EPA-AA-ECTD-79-7.1
REDUCING AIR POLLUTION FROM MOTOR VEHICLES -
DEVELOPMENTS IN THE IN-USE STRATEGY
PAPER No 79-7.1
Presented at the 72nd Annual
Meeting and Exhibition
June 25, 1979
Thomas Cackette, Chief
Inspection and Maintenance Staff
Emission Control Technology Division
U.S. Environmental Protection Agency
Ann Arbor, Michigan
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Reducing Air Pollution from Motor Vehicles -
Developments in the In-Use Strategy
by: Thomas Cackette
U.S. Environmental Protection Agency
Introduction
Widespread best describes the extent of current air quality
problems of the major populated areas of this country. In 1978,
based' on ambient air quality data, the U.S. Environmental Protec-
tion Agency (EPA) classified areas of the country as attainment
or non-attainment with the health based ambient air quality
standards. Of the 105 urban areas with populations greater than
200,000, 104 exceeded one or more of the ambient air quality
standards. The only attainment area was Honolulu. In many areas
violations were frequent with ambient concentrations of the
automotive related pollutants (ozone and carbon monoxide) often
exceeding the ambient air quality standards by several hundred
percent. For example, Los Angeles and Houston have measured
ozone levels above 0.30 parts per million (ppm), compared to the
revised ambient standard of 0.12 ppm. (In January 1979, after
extensive review of relevant data, EPA raised the ozone ambient
air quality standard from 0.08 ppm to 0.12 ppm. Preliminary
indications are that approximately 10 major urban areas will
change from non-attainment to attainment.) Chicago, Denver and
Las Vegas are among numerous cities with carbon monoxide (CO)
ambient concentrations over twice the 9 ppm eight hour ambient CO
standard.
Automobiles and other mobile sources are a major contributor to
ozone and carbon monoxide air pollution. In a typical urban
area, over 50 percent of the hydrocarbons (which react in the
presence of sunlight and oxides of nitrogen, another automobile
pollutant, to form ozone) and over 90 percent of the carbon
monoxide are emitted from mobile sources. This is true even
though automobiles, since 1975, have been designed to emit
hydrocarbons and carbon monoxide at rates that are only 35
percent and 44 percent of those from early emission controlled
vehicles.
Mobile Source Emission Control Strategies
In the Clean Air Act of 1970, Congress included an agressive
program to control mobile source pollutants. The Congress
required that automobile emissions be reduced by 90 percent by
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the 1975 model year; events have delayed the implementation of
this requirement to 1981 (The requirement for NOx reduction has
been eased to 75 percent). The enforcement of this requirement
consists of four basic elements: prototype certification,
assembly line testing (SEA), recall, and inspection and mainte-
nance. The first two elements deal with new cars, the latter two
with in-use vehicles. The period of the vehicle's life over
which each strategy applies is shown in Figure 1.
Certification
The objective of certification is to demonstrate the capability
of the complete vehicle, including emission controls, to meet the
prescribed emission standards for the vehicle's useful life
(50,000 miles for light-duty vehicles). This is accomplished by
emission testing preproduction prototypes, driven on a dynamo-
meter over a typical 7.5 mile urban driving cycle. Two types of
vehicles are tested. Early prototypes representing basic engine/
emission control system combinations are tested for 50,000 miles
to determine emission control system durability. A larger number
of prototypes, each closely representing a model to be produced,
is tested for emissions after 4000 break-in miles have been
accumulated. These test results, expressed in grams per miles,
are combined with the deterioration rates from the early proto-
types to establish a 50,000 mile emission value. If this value
is less than the emission standard, the prototype is certified
and production may begin. Over a thousand vehicles are tested in
this manner each year. The procedure establishes that each
vehicle type produced is capable of meeting emission standards
for its useful life.
Selective Enforcement Audit (SEA)
SEA is an assembly line test methodology used to ensure that
individual vehicles comply at the time of production with emis-
sion standards. Manufacturers perform the audit testing on
groups of similar vehicles; each group typically contains 10
vehicles. The model types to be tested are selected by EPA
without advance notice to the manufacturer. Sixty percent of the
vehicles in a group must meet federal emission standards, however
experience has shown that in the first year of SEA testing over
ninety percent of the vehicles produced comply on a per standard
basis (75 percent comply with all three pollutants). In 1977
thirty-four audits involving 324 vehicles were performed. Al-
though this testing represents only a small fraction of the total
number of vehicles produced annually, the presence of the SEA
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program has caused a substantial improvement in production
quality control; manufacturer assembly line testing was increased
from 1400 cars in 1974 to 19,000 cars in model year 1977.
Recall
Recall, provided for under section 207(c) of the Clean Air Act,
is designed to remedy defects in emission control equipment
caused by manufacturer design, production or unanticipated
deterioration, and to increase manufacturer concern with the in-
use emission durability of their products. Since 1972, over 12
million vehicles have been recalled; 8 million since 1975.
Noteworthy is in 1978 eighteen of 28 recalls were voluntarily
initiated and performed by the manufacturer. The percentage of
vehicles returned under the recall is only 65 percent. For the
program to be more effective, a mechanism to ensure recall
generalized repairs are performed is needed.
Inspection and Maintenance (I/M)
The fourth and final element of the mobile source emission con-
trol strategy is inspection and maintenance (I/M). Unlike certi-
fication, SEA, or recall, I/M is a state or local government
operated program. The objective of I/M is to ensure that vehicles
are achieving, in-use, the low emission levels for which they
were designed. Extensive test data have shown that proper mainte-
nance is not being performed on many vehicles, and tampering with
emission control devices is prevelent. I/M addresses these
causes of excessively high in-use emissions through the periodic
inspection and if necessary, repair of in-use motor vehicles.
Most often a short idle test is utilized to screen out those
vehicles needing maintenance.
The watchdog arm of Congress, the General Accounting Office
(GAO), recently reviewed the entire mobile source emission
control strategy. In their report, the GAO concluded that I/M
was the essential element of the mobile source control strategy
needed to., ensure emission reductions from mobile sources are
realized.
Improvements to the certification and SEA processes are also
underway. EPA recently promulgated regulations which require
that vehicles meet emission standards anywhere within the range
of adjustment of certain components. This action was in re-
sponse to data which showed improper adjustments were a major
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cause of high in-use emissions. EPA is also considering rules
which could result in maintenance performed on certification test
vehicles being more representative of that performed in-use.
Methods of factoring in-use emission deterioration into the
certification process are also being studied, as is a more strin-
gent assembly line (SEA) test criterion.
All these changes are oriented towards improving in-use emission
performance. Only I/M, however, can provide assurance that
necessary maintenance is performed and emission control system
tampering is minimized.
In-Use Vehicle Emission Performance
EPA's certification program requires that each vehicle type be
capable of meeting federal emission standards, and the SEA assem-
bly line test program results show most vehicles meet federal
emission standards at the time they are produced. Yet in-use
vehicle test programs consistently show that nearly one half of
one year old cars have emission levels above the applicable
standards. The fraction of high emitters increases from this
level with age, as shown in Figure 2.
A major test program conducted by EPA disclosed the reason for
this frequency of high in-use emissors. EPA tested 300 domes-
tic, low mileage in-use 1975 and 1976 model year vehicles. A
sequence of maintenance, beginning with correction of disable-
ments and maladjustments (except idle mixture and speed), and
followed by idle mixture and speed adjustments and finally a full
tune-up, was performed, in order, until the vehicle met emission
standards. An emission test (Federal Test Procedure) was per-
formed at each step. The program confirmed the high occurance of
vehicles exceeding federal emission standards (58%), but showed
that correction of disablements and minor idle adjustments
brought most cars (73%) under the emission standards. The conclu-
sion drawn from this study was that improper maintenance and lack
of maintenance were chief causes of high in-use emissions. The
inspection and maintenance strategy offers the most effective
solution to this problem.
A second EPA study disclosed that tampering with emission controls
is also a widespread phenomenon. This study found 19 percent of
1973-78 model year vehicles had some form of gross tampering with
emission control devices. The tampering rate increases with age,
reaching 32 percent at 5 years. The exhaust gas recirculation
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system (EGR), which is the primary control of oxides of nitrogen
emissions, was the most frequent target of tampering. Table I
presents a list of control devices often tampered with, the
frequency of tampering, and expected effects on emissions.
I/M offers the most direct method of reducing tampering. Tam-
pering reduces the chances of passing an I/M test. The tampering
study showed tampered vehicles twice as likely to fail an I/M
test incorporating New Jersey idle standards. I/M also creates
an incentive not to tamper with emission controls. Preliminary
data from New Jersey, which has an I/M program, indicate the
gross tampering rate is one half that of the national average, as
shown in Figure 3. A quick physical inspection of key emission
control devices should also be effective in further reducing
tampering. The items listed in Table I can be physically in-
spected in less than five minutes.
An additional form of tampering is use of leaded gasoline in cars
designed to use only unleaded fuel. Several surveys have indi-
cated that fuel switching is occuring in 5 to 10 percent of
vehicles. Since lead can seriously reduce the effectiveness of
the catalytic converter, used on most automobiles since 1975, the
implications on emission control are obvious, although a more
quantified assessment of the impact will have to await additional
information on frequency of switching and the effect of leaded fuel
on emissions from various control systems. The increasing price
differential between leaded and unleaded gasoline (currently
unleaded is five cents higher) coupled with projected shortages
of unleaded fuel suggest this problem will get worse.
Inspection and maintenance can reduce fuel switching in two ways.
A physical inspection can identify vehicles with tampered filler
neck inlet restrictors. The reduction in catalyst efficiency
resulting from use of leaded fuel increases the probability of
failing the I/M test. Public awareness of this fact should help
reduce fuel switching.
Inspection and Maintenance as an Emission Control Strategy
In the 1977 Amendments to the Clean Air Act (PL-95-95), Congress
established the end of 1982 as the deadline by which the states
must meet the health based ambient air quality standards. Congress
recognized that this would be a difficult goal to achieve because
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FIGURE 1
MOBILE SOURCE EMISSION CONTROL STRATEGIES
CERTIFICATION
ASSEMBLY LINE TEST
WARRANTY RECALL
INSPECTI ON/MA INTENANCE
.
CONCEPTION DELIVERY .. USEFUL
VEHICLE LIFE SPAM LIFE
FIGURE 2
PERCENT OF VEHICLES FAILING FEOERRL EMISSION SlflNOflHOS
BY VEHICLE RGE
eo
70
60
SO
*-
z
UJ
0*40
or
eo
10
13
I
I
I
HC
IS1 CO
RGE
SCRAPPAGE
FIGURE 3
GROSS TAMPERING VS AGE
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of the severity of carbon monoxide and ozone problems in many
urban areas. Thus Congress established a five year extension for
achieving the air quality standards for these two pollutants.
To obtain the extension all reasonable control strategies would
have to be adoped by the state. Congress concluded that I/M was
a reasonable control strategy, and thus 1/M became a prerequisite
for the extension. Current data indicate over 50 urban areas
will require an extension and thus must implement inspection and
maintenance programs.
A common characteristic of motor vehicle emission performance is
emissions deteriorate with time. This deterioration is present
even if proper and timely maintenance is performed. Lack of
maintenance and tampering increase the rate of deterioration.
Repair of vehicles failing an I/M test lowers the emission levels,
however, this is followed by deterioration. At the next inspec-
tion, emissions are lowered once again. Repeated inspection and
repair of the fleet leads to a growing emission benefit the
longer an I/M program has been in effect. Emission benefits
versus time for two different stringency programs are shown in
Figure 4. After five years, the carbon monoxide emission reduc-
tion (30% stringency) is nearly twice that of the first year of
the program.
EPA policy requires an I/M program to produce a 25 percent reduc-
tion in light duty vehicle emissions in 1987 compared to what the
emissions would have been in the absence of I/M. Most planners
have calculated that this mobile source emission reduction will
improve the ambient ozone levels by 3 to 10 percent and improve
the ambient carbon monoxide levels by 20 to 25 percent. There
is, of course a strong interest in verifying these estimates.
This is difficult because the many variables that influence air
pollution levels, such as meteorology and pollutant transport,
dictate that many years of data be available to establish a
trend.
An analysis linking I/M to reductions in ambient carbon monoxide
was recently published by the University of Wisconsin . The
study was based on six years of ambient CO data collected in New
Jersey. After accounting for influencing factors such as meteor-
ology and increases in vehicle miles traveled, the study attri-
buted the improvement in New Jersey CO air quality to the State's
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I/M program, which began in 1974, and more stringent new car
emission standards. Figure 5 shows the trend in New Jersey CO
air quality compared to gasoline usage.
The relationship between hydrocarbon reductions and improvements
in ozone air quality is complicated by photochemical reactions
and pollutant transport. One of the earliest hydrocarbon control
programs and the most complete ozone monitoring network is in the
Los Angeles basin. Average ozone levels in the basin have dec-
reased 45 percent since 1956, indicating emission reductions,
much of which have come from the control of mobile sources, have
resulted in improved ozone air quality.
Current Experience with I/M
Inspection and maintenance is a proven emission control strategy.
Seven states now have programs requiring mandatory inspection and
repair of failed vehicles in operation. Program features are
described in Table II.
Two basic types of administration of an I/M program exist. A
centralized I/M program features specialized inspection facilities,
operated by the state or local government or a contractor, in
which production line-like inspections are performed. Vehicles
failing the inspection obtain repairs at a private repair facility
and then return for reinspection. Features of the centralized
program include separation of inspection and repair functions;
centralized facilities which facilitate good quality control,
including computerization; and in the contractor run system, low
initial capitol cost to the governing body. Arizona and Cali-
fornia (Los Angeles area) currently operate contractor centra-
lized programs, while Oregon (Portland), Ohio (Cincinnati), and
New Jersey (statewide) have programs run by state or local govern—
ment. The New Jersey and Cincinnati programs were added to an
existing safety inspection program.
The decentralized I/M program features inspection and repair at
private garage facilities. Decentralized programs offer the
convenience of "one stop shopping", and the relative ease and low
cost of adding the emission inspection to an existing private
garage safety inspection program. The decentralized program
offers unique problems as well. Because the decentralization
means a larger number of inspection stations, each requiring an
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exhaust analyzer and trained inspector, quality control becomes a
major undertaking. The governing agency must license the inspec-
tion stations and inspect them periodically. Inspectors must be
trained to diagnose and maintain instrumentation as well as
perform the emission test. These requirements place a more
difficult administrative burden on the state than does a centra-
lized program. Nevada (Las Vegas and Reno) and Rhode Island
(statewide) currently operate decentralized I/M programs.
Two types of emission inspection tests are currently used. The
idle test is the most predominate, used by all operating programs
with the exception of Arizona. Arizona preconditions the vehicle
with a loaded mode test which requires the use of a chassis
dynamometer. The pass/fail decision is made based on idle results,
however. Loaded mode testing offers several advantages which
include better diagnostics and the ability to determine nitrogen
oxide (NOx) emission performance. A third inspection procedure,
not currently in use, is a physical and functional inspection of
the vehicle's engine and emission controls.
Portland Study
The current operating programs have demonstrated that I/M programs
can be effectively administered and produce substantial reductions
in idle emissions. The best measure, however, of vehicular
emissions is the Federal Test Procedure (FTP), a test methodology
too time consuming for use in operating I/M programs. To deter-
mine the FTP emission reductions resulting from I/M and to answer
other technical and administrative questions concerning I/M, EPA
has undertaken a study of the Portland, Oregon I/M program.
Major questions the study, which involves testing of approxi-
mately 3000 vehicles, is designed to answer are:
o Can the short test detect high emitting vehicles?
o What emission reductions (FTP) result from maintenance?
o How do emissions deteriorate after maintenance?
o What is the expected net (annualized) emission benefit?
With the study over,75 percent complete, answers to these questions
have been obtained. The conclusion of the study is I/M is
extremely effective in reducing emissions from in-use vehicles.
A brief summary of the study results is presented below.
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The short idle test used in the Portland program has proven
extremely effective in identifying those vehicles needing mainte-
nance. Emissions, as measured by the FTP, are 2 to 3 times
higher for vehicles failing the idle test than those passing, as
shown in Figure 6. The characteristic of failing the dirtier
cars while passing, on the idle test, marginally high emitters is
a key factor which contributes to the cost effectiveness of I/M.
Errors of commission (vehicles failing the idle test which do not
need maintenance) are under 5 percent.
The emission reductions resulting from corrective maintenance to
those vehicles failing the idle test are substantial. These
reductions, separated by vehicle emission control technology,
are shown below.
Emission Reduction due to Maintenance
Model Year HC % CO %
1972-74 25 37
1975-77 42 47
As previously stated, emissions deteriorate with time. J.VD
factors lead to the emission deterioration following maintenance
shown in Figures 7a and 7b. (These figures include vehicles that
both passed and failed the state inspection). In addition to
normal aging and wear, the Portland study has shown approximately
10 percent of vehicles are experiencing a rapid emission deteri-
oration. Emission results measured on each vehicle at quarterly
intervals suggest readjustments to engine parameters, particularly
idle mixture, are occurring. Investigation into this phenomenon
has not been completed at this time. As discussed below, the
fleet emission reductions occurring in Portland are substantial
even after deterioration is taken into account.
The importance of emission deterioration characteristics is
deterioration is a prime determinant of the amount of emission
reduction realized as a result of I/M. A preliminary estimate of
the annualized benefit resulting from I/M, as represented by the
area between the Eugene, Oregon and Portland, Oregon curves
(Figures 7a and 7b) shows emission reductions resulting from I/M
for the 1975-77fleet of 24 percent HC and 34 percent CO. These
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FIGURE 4
l/M. BENEFIT RELATED TO STRINGENCY
OF PROGRAM
1982
CALENDAR YEAR
; p
.GURE £
FTP EMISSION LEVELS OF CARS
PASSING AND FAILING THE OREGON
INSPECTION TEST (1975-7 HODELS)
3 •
9
a.
f ;
a_
~ 1 '
FAIL
71
x
x
x
X
X
X
x
X
X
X
X
PAS
FH
X
X
X
X
X1
/I
0
HC
FAIL
\^
si
s
NJ
\
\
\
\
\
\
\
CO
PASS
\
40
30
-o
20 =
0
-3
10
FIGURE 5
CO TRENDS IN N,J, (18 SITES)
I97Z
197]
1974
1975
1978
1977
TIME. y«
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FIGURE ZA
FTP HC EMISSION REDUCTIONS DUE TO I/M
3.0
2.5
£
X
z
CO
'2.0
u
z
a.
1.0. I l
NON-I/M CflSE
•*
..-*
20000. 24000.
28000. 32000.
KILEflGE
36000. 40000
30
o
u
a-18
u-
12. J i
FIGURE ZB
FTP CO EMISSION REDUCTIONS DUE TO I/M
*
NON-I/M CflSE
20000. 24000
28000 32000
MILEflGE
36000'. 40000
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reductions exceed those derived from Appendix N (MOBILE1) for the
same scenario. (MOBILE1 is a computer program which calculates
I/M emission reductions; documentation is available from EPA, Ann
Arbor, MI.)
Mechanic Training
Additional emission reductions can be achieved as a result of
mechanic training. EPA recognized this and in Appendix N has
provided additional emission credit for those States that imple-
ment a mechanic training program. An example of the additional
benefits is shown in Figure 8. In this example the emission
levels of 1975-76 model year vehicles restored by EPA to manufac-
turer's specifications are shown to be lower than the emission
levels of repaired Portland study vehicles. (Few mechanics in
Portland have been trained in emission related maintenance.)
Appendix N indicates mechanics training can nearly double the
emission benefit resulting from I/M for the fleet evaluated in
1987.
EPA strongly recommends that states adopt mechanic training
programs. In addition to the larger emission reductions which
can be achieved, a properly adjusted vehicle operates better,
achieves better fuel economy (3 to 4 percent), and the occur-
rence of improper or unnecessary repairs will be reduced. These
factors lead to improved consumer satisfaction with their vehicles
and I/M. EPA and Colorado State University have developed a
mechanic training course and can provide assistance in the
implementation of a mechanic training program.
Cost
A factor contributing to the consumer acceptance of I/M is the
reasonable costs of the program. Inspection fees can be expected
to range from 5 to 10 dollars. For the minority of vehicles
which fail the inspection test, repairs will average 15 to 30
dollars, with the median value typically below 15 dollars. The
actual fees and repair costs for current operating programs are
shown in Table II.
Section 207 Warranties
The Clean Air Act provides for two warranties that can benefit
the consumer. The 207(a) warranty warrants emission control
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systems from defects in materials and workmanship for 5 years or
50,000 miles, whichever comes first. The 207(b) warranty differs
in that it is triggered by failure of an I/M test. If a vehicle
fails the inspection test and has been properly maintained, the
manufacturer is responsible for repairing the vehicle. The
207(b) warranty, which is expected to be available for 1981 model
year and later vehicles only, is applicable for 50,000 miles for
most emission control devices. Certain engine components which
affect emissions but were in common use prior to emission stan-
dards (1968) are warranted for only 24,000 miles. It is planned
to have the 207(b) warranty available for the idle test (free
idle and 2500 rpm) and 2 mode loaded test. Preliminary indications
are the 207(b) standards will be at least as stringent as state
I/M emission standards now in use.
Future Technology Vehicles
The most common emission related malperformances of current
technology vehicles are idle mixture and other tune-up adjust-
ments. The parameter adjustment regulations and a significant
change in technology in the 1981 model year will result in a
reduction of the occurrence of these failure modes. This change
in technology is resulting from a more stringent federal nitrogen
oxide (NOx) emission standard in addition to other factors such
as fuel economy standards.
The technology to be introduced on most domestic models in 1981
consists of a computer controlled fuel system. An oxygen sensor
located in the vehicle exhaust pipe senses the correct (stoichio-
metric) air/fuel ratio and commands the carburetor to provide the
correct amount of fuel. The development of this concept, required
to effect a reduction in NOx using a 3-way catalyst, has lead to
the computer control of other engine parameters such as ignition
spark timing, exhaust gas recirculation rates, idle speed, evapora-
tive cannister purge rate, air pump control, and so on.
The assessment of the emission failure rate of these new technology
vehicles, in the absence of significant field experience, is a
matter of conjecture and history at this time. A second factor
which affects the impact of these vehicles on the environment,
and relates to the need for continued I/M, is the severity, in
terms of emission levels, of potential failure modes. Data on
this factor are now becoming available.
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EPA has recently tested several prototype vehicles to determine
their emission levels resulting from certain component failures.
Failure modes investigated include failure of the input devices
and outputs of the onboard microcomputer. (A key input is the
oxygen sensor, a maintainable item with current replacement
intervals ranging from 15,000 to 50,000 miles). Based on the
current prototype designs, failures or disconnects of the input
and output devices result in a discrete calibration being selected
for the continued operation of the vehicle. The operating points
selected are usually at the fuel rich or lean limit of the car-
buretor control system. Designs examined to date predominately
select fuel rich operation.
Emission tests of a 1981 prototype vehicle operated at rich and
lean limit failure modes are shown in Figure 9. Rich operation
for this and other prototypes tested to date usually results in
emissions of HC from 2 to 8 times the Federal standard, and up to
12 times the Federal CO standard. Lean operation typically
increases hydrocarbon emission levels to 2 to 3 times the stan-
dard. Noteworthy is the failed rich condition is the most common
selected failure mode. Driveability tests of several prototypes
indicate vehicle performance is unaffected by the failure, leaving
little incentive for the owner to fix the car. (Fuel economy
will drop 10 to 30 percent, however).
The extremely high emission levels in the failed modes suggest
that inspection and repair will be necessary even if the in-use
failure frequency decreases. Also, these vehicles will not be
maintenance free; periodic replacement of the oxygen sensor is
one example of required maintenance. In addition there is no
evidence the current frequency of tampering and misfueling will
decrease as a result of the new technology. These factors all
suggest periodic inspection of post-1981 vehicles will be an
effective and necessary emission control strategy.
An on-board computer offers the possibility of a self diagnostic
capability. General Motors will feature on its 1981 models a
dash-board light which, through a Morse code like system, can
tell the mechanic which element of the electronic control system
is defective. No special tools are required. Incorporating such
a check into an inspection and maintenance program is an attrac-
tive possibility.
EPA's advanced prototype testing has shown that the idle test may
not be effective in detecting high emitters on certain advanced
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3.0
2.0
X.
a.
1 .0
0.0
FIGURE 8
POTENTIflL EMISSION REDUCTION HITH MECHBNIC THHINING
(1975-77 MODELS)
FLEETHIDE
1.80
OBSERVED
REDUCTION
1.30
U6X POTENTIflL
REDUCTION
0.94
BEFORE
MAINTENANCE
AFTER
MfllNTENflNCE
flFTER
MfllNTENfiNCE
30
'ao
10
22
31% OBSERVED
REDUCTION
15
63% POTENTIflL
REDUCTION
8
BEFORE
HfllNTENflNCE
H/0 TRAINING WITH TRAINING
flFTER
HfllNTENflNCE
M/0 TRAINING
flFTER
HfllNTENflNCE
WITH TRAINING
FIGURE 9
FfllLURE MODE EMISSION LEVELS
PROTOTYPE V-8, 3-WflY PLUS OXIDflTION CflTflLYST
1500
en
0
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technology vehicles. Two other tests have shown promise, however.
The high speed idle (2500 rpm) appears to be effective as does a
loaded test. These tests measure performance in the off-idle
mode. The high-idle test is now used as a preconditioning for
the idle test. Due to equipment considerations the loaded test,
which requires a dynamometer, is usually only considered for
centralized systems. Arizona has reduced the time required to
perform the loaded test to a point at which the time is comparable
to the idle test. This implies that states developing centralized
programs should consider loaded mode testing as an investment
towards effective testing of advanced technology vehicles. States
could incorporate the necessary dynamometer pits and utility
connections in the design of their inspection facilities. Dynamo-
meters could be added at a later date if necessary. (The dynamo-
meter adds only a few cents to the cost of each inspection).
Conclusions
This paper has touched on a wide number of subjects relevant to
the decision on establishing a vehicle emission inspection program.
The major points and conclusions are:
o Inspection and maintenance programs are the necessary
completing link in the mobile source emission control
strategy.
o The majority of in-use motor vehicles are exceeding the
federal emission standards to which they were designed.
o Lack of proper maintenance is the main cause of these
emission failures.
o Tampering, and misfueling catalyst vehicles with leaded
gasoline, also contribute to excessively emitting
vehicles.
o Inspection and maintenance programs can effectively
deal with these causes of excess emissions.
o EPA's Portland Study demonstrates that I/M is effective
in reducing emission levels.
o The short idle test is an extremely effective mechanism
for screening out those vehicles most in need of repair.
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o The cost of repair for those vehicles failing the
inspection test is low; the average cost in current
operating I/M programs is 15 to 30 dollars.
o I/M will be needed for the new technology vehicles that
will be introduced in the early 1980's.
References
1. "Better Enforcement of Car Emission Standards - A Way to
Improve Air Quality," Report by the Comptroller General of
the United States, CED-78-180, January 23, 1979.
2. Federal Register, 44FR2960, January 14, 1979.
3. "An Evaluation of Restorative Maintenance on Exhaust Emis-
sions of 1975-76 Model Year In-Use Automobiles," U.S. EPA,
Ann Arbor, MI, December 1977, EPA-460/3-77-021.
4. "Motor Vehicle Tampering Survey (1978)," U.S. EPA, Mobile
Source Enforcement Division, Washington, D.C., November
1978.
5. "Statistical Analysis of Multiple Time Series Associated
with Air Quality Data: New Jersey CO Data," Ledolter, J.,
et al., University of Wisconsin-Madison, June, 1978, Techni-
cal Report 529.
6. "Analysis of Oregon's Inspection and Maintenance Program,
Becker, J.and Rutherford, J.; June 1979, APCA technical paper
79-7.3.
7. "Effects of Inspection and Maintenance Programs on Fuel
Economy," U.S. EPA, Ann Arbor, MI, March 1979, IMS-001/FE-1.
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-19-
Table 1
Tampering Rates and Emission Impact
(Reference 4)
Item Tampering Rate % HC CO NOx
PCV Valve
Evap Cannister
Air Pump Removed
Air Pump Belt Missing
Catalyst Removed
EGR Valve
Fuel Filler Neck Removed
Vacuum Spark Retard
Air Cleaner
3
3
3
6
1
12
3
10
1
t
t
t
t
t
+
t
t
t
i
t
t
t
+
t
t
Table II
Operating I/M Programs
Average
Location Type Test Type Began Fee Repair Cost
New Jersey Centralized Idle , 1974 $2.5CR $16
Arizona Centralized Loaded^' 1977 $5.00 $23
Oregon Centralized Idle 1975 $5.00,, $29
Rhode Island Decentralized Idle 1979 $4.00- , -
Nevada Decentralized Idle 1977 $14-16- -
California (LA) Centralized Idle 1979 $11.00
Ohio ,/
(Cincinnati) Centralized Idle 1975 $3.75-'
a/
— includes basic engine adjustments
— includes safety inspection
c/
— pass/fail decisions based on the idle portion only
US. GOVERNMENT PRINTING OFFICE: 1979- 650-029/0012
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