Vancouver mechanics may want  to tune for low emissions having  heard  of
the Portland  I/M  program.   For  the  reasons mentioned  in  the  last  paragraph,
however, it is unlikely that  they would have much success.

Third,  if Vancouver  owners  buy  cars  from Portland  dealers,  the  dealership
warranty  service  may have  an  impact on  emissions,  since  these dealers  are
experienced in I/M.  Oregon  officials who  were  questioned  felt  that  very few
Vancouver  residents  buy  cars  in Portland,  however.    There   is no  economic
incentive to do  so and,  except  for a  larger variety of  foreign car dealerships
in Portland,  there is a sufficient number  of dealerships  in Vancouver  to serve
the residents there.

For  the  reasons  mentioned,   it  is  unlikely   that  a  significant  number  of
Vancouver vehicles receive  I/M-type repairs which would lower  their emissions.

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3.6 Summary of Factors

Vehicle  age  and  mileage  are  generally  considered  to  be  the most  important
factors  affecting emissions.   Since these were  controlled for the  two groups
of vehicles,  we  can  say  with  confidence  that  the  only  important  difference
between  the groups of .vehicles from the  two  cities is that one group  has been
involved in I/M.

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                                      10

4.0 RESULTS

4.1 Atypically Low Emissions From 1978 Model Year Vehicles in Both Cities

4.1.1 Discussion

Study results show that  emission  levels  of the 1978 model year  in both cities
were similar.  They were both less than  in other  sites  recently  studied by EPA
and also  both less than predicted  by MOBILE2, an  EPA computer  program which
estimates fleet emissions  with  and  without I/M.  This  phenomenon is discussed
first, because it has implications as to the meaning of the other results.

The cause of  the  unexpectedly  low emissions is unknown.   For  whatever reason,
the meaning  is that  I/M had no  significant  opportunity  to  provide  emission
reductions in Portland  on 1978  cars,  since  the  1978 model  year  cars  there
would have been relatively clean  prior  to  their I/M test, as  clean  or cleaner
than  the  Vancouver  cars.   I/M  can  only  have an  impact  on cars  with  high
emissions.  Consequently,  the  1978  model  year results  should be  given little
weight.   Results  will  show  the  two  model years  separately,  as  well  as  the
combined results.

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                                      11

4.1.2 Emission Comparison of Portland/Vancouver Vehicles With Non-I/M Vehicles
      in Other EPA Programs

In the  ongoing  EPA Emission Factors  (EF)  program, in-use  vehicles  are tested
in their as-received  condition at many sites around  the  country.  Vehicles of
the same model years  as those  tested in Vancouver and  Portland  were tested by
EPA in  four major  cities during  1979/80  for  the FY79  EF program.   That EF
program tested vehicles  very similar to the  Vancouver and Portland vehicles in
terms of make  and model, although  it  had  a slightly  broader  cross-section of
vehicle types and lower  average mileage.

1976 Model  Year  - Emissions for  each  site are shown  in  Table  3  and  Figure 1
for each  model  year.   Emissions  of  the  1976 model year  in  Vancouver  were
higher than  the  average EF  emissions.   The average mileage  was  also higher in
Vancouver,  a factor which would  tend  to  result  in  higher  emissions,  but not
enough  to  account for  the  total  difference.  It  is  interesting  to  note  that
the Phoenix HC  and CO  emissions were  quite  a  bit  lower  than  the  other EF
sites, which is only partly due to  the  significantly  lower mileage of the cars
tested  there.    The  I/M program  in Phoenix  may  also  explain  some  of  the
difference.   If  Phoenix is   removed   from  the  comparison,  HC  emissions  in
Vancouver  are  lower  than  the  non-I/M  EF  sites,   and  CO  emissions  are  nearly
equal.

1978 Model Year - HC and CO emissions of the  1978 model year in Vancouver were
much lower than the average EF emissions;  its  CO  emissions were  lower than any
of the  EF  sites,  a  surprising change  from the  1976 year.   No reasons  are
apparent for this.   Again,  the average mileage  was  higher in  Vancouver  than
the EF sites.
Site
EF Average
                                         Table 3

              Emission Factors Program Compared With Vancouver and Portland
                          FTP Emissions by Model Year and Site
N
  1976 Model Year
Mileage  HC     CO
NOx
       1978 Model Year
N    Mileage   HC     CO
75   42,798   2.50   25.4   2.84
EF Average
Without Phoenix 50
     45,850   2.80   29.4   2.86
NOx
Phoenix
St. Louis
Wash. O.C.
Houston
25
25
0
25
36,693
50,715
-
40,985
1.92
3.00
-
2.59
17.3
30.0
-
28.8
2.79
2.31
-
3.41
75
75
75
75
13,
23,
20,
27,
258
543
383
529
1.12
1.94
1.68
1.73
16.4
27.8
20.6
23.8
1.83
1.34
1.92
2.26
                                  300  21,170    1.62   22.2   1.96
                                  225  23,818    1.78   24.1    2.01
Vancouver
Port land
50   53,650   2.56   30.7   2.90
50   55,169   1.88   24.0   3.25
                                  50   32,705    1.33   15.1    2.45
                                  50   33,177    1.30   15.3    2.41

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                                    Figure 1

           Emission Factors  Program Compared With  Vancouver and Portland
                        FTP  Emissions by Model Year  and Site
   MC  COMPARISON   1976 MTR
  CO COMPARISON   1376  MTR
u.o
3.5
3.0
2.5
2.0
l.S
1.0
O.S
0.0


ST.L
X
HOUS ^
^S^ VANC
^^C\ r\
MOBILEZ^x^^ pJj~E ®
•
i i i i t
0 20000 40000 600
10000 30000 SOOOO
MILEAGE
KO
35
- 30
a.
»
" 25
520
o
in
x
IftJ
a 10
u
S
0
00


^xi^X xV"N
^^ 5T.L
^ — HOUS
PORT
PMOE
•
i i i i i
0 20000 KOOOO 600C
10000 30000 SOOOO
MILEAGE
x =• Emission Testing Site with no I/M
0= Emission Testing Site. .with. I/M
4.0
3.5
3.0
2.5
2.0
l.S
1.0
O.S
0.0
HC COMPBRJSON 1978 MTR
.
	
^^^HASH "°US
0 VANC
PMOE
i i i i i
HO
35
- 30
s
a.
ts
" 25
220
a
f^
2 15
JC
UJ
a 10
u
S
0
CO COMPARISON 1978 MTR

i ^^^^
^^^^ *HOU3
HASH
® 00RT
M VANC
i i i i i
0       20000       1(0000       SOOOO
  10000        30000       50000
             MILEAGE
0       20000       1(0000      60000
  10000       30000       SOOOO
             MILEAGE

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                                      13

    Other evidence  also shows that  the  1978 model  year vehicles  in Portland
    and  Vancouver  had  lower  as-received  emissions  than expected.    In  the EF
    programs, vehicles  are sometimes given maintenance  by contractor personnel
    in order  to lower  their  FTP emissions.   Many vehicles  from the  FY77 EF
    program are appropriate for  comparison to the Portland  and Vancouver 1978
    model year vehicles.  These  EF  vehicles  were all certified  to  the  same HC
    and  CO  standards as the  Portland  and Vancouver  vehicles,   and  had nearly
    identical average mileages,   although  they  were  of  1975-77 model  years.
    The  EF  vehicles  used  for comparison all  would  have failed the Portland
    idle  standards  in  their  as-received condition.   Table  4  shows that  the
    emissions  of  the  EF  vehicles  after  repair were   very similar  to  the
    Portland and Vancouver  vehicle emissions  as-received.    This supports  the
    contention  that  the  Portland  and  Vancouver  vehicles   had unusually  low
    emissions in their  as-received  condition and  that  there was little  or no
    room  for  improvement from I/M repairs,  thus the  observed  similarity of
    emissions of the  Portland  and Vancouver vehicles.
                                    Table  4

                Comparison of Repaired  Emission Factor  Vehicles
             With 1978 Model Year Portland and Vancouver vehicles

    Group        N             Mileage       FTP HC          FTP CO

EF Before Repair 142           31,970        3.09            44.8
EF After Repair  142           31,970        1.59            15.9

Vancouver         50           32,705        1.33            15.1
Portland          50           33,177        1.30            15.3

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                                      14

4.2 Federal Test Procedure. Idle Emissions and Fuel Economy Results

The average vehicle  inertia weight  is  3795  pounds for  all  Vancouver vehicles
and  3793  pounds  for  Portland  vehicles.    The   time   since   the  last  State
Inspection Test  (SIT)  for  all  Portland  vehicles  averages 6.3 months.  Vehicles
are matched by  make,  model year,  engine  size, transmission  type,  fuel system
and (generally)  odometers  within  5000 miles  of each other.   A  listing of each
group of 100 vehicle types is shown in Appendix A.

Average  results of  the Portland  and  Vancouver  vehicle groups  are  shown  in
Table  5.   A  statistical test  at   the  .05 confidence level  shows that  the  HC
emissions  are  significantly different between Portland* and Vancouver,  but  CO
and NOx emissions are not.

Table  6  presents the  FTP emissions by model  year.  Note that  essentially all
of  the  FTP HC  and  CO differences shown  in  Table 5 come  from the  1976 model
year,   as  shown in Table 6.   As stated earlier,  the  Portland  I/M program has
had  little opportunity to  create  a  difference  in   the  emissions  of  1978
vehicles, because even without I/M these vehicles are remarkably clean.

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                                       15
                                    Table 5

                 As-Received Emissions and Fuel Economy Levels
                              (100 Matched Pairs)
             Odometer
                           Federal Test
                            Procedure
                            Emissions
                         (grams per mile)
                        HC      CO      NOx
Idle Emissions *
(Using Garage-
Type Analyzer)
HC (ppm)  CO (%)
  Fuel
 Economy
 (miles
per gallon)
 FTP  HFET
Vancouver    43,178    1.95    22.9    2.68    230.0     1.53

Portland     44,173    1.59    19.6    2.83    166.4     1.18
                                    Table 6

               As-Received FTP HC and CO Emissions by Model Year
                                                                   15.81 22.24

                                                                   15.75 22.00
Percent
Difference   +2.32   -18.52** -14.42  +5.62   -27.62    -22.92    -0.42 -1.12
                          1976 Model Year
                       N      HC    CO
                                                        1978 Model Year
                                                     N      HC•   CO
Va nc ouver

Portland

Percent Difference
                       50    2.56  30.7

                       50    1.88  24.0

                            -272** -222
       50    1.33  15.15

       50    1.30  15.31

             -22   +12
*   From the second idle portion of the State Inspection Test.
**  Emission differences were  statistically significant at  the  .05 confidence
    level using a paired t-test.

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                                      16

4.3 State Inspection Test Failure Rate

The overall State  Inspection Test (SIT)  idle  emission failure  rates  were 39%
for  Vancouver  vehicles  and 27%  for  Portland vehicles.   Table  7  shows  the
number  of vehicles  by  pass-fail  status  for  SIT  idle HC  and  CO  and  their
associated FTP emission levels.

The 39 out of  100  Vancouver vehicles  which failed the  SIT  ("Fail Any" column)
accounted for 60%  of  the  total Vancouver HC emissions and 72% of the  total CO
emissions.  The 27 Portland vehicles which  failed the SIT accounted  for 41% of
the total Portland HC emissions and 49%  of  the total  CO emissions.  Concerning
the  identification of excess  emissions  (emissions  above  the FTP standards),
the idle  test  identified 76%  of  the  excess FTP  HC  emissions  and 81%  of the
excess FTP CO emissions from the total sample of 200 cars.

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                                      17

                                    Table 7

                     Pass-Fail Status of State Inspection
                      Test, and Associated FTP Emissions
                        FTP Standards: HOI.5, CO-15.0
1976 Model Year
Vancouver
Total N»50
Portland
Total N-50
No. Vehicles
FTP HC
FTP CO

No. Vehicles
FTP HC
FTP CO
                            Fail HC,
                            Pass CO
                           Pass HC,
                           Fail CO
0
-
—
2
3.16
28.2
6
1.89
33.0
8
2.01
33.5
22
3.74
51.1
10
2.88
39.7
28
3.34
47.2
20
2.56
36.1
22
1.57
9.77
30
1.43
15.9
1978 Model Year

Vancouver   No. Vehicles
Total N-50  FTP HC
            FTP CO

Portland    No. Vehicles
Total N=50  FTP HC
            FTP CO
2
2.27
23.4
0
-
-
1
2.04
18.0
1
2.28
42.1
8
2.22
32.4
6
2.11
31.7
11
2.21
29.5
7
2.13
33.2
39
1.08
11.1
43
1.17
12.3
1976 and 1978 Combined

Vancouver   No. Vehicles
Total N=100 FTP HC
            FTP CO

Portland    No. Vehicles
Total N=100 FTP HC
            FTP CO
2
2.27
23.4
2
3.16
28.2
7
1.91
30.9
9
2.04
34.5
30
3.33
46.1
16
2.59
36.7
39
3.02
42.2
27
2.44
35.3
61
1.26
10.6
73
1.28
13.8

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                                      18

4.4 Effect of  Time  Since Last  State  Inspection Test on  Emissions of Portland
    Vehicles

Portland  test  vehicles  are  evenly distributed  by  time since  their last State
inspection.  The  average time since  inspection  is 6.3 months  with a standard
deviation  of  3.5  months.    The  correlation  between  time  and   odometer  is
extremely low; thus, odometer does'not influence the calculations.

A total of 107 vehicles  were  tested  in Portland and 105  in Vancouver in order
to end  up with the  100  matched pairs.  For  Section 4.4 all vehicles  will be
used in analysis, since  the importance of  the matched  sample  is not present in
the regression equations of these sections.

I/M substantially reduces FTP  emissions  at the time of  inspection and repair.
A logical assumption is  that  emissions  then  increase over  time until the next
inspection.   This  behavior  has  in  fact  been  observed  by  EPA   in  previous
studies conducted in Portland.*  It is of  interest to  see if  this behavior can
also be observed among the Portland vehicles  in  this study.  In order to check
the emission deterioration  of the Portland vehicles in  this  study, regression
equations were calculated for emissions  versus  time since inspection.  Table 8
shows the constants and  regression slopes for  the Portland vehicles including
the  1976  model   year  separately.    Regression  equations  show   the  expected
positive slope for  both  FTP HC  and CO versus time since  inspection.  However,
none of  the  slopes  are  statistically significant,  which  is  a common  result
with relatively   low  sample  sizes  and  quite variable  emission  levels.   The
previous EPA studies were able  to  observed significant  slopes  because the same
vehicles  were  tested several  times  since inspection,  resulting  in  much less
variability.
* 1.     "Portland  Study  Element  III  Post-I/M   Deterioration  Study",   EPA
         Contract No. 68-03-2513, by Hamilton Test Systems, Inc., July, 1979.
  2.     "Analysis of Oregon's Inspection and Maintenance  Program",  Becker and
         Rutherford,  APCA  No. 79-7.3,  presented  at  72nd  Annual Meeting  and
         Exhibition, June 25, 1979.
  3.     "Update on EPA's Study  of  the Oregon  Inspection/Maintenance Program",
         Rutherford  and  Waring,  APCA No.  80-1.2,  presented  at 73rd  Annual
         Meeting and Exhibition,  June 24,  1980.

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                                      19

                                    Table  8

                                 FTP Emissions
                        Regression Equation  Results  for
                       FTP HC and CO Versus  Months Since
                      State Idle Test -  Portland Vehicles
                                                        Regression
Sample          Emission          Constant                Slope

1976 MYR           HC                1.71                  .020
  N=52             CO               20.9                   .266
All Portland       HC                1.48                  .016
  N-107            CO               16.3                   .464
Regression equations  were calculated  for idle  emissions  versus months  since
inspection for  all cars and  cars  by model year.   The  second idle  portion  of
the SIT was used in the calculations.  Results are shown in Table 9.

As  before,   none  of   the   equations   shows   a   statistically   significant
relationship between emissions and months  since  inspection.   This  again merely
indicates  that  the   large  vehicle-to-vehicle  variations  in  idle   emissions
overshadow any deterioration effect.

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                                      20

                                    Table  9

                                Idle Emissions
                        Regression  Equation  Results  for
                      Idle EC and CO Versus Months Since
                      State  Idle  Test  - Portland  Vehicles
                                                           Regression
Sample             Emission           Constant               Slope
All Portland          HC                169                   -.252
  N=107               CO                0.70                  .027

1976 MYR              HC                252                   -5.98
  N-52                CO                1.26                  .011

1978 MYR              HC                116                   1.50
  N=55                CO                0.38                  .009

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                                      21

5.0 COMPARISON  OF ACTUAL  EMISSIONS  VERSUS  PREDICTED  EMISSIONS  FROM  MOBILE2
    PROGRAM

An EPA  computer program named  MOBILE2  models  the  emissions performance  of a
vehicle fleet over  time,  both with and without I/M.   The I/M  case  assumes an
annual  program.   To  estimate  the  emissions   of  the  Portland  vehicles,  a
modification was  made  to  the program,  since  Portland vehicles  are  subject to
inspection only once every  two years.   Table  10 presents  the 'FTP HC  and CO
emission comparisons for the vehicles in the study versus MOBILE2 predictions.*

Results show a  similar phenomenon that  was seen in  Table 3,  i.e., emissions of
the  1978  model  year in  Vancouver are much  lower  than  expected making  the
average Vancouver emissions  also  substantially  lower  than expected.   Emissions
of 1978 vehicles  in  Portland are  also lower than expected,  making the  average
Portland  emissions   slightly lower than  expected.   Emissions  from the  1976
model year from both cities  are very close to the predicted levels.
                                   Table 10

                            Actual Versus Predicted
               FTP Emissions for Portland and Vancouver  Vehicles
                                    Vancouver             Portland
                                    (No I/M)                (I/M)
                                     H£     C£             HC     CO

       1978 MYR
           Actual                   1.33   15.1           1.30   15.3
           Predicted by MOBILE2     2.10   28.0           1.60   20.7

       1976 MYR
           Actual                   2.56   30.7           1.88   24.0
           Predicted by MOBILE2     2.85   35.3           1.85   23.1
       Total
           Actual                   1.95   22.9           1.59   19.6
           Predicted                2.48   31.8           1.72   21.9
*  The  MOBILE2 predictions  shown here differ  from published  standard  MOBILE2
predictions in that an  adjustment  to account for misfueling has  been excluded
here.  This  is appropriate if  the  MOBILE2 predictions are  to be compared  to
vehicle samples without  evidence of any misfueling,  such  as  the  Portland  and
Vancouver samples in this study.

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                        22




                    APPENDIX A




           VEHICLE LIST FOR EACH GROUP
1976 Model Year
1978 Model Year
Mfr
AMC

GM















Ford





Chrysler


Datsun

Honda

Toyota

VW






Make Qty
2

Buick 2

Cadillac 2

Chevrolet 1
Chevrolet 1
Chevrolet 3
Chevrolet 4
Chevrolet 2

Olds 1
Olds 4

Pontiac 2
Pontiac 1

1
1
2
3
4

3
3

2

1

3

2

50~




Descr.
258-A1

350-A4

500-A4

085-M1
250-A1
305-A2
350-A2
400-A4

260-A2
350-A4

350-A2
400- A2

140-A2
140-M2
250-A1
302-A2
351-A2

225-A1
318-A2

085-M2

091-M3

097-M2

097-M2






Mfr Make
AMC
GM Buick



Cadillac

Chevrolet
Chevrolet
Chevrolet
Chevrolet
Chevrolet
Chevrolet

Olds
Olds

Pontiac
Pontiac
Pontiac
Pontiac

Ford







Chrysler



Datsun

Honda
Toyota
VW

Qty
1
2
1
1

2

1
1
1
1
5
2

2
2

1
2
1
1

1
2
1
2
3
2
1

1
2
2

2

1
2
1
Jo
Descr.
258-A1
231-A2
350-A4
403-A4

425-A4

098-M1
151-A2
200-A1
250-A1
305-A2
350-A2

260-A2
350-A4

231-A2
301-A2
305-A2
400-A4

098-M2
140-M2
171-M2
250-A2
302-A2
351-A2
460-A4

105-A2
225-A2
318-A2

085-M2

091-M3
097-M2
08 9 -MO


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                                      23

                                  APPENDIX B

                                TESTS PERFORMED


The  following  tests  were  performed  on  the  vehicles  in  the  as-received
condition only.  All tests except No* 6 were performed by contractor personnel.

    1.   Federal Test Procedure
    2.   50 mph Cruise Test
    3.   Highway Fuel Economy Test
    4.   Four-Mode Idle Test
    5.   Loaded Two-Mode
    6.   State Inspection Test  at a State Department of  Environmental Quality
         (DEQ) station
    7.   State Inspection Test at HTS laboratory.
    8.   Four-Mode Idle Test with one spark plug disconnected*
    9.   Four-Mode Idle Test on gasohol fuel*
    10.  Diagnostic Inspection
* These  tests were  performed for  purposes  unrelated  to  the  Portland  versus
Vancouver  comparison.    Results   from  the  tests  will  be  reported  in  later
reports.

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                                       24

                                  APPENDIX  C

                          BRIEF DESCRIPTION OF TESTS
 1.  Federal Test Procedure

 The Federal  Test Procedure (FTP) is  a  non-repetitive driving cycle  simulating
 urban  driving.   The  cycle  covers  7.5  miles in  1372 seconds with  an  average
 speed of 19.6 mph.  The maximum  speed in the cycle is 57 mph.  Because  the  FTP
 simulates  some  stop-and-go  city  driving, there is also considerable  time  spent
 at idle -  about  19Z of the  time.

 Each  vehicle  is driven  on  a  chassis dynamometer  which  reproduces  vehicle
 inertia  with flywheels,androad  load with  a  water  brake  system.   Vehicle
 exhaust  is collected,^gTluted^  and  mixed  with  filtered  background  air  to a
 known  constant  volume  flow.    This  procedure  is  known  as Constant  Volume
 Sampling  (CVS).   The  exhaust  is analyzed  for mass  emissions  of hydrocarbons
 (HC),  carbon monoxide (CO),  oxides of nitrogen (NOx),  and  carbon  dioxide
 (002).    Fuel   economy   calculations   are   also  made   from   the   exhaust
measurements, using a carbon balance  technique.

 2.  50 MPH Cruise Test

 This  test  is  run  as  part  of the_ 3 minute  50  mph  preconditioning  for  the
 Highway  Fuel  Economy  Test.   ^UndilutecT) concentrations   of  HC,  CO and   NOx
 emissions  were measured.         —•-<:—

 3.  Highway Fuel Economy Test

 For this  test,  the vehicle starts  from a  warm,  but engine-off  condition  and
 then accelerates to  highway speed.   It maintains  high  speed until  the cycle
ends in  a  deceleration back to  idle.   The  high speed portion is  not a steady
cruise  condition,  but varies _slightly.   Average speed  is  48.2  mph  and  the
cycle length is  10.2  miles. (^VS^/mass emissions are  sampled  from the start of
 the  engine until  the  vehicle  is  brought  back  to  idle.   Fuel economy  is
calculated from the emissions.

4.  Four-Mode Idle Test

This test  has four modes  for  vehicles  with  automatic  transmissions,  and three
modes for others.  The order of  testing  is:  1)  idle  in neutral (gear),  2) 2500
engine  rpm  unloaded^,  3)  idle   in  neutral  and   4)  idle  in  drive  (for
automatics).  0ndilutedyHC, CO and NOx emissions are sampled at all modes.

 5.  Loaded Two-Mode

This  test  consists   of  two  operating   conditions.    The   first   condition  is
constant 30 mph with a dynamometer  load  of  9.0 hp for all  vehicles.   Following
sampling in  this mode the  vehicle  is returned to idle in neutral. ^TJndiluted
HC, CO and NOx emissions are sampled at  both modes.

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                                      25

6.  State Inspection Test (SIT) at a Department of Environmental Quality
    (DEQ) Station

Vehicles  were  taken  by contractor  personnel to  a  State  operated  inspection
station  for  this  test.   This test is  the  same as the  first  three portions of
the Four-Mode  Idle Test, i.e.,  idle neutral,  2500  engine rpm,  idle neutral.
          HC and CO emissions are sampled by  State personnel.
7.  State Inspection Test (SIT) at the Hamilton Test Systems (HTS) Laboratory

The  laboratory__personnel  perform an  identical  test  to  the  one  at  the DEQ
station. rUndiluteJ^HC, CO and NOx emissions are sampled.
         ^**~ i i. ....... -r**^

8.  Four-Mode Idle Test With One Spark Plug Disconnected

This test is  the  same  as  the normal Four-Mode Idle Test  except  with one  spark
plug disconnected.

9.  Four-Mode Idle Test With Gasohol

Commercial gasohol fuel was used for this test.

10. Diagnostic Inspection

An  engine  diagnostic  check  was  conducted  using  an  Autosense  Diagnostic
System.   This system  checks many  parameters  such as  the  electrical  system,
engine timing, idle speed and emissions, and cylinder power contribution.

-------