REGULATORY AMLYSIS
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FEMJARY 20,
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Regulatory Analysis
Light-Duty Diesel Particulate Regulations
Environmental Protection Agency
Office of Air, Noise, and Radiation
Mobile Source Air Pollution Control
Approved by:
Michael P. Walsh, Deputy Assistant Administrator
for Mobile Source Air Pollution Control
Date: February 20, 1980
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NOTE
This document has been prepared in satisfaction of the Regu-
latory Analysis required by Executive Order 12044 and the Economic
Impact Assessment required by Section 317 of the amended Clean Air
Act. This document also contains an Environmental Impact Statement
for the proposed Rulemaking Action.
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Table of Contents
Chapter Page
I. Summary 1
II. Introduction 13
III. Description of LDV and LDT Industry .... 20
IV. Standards and Technology 30
V. Environmental Impact 62
VI. Economic Impact 106
VII. Cost Effectiveness 124
VIII. Alternative Actions 136
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CHAPTER I
SUMMARY
A. Background
Light-duty vehicles powered by diesel engines are projected to
be a significant source of particulate emissions in the late
1980"s. Currently, this is not the case due to the small number of
light-duty diesels on the road today. By 1990, though, it is
projected that diesels could comprise as much as 20 percent of
light-duty vehicle sales. By 1990, they are projected to become
the seventh largest source of particulate emissions and to have the
third greatest available potential for total particulate emission
reduction of any source, mobile or stationary. The majority of
these emissions will occur in urban areas, where the total sus-
pended particulate problems are most acute.
Based on the above and the fact that Congress has required the
control of particulate emissions from these vehicles through the
1977 Amendments to the Clean Air Act, EPA is establishing emission
standards to control particulate emissions from light-duty vehicles
and trucks powered by diesel engines. Also included are changes in
the test equipment and procedures currently used to measure gaseous
emissions from these vehicles. These changes will allow the
measurement of particulate emissions concurrently with the mea-
surement of the currently regulated gaseous emissions without
affecting the stringency of current 'gaseous emission standards.
B. Proposed Rulemaking
Section 202(a)(3)(A)(iii) of the Clean Air Act as amended,
requires the Administrator to prescribe particulate emission
standards by the 1981 model year. It is under this authority that
EPA is now promulgating Federal light-duty diesel particulate
emission standards for 1982 and later model year vehicles. The
changes to the existing regulations include:
1. The addition of a dilution tunnel and other equipment to
measure particulate emissions;
2. The implementation of exhaust emission standards for
particulate matter from diesel-powered light-duty vehicles and
light-duty trucks of 0.60 gram per mile (0.37 gram per kilometer
(g/km)) beginning with the 1982 model year; and
3. The reduction of the standards to 0.20 g/mi (0.12 g/km)
for diesel-powered light-duty vehicles and 0.26 g/mi (0.16 g/km)
for diesel-powered light-duty trucks beginning with the 1985 model
year.
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u. Light-Duty Diesel Characterization and Industry Description
The particulate regulations being promulgated apply to two
classes of dies el-powered vehicles. The first class consists of
diesel-powered light-duty vehicles (LDV-D), which are defined as
passenger cars or passenger car derivatives capable of seating 12
persons or less. The second class is the diesel-powered light-duty
truck (LDT-D) class, which consists of vehicles rated at 8,500
pounds (3,546 kg) gross vehicle weight rating (GVWR) or less
designed primarily for transportation of property or for transpor-
tation of more than 12 passengers. While LDT-D1s are designed for
periodic carrying of cargo, these vehicles are used most often in
ways more analogous to passenger cars than to cargo-carrying
trucks.
Currently, only about 0.5 percent of all light-duty vehicles
are powered by diesel engines. Over the next 10 years, the use of
diesel engines in light-duty vehicles is expected to increase
dramatically. Current projections foresee as many as 25 percent
diesels in these markets by 1990. Two maximum penetrations of 15
percent and 25 percent were used for determining the range of
environmental and economic impacts described below.
The primary manufacturers of these vehicles, both gasoline and
diesel-fueled, produce vehicles in both classes. The three largest
are General Motors, Ford, and Chrysler. Most foreign manufac-
turers, such as Toyota, Datsun and VW, produce only light-duty
vehicles and trucks under 6,000 pounds GVWR.
D. Standards and Technology
The light-duty diesel vehicle particulate standards of 0.6
g/mi (0.37 g/km) in 1982 and 0.2 g/mi (0.12 g/km) in 1985 are based
on several precepts. To comply with the "greatest degree of
emission reduction" mandate of Section 202(a)(3)(A)(iii) and to
give "appropriate consideration" to leadtime, cost, noise, energy,
and safety factors (required by the same Section) as well, EPA
based these standards on the lowest particulate levels achievable
by the worst light-duty diesel with respect to particulate emis-
sions. This basis requires best available control technology, at
least for those diesels which have the highest particulate emission
levels. The initial standard was based on the lowest particulate
level determined to be achievable by the worst case diesel in 1981,
as there was too little leadtime to expect any major technological
breakthroughs. In fact, due to certification leadtime constraints,
EPA has had to delay the implementation date of the initial stan-
dard until 1982. The second standard was based on the lowest
particulate level determined to be achievable by 1985, as EPA
expects significant particulate reductions by then due to the
successful application of trap-oxidizers. The 0.2 g/mi (0.12 g/km)
level clearly cannot be met by all diesel vehicles at this time,
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thus the 1985 standard is a technology-forcing standard. EPA is
confident that a concerted effort by the industry will produce a
successful trap-oxidizer by the 1985 model year.
Exhaust gas recirculation (EGR), the primary NOx emission
control technique used at this time, is known to increase diesel
particulate emissions. Presently, there is a trade-off involved
between diesel NOx and particulate emissions. While the statutory
NOx standard is 1.0 g/mi (0.62 g/km) beginning in 1981, EPA has the
authority to waive the standard to 1.5 g/mi (0.93 g/km) for model
years 1981 to 1984. EPA has decided that manufacturers are
eligible for the NOx waiver if they can meet the 1.0 g/mi (0.62
g/km) NOx standard only by significantly increasing the particulate
emission levels of their vehicles. EPA has already granted NOx
waivers for several 1981-82 model year light-duty diesel engine
families and those manufacturers which had waiver applications
rejected due to insufficient information are eligible to re-apply
for the waiver.
EPA recognizes the necessity of designing prototype vehicles
to emission levels below those of the standards, due to prototype-
to-certification slippage, car-to-car variability, test-to-test
variability, and deterioration factors. Analysis has shown that
the safety margins claimed to be necessary by the manufacturers are
often exaggerated; at most a 20 percent margin seems quite ade-
quate.
The technical analysis has indicated that the manufacturers
could all meet the 0.6 gpm (0.37 g/km) particulate standard in
1981. Many of the manufacturers (Daimler-Benz, Peugeot, Fiat)
admitted or strongly implied such in their comments to the NPRM.
The technical staff has determined that, based on the data provided
during the comment period, General Motors and Volkswagen (which
claimed the Audi 5000D could not meet the proposed standard in
1981) could meet the 0.6 g/mi (0.37 g/km) level in 1981 as well.
The significant particulate reductions that have been achieved,
especially on the largest diesel vehicles which had the highest
baseline levels, have been almost completely due to engine modifi-
cations and optimizations, the effect of which EPA had under-
estimated in its original analysis. Turbocharging, which EPA had
emphasized as a particulate control strategem, has been adopted
only by Fiat and Peugeot, with Mercedes continuing to market one
turbocharged model.
Although it has been determined that the 0.6 g/mi (0.37 g/km)
standard is technologically feasible for the 1981 model year for
those manufacturers (mentioned above) which reported on their
particulate control programs, certification leadtime requirements
dictate the delay of its implementation until the 1982 model year.
For those manufacturers which did not report any particulate data
to EPA, we can only conclude that the 0.6 g/mi (0.37 g/km) standard
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can be met, and must be met, in order for them to sell light-duty
diesel vehicles during the 1982, 1983 and 1984 model years.
The 0.2 g/mi (0.12 g/km) standard in 1985 is predicated upon
the successful development of trap-oxidizer technology. The
research that has been done to date has convinced the technical
staff that trap-oxidizers will be feasible for production appli-
cation by the 1985 model year, though improvements are necessary in
the areas of efficiency (need approximately 60 percent efficiency),
durability (must last 50,000 + miles), and regeneration initiation
and control. Experience has shown that in the absence of direct
regulatory incentive, manufacturers have rarely invested the
necessary resources into new emission control technologies. With
such an incentive, EPA is confident that the trap-oxidizer will be
successfully applied by the 1985 model year.
The last data EPA received concerning trap-oxidizers was in
response to the NPRM. It was determined that approximately 2 to
2-1/2 years of development leadtime was still necessary from that
time. Allowing the manufacturers an additional 2 to 2-1/2 years of
production leadtime (during which minor engineering changes could
still be made) would delay implementation until approximately 4-1/2
years from the publication of the NPRM, or until the 1984 model
year.
While our technical analysis concluded that there is a strong
likelihood that trap-oxidizers will be feasible for vehicle appli-
cation by 1984, the uncertainty that exists with regard to trap-
oxidizer durability and vehicle application has convinced EPA to
minimize the economic risk of this rulemaking by delaying the
implementation of the 0.20 g/mi (0.12 g/km) standard until 1985.
This extra year will have only a marginal effect on ambient sus-
pended particulate levels yet will ensure that the manufacturers
have enough time to optimize trap-oxidizer development.
In addition to the 0.2 g/mi (0.12 g/km) particulate standard
in 1985, the diesel manufacturers will also have to comply with the
1.0 g/mi (0.62 g/km) NOx standard in 1985 or possibly earlier
(depending on future NOx waiver decisions). This may likely
require the use of higher EGR rates which would be expected to
increase particulate levels. EPA expects that as the particulate/
EGR relationship becomes better understood, the deleterious effect
of EGR on particulate levels will be lessened. It is also likely
that other NOx control strategies will be developed which will not
impact as much (or at all) on particulate levels. Finally, in
addition to the particulate reduction expected from the successful
application of trap-oxidizers, EPA expects additional particulate
reductions due to further engine modifications and engine system
optimizations, turbocharging, and downsizing, the latter motivated
by the progressively higher corporate average fuel economy stan-
dards in the early 1980's.
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EPA has determined that the combined effect of the greater
inertia weight and road load horsepower settings of the heaviest
typical light-duty truck (compared to the heaviest typical light-
duty vehicle) justify particulate standards 20 percent greater than
the light-duty vehicle standards, all other things being equal.
Light-duty trucks will have a NOx standard of 2.3 g/mi (1.43 g/km)
until model year 1985 while diesel light-duty vehicles will be
required to meet a NOx level in the range of 1.0 to 1.5 g/tni (0.62
to 0.93 g/km), depending on the NOx waiver decisions, until model
year 1985. At the minimum, light-duty diesel trucks will have a 53
percent greater NOx standard than will light-duty diesel vehicles.
This NOx cushion can account for both the greater NOx emissions
(approximately 20 to 30 percent) that would be expected from
light-duty diesel trucks, and the 20 percent greater particulate
emissions. The trade-off is feasible because of the relationship
of particulate and NOx emission levels to EGR. Thus, the 1982
standard of 0.6 g/mi (0.37 g/km) will apply to both light-duty
vehicles and light-duty trucks. An examination of current light-
duty truck particulate levels has shown that they all can meet the
standard.
In 1985, the cushion that now exists for light-duty truck NOx
emissions is expected to disappear. Thus, the light-duty truck
particulate standard should be 20 percent greater than the light-
duty vehicle standard, all other things being equal. In addition,
it has been determined that an additional 10 percent factor should
be applied to the standard because downsizing and the use of
smaller engines will likely not take place as rapidly with light-
duty trucks as with light-duty vehicles. The 1985 light-duty truck
particulate standard has thus been set at 0.26 g/mi (0.16 g/km).
E. Environmental Impact
Despite significant gains made in the control of particulate
emissions from stationary sources, there are many air quality
regions which are not able to meet the primary National Ambient Air
Quality Standard (NAAQS) for total suspended particulate matter
(TSP) of 75 micrograms per cubic meter (annual.mean). As diesel-
fueled vehicles assume an increasing portion of the light-duty
vehicle market, their contribution to ambient TSP levels will
increase, because diesel-fueled engines emit approximately 40 times
the amount of particulate that is emitted by gasoline-fueled
engines equipped with catalytic converters.
It is expected that between 15 and 25 percent of all new
light-duty vehicles and trucks sold by the late 1980s will be
powered by diesel engines. These light-duty diesels would have
emitted between 152,000 and 253,000 metric tons of particulate
matter annually by 1990 without control. EPA arrived at this
figure by estimating that between 10 and 17 percent of all light-
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duty travel would be by diesels in 1990. Urban areas would have
been the areas most heavily affected by these emissions. Ambient
particulate levels from light-duty diesels alone would have reached
2-11 micrograms per cubic meter (annual geometric mean) in cities
such as Chicago, Los Angeles, New York, and Dallas. Somewhat
smaller levels of 2-4 micrograms per cubic meter (annual geometric
mean) would have occurred in smaller cities such as St. Louis,
Denver, and Phoenix. These levels would have been expected to
occur over large-scale areas within these cities. Additional
particulate levels of 5-9 micrograms per cubic meter (annual
geometric mean) would have been expected in localized areas within
90 meters of very busy roadways.
This regulation will reduce particulate emissions from light-
duty diesels by 74 percent in 1990 with respect to what would be
expected without these regulations. National particulate emissions
in 1990 from light-duty diesels will be reduced by approximately
112,000-187,000 metric tons per year to 40,000-66,000 metric
tons per year. Urban emissions from these vehicles will also
decrease 74 percent in 1990 from 84,000-141,000 metric tons
per year to 22,000-37,000 metric tons per year. This emission
reduction will reduce ambient light-duty diesel particulate
levels in large cities (e.g., New York, Chicago, Dallas) by
1.5-8 micrograms per cubic meter down to 0.5-3 micrograms per cubic
meter. Light-duty diesel particulate levels in smaller cities
(e.g., St. Louis, Phoenix) will also decrease by 1-3 micrograms
per cubic meter to a level of 0.5-1.0 micrograms per cubic meter.
Localized levels which occur over and above these larger-scale
impacts will also decrease by 4-6 micrograms per cubic meter to 1-2
micrograras per cubic meter. These latter impacts could occur as
far as 90 meters from very busy roadways.
F. Economic Impact
It is expected that the retail price of light-duty diesel
vehicles and trucks will increase by approximately $11-12 in 1982
and $138-164 in 1985 due to the vehicle modifications necessitated
by this regulation. In addition, lifetime maintenance costs are
expected to decrease by $50 beginning in 1985. Due to past and
future increases in the price of gasoline-fueled vehicles due to
emission controls, EPA expects no decrease in diesel sales relative
to the sales of gasoline-fueled vehicles due to aggregate environ-
mental regulation. The aggregate cost of the first standard over
the three years it will be in effect will be $42-76 million de-
pending on total light-duty diesel sales. The aggregate cost of
the second standard over five years (1985-1989) will be $897-1857
million (present value in 1985). All these costs are in 1979
dollars.
The range of per vehicle costs for the 1985 standard is due to
possible differences in trap-oxidizer systems which may be used on
various models. The wider ranges given for the aggregate cost of
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the two standards is due to uncertainty in the actual number of
Light-duty diesels which will be built in that time frame. The
lower limit of the aggregate cost in each case assumes the lower
per vehicle cost and the lower limit of EPA's estimate of light-
duty diesel production. The upper limit of the aggregate cost
assumes the higher limit of both these factors.
G. Cost Effectiveness
In addition to determining the cost effectiveness of the
1982 and 1985 standards, the traditional methodology used to
determine cost effectiveness was examined and found to be in-
adequate when used to compare the cost effectiveness of different
particulate control strategies. In general, the traditional
methodology only focuses on total emission reductions, which may
not relate directly to air quality, health and welfare improvements
with respect to particulate emissions.
For example, the traditional measure of cost effective-
ness (dollars per metric ton of particulate controlled) can be
made more relevant to health improvements by considering only the
inhalable or fine particulate that is controlled. Based on avail-
able data, the inhalable and, especially, the fine fractions of
suspended particulate may have the greatest potential adverse
health impact. When this is done, the marginal cost-effectiveness
ratio for the 1985 standard is $2,400-3,025 per metric ton of
inhalable particulate and $2,500-3,150 per metric ton of fine
particulate. When these bases are used the cost effectiveness of
the 1985 diesel standard is found to be consistent with stationary
source control strategies which have been adopted in the past.
There is another step which can be taken to improve the
measure of cost effectiveness and that is to relate it to reduc-
tions in ambient pollutant concentrations instead of emission
reductions. People's exposure to pollutants is directly related to
the ambient pollutant concentration of the air they breathe, but
only indirectly related to the emissions from various sources.
However, the data necessary to perform such an analysis are diffi-
cult to obtain and not generally available. Still, to indicate the
potential effects such factors can have on a cost-effectiveness
analysis, some rough calculations were performed. Using some rough
indicators of a source's impact on air quality relative to its
emissions, it was found that light-duty diesels produce between 32
and 134 times the ambient pollutant concentration as the largest
power plants (2,920 megawatt heat input) based on equivalent
emission rates. Similarly, light-duty diesels produce between 0.8
and 3.4 times the ambient pollutant concentration as smaller power
plants (73 megawatt heat input), based on equivalent emission
rates. Only large-scale impacts were examined. Had localized
impacts been included, the results could have been different.
Similarly, a comparison of a different stationary source to light-
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duty diesels could have a much different result. One can imagine
the potential effects of adding five to ten such factors to the
cost-effectiveness analysis. The results of the previous paragraph
could be made meaningless. Thus, while the cost-effectiveness of
light-duty diesel control appears to be consistent with that of
past EPA actions, the use of cost-effectiveness to compare dif-
ferent source strategies should be taken very cautiously. The type
of factors which need to be included are simply not available and
could drastically affect the results. The size of these factors
also shows the need to further develop the methodology used to
determine particulate cost effectiveness before it can really be
used to identify strategies which should be implemented from those
which should not.
The marginal cost effectiveness of the 1985 standard could
only be compared with those from a few other strategies. Because
the use of a marginal cost effectiveness is relatively new,
these values are not readily available for most existing control
strategies. Similarly, it was available for only one future
control strategy, the control of emissions from mid-sized steam
generators (3-73 megawatt heat input). As more future control will
be needed than this regulation being promulgated and this one
additional NSPS if the nation is to meet the national ambient air
quality standard for suspended particulate, the cost effectiveness
of the 1985 standard should really be compared to those strategies
which will be needed in the future, which haven't yet been devel-
oped and implemented. These strategies will likely be more costly
than those of the past, since EPA has been attempting to implement
the most cost effective strategies first. This being the case, the
cost effectiveness of the 1985 standard would appear even more cost
effective than it did against the past strategies. This is all the
more reason why the 1985 standard appears to be a reasonable
control strategy.
H. Alternative Actions Considered
Control of particulate emissions from light-duty diesel
vehicles and trucks is required by the Clean Air Act. Thus, EPA
does not have the authority to forego control of light-duty diesel
particulate emissions in favor of other particulate control stra-
tegies. However, other control strategies were examined in the
course of this rulemaking. Further control of stationary sources
and other mobile sources of particulate emissions was considered.
Various techniques which would apply the emission standard to the
average emissions of a manufacturer's fleet were also considered.
Finally, per vehicle emission standards for light-duty diesels of
varying stringency were also considered as alternatives.
The alternative of further controlling stationary sources of
particulate emissions as a substitute for these regulations was
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rejected for two reasons. First, while stationary source controls
can mitigate the effects of future growth, they cannot be expected
to reduce TSP concentrations in urban areas. Secondly, further
control of stationary sources would not diminish the high levels of
diesel particulate near roadways where significant adverse impacts
occur.
The control of other nubile sources was also considered as an
alternative to these regulations. It was determined that control of
heavy-duty diesel particulate emissions will be necessary, but even
the removal of these emissions would not remove the necessity of
these light-duty regulations. The Clean Air Act requires heavy-
duty diesel particulate regulations. Regulations for heavy-duty
diesel particulate emissions are not being proposed at this time,
however, as a transient test procedure is necessary to adequately
measure heavy-duty diesel particulate emissions. This type of test
procedure will not be required for diesels until 1985, when it will
be used to measure gaseous emissions and when heavy-duty particu-
late regulations are currently planned to come into effect.
Two distinct averaging approaches were proposed by commenters
as alternatives to EPA's individual per vehicle particulate stan-
dards. General Motors' proposal would require each manufacturer's
sales-weighted average particulate level over its entire (diesel
and gasoline-powered) light-duty vehicle fleet to be equal to or
less than the Corporate Average Particulate Standard (CAPS).
Volkswagen proposed that the particulate emission levels from
diesel vehicles only be averaged, and that each manufacturer's
sales-weighted particulate level be required to comply with the
Diesel Average Particulate Standard (DAPS). The primary advantage
of both proposals is the added flexibility the manufacturers would
have in meeting the standards, both with respect to model line
mix and economics. Theoretically, CAPS allows the maximum flexi-
bility since its inclusion of gasoline-powered vehicles allows the
averaging of near-zero particulate emission levels. DAPS allows
somewhat less flexibility since it can only "balance out" high-par-
ticulate emitting diesels with low-particulate emitting diesels,
and there is a limit to the extent to which this can be effective.
In practice, the adoption of either CAPS or DAPS would necessitate
lower average levels than those proposed by the manufacturers, and
these lower levels would limit the flexibility even more. There
would likely be very little flexibility with DAPS at average levels
consistent with the concept of best available control technology.
CAPS would place an implicit ceiling on the total light-duty diesel
particulate loading to the atmosphere (assuming total light-duty
vehicle sales to be relatively constant). DAPS would limit only
the average diesel particulate level of a manufacturer.
While CAPS does provide the advantages discussed above,
EPA finds far too many difficulties associated with its implemen-
tation and we reject it as an alternative to the individual vehicle
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standards. CAPS would violate the regulatory tenet that all
light-duty vehicles should be required to meet the same emissions
standards. Each engine family, in effect, would have a different
standard. This is difficult to reconcile with the structure of
Title II of the Clean Air Act which assumes individual vehicle
standards. It would also allow vehicle A to legally emit more than
vehicle B, even though both vehicles satisfied the same general
function. A final drawback in this regard involves manufacturer
equity. Since the CAPS concept averages diesel and gasoline-
powered vehicle particulate levels, and since the latter are
typically very low, a manufacturer's corporate average particulate
level would be dependent not only on its diesel vehicle particulate
levels but also on its relative proportion of diesel to gasoline-
powered vehicles. A manufacturer which produces a small percentage
of diesels could tolerate much higher particulate levels on its
diesels, and still comply with a specific CAPS, than could a
manufacturer which markets a much higher percentage of diesels.
CAPS licenses a manufacturer to produce greater quantities of and
progressively higher-particulate emitting diesels as it increases
its gasoline-powered vehicle production. EPA considers this to be
unacceptable. CAPS might also act to restrain competition in the
industry as a firm which wanted to produce light-duty diesel
vehicles would likely find it impossible to comply with CAPS
without also producing similar quantities of gasoline-powered
vehicles. This implicit limitation on diesel sales is inconsistent
with the statutory authority for this Rulemaking. Another major
problem with CAPS concerns enforcement. Changing from enforcement
on an engine family basis with each family having to meet the same
standard to enforcement on a fleetwide basis with a multitude of
different standards would require a whole new enforcement apparatus
and would likely result in a whole new series of problems. Final-
ly, CAPS would allow the possibility of localized particulate
impact problems in certain cities, downtown areas, or roadways
which might have an unusually high concentration of diesels emit-
ting at or near the maximum level allowed.
DAPS is much more equitable to diesel manufacturers than
is CAPS. Regardless of the quantity of gasoline-powered or
diesel vehicles a manufacturer produces, each manufacturer would
have to comply with the same average diesel particulate level.
Analysis has shown that DAPS levels consistent with best available
control technology would not provide much flexibility to the
manufacturers, however, since DAPS precludes the averaging of
gasoline-powered vehicle particulate levels and since it becomes
more difficult to "balance out" a high particulate-emitting diesel
with lower particulate-emitting diesels as the standard decreases.
Although DAPS does not share the manufacturer inequity prob-
lems of CAPS, it does share the remaining problems discussed
above: it is inconsistent with Title II of the Clean Air Act, it
would allow vehicle/vehicle inequities, it would involve cumbersome
enforcement problems, and it would increase the likelihood of
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11
localized impact problems. Based on these problems, and ^.ie fact
that DAPS would not really provide very much flexibility to the
manufacturers anyway, EPA rejects the use of DAPS in favor of the
individual vehicle standards.
Alternative per vehicle standards were also examined for 1982
and 1985, as well as adjustments to the years of implementation.
With respect to 1982, a standard significantly more stringent than
0.6 g/mi (0.37 g/km) would have prevented some current light-duty
diesels from being sold. This would have been against EPA's policy
of basing the standard on the worst case vehicle, which was out-
lined in the Preamble to the Proposed Rulemaking. A standard less
stringent than 0.6 g/mi (0.37 g/km), for example 0.8 g/mi (0.50
g/km) or 1.0 g/mi (0.62 g/km), would certainly reduce the effort
needed to comply with the initial standard and would only margin-
ally affect air quality. On the other hand, 1) these levels would
hardly require any control, 2) the 0.6 g/mi (0.37 g/km) standard is
clearly achievable, and 3) the cost effectiveness of the 0.6 g/mi
(0.37 g/km) standard is very good. Given these three reasons, any
standard higher than 0.6 g/mi (0.37 g/km) was rejected.
Two alternatives to the 1982 implementation date were exam-
ined, 1981 and 1983. It appeared that the technology necessary to
meet a 0.6 g/mi (0.37 g/km) standard would be available in time for
the 1981 model year. However, the date of promulgation of the
regulation would have been too late to allow the manufacturers to
certify all of their vehicles in time for the start of the 1981
model year. To prevent the introduction of 1981 model year light-
duty diesels from being delayed, 1981 was rejected. Postponing the
standard to 1983 would have allowed the manufacturers an additional
year to meet the standard. If it was actually achievable in 1981
and was delayed a year only because of a lack of testing time,
there would appear to be little need to delay another year. Thus,
1983 was also rejected.
In determining the second level of control and its timing, the
analysis focused on the trap-oxidizer, its cost, effectiveness and
availability. The primary alternatives examined were 0.2 g/mi
(0.12 g/km) and 0.5 g/mi (0.31 g/km) standards being implemented in
1984 or 1985. (For simplicity of discussion, only the light-duty
vehicle standard will be stated.) The more stringent standard
represented the level achievable using trap-oxidizer technology and
the less stringent standard represented what was achievable without
trap-oxidizers. The air quality difference between the two stan-
dards was significant. Regional particulate levels in the nation's
largest cities would be 0.7-7 microgram per cubic meter higher
under the less stringent standard than the more stringent standard.
Also, while the cost of trap-oxidizer technology is high, the
incremental cost effectiveness of adding trap-oxidizers was not out
of line with those of past strategies. Thus, the air quality
benefits appeared to be well worth the cost and the 0.5 g/mi (0.31
g/km) standard was rejected.
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With respect to the implementation date of the 0.2 g/mi (0.12
g/km) standard, the question revolved around the date that trap-
oxidizer technology would be available. This was determined to be
1984 or 1985. The delay until 1985 will ensure a more optimum
application of trap-oxidizer technology but will marginally worsen
air quality. Because of the major economic commitment and techno-
logical uncertanties involved, EPA decided to delay implementation
until the 1985 model year.
The analysis for light-duty trucks was the same as that for
light-duty vehicles described above. The only alternative not yet
addressed was that of alternate levels other than 0.26 g/mi (0.16
g/km) in 1985. The available data on the effects of inertia weight
and road load on particulate emissions show that light-duty trucks
could have up to 30 percent higher emissions than light-duty
vehicles using equivalent technology. A standard either lower or
higher than 0.26 g/mi (0.16 g/km) then would either be less or more
stringent than the light-duty vehicle standard of 0.2 g/mi (0.12
g/km). This would create an artificial bias toward the sale of the
worst polluting class and have a negative impact on air quality.
Thus, any standard other than 0.26 g/mi (0.16 g/km) was rejected.
-------
13
CHAPTER II
INTRODUCTION
A. Background of Light-Duty Diesel Particulate Emission Regu-
lation
The regulations examined in this document are intended to
limit the emission of particulate matter from light-duty diesels.
The regulations were mandated by Congress via the 1977 Amendments
to the Clean Air Act and apply to diesel-powered light-duty vehi-
cles (LDV-D's) and trucks (LDT-D's) hereafter designated light-duty
diesels. Section 202(a)(3)(A)(iii) of the Act as amended states:
The Administrator shall prescribe regulations under paragraph
(1) of this subsection applicable to emissions of particulate
matter from classes or categories of vehicles manufactured
during and after model year 1981 (or during any earlier model
year, if practicable). Such regulations shall contain stand-
ards which reflect the greatest degree of emission reduction
achievable through the application of technology which the
Administrator determines will be available for the model year
to which such standards apply, giving appropriate considera-
tion to the cost of applying such technology within the period
of time available to manufacturers and to noise, energy, and
safety factors associated with the application of such tech-
nology. Such standards shall be promulgated and shall take
effect as expeditiously as practicable taking into account
the period necessary for compliance.
These regulations were necessitated because of the current
national urban particulate problem-II >2j With current projections
showing a likely 20% penetration of diesels into the light-duty
and medium-duty market by the late 1980's, particulate emissions
from these diesel-powered vehicles will become a significant source
of particulate emissions in urban areas and a major source in areas
immediately nearby busy roadways.
These regulations were proposed on February- 1, 1979._3/ A
public meeting was held on March 16, 1979 to allow General Motors
to present its corporate averaging proposal and a public hearing
was held March 19-20, 1979 for all interested parties to comment on
the proposed regulations. The comment period for the submittal of
written comments was held open until April 19, 1979. A detailed
summary and analysis of these comments is contained in a separate
document.4/
* Bracketed numbers (JY) indicate references at the end of this
chapter.
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14
B. Description of Particulate Emission ontrol from Light-Duty
Diesels
1. Test Procedure and Instrumentation
The test procedure under which particulate emissions will be
determined is essentially the same test procedure currently used to
determine gaseous exhaust emissions. The test for particulate
emissions will be performed simultaneously with the test for
gaseous pollutants. Thus, the driving cycles, weighting procedure,
inertia weight and road load determination procedures, etc., will
remain the same as currently set forth in the current Federal Test
Procedure. The changes required include the need for additional
equipment and instrumentation to allow for the determination of the
amount of particulate matter being emitted.
The most significant change in the test equipment will be the
substitution of a dilution tunnel for the current baffle box. The
baffle box causes a measurable decrease in particulate emissions
from diesels due to particle deposition on the baffles.5/ The
dilution tunnel will allow the diesel exhaust to be diluted with
ambient air with a minimum of particle deposition.
Also, a larger constant volume sampler than is currently
necessary for light-duty testing may be required for the larger
diesel engines. The need to reduce the exhaust temperature to less
than 125°F (52*C) dilution with ambient air will require more
dilution air than is currently available in these cases. Thus, the
purchase of CVS units as large as 600 cfm (0.28 cubic meters per
second) may be required.
2. Emission Standards
Light-duty vehicles and trucks are currently required to meet
emission standards for hydrocarbons, carbon monoxide, and oxides of
nitrogen, but no standards exist for particulate emissions. The
current and future standards for the gaseous pollutants are shown
in Tables II-l and II-2. The initial standard for particulate
emissions from LDV-D' s and LDT-D's is 0.60 gram per mile (g/mi)
(0.37 gram per kilometer (g/km)) beginning with the 1982 model
year. This level of control is expected to be reached via minor
engine modifications. The second and more stringent particulate
standard is being implemented in 1985 and is 0.20 g/mi (0.12 g/km)
for LDV-D's and 0.26 g/mi (0.16 g/km) for LDT-D's. This level of
control is expected to require the use of trap-oxidizers on most
vehicles.
If a final market penetration for diesels of 15-25% is es-
timated, these standards will result in a 74% reduction in partic-
ulate emissions from these motor vehicle classes in 1990 with
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15
Table II-l
Gaseous Emission Standards for Light-Duty Vehicles
Grams Per Mile (grams per kilometer)
Federal
1978-79
1980
1981 and on
California
1978-79
1980 V
198 1-A jZ/,2/
-B
1982-A 2] ,Z]
-B
1983 V
and on
1.
0.
0.
0.
0.
0.
0.39/0.
0.39/0.
0.39/0.
0.39/0.
HC
5 (0.
41 (0.
41 (0.
HC
41 (0.
41 (0.
41 (0.
41 (0.
41 (0.
41 (0.
41 (0.
CO
93) 15.0
25)
25)
7.0
3.4
(9.
(4.
(2.
3)
3)
1)
2
2
1
CO
25)
25)
25)
24/0.25)
24/0.25)
24/0.25)
24/0.25)
9.0
9.0
3.4
7.0
7.0
7.0
7.0
(5.
(5.
(2.
(4.
(4.
(4.
(4.
6)
6)
1)
3)
3)
3)
3)
1
1
1
0
0
0
0
NOx
.0 (1.
.0 (1.
.0 (0.
NOx
.5 (0.
.0 (0.
.0 (0.
.7 (0.
.4 (0.
.7 (0.
.4 (0.
HC Evap. I/
24)
24)
62) 4/
6
6
2
.0
.0
.0
HC Evap. I/
93)
62)
62)
43)
25)
43)
25)
6
2
2
2
2
2
2
.0
.0
.0
.0
.0
.0
.0
J7 SHED test (grams per test).
2] Manufacturers have the option of using "A" for 1981 and 1982
or of using "B" for 1981 and 1982. Also, manufacturers have a
choice between a 0.24 g/km non-methane hydrocarbon standard and the
0.25 g/km total hydrocarbon standard.
2/ If emission durability is established for 160,000 km (100,000
miles) the NOx standards for Option A are 0.93 g/km (1980-81) and
0.62 g/km (1982-83).
47 Waiver to 1.5 g/mi (0.93 g/km) possible until 1985.
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16
Table II-2
Gaseous Emission Standards for Light-Duty Trucks
Grams Per Mile (grains per kilometer)
Federal
1978
1979 21
1980 and on
1981 and on
California
1978
1979-80
(0-3999 IW)
(4-5999 IW)
1979
1980 and on
1981-82
(0-3999 IW)
(4-5999 IW)
1983 and on
(0-3999 IW)
(4-5999 IW)
California
1978-80
1978-79
1980 and on
1981-82
1983 and on
2.
1.
1.
HC
00 (1
70 (1
70 (1
.24)
.06)
.06)
20
18
18
CO
.0 (
.0 (
.0 (
12
11
11
.4)
.2)
.2)
3.
2.
2.
1
3
3
NOx
(1
(1
(1
.93)
.43)
.43)
(0-5999 GVWR)
0.
0.
0.
0.
0.
0.
0.
(6,000 and
0.
0.
0.
HC
90 (0
41 (0
50 (0
41 (0
50 (0
41 (0
50 (0
.56)
.25)
.31)
.25)
.31)
.25)
.31)
17
9
9
9
9
9
9
CO
.0 (
.0
.0
.0
.0
.0
.0
10
(5
(5
(5
(5
(5
(5
.6)
.6)
.6)
.6)
.6)
.6)
.6)
2.
1.
2.
1.
2.
0.
1.
0
5
0
0
0
NOx
(1
(0
(1
(0
(1
4 (0
0
(0
.24)
.93)
.24)
.62) 3/
.24) 4/
.25) 5/
.62) 3/
Larger GVWR)
HC
90 (0
60 (0
60 (0
.56)
.37)
.37)
17
9
9
CO
.0 (
.0
.0
10
(5
(5
.6)
.6)
.6)
2.
2.
1.
3
0
5
NOx
(1
(1
(0
.43)
.24) 6/
.93) 4/
JY SHED test (grams per test).
2J Federal weight class for LDT changes from 0-6000 GVWR to
0-8500 pounds GVWR.
.3 / ,.4/, 5/> 6/ If emission durability is established for 160,900
kilometers the NOx standard is: 0.93,_3/ 1.24,_4/ 0.62,_5_/ or 1.43.6/
grams per kilometer.
HC Evap. I]
6.0
6.0
6.0
2.0
HC Evap. I/
6.0
6.0
2.0
HC Evap. I/
6.0
2.0
-------
17
respect to what would be expected without these regulations.
National particulate emissions in 1990 from light-duty diesels will
be reduced from approximately 152,000-253,000 metric tons per year
to 40,000-66,000 metric tons per year. Urban emissions from these
vehicles will also decrease 74% in 1990 from 84,000-141,000 metric
tons per year to 22,000-37,000 metric tons per year. This emission
reduction will reduce light-duty ambient diesel particulate levels
in large cities (e.g., New York, Chicago, Dallas) from 2-11 to
0.5-2.9 micrograms per cubic meter. Light-duty diesel particulate
levels in smaller cities (e.g., St. Louis, Phoenix) will also
decrease from 2-4 to 0.5-1.0 micrograms per cubic meter. Localized
levels which occur over and above these larger-scale impacts will
also decrease from 5-9 to 1-2 micrograms per cubic meter. These
latter impacts could occur as far as 90 meters away from very busy
roadways. The primary national ambient air quality standard
(NAAQS) for TSP is 75 micrograms per cubic meter.
While these standards are projected to reduce particulate
emissions from light-duty deisels by 74%, particulate emissions
from these vehicles will still be about 15 times greater than the
particulate emissions from a typical catalyst-equipped vehicle
powered by a gasoline engine. Thus, while the standards call for
significant control, they do not call for control to a level
attainable by an alternative type of motor vehicle.
No standards are being promulgated at this time to control any
other aspects of diesel particulate besides its total weight.
While EPA health effects studies performed thus far indicate that
certain organic materials present on the filter used to determine
diesel particulate mass emissions may present a greater health
hazard than the particulate's effect on ambient TSP levels, there
is currently not enough data available on which to base special
control of these substances. It is possible, though, that addi-
tional standards will be promulgated in the future to control the
emission of any particularly dangerous compounds as more becomes
known about their effect on health.
The new standard for particulate emissions could affect the
stringency of current gaseous emission standards, especially the
NOx standard, since some techniques for controlling NOx emissions
increase particulate emissions. This effect has been taken into
account in setting the level of the particulate standards contained
in this regulation and should not be a problem. The accompanying
changes in the test equipment are not expected to affect the
stringency of the gaseous emission standards already in effect.
The dilution tunnel should be equally effective as the baffle box
in mixing the exhaust with the dilution air and the additional
dilution air should not affect the measurement of gaseous emis-
sions.
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18
C. Organization of the Statement
This statement presents an assessment of the environmental and
economic impacts of the particulate emission regulations for
light-duty diesels which EPA is promulgating. It provides a
description of the information and analyses used to review all
reasonable alternative actions and make the final decision.
The remainder of this statement is divided into six major
sections. Chapter III presents a brief description of the manu-
facturers of light-duty vehicles and the market in which they
compete.
An analysis of available particulate control technology is
presented in Chapter IV. Potential emission standards and their
timing are also discussed in detail.
An assessment of the primary and secondary environmental
impacts attributed to these particulate regulations is given in
Chapter V. The degree of control reflected by the standards is
described and a projection of national particulate emissions in
1990 is presented. The impacts of these regulations on urban and
roadside air quality are also presented. Secondary effects on
other air pollutant emissions, water pollution and noise are also
discussed in this section.
An examination of the cost of complying with the new regula-
tions is presented in Chapter VI. These costs include those
incurred to install emission control equipment on vehicles and
trucks, costs required to purchase new emission testing equipment,
and the costs to certify new vehicles for sale, as well as any
increased vehicle operating costs which might occur. Analysis is
made to determine aggregate cost for the 1982-1989 time frame.
Finally, the impact that this regulation will have on industry and
consumers will be reviewed.
Chapter VII will present a cost effectiveness analysis of this
action and compare the results of this analysis with those per-
formed on other mobile source and stationary source control stra-
tegies.
Chapter VIII will examine alternative mobile source control
options including alternative approaches to regulating light-duty
diesel particulate emissions and alternative per vehicle emission
standards. It also will explain why the alternatives of achieving
additional reduction of emissions from other mobile sources or
stationary sources were not considered to be acceptable substitute
actions for these regulations.
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19
References
\J "National Air Quality and Emissions Trends Report, 1976,"
OAQPS, OAWM, EPA, December 1977, EPA-450/1-77-002.
2/ "National Assessment of the Urban Particulate Problem, Volume
~ I: National Assessment," OAQPS, OAWM, EPA, July 1976, EPA-
450/3-76-024.
_3_/ "Particulate Regulation for Light-Duty Diesel Vehicles,"
Federal Register, Vol. 44, No. 23, Thursday, February 1, 1979,
pp. 6650-6671.
_4/ "Summary and Analysis of Comments, Light-Duty Diesel Partic-
ulate Regulations," MSAPC, EPA, October 1979.
_5_/ Black, Frank, "Comments on Recommended Practice for Measure-
ment of Gaseous and Particulate Emissions from Light-Duty
Diesel Vehicles," ORD, EPA, April 13, 1978.
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20
CHAPTER III
DESCRIPTION OF LDV AND LOT INDUSTRY
A. Definition of Product
A light-duty vehicle (LDV) is currently defined as a passenger
car or passenger car derivative capable of seating 12 passengers or
less.
A light-duty truck (LOT) is any motor vehicle rated at 8500
pounds (3546 kg) Gross Vehicle Weight Rating (GVWR) or less, has a
vehicle curb weight of 6000 pounds (2722 kg) or less and a maximum
basic vehicle frontal area of 46 square feet (4.3 square meters)
and is: a) designed primarily for purposes of transportation of
property or is a derivative of such a vehicle, b) designed pri-
marily for transportation of persons having a capacity of more than
12 persons or c) available with special features enabling off-
street or off-highway operation and use.
B. Structure of the Industry (Production and Marketing)
U.S. manufacture of light-duty vehicles is almost entirely
done by the five major motor vehicle manufacturers: General
Motors, Ford Motor Company, Chrysler Corp., Volkswagen of America,
and American Motor Corp. In 1978, sales of passenger cars totalled
11.4 million of which 9.3 million were of domestic origin, 0.8
million were from Canada and 1.3 million were from foreign manu-
facturers. The major foreign importers were Toyota, Volkswagen,
Nissan, Honda and Fiat.
The manufacture of light-duty trucks sold in the U.S. is
primarily accomplished by the major domestic passenger car pro-
ducers. General Motors Corporation (Chevrolet and CMC divisions),
Ford Motor Company and Chrysler Corporation (Dodge Truck Division)
all have separate truck divisions which produce light-duty as well
as heavy-duty trucks. American Motors Corporation operates the
Jeep division which manufactures light-duty trucks. The other
major domestic manufacturer of LDT's is the International Harvester
Corporation (IHC).
Some LDT's sold in the U.S. are imported. The majority of
U.S. imports of trucks come from the Canadian plants operated by
U.S. domestic producers. Some imports, primarily light pick-up
trucks, under 4,000 pounds (1814 kg) GVWR, come from Japanese
producers. The major importers are Nissan (Datsun), Toyota, Isuzu,
and Toyo Kogyo. Both Toyota and British Leyland Company import
utility vehicles under 6,000 Ibs. (2722 kg) GVWR. Imports ac-
counted for about 6% of all 1978 factory sales of trucks with a
GVWR less than 8500 pounds (3856 kg) GVWR.
-------
21
Table III-l shows unit factory sales for LDV's and LDT's from
U.S. plants. Most data available on LDT's are presented in a
0-10,000 pound (0-4536 kg) category. Since the definition of LDT's
includes only vehicles up to 8,500 pound (3846 kg) GVWR, some
adjustment to the 0-10,000 pound category was necessary for this
analysis. The industry production data available to EPA indicates
that slightly over five percent of all trucks with GVWR's less
than 10,000 pounds (4536 kg) have GVWR's of more then 8,500 pounds
(3856 kg). This five percent figure is used in Table III-l and
throughout this analysis to adjust production data to fit the new
LOT definition.
Table III-2 shows new car and truck registrations for 1974
through 1976. These figures represent the numbers of both domestic
and imported vehicles bought by U.S. consumers in those years.
This table also includes total passenger car and motor trucks that
were registered in 1974 through 1976.
Table III-3 is a breakdown of registrations by manufacturer
for 1978 LDV's. Also included is the percent of the passenger car
market registrations for each manufacturer.
Table III-4 gives similar information for the LOT industry.
It should be noted that Table III-4 gives market shares for 0-
10,000 pounds (0-4536 kg) GVW truck sales. Data indicating the
portion of sales for 0-8,500 pounds (0-3856 kg) GVW LOT for each
manufacturer were not available and the assumption that slightly
over 5 percent of sales would be over 8500 Ibs. (3856 kg) GVWR is
not valid for all manufacturers.
Sales of diesel powered light-duty vehicles and trucks are
still a small fraction of total production, but are steadily
increasing each year. Diesel penetration into the two markets by
the late 1980's has been projected to be a high as 25%. Table
III-5 shows past sales and 1979 projections of diesel sales in
the U.S.
U.S. light-duty vehicle and truck manufacturers operate with a
fair degree of vertical integration. As is typical of many capital
intensive industries, the manufacturer seeks to assure itself of
some control over the quality and availability of the final pro-
duct. Thus, the major manufacturing companies have acquired sub-
sidiaries or started divisions to produce many of the parts used in
the manufacture of their cars and trucks. None, however, build
their vehicles without buying some equipment from independent
vendors.
The vertical integration typical of passenger car and truck
manufacturers extends beyond the production of the vehicle into its
sale. The manufacturers establish franchised dealerships to handle
retail trade and servicing of their products. Most also produce
and sell the parts and accessories required to service their
-------
Table IH-1
LPT and LPT Factory Sales from U.S. Plants I/
Type of Vehicle
Light-Duty Vehicle
Light-Duty Truck 5/
1978 2/
9,165,190
3,099,966
1977 2/
9,200,849
2,897,080
1976 3/
8,497,603
2,505,448
1975 3/
6,712,852
1,848,223
1974 4/
7,331,946
2,154,892
1973
9,657,647
2,372,269
TOTAL: 12,265,156 12,097,929 11,003,051 8,561,075 9,486,838 12,029,916
Source: Motor Vehicle Manufacturers Association of the United States, Inc.
\J Includes those vehicles produced in U.S. that are exported.
2J Data from Automotive Hews, 1979 Market Data Book, April 25, 1979, pp. 20, 40.
"$] Data from Automotive News, 1977 Market Data Book, pp. 48, 62.
l\J Data from Automotive News Almanac, 1975.
5/ Assumed to be 95% of sales of trucks less than 10,000 Ib. GVW.
-------
23
Source
LDV
LDT
TOTAL:
Table III-2
New Vehicle Registrations _!_/
New Vehicle Registrations
1976 1975 1974
9,751,485
2,588,213
12,339,698
8,261,840
2,397,417
10,659,257
8,701,094
2,656,918
11,358,012
Source
LDV
LDT and HDV
TOTAL:
1976
110,583,722
26.560.296
137,144,018
Total Vehicle Registrations
1975 1974
107,371,000
26,356,000
133,727,000
104,901,066
25,036,736
129,937,802
Source: 1974 and 1975 Data: Automotive News Almanac, 1976.
1976 Data: Automotive News, 1977 Market Data Book Issue.
_!_/ Includes imports.
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24
Table III-3
New Car Registration of Light-Duty Vehicles
by Manufacturer for 1978
Manufacturer
General Motors
Ford
Chrysler
Toyota
Nissan (Datsun)
Honda
Volkswagen
American Motors
Other
TOTAL
Source: Automotive News,
Number of
Units Produced
5,217,554
2,508,249
1,112,111
427,465
337,523
258,151
239,612
157,797
687,642
10,946,104
1979 Market Data Book Issue,
% of Passenger
Vehicle Market
47.7
22.9
10.2
3.9
3.1
2.4
2.2
1.4
6.2
100.0
p. 14 and
61.
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25
Table III-4
U.S. Sales of Light-Duty Trucks
by Manufacturer for 1978 I/
Manufacturer
Chevrolet
CMC
Ford
Chrysler
AMC/Jeep
IHC
Other Manufacturers 2/
Number of
U.S. Sales
1,233,932
283,540
1,219,693
404,514
163,548
36,065
210,041
% of Light
Truck Market
35
8
34
11
5
1
6
TOTAL 3,551,333 100%
Source: Automotive News, 1979 Market Data Book, P. 44.
y LDT defined as 0-10,000 pounds GVW.
2/ Includes imports.
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26
Table III-5
U.S. Sales of Diesel-Powered Light-Duty Vehicles and Trucks
Model 1976 1977 1978 1979*
Mercedes-Benz \J
240D
300D
300SD
9,024
12,521
-0-
9,770
11,333
-0-
6,600
16,000
5,200
8,600
15,300
9,300
jn v - -0- 7,500 36,386 110,000
and Dasher '
Peugeot 504D V 4,549 4,914 5,547 8,100
General Motors 4/
350 Oldsmc
350 Pick-up
260 Oldsmc
IHC Scout V
TOTAL 27,064 34,754 123,064 351,300
bile -0-
p -0-
bile -0-
970
-0-
-0-
-0-
1,237
35,180
16,920
-0-
1,231
118,000
31,000
50,000
1,000
* Projections.
\J Personal communication with Martin Emberger, Mercedes-Benz,
April 3, 1978.
2J Personal communication with L.L. Nutson, Volksagen, April 4,
1978.
2/ Personal communication with Richard Lucki, Peugeot, March 1978.
b] Personal communication with A. Lucas, General Motors, April 7,
1978.
5/ Personal communication with T.A. Jacquay, . IHC, March 1978.
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27
vehicles. Many of the truck dealerships are coupled with the
passenger car dealerships. As of January 1979, there was a total
of 24,051 passenger car dealerships and 22,189 truck dealerships
The total truck dealerships include dealerships for heavy-duty as
well as light-duty trucks, and accounts for those dealerships
operating jointly with passenger car sales offices.
Table III-6 provides a breakdown of all light-duty vehicle
dealerships by manufacturer and Table III-7 provides this infor-
mation for truck dealerships. The "Others" category in Table III-7
includes dealerships of manufacturers that produce only heavy-duty
vehicles, and also 1,211 dealerships for Plymouth which introduced
the 4-wheel drive Trail Duster (an off-road utility vehicle) in
1974.
C. Sales and Revenues
Vehicle sales from domestic manufacturers for 1978 were 14.6
million vehicles at a total wholesale value of about $122 billion.
For 1977, 14.4 million vehicles were sold at a wholesale values of
$112 billion. Total profits for the domestic manufacturers were
$4.9 billion in 1978 and $5.2 billion in 1979.
D. Employment
It is estimated that about three and a half million workers
are employed in the manufacturing, wholesaling and retailing of
motor vehicles (passenger cars, trucks, and buses) with a total of
about $53 billion in wages paid to those employees. Most employ-
ment data are aggregated for producers of all classes of cars and
trucks since some production facilities manufacture both cars and
trucks. Statistics show that over 14 million workers were employed
in 1973 by motor vehicle related industries. The total annual
payroll of these workers amounted to over $119 billion (1973).
Much of this employment is centered in California, Michigan, Ohio,
New York, Indiana, Illinois, Missouri, and Wisconsin.
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28
Table III-6
Passenger Car Dealerships by Manufacturer
Total
Franchises as Dealers as
Manufacturer of
American Motors
Chrysler Corp.
Chrysler
Dodge
Plymouth
Ford Motor Co.
Ford
Lincoln
Mercury
General Motors Corp.
Buick
Cadillac
Chevrolet
Oldsmobile
Pontiac
TOTALS :
Minus Intercorporate
Net
Jan. 1,1979 of Jan. 1, 1979
1661 1661
9174 4786
3343
2816
3015
10190 6639
5564
1642
2948
17210 11565
3050
1635
5950
3330
3245
38235 24651
Dealers 600
Dealers: 24051
Unit Sales
Per Outlet
1978 1977
105
326
115
195
256
215
394
302
277
112
89 96
158 162
133 143
335
112
172
245
207
381
294
249
Source: Automotive News, 1979 Market Data Book, pp. 62,71.
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29
Table III-7
Truck Retail Outlets by Manufacturer
Manufacturer
Ford
Chevrolet
CMC
Dodge
IHC
American Motors
Others
TOTALS:
Adjustment for
Multiple Franchises
Net Dealers:
Outlets as
of Jan. 1,1979
5648
5939
2721
3284
1675
1768
2822
23827
1638
Unit Sales
Per Outlet
1978
233
215
121
141
70
93
24651
22189
Source: Automotive News, 1979 Market Data Book, pp. 44, 98.
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30
CHAPTER IV
STANDARDS AND TECHNOLOGY
A. Background
1. Basis and Nature of Standards
The first federal air pollution legislation was the Air
Pollution Control Act passed by Congress in 1955. It was not
until 1963, however, that the federal government confronted
the seriousness of the air pollution problems then facing the
United States. Finding that "the predominant part of the Nation's
population is located in its rapidly expanding metropolitan and
other urban areas, which generally cross the boundary lines of
local jurisdictions and often extend into two or more states,"!/
and that "the growth in the amount and complexity of air pollution
brought about by urbanization, industrial development, and the
increasing use of motor vehicles, has resulted in mounting dangers
to the public health and welfare, including injury to agricultural
crops and livestock, damage to and the deterioration of property,
and hazards to air and ground transportation,"^/ Congress passed
the Clean Air Act of 1963 to (among others) "protect the Nation's
air resources so as to promote the public health and welfare and
the productive capacity of its population."^/ Since that time,
Congress has modified the Clean Air Act with the Motor Vehicle Air
Pollution Control Act of 1965, the Clean Air Act Amendments of
1966, the Air Quality Act of 1967, the Clean Air Act Amendments of
1970, and the Clean Air Act Amendments of 1977.
In view of the substantial air pollution contribution made by
motor vehicles, and the transient, interstate nature of their
usage, the Administrator of the Environmental Protection Agency
(EPA) has been given broad authority to: "prescribe (and from
time to time revise) in accordance with the provisions of this
section, standards applicable to the emission of any air pollutant
from any class or classes of new motor vehicles or new motor
vehicle engines, which in his judgment cause, or contribute to, air
pollution which may reasonably be anticipated to endanger public
health or welfare."^/ In many cases, Congress itself has mandated
specific motor vehicle emissions reductions, as with hydrocarbon
(HC), carbon monoxide (CO), and nitrogen oxides (NOx) emissions.
As a result of the concern over the public health and welfare
implications of an increasingly dieselized motor vehicle popula-
tion, Congress approved an amendment to the Clean Air Act in 1977
that mandates the particulate regulations for motor vehicles.
Section 202(a)(3)(A)(iii) states that: "The Administrator shall
prescribe regulations under paragraph (1) of this subsection
applicable to emissions of particulate matter from classes or
categories of vehicles manufactured during and after model year
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31
1981 (or during any earlier model year, if practicable). Such
regulations shall contain standards which reflect the greatest
degree of emission reduction achievable through the application of
technology which the Administrator determines will be available for
the model year to which such standards apply, giving appropriate
consideration to the cost of applying such technology within the
period of time available to manufacturers and to noise, energy, and
safety factors associated with the application of such technology.
Such standards shall be promulgated and shall take effect as
expeditiously as practicable taking into account the period neces-
sary for compliance."
There has been considerable confusion over the role of the
carcinogenicity question in this rulemaking. Many diesel health
effects programs have been undertaken, with special emphasis on the
questions of tnutagenicity and carcinogenicity, but these programs
will not produce final results for some time. This Rulemaking is
in direct response to Section 202(a)(3)(A)(iii) and as such is
concerned with total particulate and not with any particular
component of the particulate.
Clearly, it is only through the application of best available
control technology that "the greatest degree of emission reduction"
can be achieved. EPA examined a number of approaches that could
have been used in setting the particulate standards. The approach-
es considered included setting a standard requiring the best
available control technology, and:
1) Based on the lowest particulate level achievable by the
best light-duty diesel with respect to particulate emissions;
2) Based on the lowest particulate level achievable by the
best light-duty vehicle (gasoline or diesel) with respect to
particulate emissions;
3) Based on the lowest particulate level achievable by the
worst light-duty diesel with respect to particulate emissions;
4) • Requiring an equal level of effort by all manufacturers
on each of their vehicle lines.
We rejected the first approach because it would have prevented
all diesels from being marketed except for subcompacts and possibly
small pick-ups with small engines. The "appropriate consideration"
to leadtime, cost, noise, energy, and safety factors required by
Section 202(a)(3)(A)(iii) has convinced EPA that Congress did not
intend, as a result of this Section, to force any diesel powered
vehicles out of production. We did not select the second approach
for the same reason; in fact, since gasoline-powered vehicles with
three-way catalysts emit very low levels of particulate, a standard
based on this approach would likely prevent any light-duty diesel
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32
vehicles from being sold in this country. The fourth approach
would be workable only if an engine or vehicle parameter could be
determined to affect particulate emissions to such an extent that a
graduated standard could be based on that parameter. No such
parameter has been identified. In addition, adoption of the fourth
approach would result in different standards for vehicles competing
in the same market. This would conflict with the standard policy
of equal treatment towards all light-duty vehicles which have the
general purpose of personal transportation. Thus, we based the
particulate standards on the lowest particulate levels achievable
by the worst light-duty diesel with respect to particulate emis-
sions. This approach allows standards which provide significant
particulate reductions, but which do not force any diesel models
out of production, unless the manufacturer refuses to make the
necessary changes to meet the standards. This approach requires at
least some manufacturers to utilize the best available control
technology.
When projecting a near-term standard when little time exists
for technological advances, it is relatively simple for a regula-
tory agency to predict what the best available control technology
will be, and to set a standard based on its application. It is
more difficult to regulate on this basis in the long-term because
of the uncertainty that inevitably surrounds expected technological
improvements. Nevertheless, to fulfill the "greatest degree of
emission reduction" mandate of the Clean Air Act, EPA has concluded
that it is absolutely necessary to issue standards which motivate
the private sector to maximize its efforts in reducing particulate
emissions from light-duty diesel vehicles. Experience has shown
that in absence of the regulatory incentive, the automotive indus-
try has often ignored environmental concerns. This is not surpris-
ing, as emission control is a classical economic externality to the
automotive manufacturer, and as such would receive little or no
attention due to pressure from the marketplace. The attempt to
require best available control technology in the future often
requires technology-forcing standards, standards which are admit-
tedly unattainable at the time they are proposed, but which the
regulatory agency expects to be attainable by the time they take
effect. While recognizing the inherent uncertainty of technology-
forcing standards, EPA reaffirms its support of. them in general,
and of their application in this particular rulemaking. Both the
1982 and 1985 particulate standards have been based upon the levels
achievable by the highest particulate-emitting light-duty diesel
vehicle utilizing best available control technology.
2. Particulate/KOx Relationship
One factor that had complicated the diesel particulate regu-
lations was the uncertainty surrounding the diesel NOx standard for
the years 1981 to 1984. The Clean Air Act mandated a light-duty
vehicle NOx standard of 1.0 g/mi (0.62 g/km) beginning with the
1981 model year,J5/ but it included a provision allowing EPA to
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33
waive the NOx standard to 1.5 g/mi (0.93 g/km) for light-duty
diesel vehicles for model years 1981 to 1984.6J
The primary NOx control technique presently used is exhaust
gas recirculation (EGR). It is expected that EGR would be used by
many manufacturers to meet a 1.5 g/mi (0.93 g/km) NOx standard, and
by practically every manufacturer (at higher rates) to meet a 1.0
g/mi (0.62 g/km) NOx standard. It is well known that EGR increases
particulate emissions, and that the greater the EGR rate, the
greater the increase in particulate emissions. Thus the level of
the diesel NOx standard has a significant effect on the level and
feasibility of the diesel particulate standards.
In the Notice of Proposed Rulemaking (NPRM), EPA assumed that
the NOx waiver would not be granted to any manufacturer.^/ Thus,
the proposed standards were based on the worst-case scenario for
particulate emissions, i.e., on the assumption that light-duty
diesel vehicles would require relatively large EGR rates to meet
the most stringent NOx standard.
Data received from the industry have convinced EPA that
with the current state of diesel emission control technology, NOx
control to 1.0 g/mi (0.62 g/km) is not feasible at this time with
acceptable durability and particulate emissions control for all
engine families. Thus, EPA has granted NOx waivers for several
1981-82 model year light-duty diesel engine families. Those
waivers which were rejected were rejected based on insufficient
information. If sufficient emissions data are provided, the
remaining engine families are also eligible for NOx waivers.
In the near-term, it has been important to consider the diesel
particulate and diesel NOx issues simultaneously, because of their
interrelationship through the use of EGR. EPA has done this in its
technical analyses. In the future, EPA expects this interrelation-
ship to lessen as NOx control technologies are developed which do
not impact on particulate emissions.
3. Design Targets
EPA recognizes the problems involved in setting emissions
standards that future production vehicles will be required to meet,
based on data primarily from low-mileage, research-prototype
vehicles. We understand the necessity of designing such research
prototypes to emissions levels below the standards with which the
production and durability vehicles must ultimately comply. Proto-
type-to-certification slippage, car-to-car variability, test-to-
test variability, and deterioration factors must all be taken into
account when anticipating the emission level that will be achiev-
able for production vehicles based on low-mileage, research-proto-
type vehicles.
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34
There will likely be a certain slippage between the particu-
late levels of research-prototype vehicles and the levels a manu-
facturer could confidently expect to achieve with certification
vehicles. Based on our experience with the certification process,
we would expect this margin to be small. It is now fairly common
for major manufacturers to perform their emissions control develop-
ment on duplicate vehicles,8/ which reduces the likelihood of
erroneously obtaining very low emissions levels due to an atypical
vehicle.
EPA considers the concerns over car-to-car variability to be
misplaced. Although there will likely be production variability
with respect to particulate emissions, it is expected to be small.
The statistical sampling program used in Selective Enforcement
Auditing also considers production variability. Test-to-test
variability, which can be considered a part of car-to-car varia-
bility, also is not a serious problem. EPA has found diesel
particulate test-to-test variability to be less than 5 percent and
GM has reported similar result s.9_/ In any case, we expect both
car-to-car and test-to-test variability to improve in the future as
the manufacturers become more familiar with diesel particulate
control techniques and the test procedures.
Our original assumption of a negligible diesel particulate
deterioration factor_H>y was based on the low HC deterioration
factors of 1978 certification diesel vehicles and on the well known
stability of the compression ignition engine. The stability of
diesel HC with mileage accumulation is reaffirmed by the 1979
certification data; the average HC deterioration factor for light-
duty diesel vehicles was 1.06. While we do not claim that RC
deterioration factors are perfect indicators of particulate deter-
ioration factors, the former are one gauge we have to predict the
latter.
GM was the only manufacturer to report any particulate dura-
bility data. GM calculated particulate deterioration factors for
four cars, shown in Table IV-1. They were all based on limited
data.
It is rather difficult to draw any conclusions from the data
in Table IV-l. The 1976 Opel was used for particulate trap devel-
opment by GM. The data used in the deterioration factor calcula-
tion for this vehicle were all gathered as baselines with standard
exhaust systems during this development program except for the
5,000-mile data which were gathered prior to the trap development
program. If the 5,000-mile data were excluded, the particulate
deterioration factor would be very close to 1.0. It should also be
noted that the lowest deterioration factors were for the 5.7-liter
GM engine, while the higher values were for the Opel 2.1-liter
engine that is not sold in the U.S. Finally, particulate data were
reported for one other GM 1980 5.7-liter, 4,500-pound vehicle with
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35
Table IV-1
GM Particulate Deterioration Factors 11/
Car/Displacement Test Particulate DF
80 Olds Delta 88/5.7 L 50 K AMA 1.03
80 Olds Delta 88/5.7 L + EGR 27.6 K AMA 0.66
78 Opel/2.1 L + EGR 50 K AMA 1.26
76 Opel/2.1 L Trap development 1.53
Baseline Tests
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36
limited mileage accumulation in GM's NOx Waiver Application sub-
mitted to EPA in May, 1979.12_l Four emissions tests were per-
formed both at 5,500 and at 19,000 miles on car 86597, two tests
with EGR and two tests without EGR at each mileage. All mileage
accumulation was with EGR. With EGR the particulate emissions
dropped from 0.86 g/mi (0.53 g/km) at 5,500 miles to 0.67 g/mi
(0.42 g/km) at 19,000 miles. Without EGR the particulate emissions
went from 0.47 g/mi (0.29 g/km) to 0.42 g/mi (0.26 g/km). Thus,
for car 86597 the particulate deterioration factor appears to be
less than one, both with and without EGR.
GM somehow interpreted the data in Table IV-1 to conclude that
particulate deterioration factors would be in the range of 1.2 to
1.4._1_3_/ The foregoing analysis of GM's own data indicates that
there is no basis for that conclusion. Rather, GM's durability
data, the low diesel HC deterioration factors, and the stable
nature of the diesel engine all indicate that particulate deterior-
ation factors will be very low, most likely in the range of 1.0 to
1.1.
The EPA technical staff concludes that the claims made by
many manufacturers that they must design to levels 40 to 50 percent
lower than the particulate standard are greatly exaggerated.
Certainly design targets are necessary, but at most a 20 percent
safety margin appears quite adequate.
4. Baseline
As part of the initial particulate characterization process, a
comprehensive particulate baseline was developed by testing 25
light-duty diesel vehicles and trucks. The most relevant particu-
late data, those from 1979 certification diesel vehicles, are given
in Table IV-2.
B. 1982 Standard
EPA had proposed that a 0.60 g/mi (0.37 g/km) particulate
standard be set for the 1981 model year and had predicted that
every manufacturer would be able to meet that standard through
engine modifications and minor engine redesign. This position was
primarily based on the fact that although many diesel engine
designs had been optimized for smoke-limited performance, none had
been optimized for particulate emissions. Thus, EPA expected that
particulate optimization would be possible, especially at light
loads where the correlation between smoke opacity and particulate
emissions is not very strong. Recognizing most engine modifica-
tions to be manufacturer-specific, the one control technology we
predicted to be universally applicable was turbocharging. Data
available to us during our initial analysis indicated that turbo-
charging reduced particulate emissions by approximately one-third.
15/
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37
Table IV-2
1979 Light-Duty Diesel Certification Particulate Baseline 14/
Part iculate
Vehicle (g/mi) (g/km)
Typical Gasoline-powered vehicle (w/catalyst) 0.008 0.005
VW Rabbit 0.23 0.14
Peugeot 504 0.29 0.18
VW Dasher 0.32 0.20
IHC Scout (Nissan) 0.32-0.47 0.20-0.29
Daimler-Benz 300 SD 0.45 0.28
Daimler-Benz 240D 0.53 0.33
Chevrolet Pickup (Oldsmobile) 0.59 0.37
Dodge Pickup (Mitsubishi) 0.61 0.38
Oldsmobile 260 0.73-1.02 0.45-0.63
Daimler-Benz 300D 0.83 0.52
Oldsmobile 350 0.84 0.52
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38
The position that particulate reductions due to minor engine
modifications are dependent on each individual manufacturer and
design is supported by the fact that no specific modification was
unanimously endorsed by the manufacturers in their comments to the
NPRM, yet almost every manufacturer found one or more areas in
which improvements could be made. GM and Fiat both claimed that
redesigned fuel injectors could be effective; in fact, GM credited
much of their very substantial particulate reduction in their 1980
design to their new poppet fuel injectors. Combustion chamber
optimization was performed by both GM and Daimler-Benz, with the
latter adding a hole in their prechamber. An area where some
success has been achieved but where more work is necessary is
injector timing adjustments. Daimler-Benz reported particulate
reductions due to retarded timing at part load, and GM indicated
the possibility of doing likewise, but Peugeot pointed out the
necessity of optimizing HC and particulate simultaneously, and Fiat
provided data showing particulate increasing with retarded timing;
to lower particulate Fiat would have to advance its timing and
raise its NOx emissions. Derating was supported by Ricardo and DOE
but Fiat claimed it would not work for light-duty diesels because
of the part load nature of the FTP. Manufacturers disagreed over
whether turbocharging reduced particulate emissions. Peugeot and
Fiat both incorporated turbochargers into their 1981 designs and
claimed that turbocharging does reduce particulate; Daimler-
Benz and GM denied that turbocharging reduced particulate; the
remaining manufacturers did not take positions on the issue. EPA
is convinced that turbocharging can be an effective particulate
control strategy, provided that a concerted effort is made to match
and optimize the turbocharger application to the engine's intake,
exhaust, and injection systems, and that the increased thermal
efficiency is utilized to optimize transmission gearing and axle
ratio for emissions rather than for increased performance. (For a
more complete discussion of the turbocharging issue, see Reference
16).
Table IV-3 summarizes the most promising particulate/NOx data
received from the manufacturers' in-house diesel development
programs. The data generally includes the best particulate data at
NOx levels of 1.5 g/mi (0.93 g/km) or less, but for Daimler-Benz
and Volkswagen the data listed are the only data submitted to EPA.
The considerable progress that has been made in particulate emis-
sion control can be seen in Table IV-4 which compares the 1981
prototype and 1979 certification particulate levels for those
models for which the data is available. It is important to note
that the greatest particulate reductions achieved by engine modi-
fications were by GM and Daimler-Benz, the manufacturers which had
the highest particulate baseline levels.
Based on the data in Table IV-3, and the analyses that follow,
EPA has concluded that all manufacturers would be able to comply
with a 0.60 g/mi (0.37 g/km) particulate standard in 1981 with
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Table IV-3
Best Particulate/NOx Data as Reported by Manufacturers
Manufacturer
and Model
Daimler-Benz
240D
300D
300SD
Peugeot 19/
504D
504D
Engine
Size (1)
17/, 18/
2.4
3.0
3.0
2.3
2.3
Vehicle
Weight (Ib)
3,500
3,875
4,000
3,500
3,500
Particulate
(g/mi)
0.40
0.30
0.47
0.49
0.44
(g/kro)
0.25
0.19
0.29
0.30
0.27
NOx
(g/mi)
1.47
1.31
1.21
1.51
1.08
(g/kra)
0.91
0.81
0.75
0.94
0.67
Volkswagen 20/
Rabbit
Dasher
Audi 5000D
Audi 5000D
Fiat 21/
1.5
1.5
2.0
2.0
2,250
2,500
3,000
3,000
0.33
0.42
0.65
0.58
0.21
0.26
0.40
0.36
1.07
1.46
1.73
1.87
0.67
0.91
1.08
1.16
2.4
General Motors 22/,23/,247
"260" 4.3
"260" 4.3
"260" 4.3
"260" 4.3
3,000
0.53
0.33
1.19
0.74
4,000
4,000
4,000
4,000
0.27
0.41
0.50
0.56
0.17
0.25
0.31
0.35
1.01
1.06
1.29
1.10
0.63
0.66
0.80
0.68
Comments
"1981 Projections" w/EGR, 2 tests
"1981 Projections" w/EGR, 2 tests
"1981 Projections" w/EGR, TC, 2 tests
Prototype
Prototype w/EGR, TC
Seven Production Vehicles
Ten Production Vehicles
Eight Production Vehicles
Three Prototypes w/TC
Prototype w/EGR, TC
Prototype 72204 w/EGR, 3 tests
Prototype 93516 w/EGR, 4 tests
Prototype 93513 w/EGR, 2 tests
Prototype 93514 w/EGR, 2 tests
"350"
"350"
"350"
"350"
5.7
5.7
5.7
5.7
4,500
4,500
4,500
4,500
0.43 0.27 1.20 0.75 Prototype 96558 w/EGR, inter-
polated from GM graph
0.36 0.22 1.15 0.71 Prototype 96589 w/EGR, 3 tests
0.39 0.24 1.00 0.62 Prototype 96589 w/EGR, 2 tests
0.56 0.35 1.10 0.68 Prototype 86634 w/EGR, 2 tests
8,000 miles
(2/79)
(6/79)
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40
Table IV-4
Comparison of Particulate Levels of 1979
Certification Vehicles and 1981 "Best" Prototypes
Manufacturer
Model
1979 Baseline Best 1981 Prototype
Particulate Level 14/ Particulate Level* 177,18/ ,197
22/,23/,24/
(g/mi) (g/km) (g/mi) (g/km)
General Motors
"260" 0.73-1.02 0.45-0.63 .0.27-0.56 0.17-0.35
"350" 0.84 0.52 0.36-0.56 0.22-0.35
Daimler-Benz
240D 0.53 0.33
300D 0.83 0.52
300SD 0.45 0.28
0.40 0.25
0.30 0.19
0.47 0.29
Peugeot
504D 0.29
0.18
0.49
0.30
*At NOx levels of 1.5 gpm or less.
Table IV-5
EPA/Volkswagen Particulate Measurement Comparisons
Model
EPA Particulate
Result
(g/mi) (g/km)
VW Particulate
Result 207
(g/mi)(g/km) Difference
79 Rabbit
0.23 14/ 0.14
0.33 0.21
43%
79 Dasher
0.32 14/ 0.20
0.42 0.26
31%
79 Audi 5000D 0.46 26/ 0.29
0.65 0.40
41%
DOT Special
Build Rabbit
0.20 14/ 0.12
0.25 0.16
25%
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41
currently available designs. Unfortunately, however, there is
insufficient certification leadtirae available for 1981. A manufac-
turer which waited until after the final rule was published would
not have sufficient time to fulfill durability and certification
requirements. Thus, the 0.60 g/mi (0.37 g/km) particulate standard
will not apply until the 1982 model year. It must be emphasized
that the delay is due to insufficient certification leadtime and
not technological infeasibility.
In their comments to the NPRM, Daimler-Benz, Peugeot, and Fiat
all stated that it was quite probable that they could meet a 0.60
g/mi (0.37 g/km) particulate standard in 1981 at a NOx level of 1.5
g/rai (0.93 g/km) or less .J_7_/ ,_19_/ ,_2J7 The data in Table IV-3
support their conclusions. EPA has already granted NOx waivers for
several 1981-82 model year light-duty diesel engine families in
order to allow those manufacturers which showed an inability to
achieve the 1.0 g/mi (0.62 g/km) NOx standard in 1981 sufficient
leadtime to reduce NOx emissions with acceptable durability and
particulate emissions control (Federal Register, January 23, 1980).
Daimler-Benz received the NOx waiver for its 240D, 300D, and 300SD
engine families, Peugeot was denied a waiver because of insuffi-
cient data, and Fiat did not apply for a waiver. Fiat and Peugeot
will be eligible for NOx waivers if and when sufficient emissions
data are provided to show that they cannot meet 1.0 g/mi (0.62
g/km) NOx without significantly increasing particulate emissions.
The availability of the NOx waiver ensures that Daimler-Benz,
Peugeot, and Fiat will all be able to comply with the 0.60 g/mi
(0.37 g/km) particulate standard in 1982.
Volkswagen has admitted that their two most popular models,
the Rabbit and the Dasher, would have no problem meeting the 0.60
g/mi (0.37 g/km) standard. VW intends to replace the 1.5-liter
engine with a 1.6-liter engine in both the Rabbit and the Dasher
in 1981. VW expects slightly higher emissions but not to the
extent that either model would be in jeopardy of exceeding 0.60
g/mi (0.37 g/km) particulate. They claim that their Audi 5000D
cannot meet 0.60 g/mi (0.37 g/km) until the 1982 model year.25/
As Table IV-3 shows, VW reported typical Audi 5000D emissions of
0.65 g/mi (0.40 g/km) particulate and 1.73 g/mi (1.08 g/km) NOx for
naturally-aspirated production vehicles and 0.58 g/mi (0.36 g/km)
particulate and 1.87 g/mi (1.16 g/km) NOx for turbocharged proto-
type vehicles. Thus, the Audi appears to have a NOx problem as
well as a particulate problem. Because of its relatively small
size (2.0-liter engine, 3,000-pound vehicle), we were surprised at
VW's assertion that it could not meet 0.60 g/mi (0.37 g/km) parti-
culate and 1.5 g/mi (0.93 g/km) NOx in 1981 and have examined the
situation further. First of all,the 1979 Audi 5000D durability
vehicle emitted 1.30 g/mi (0.81 g/km) NOx (the interpolated value
at both 5000 and 50,000 miles) and thus we would not expect 1.5
g/mi (0.93 g/km) NOx in 1981 to be difficult to achieve. Secondly,
since the data above are on production vehicles, we are confident
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42
that particulate arid NOx improvements have been achieved through
engine modifications since the data were collected. Thirdly, we
have found that Volkswagen seems to get consistently higher par-
ticulate measurements at their German laboratory when compared to
EPA test results in Ann Arbor. Table IV-5 gives the comparisons
that have led us to this conclusion. In every case Volkswagen
measured significantly higher particulate levels, from 25 to 43
percent higher. The EPA Audi value was based on two tests of one
vehicle, while the VW Audi value was an average of eight production
vehicles, yet the EPA value was lower than all eight of the VW
values. Thus, based on its small size, the 1979 durability vehi-
cle, the expected particulate and NOx reductions achieved through
engine modifications, and the significantly lower particulate
values that EPA has obtained for VW vehicles, it is anticipated
that the Audi 5000D could meet a 0.60 g/mi (0.37 g/km) particulate
standard in 1981 at a NOx level of 1.5 g/mi (0.93 g/km) or less.
As VW itself has stated, the Audi should easily meet the standards
in 1982.
Volkswagen's applications for NOx waivers were all denied by
EPA due to insufficient emissions data. As mentioned above,
Volkswagen is still eligible for NOx waivers if and when it pro-
vides sufficient data proving that they cannot meet 1.0 g/mi (0.62
g/km) NOx without significantly increasing particulate emissions.
General Motors is undeniably in a more difficult technical
position, due to its larger engines (5.7 and 4.3 liters) and
heavier vehicles (4,500 and 4,000 pounds). GM's particulate
reduction program has produced promising results, however, and the
data we received in its comment and in its NOx waiver request lead
us to the conclusion that GM could meet 0.60 g/mi (0.37 g/km)
particulate at a NOx level of 1.5 g/mi (0.93 g/km).
Table IV-3 gives the most promising part iculate/NOx data for
the GM 4,000 and 4,500-pound diesel vehicles. GM considers the
5.7-liter, 4,500-pound vehicle to be its worst-case vehicle for
particulate and NOx emissions. As of June 19, GM still had not
selected a "prime system" for its 1981 5.7-liter engine family.
Prototype car 96558 was one design being considered.^/ GM re-
ported only four particulate data points for car 96558, two tests
without EGR (low particulate emissions) and two tests with a
relatively high EGR rate (low NOx emissions); GM averaged each pair
of tests and plotted the data in Figure IV-1 (Figure II.C.29 in
GM's NOx Waiver Application). The parabola drawn by GM represents
its best estimate of the particulate/NOx levels that would be
expected for car 96558 at varying EGR rates. From Figure IV-1, it
can be determined that car 96558 would emit approximately 0.43 g/mi
(0.27 g/km) particulate with a NOx level of 1.2 g/mi (0.75 g/km).
Also shown on Figure IV-1 are four tests on car 96589 at approxi-
mately 0.5 g/mi (0.31 g/km) particulate and 1.2 g/mi (0.75 g/km)
NOx. Not shown on the GM graph, but reported on the individual
-------
FIGURE IV-1 43
GM
"a
:5.->ciD^7=:
32AC21
•^—tgHxlOx-
^V±f_H=E;
[Q.
\~ "•
^
d
./ 1
k V*\
i \ \u Y
*From General Motors Application for Waiver of the 1931-1934
NOx Emission Standards for Light-Duty Diesel Engines, May 1979
-------
44
data sheets in the GM NOx Waiver submissions, are two sets of
baseline tests when car 96589 was being used for development work
with EGR, a four-speed transmission, and a torque converter clutch
(TCC). Three tests with 96589 in February, 1979, with a 3-speed
transmission and without the TCC, resulted in average emissions of
0.36 g/mi (0.22 g/km) particulate and 1.15 g/mi (0.71 g/km) NOx.
In June, 1979, two more baseline tests produced average emissions
of 0.39 g/mi (0.24 g/km) particulate and 1.00 g/mi (0.62 g/km)
NOx. The final 5.7-liter, 4,500-pound vehicle listed in Table IV-3
is car 86634. The only emissions results submitted to EPA for this
vehicle were four tests performed after it had accumulated 8,000
miles. The two tests with EGR gave 0.56 g/mi (0.35 g/km) particu-
late and 1.10 g/mi (0.68 g/fcm) NOx. The non-EGR tests gave pre-
dictably higher NOx and lower particulate emissions. These
data have convinced EPA that the GM 5.7-liter, 4,500-pound vehicle
could meet the 0.60 g/mi (0.37 g/km) particulate standard iti 1981,
taking into account the necessary safety margin for variability and
deterioration. In addition, it should be noted that all the
particulate data above were at NOx levels of 1.0 to 1.2 g/mi (0.62
to 0.75 g/km) and thus the EGR rates could possibly be lessened, if
necessary, to lower the particulate levels even more. Since diesel
NOx deterioration factors are typically 1.0, this would be quite
possible. GM has received the NOx waiver for 1981 and 1982 model
years for the 5.7-liter engine.
Data from four 4.3-liter, 4,000-pound GM diesel prototypes are
also shown in Table IV-3. Three of the four prototypes were of the
very same design, with car 93514 a "slightly different technology."
28/ Car 72204 emitted just 0.27 g/mi (0.17 g/km) particulate and
1.01 g/mi (0.63 g/km) NOx (average of 3 tests), but GM stated that
these very low emissions have not been repeatable. The two other
prototypes of the same design also gave promising results. Car
93516 emitted 0.41 g/mi (0.25 g/km) particulate and 1.06 g/mi (0.66
g/km) NOx (average of 4 tests) and car 93513 emitted 0.50 g/mi
(0.31 g/km) particulate and 1.29 g/mi (0.80 g/km) NOx (average of 2
tests). Car 93514 emitted 0.56 g/mi (0.35 g/km) particulate and
1.10 g/mi (0.68 g/km) NOx (average of 2 tests). Thus, we have
three prototypes of the same design and one vehicle of a slightly
different design which all meet the particulate standard at low NOx
levels. We are convinced that the 4.3-liter, 4;000-pound GM
vehicle could meet the 0.60 g/mi (0.37 g/km) particulate standard
in 1981. GM's application for the NOx waiver for the 4.3-liter
engine was denied due to insufficient data. GM may reapply for the
waiver.
GM's primary concern with the design of these prototypes is
the durability of the engines. This is because of the greater oil
contamination apparently due to the greater EGR rates. As men-
tioned above, the EGR rates of these prototypes might be slightly
higher than necessary, and might be lowered, thus lessening any
durability concerns. In any case, EGR is used for NOx control,
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45
and will be utilized on GM's diesels regardless of the particulate
standard. Thus, any durability problems will not be due to par-
ticulate control.
While GM was adamant in its comments to the particulate NPRM
that it could only meet 1.0 g/mi (0.62 g/km) particulate and 1.5
g/mi (0.93 g/km) NOx in 1981, it did not make any such claim in its
NOx waiver request. Of interest was a section on the effect of the
NOx waiver on public health. In that section GM performed a "worst
case" air quality analysis and had to select emission rates. To
quote:
"The emission rates assumed for this analysis are: 1.5 gpm
NOx (20 percent of which is N02), 0.6 gpm particulate if the
waiver is granted, and, 1.0 gpm NOx (10 percent of which is
N02), 1.0 gpm particulate if EPA denies the waiver. These
emission values agree with observed data discussed later in
this section and also agree with comments by various manu-
facturers at the recent EPA hearing on particulate stan-
dards . "29_/
It is not clear what GM meant by this statement, but it does seem
to support our conclusion that GM can meet the 0.60 g/mi (0.37
g/km) particulate standard in 1981. In any case, with the extra
full year there should be no question that GM can meet 0.60 g/mi
(0.37 g/km) particulate at 1.5 g/mi (0.93 g/km) NOx or less by
1982.
No other manufacturer reported particulate data from in-house
diesel development programs. International Harvester currently
markets a diesel Scout, a light-duty truck, but as Table IV-2
shows, it should easily comply with the 0.60 g/mi (0.37 g/km)
standard. Testimony at the NOx Waiver Hearing confirmed that Volvo
intends to introduce a 3500-pound light-duty vehicle powered by a
6-cylinder, 2.4-liter Volkswagen diesel engine in the U.S. in the
1980 model year. The only particulate data reported to EPA for
this vehicle were very, very sketchy, ranging from 0.30 to 0.65
g/mi (0.19 to 0.40 g/km) on one 1979 European production vehicle.
30/ It is also quite possible that Chrysler, Ford, Toyota, AMC,
and/or BMW (or others) might market light-duty diesels in the U.S.
in the near future, but since these manufacturers did not provide
EPA with any particulate data, we are unable to assess their
technical positions. We can only conclude that these manufacturers
will have to meet the particulate standards should they decide to
market diesels in this country. Since these manufacturers' diesel
designs are still in the developmental stages, particulate control
should not be a great problem as it will simply be an additional
design constraint that will have to be considered.
In summary, EPA's technical staff has concluded that every
light-duty diesel vehicle manufacturer can meet a 1981 particulate
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46
standard of 0.60 g/mi (0.37 g/km) at NOx levels of 1.5 g/mi (0.93
g/km) or less, utilizing readily available technology. Because of
insufficient certification leadtitne, however, the particulate
standard will not apply until the 1982 model year.
C. 1984 Standard
EPA had proposed that a 0.20 g/mi (0.12 g/km) particulate
standard be set for the 1983 model year. EPA expected that most
light-duty diesel vehicles would require an after-treatment device
of approximately 67 percent efficiency to meet the 0.20 g/mi (0.12
g/km) particulate level. It was recognized that the proposed 1983
particulate standard was a technology-forcing standard, i.e.,
after-treatment devices were not then sufficiently developed to
fulfill the basic criterion of 67 percent particulate reduction
over the lifetime of a vehicle, but EPA postulated that there was
sufficient lead time for after-treatment devices to be developed by
the 1983 model year.
EPA's technical staff expects additional particulate reduc-
tions in the years 1981 to 1985 other than the reduction due
to the addition of an after-treatment device. We expect that
progress will continue in the area of engine modifications to
reduce particulate emissions. Certainly there is a strong prob-
ability of additional reductions due to fuel injector and com-
bustion chamber redesign (especially for those manufacturers
which have not seriously investigated these areas), timing adjust-
ments and controls, and engine derating. Should additional manufac-
turers turbocharge their engines, it would enable them to utilize
smaller engines with reduced particulate levels, while retaining
comparable performance. It is very unlikely that all of these
parameters have been optimized in just two years of develop-
ment work. There is also a high probability that other, as yet
unforeseen, engine modifications will be found that will reduce
particulate emissions. For example, in preliminary testing at the
Ann Arbor laboratory, intake air throttling has been found to
reduce particulate emissions.^/ It is hypothesized that this
might be due to reduced quenching around the fuel droplets due to
the lower air/fuel ratio of the throttled engine. Despite the fact
that intake air throttling is a rather simple concept, and has been
investigated in the past for other reasons, no comments were
received with respect to its effect on particulate emissions. We
consider it very likely that other possible engine modification
control technologies will be discovered and investigated in the
near future. Finally, with the Corporate Average Fuel Economy
Standards increasing annually until 1985, and with other emissions
standards decreasing, EPA expects that many manufacturers (espe-
cially those who produce larger vehicles) will continue to lighten
their vehicles in order to facilitate compliance with the impending
regulations. It is public knowledge that GM intends to downsize
both their mid- and full-size cars a second time in the early
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47
1980s;32/ the Department of Transportation has estimated these
reductions to be in the 200 to 400 pound range._33/ Other manufac-
turers are also expected to make their vehicles lighter. All of
these factors should contribute to lower particulate levels by
1985. In fact, EPA anticipates that a 15 to 20 percent particulate
reduction will be achieved by the worst-case vehicles due to
continued engine design optimization, derating, turbocharging, and
downsizing. Thus we expect that all light-duty diesels could meet
a 0.50 g/mi (0.31 g/km) particulate standard by 1984 or 1985 even
without the application of an after-treatment device.
It is quite likely that one light-duty diesel, the VW Rabbit,
will not even require an after-treatment device to meet the 0.20
g/mi (0.12 g/km) standard. The 1979 certification Rabbit that EPA
tested as part of the particulate baseline emitted 0.23 g/mi (0.14
g/km) particulate and 0.87 g/mi (0.54 g/km) NOx while the DOT
Special Build turbocharged Rabbit which EPA tested emitted just
0.20 g/mi (0.12 g/km) particulate and 0.93 g/mi (0.58 g/km) NOx
14/. These very low emissions and the expectation of further
improvements indicate that by 1985 it is very unlikely that
the Rabbit will need an aftertreatment device to meet the 0.20
g/mi (0.12 g/km) particulate standard.
Except for the VW Rabbit, EPA expects every other light-duty
diesel vehicle to require after-treatment control to meet the 0.20
g/mi (0.12 g/km) standard in 1985. The after-treatment device will
have to reliably remove particulate from the diesel exhaust gas
stream with at least 60 percent efficiency (from 0.50 g/mi to 0.20
g/mi, from 0.31 g/km to 0.12 g/km) over the useful life of the
vehicle. Three types of after-treatment devices are currently
being developed by industry: catalytic converters, traps, and
trap-oxidizers.
The catalytic converter can be considered to be a continuous-
burn trap-oxidizer. As such, its successful application on light-
duty diesels would remove many of the problems now associated with
trap-oxidizer regeneration. The primary difficulty in utilizing
catalytic converter technology to reduce diesel particulate is in
continuously maintaining both the high temperatures and sufficient
residence times that are necessary for oxidation of the partic-
ulate. Although it has been shown that catalytic converters can be
effective in reducing the organic component of the particulate,
they have not been as effective in reducing the less easily oxi-
dized carbon (soot) component of the particulate._34_/ Some inves-
tigations have also shown increased sulfate emissions with catal-
ytic converters, but the selection of the proper catalyst might
obviate that problem^35_/^36/ While we consider it unlikely that
converters will be a primary particulate after-treatment tech-
nology, it is quite possible that they will be used in the future
for HC and organics control, with some resulting reduction in total
particulate emissions.
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48
The use of simple exhaust traps (or filters) has been investi-
gated for many years, at one time primarily for removing lead from
non-catalyst gasoline-powered vehicles. The particulate collection
efficiencies of many trap materials, when new, are very good.
Daimler-Benz reported initial efficiencies as high as 80 percent,
and General Motors reported efficiencies for paper elements as high
as 90 percent, and for alumina-coated metal mesh, metal wool,
quadralobe catalyst beads, and alumina-fiber material of 60 to 65
percent. GM was the only commenter to provide a comprehensive
evaluation of trap material efficiencies, a summary of their data
is shown in Table IV-6. EPA expects that collection efficiencies
of approximately 67 percent will be feasible on trap-oxidizers in
the near future. Since a trap does not attempt to oxidize the
particulate continuously, particulate matter builds up on the trap
as mileage accumulates, resulting in decreasing trap collection
efficiency and increasing exhaust gas backpressure which, in
extreme cases, can affect engine performance and fuel economy.
Because of the low bulk density of diesel particulate, an efficient
trap might collect over a gallon of particulate every thousand
miles._37_/ Clearly a method is needed to periodically replace or
regenerate the trap in order to maintain the collection efficiency
and backpressure at acceptable levels. The two basic ways this
could be done are external trap servicing and on-board incin-
eration. The latter way of regenerating the trap is the distin-
guishing characteristic of the trap-oxidizer and will be discussed
later in this section.
External trap restoration could take many forms. If paper
trap elements were used, chemical dipping, backward pulsed air
flow, or even low-cost changeable filters could be used. With
permanent filter cartridges, high-temperature oven incineration,
pressurized washing, chemical dipping, or sonic cleaning could be
possible techniques. At this time, none of these techniques has
fulfilled the basic criteria of restoring the collection efficiency
and backpressure of any trap to desirable levels.
Another critical issue is the frequency of external servicing
and the certainty that the vehicle owner would order the servicing.
Since excessive backpressure levels can result in performance
and/or fuel economy losses, the vehicle owner would certainly have
some motivation to service his or her trap at regular intervals.
GM has suggested the inclusion of a bypass valve in the trap to
allow exhaust pressure to be partially relieved under certain
conditions to protect the trap. The existence of such a valve
might allow the vehicle owner to abdicate his or her responsibility
to service the trap, while also avoiding excessive backpressure
problems which would otherwise provide the motivation for servicing
the trap. Also at issue is the magnitude and frequency of the
possible inconvenience to the vehicle owner, and the effects that
the perceived inconvenience may have on the public's acceptability
of the diesel.
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49
Table IV-6
General Motors' Summary of Trap Material Efficiencies 38/
Opel 2.1-Liter Engine
Material Efficiency, %
Corrugated Foil Fecralloy 36
Chopped Fecralloy 29
Chromium Alloy Ribbon 37
Glass Fiber Fabric 34-65
Fiberfrax Fiber Fabric 46
Alumina Fiber 32-61
Catalyst Beads <10-62
Ceramic Monolith Extruded <10-52
Ceramic - Torturous Path 39-49
Ceramic Bobbin 42
Alumina Coated Metal Mesh 63
Metal Mesh 28-44
Olds 5.7-Liter Engine
Material Efficiency, %
Corrugated Fecralloy 30
Catalyst Beads 56
Ceramic Monolith Extruded 30
Alumina Coated Mesh 65
Metal Wool 60
Fiberglass 76
Paper Element 90
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50
Because of the above concerns about external trap servicing,
it is likely that on-board incineration will be the preferred
method of trap restoration. Nevertheless, should the trap-oxidizer
be rejected on technical or economic grounds, traps with external
restoration could be a feasible particulate control technology,
presuming that extensive research continues.
A trap-oxidizer is simply a trap with a mechanism by which the
collected particulate is periodically oxidized in order to restore
the collection efficiency and exhaust gas backpressure to accept-
able levels. Having this periodic, on-board regeneration avoids
the necessity of either maintaining the conditions for continuous
oxidation (catalytic converter) or of relying on the vehicle owner
and/or service center to consistently and reliably replace or clean
the trap. Research is continuing on regeneration initiation and
control.
The general consensus is that the minimum temperature required
for combustion of the particulate is approximately 450-500°C.
Since the exhaust gas temperature of a diesel powered vehicle
operated over the LA-4 driving cycle rarely exceeds 400°C, this
raises the question of how to elevate the exhaust temperature to
the requisite levels. GM suggested two approaches, air intake
throttling and use of an external heat supply that both seem
promising. GM reported that over a 1,000-mile load up and inciner-
ation test with throttling utilized to initiate incineration and
100-mile trapping periods, the collection efficiency actually
improved s 1 ight ly ._39/ Further research needs to be done to
examine -the impact of throttling on emissions and fuel economy. It
is quite possible that throttling might tend to reduce particulate
formation in the combustion chamber. The use of an external heat
supply to initiate incineration has been shown in preliminary
testing to reduce collection efficiency only slightly.^0/ With
this technique, there is the possibility of a dual path trap,
designed with dual heating elements and a valve which would route a
small fraction of the exhaust flow to the trap that was being
incinerated, and the rest to the trap that was not. The advantage
of the dual path trap is that it would significantly reduce the
necessary power requirement to initiate incineration. A third
mechanism of raising the exhaust gas temperature would be to better
insulate the exhaust system. Port liners, insulated exhaust
manifolds, and an insulated exhaust pipe would all contribute to
slightly higher exhaust temperatures. Finally, the temperature
required for oxidation could be lowered through the use of a noble
metal catalyst. The use of a noble metal catalyst "could be suffi-
cient in itself to initiate oxidation (which would then be, in
effect, a catalytic converter) or could be used in conjunction with
either throttling or an external heat supply.
Clearly, some form of controller unit would be an integral
part of the regenerative process. It might suffice to have a
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51
relatively simple control system whereby (for example) the throttle
actuator mechanism could be based on the odometer reading and rack
position, throttling at periodic intervals, or it might be neces-
sary to have a much more complex electronic control unit to monitor
a large number of sensors and controllers. The latter might be
necessary in order to coordinate backpressure levels with EGR, for
example.
It is impossible at this time to delineate the exact design
that will prove to be the appropriate trap-oxidizer for various
manufacturers. At this time, throttling in conjunction with an
insulated exhaust system, possibly with a noble metal catalyst,
seems to be the most promising system. Either a simple mechanical
control or a more complex electronic control unit would be neces-
sary. Four different trap-oxidizer systems, all with a throttle
and some degree of exhaust system insulation, but with varying
control units and differences in the use of noble metals, are
discussed in Chapter V of the Summary and Analysis of Comments.
Another critical area where improvements must be made is with
the durability of the trapping material in the trap-oxidizer.
It should last at least 100,000 miles. To date, the best dura-
bility of a trap reported to EPA was a metal mesh trap on an Opel
vehicle, run on a modified AMA driving schedule with no hard
accelerations, hills, or speeds above 45 mph. The trap survived
12,800 miles and at that time had a collection efficiency similar
to its zero-mile efficiency of 55 percent. GM reported some
particulate blow-off and self incineration.41/
Various other concerns have been expressed about trap-oxidiz-
ers. EPA agrees that the emissions characteristics of a diesel
vehicle during the regeneration mode should be thoroughly investi-
gated, both with respect to the regulated pollutants and particu-
late, and to any unregulated pollutants as well. There was major
concern expressed by Daimler-Benz^/ over the effect of increased
exhaust backpressure (due to the trap-oxidizer) on diesel perform-
ance and fuel economy. Certainly it is true that excessive back-
pressure can have a debilitating effect on the diesel engine. But
assuming the optimization of on-board regeneration, such excessive
backpressure should not occur. GM's 1,000-mile load up and incin-
eration test, with 100-mile trapping periods, utilizing throttling
to initiate incineration, showed backpressure to increase slightly
with mileage, but clearly indicated a trend of flattening out with
time. Daimler-Benz's second point, of the deleterious effect of
variable backpressure on the effectiveness of EGR systems, is a
very real concern. As discussed above, we expect that some form of
control over the incineration process will be necessary, though it
is not clear at this time how complex that control might have to
be. Certainly EGR and backpressure could be accommodated within
such a control system. The possibility that the trap-oxidizer
could be a safety hazard (accidental ignition, uncontrolled oxida-
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52
tion, etc.) should also be investigated, though at this time EPA
does not foresee this to be a major problem. We would expect the
safety ramifications of trap-oxidizers to be similar to those of
oxidation catalytic converters, which have not been significant.
Finally, Ford's concern over the possibility that the regeneration
mode might not occur during CVS testing is well taken._43/ It is
recognized that the FTP may have to be modified in order to ensure
that regeneration occurs.
Clearly, more basic research still needs to be done in the
areas of regeneration initiation and control, and trap durability.
Enough progress has been achieved to convince EPA that a successful
trap-oxidizer can be developed, but as of this time, no design has
proven to have the required collection "efficiency over the desired
length of time. With the research that has been, and is, going on
with regards to trap-oxidizer development, and a determined broad-
based effort by the manufacturers to comply with the final stand-
ards, EPA's technical staff has concluded that it is very likely
that a successful trap-oxidizer design can be optimized within the
next 1-1/2 to 2 years.
This brings us to the general issue of leadtime. The time
needed from the end of the development phase for a design change to
when that design change can be integrated into mass production can
be dependent on many factors, such as the complexity of the change,
the size of the manufacturer, whether the manufacturer has the
capability to produce the new hardware, etc. We received differing
estimates of production lead time requirements for trap-oxidizers.
Volkswagen projected 1-1/2 to 2 years^A/, while Daimler-Benz
estimated 3 years (for major engine modifications in general ).45_/
General Motors appears to have given two different lead time
estimates. In its prepared statement at the public hearing, it
stated that 2-1/2 to 3 years production leadtime would be required
"after an acceptable method is defined,'^46/ while in its written
comment GM claimed it needed 50 months from "system design selec-
tion."^/ In response to questions about leadtime at the public
hearing, GM reaffirmed the 2-1/2 to 3 years estimate. Based on our
own understanding of lead time requirements and the authority of
the GM representatives at the public hearings, we accept the 2-1/2
to 3 years figure as GM's best estimate of the leadtime necessary
for trap oxidizers, once a design is selected.
Based on the differing leadtime estimates from the manufac-
turers, and confident that the industry will maximize its efforts
to achieve particulate reductions in the coming 'years, we have
concluded that the manufacturers could integrate trap-oxidizers
into mass production within 2 to 2-1/2 years after a design is
selected. Thus, combining the 1-1/2 to 2 years development time
and 2 to 2-1/2 years production leadtime that we expect to be
necessary, we conclude that trap-oxidizers could be feasible on
production vehicles within 4 years. Starting from late 1979 then,
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53
trap-oxidizers could be integrated into production by late 1983, or
in time for the 1984 model year.
While our technical analysis concluded that there is a strong
likelihood that trap-oxidizers will be feasible for vehicle appli-
cation by 1984, the uncertainty that exists with regard to trap-
oxidizer durability and vehicle application has convinced EPA to
minimize the economic risk of this ruletnaking by delaying the
implementation of the 0.20 g/mi (0.12 g/kra) standard until 1985.
This extra year will have only a marginal effect on ambient sus-
pended particulate levels yet will ensure that the manufacturers
have enough time to optimize trap-oxidizer development.
It should be noted that while EPA expects trap-oxidizers to be
approximately 67 percent efficient in reducing particulate emis-
sions, the worst-case manufacturer is expected to need only a 60
percent reduction to meet the 1985 standard, and other manufac-
turers will need correspondingly less.
Another factor that must be considered is the statutory 1.0
g/mi (0.62 g/km) NOx standard in 1985. EPA does not expect the
0.20 g/mi (0.12 g/km) particulate and 1.0 g/mi (0.62 g/km) NOx
standards to force any diesel models out of production. As has
been discussed earlier in this chapter, the use of EGR, the primary
NOx control technique at this time, significantly increases partic-
ulate emissions. But EPA is convinced that as the particulate/EGR
relationship becomes better understood, the deleterious effect of
EGR on particulate levels will be lessened. In addition, it is
expected that other NOx control techniques will be implemented
which will not necessarily increase particulate emissions; it is
certainly possible that a NOx control technique might reduce
particulate emissions.
In summary, EPA's technical staff has concluded that with the
expected successful application of trap-oxidizer technology, every
light-duty diesel vehicle manufacturer can meet a 0.20 g/mi (0.12
g/km) particulate standard in model year 1985. This is a delay of
two years from the NPRM. EPA is also confident that the manufac-
turers can comply with the 0.20 g/mi (0.12 g/km) particulate and
1.0 g/mi (0.62 g/km) NOx standards in 1985.
D. Light-Duty Trucks
The Code of Federal Regulations defines a light-duty truck
(LDT) to be "any motor vehicle rated at 8,500 pounds gross vehicle
weight rating or less which has a vehicle curb weight of 6,000
pounds or less and which has a basic vehicle frontal area of 46
square feet or less, which is: 1) designed primarily for the
purposes of transportation of property or is a derivation of such a
vehicle, or 2) designed primarily for transportation of persons and
has a capacity of more than 12 persons, or 3) available with
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54
special features enabling off-street or off-highway operation and
use."48/ Thus, light-duty trucks (LDT's) and light-duty vehicles
(LDV'~sT are distinct classes of motor vehicles. The NPRM proposed
that the LDT particulate standards be equal to the LDV standards.
There were no data available to justify a separate LDT standard.
LDT's are typically tested at higher road load horsepower and
inertia weight settings than are LDV's. Any increased particulate
levels that would be justified by the unique uses of LDT's would be
caused by these higher settings. In the comments to the NPRM, we
received a small amount of data on the effects of higher road load
and inertia weight settings on diesel particulate emission levels.
All of the EPA and industry data are plotted in Figures IV-2 (road
load) and IV-3 (inertia weight).
As can be seen in Figure IV-2, there is only a very, very
slight effect of road load on particulate emissions. Only the Opel
data indicated any significant effect, and that was mostly at
unusually high inertia weight settings. At most, the higher road
load settings of LDT's might account for a few percent increase in
particulate levels.
From Figure IV-3, however, it is apparent that the inertia
weight setting of a LDT does have a significant effect on its
particulate emission level.
In setting the LDT gaseous standards for the 1979 model year,
EPA extrapolated available data from 5,500 pounds inertia weight to
represent the heaviest "typical" LDV test to 6,500 pounds inertia
weight which represented the heaviest "typical" LDT test. Applying
these same guidelines to the GM data (Vehicles #89589 and #78504)
and the EPA data on a Dodge truck (shown in Figure IV-3) resulted
in the following increases in particulate:
Increase in Particulate
from 5,500 Lbs. IW to
Vehicle 6,500 Lbs. IW
GM #89589 19%
GM #78504 10%
Dodge Truck 18%
Average 16%
Recognizing that vehicle weights and hence test inertia
weights are decreasing, and to be consistent with existing test
inertia weights, a more current inertia weight comparison would be
between 4,500 Ibs. (current heaviest "typical" LDV) and 5,500 Ibs.
(current heaviest "typical" LDT). This analysis of the data in
Figure IV-3 results in the following increases in particulate:
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1.0 _
• 3
FIGOTE IV-2
PARTICUIATE EMISSIONS AS A FUNCTION OF ROADLOAD
FTP DRIVING CYCLE
I -7
s
3
M .6
en
CO
w
I 'k
o
I -
(U
OPEL 2100D UOOO LBS. IW
OPE1 2100D 3000 LBS. IW
OPEL 2100D 2000 LBS. IW
MERCEDES BENZ 300D D " 3000 LBS. IW
" Uooo LBS. iw
'DGE TRUCK 5500 LBS. Iffu;
DODGfi TRUCK l^OOLBS . IW
.1
0.0
0.0
10 12 m 16
ROADLOAD IN HORSEPOWER
18
20
22
2h
-------
s
to e.
§ *6
M
CO
to
o
.3
.2
.1
FIGURE IV-3
PARTICULATE EMISSIONS AS A FUNCTION OF INERTIA WEIGHT
FTP ERIVING CYCLE
1.0 „
.9 . .
GM VEHICLE #?8SOU
OPEL 2100D ?! -12 HP
ESTIMATED
MERCEDES BENZ 300D @ 12.8 HP
GM VEHICLE # 8958? 8 lU HP
OLDSMOBILE 350D INSTALLED
IN LD TRUCK @ 20 HP
DODGE TRUCK Qlh & 20 H?
Oi
0.0
0.0
1000
2000 3000 liOOO
INERTIA I/EIGHT IN POUNDS
5000
6000
700T
-------
57
Increase in Particulate
From 4,500 Lbs. IW to
Vehicle 5,500 Lbs. IW
GM #89589 22%
GM #78504 11%
Dodge Truck 22%
Average 18%
In the above cases, the increases are 16 percent and 18
percent, respectively. These values are in very good agreement
with Chrysler which claimed there was an approximate 17 percent
increase in particulate emissions for a 1,000-pound inertia weight
increase (or 33 percent for a 2,000-pound increase).
The GM Oldsmobile 350 data was considered to be non-typical
because of the extreme slope as compared with the other data, and
therefore was not analyzed. Furthermore, GM labeled this data as
"fragmentary."^/ Similarly, the Opel (Ricardo) data and the
Mercedes (Daimler-Benz) data were not considered because these did
not represent the "worst case" situation.
Thus, the data clearly indicate the need to take the increased
inertia weight settings of LDTs into consideration. The above data
indicate that the combined effect of inertia weight and road load
settings appears to be approximately 20 percent. If all other
considerations were equal, EPA would promulgate LDT particulate
standards that would be 20 percent greater than the corresponding
LDV standards.
But one other factor must be considered. Diesel LDTs will
only have to meet a NOx standard of 2.3 g/mi (1.43 g/km) until
model year 1985 when a reduction is mandated by the Clean Air Act
for trucks having GVWs over 6,000 pounds. Diesel LDVs will be
required to meet a NOx level in the range of 1.0 to 1.5 g/mi (0.62
to 0.93 g/km), depending on the NOx waiver decisions, until 1985
when the Clean Air Act mandates a 1.0 g/mi (0.62 g/km) NOx stan-
dard. Even assuming the maximum NOx waiver for diesel LDVs to 1.5
g/mi (0.93 g/km), diesel LDTs will have a NOx standard 53 percent
greater than the diesel LDV NOx standard for model years 1982 to
1984. Not only does this much larger NOx level account for the
greater NOx emissions (approximately 20 to 30 percent) that
would be expected from LDTs, but because of the relationship
between NOx and particulate emissions due to EGR, it also can allow
for the 20 percent higher particulate emissions than would other-
wise be expected due to the greater inertia weights of LDTs. For
example, it is unlikely that any diesel LDT would need very heavy
EGR in order to meet a NOx standard of 2.3 g/mi (1.43 g/km). These
trucks would emit less particulate than they would if greater
amounts of EGR were required to meet a lower NOx level. For this
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58
reason, LDTs should be able to meet the 0.60 g/mi (0.37 g/km) level
of control in 1982 through 1984. Since the particulate standards
are technology based standards, EPA is promulgating the 1982 LDT
particulate standard to be 0.60 g/mi (0.37 g/km).
An examination of the LDT data in Table IV-2 confirms our
expectation that LDTs will be able to comply with the 0.60 g/mi
(0.37 g/km) particulate standard in 1982. The Chevrolet and Dodge
LDTs emitted 0.59 and 0.61 g/rai (0.37 and 0.38 g/km) particulate,
respectively, and thus need just a small improvement to comfortably
meet the 1982 standard. It should be noted that GM diesel LDTs
utilize the same 5.7-liter diesel engines that are used in the GM
4,500-pound LDV's; their particulate reductions since the baseline
data were taken were discussed earlier in this chapter. The
International Harvester light-duty truck emitted 0.32 to 0.47 g/mi
(0.20 to 0.29 g/km) particulate and thus it already meets the 1982
standard.
Two factors change this situation in 1985. First, as a result
of the statutory requirement for a 75 percent NOx reduction, the
LDT NOx standard is expected to drop to a stringency level much
nearer to the LDV statutory NOx level of 1.0 g/mi (0.62 g/km). The
"cushion" that now exists for LDT NOx control would disappear.
Based on the analysis above, the particulate standard for LDTs
should be 20 percent greater (all other things being equal) than
the LDV standard due primarily to the greater inertia weight
settings of LDTs. Second, the expected trends in downsizing and
the use of smaller engines in LDVs will likely not take place as
rapidly with LDTs. The EPA technical staff estimates that this
discrepancy justifies an additional 10% particulate cushion for
LDTs. Thus, the 1985 LDT particulate standard should be 30 percent
greater than the 1985 LDV particulate standard and will be 0.26
g/mi (0.16 g/km).
Thus, the LDT diesel particulate standards are 0.60 g/mi (0.37
g/km) in 1982 and 0.26 g/mi (0.16 g/km) in 1985.
-------
59
References
\J Clean Air Act of 1963, Section l(a)(l).
_2/ Clean Air Act of 1963, Section l(a)(2).
2/ Clean Air Act of 1963, Section l(b)(l).
kj Clean Air Act, Section 202 (a)(l).
51 Clean Air Act, Section 202 (b)(l)(B).
6/ Clean Air Act, Section 202 (b)(6)(B).
]_/ Federal Register, February 1, 1979, Volume 44, Number 23, p.
6650.
SJ "NOx Diesel Waiver Hearing" - General Motors Transcript, June
19, 1979, p. 58.
9/ "General Motors Response to EPA Notice of Proposed Rulemaking
on Particulate Regulation for Light-Duty Diesel Vehicles,"
April 19, 1979, Attachment 1, p. 159.
10/ "Light-Duty Diesel Particulate Regulations Draft Regulatory
Analysis," EPA, OMSAPC, ECTD, SDSB, December 22, 1978, p. 48.
ll/ "General Motors Response...," Attachment 1, p. 148.
12/ "General Motors Application for Waiver of the 1981-1984 NOx
Emission Standard for Light-Duty Diesel Engines," May 1979,
Figure II.B.ll.
13/ "General Motors Response...," Attachment 1, p. 157.
14/ Danielson, Eugene, "Particulate Measurement - Light-Duty
Diesel Particulate Baseline Test Results," SDSB Technical
Support Report 79-03, January 1979.
15/ "Draft Regulatory Analysis," p. 45.
16/ "Summary and Analysis of Comments on the Notice of Proposed
Rulemaking for Light-Duty Diesel Particulate for 1981 and
Later Model Year Vehicles," EPA, OANR, OMSAPC, ECTD, SDSB,
October 1979.
17/ "Statement of Daimler-Benz AG on the Notice of Proposed
Rulemaking Concerning Diesel Particulate Emissions," March
1979, p. 24.
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60
18/ Personal communication with Mr. Trexl, Daimler-Benz, July 10,
1979.
197 "Comments of P.S.A. Peugeot-Citroen on EPA Proposed Light-Duty
Diesel Particulate Regulation," April 6, 1979, Chart 3.
207 "Supplementary Information to the Record of the EPA Hearing on
March 19, 1979 Concerning Proposed Particulate Emission
Standards for Light-Duty Diesel Vehicles" - Volkswagen, April
1979, Section 1.
217 "Comments of Fiat S.p.A., Italy on Proposed Particulate
Regulation for Light-Duty Diesel Vehicle," March 19,1979,
Table 1.
227 "General Motors Response...," Attachment 1.
23/ "General Motors (NOx Waiver) Application...," Attachment
II.B.I,
247 Additional General Motors NOx Waiver Application Information
submitted to EPA on July 18, 1979, Attachments.
257 "Public Hearing on the Proposed Particulate Emission Standards
for Light-Duty Diesel Vehicles" - Volkswagen Testimony, March
20, 1979, Volume 2, p. 40.
26/ Earth, Edward Anthony, "Audi 5000 Diesel Gaseous and Particu-
late Tests," EPA-TAEB Memorandum to Ralph Stahman, February
15, 1979.
277 "NOx Diesel Waiver Hearing" - General Motors Transcript, June
19, 1979, p.33.
28/ "General Motors (NOx Waiver) Application...," p. 11-30.
297 Ibid,p. III-3.
307 "NOx Diesel Waiver Hearing" - Volvo Transcript, June 21, 1979,
p. 11.
317 Penninga, T., "Second Interim Report on Status of Particulate
Trap Study," EPA-TAEB Memorandum to R. Stahman, August 9,
1979.
32/ Ward's Engine Update, June 8, 1979, p. 6.
337 Rulemaking Support Paper Concerning the 1981-1984 Passenger
Auto Average Fuel Economy Standards, DOT-NHTSA, July 1977.
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61
347 "Notes on the Proposed Particulate Regulations for Light-Duty
Diesel Vehicles," Ricardo Consulting Engineers, January 12,
1979, p. 5.
357 "Comments of Fiat...," p.4.
36/ "Volkswagen Supplementary Information...," April 1979, Appen-
dix 2.
37/ "General Motors Response ," Attachment 1, p. 98.
38/ Ibid, Attachment, pp. 86-90.
397 Ibid, Attachment 1, Figure V-23, p. 111.
40/ Ibid, Attachment 1, p. 116.
417 Ibid, Attachment 1, p. 94.
42/ "Statement of Daimler-Benz...," D. 16.
437 "Public Hearing on the Proposed Particulate Emission Standards
for Light-Duty Diesel Vehicles" - Ford Testimony, March 19,
1979, Volume 1, p. 249.
44/ "Public Hearing..." - Volkswagen Testimony, March 20, 1979,
Volume 2, p. 36.
457 "Statement of Daimler-Benz...," pp. 5-6.
46/ "Public Hearing..."- General Motors Testimony, March 19, 1979,
Volume 1, p. 64.
47/ "General Motors Response...," Attachment 1, p. 175.
487 Code of Federal Regulations, Title 40, Part 86.079-2.
497 "General Motors Response...," Attachment 1, p. 44.
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62
CHAPTER V
ENVIRONMENTAL IMPACT
A. Health Effects of Total Suspended Particulate
Suspended particulate matter has long been recognized as a
major pollutant of our nation's air. Of the greatest concern is
the effect of total suspended particulate (TSP) matter on human
health. Research has shown that TSP can be correlated with res-
piratory and pulmonary functions, and that effects of high TSP
levels range from increased discomfort to healthy persons and
aggravation of cardio-respiratory symptoms in elderly persons, to
increased susceptibility to bronchitis, asthma, and pneumonia, to
increased mortality. Some of the most important research on the
health effects of TSP are listed in Tables V-l and V-2. Table V-l
lists many of the major health effects studies examining relatively
short exposure times (1 to 2 days) while Table V-2 shows the
results of studies which utilized longer averaging times (1 to 2
years). When the Clean Air Act Amendments of 1970 mandated the
establishment of National Ambient Air Quality Standards (NAAQS),
TSP was among the first six pollutants for which a standard was
promulgated. Many of the studies given in Tables V-l and V-2 were
utilized in the establishment of the NAAQS for TSP. The primary
NAAQS for TSP, which are intended to provide protection to the
public health, are 75 micrograms per cubic meter (annual geometric
mean) and 260 micrograms per cubic meter (maximum 24-hour concen-
tration, may be exceeded once per year). The secondary NAAQS for
TSP, which is intended to protect the public welfare, is 150
micrograms per cubic meter (24-hour average to be exceeded only
once per year).
The National Academy of Sciences has extensively reviewed all
aspects of TSP, and for a detailed treatment of the health and
welfare effects of TSP one should see their document.I/ EPA is
currently conducting a review of the NAAQS for TSP. The scientific
consensus that TSP levels impact on human health will be taken as
given here. The emphasis of this section will be on the contri-
bution of light-duty diesel particulate emissions to ambient TSP
levels, and to any special health impacts that might result from
diesel particulate matter.
B. Health Effects of Diesel Particulate
This section will highlight only those aspects of the health
effects of diesel particulate which differ from those of TSP in
general. Much has been learned in the years since the NAAQS (based
* Bracketed numbers (_!/) indicate references at the end of this
chapter.
-------
Table V-l
Research on Short-Term Health Effects of Total Suspended Particulate Matter
Adverse Health Effect
Concentration at Which Effect Was Observed
Concentration, pg/m^ Averaging Time
1. Increased mortality.
2. Increased infant mortality
and cancer mortality.
3. Increased respiratory
infection and cardiac morbidity.
4. Excess bronchitis mortality.
5. Bronchitis symptoms.
6. Cough, chest discomfort,
restricted activity.
7. Cardio-respiratory symptoms
in healthy persons. Asthma
attacks in asthmatics.
8. Aggravated symptoms in
elderly with heart or
chronic lung disease.
750 or a rise of 200
200
375
200
300
100-269
80-100
76-260
24-48 Hours
2 Days
24 Hours
24 Hours
Daily
24 Hours
24 Hours
24 Hours
References
Martin et al., 1960
Lawther, 1963
International Joint
Commission, 1960
Martin et al., 1960
Lawther, 1963
Buck et al., 1964
Greenburg et al., 1962
Holland et al., 1965
Douglas et al., 1966
Douglas et al., 1966
a\
LO
Source: Suspended Particulate Matter - A Report to Congress, Environmental Criteria
and Assessment Office, ORD, EPA, October 1978.
-------
Table V-l
Research on Longer-term Health Effects Of Total Suspended Particulate
Adverse Health Effect
Concentration at Which Effect Was Observed
Concentration, ug/ra Averaging Time
(adults, children) and decreased
pulmonary function (children).
3. Decreased pulmonary function in
school children.
4. Increased frequency and sever-
ity of acute lower respiratory
disease in school children.
5. Increased chronic respiratory
disease symptom prevalence in
adults.
110
100
100
Annual
Annual
Annual
References
1. Increased mortality (all causes).
2. Increased respiratory disease
100
100-200
2 Years
Annual
Greenburg et al., 1962
Buck et al., 1964
Winkelstein, 1967
Lunn et al., 1967
French et al., 1973*
Chapman et al., 1973*
o\
* These two studies were part of the Community Health and Environmental Surveillance System (CHESS),
For appropriate qualification with regards to the proper use and interpretation of CHESS studies in
general, see 1) United States House of Representatives, 1976. The Environmental Protection Agency's
Research Program with Primary Emphasis on the Community Health and Environmental Surveillance System
(CHESS): An Investigative Report by the Committee on Science and Technology, Publication No. 77-590;
2) Research Outlook 1978, EPA 600/9-78-001, June 1978; or 3) Research Outlook 1979, EPA 600/9-79-005,
February 1979.
Source: Suspended Particulate Matter - A Report to Congress, Environmental Criteria and Assessment
Office, ORD, EPA, October 1978.
-------
65
on total mass of parti jlate) was promulgated, and it is now
accepted by most scientists that some particulate emissions are
more deleterious than others, and that some sources necessitate
priority control over others. There are two characteristics of
diesel particulate matter which place it among the most harmful
types of particulate matter. The first is size and the second is
chemical composition. These will be discussed below.
1. Size-Related Effects
It is now generally accepted that size is one of the most
critical characteristics of particulate matter. The size of a
particle primarily affects three parameters which, in turn, help
determine the health effect of that particle: total deposition, or
how efficiently the particles are deposited in the respiratory
tract; regional deposition, or where the particle is deposited in
the respiratory tract; and clearance time, or how long it takes to
remove the particle from the respiratory tract. When examining
data presented, it will be important to note the differences in
deposition between nose and mouth breathers. As the nasal passages
are more efficient in capturing large particles than the mouth,
the sizes of particles reaching various sections of the respiratory
tract depend on how the air is being inhaled.
Total deposition by particle size for a mouth breather is
shown in Figure V-l. As can be seen, the fraction decreases with
particle diameter, until about 0.5-0.7 micrometers when the trend
begins to reverse.
More important than total deposition, however, is the deposi-
tion occurring in selected regions of the respiratory tract,
because the health effect of a particle is dependent on the region
in which it is deposited. Deposition in three regions will be
discussed, the head (nasal passages), the tracheo-bronchial zone
and conducting airways, and the alveolar zone. These regions are
depicted in Figure V-2,2/
Deposition in the head (for nose breathers) is highest for
large particles and negligible for very small particles. Deposi-
tion is complete somewhere between ten and fifteen micrometers and
higher, while deposition is less than 10% below one to two micro-
meters.^/ Fewer studies of this type have been performed with
mouth breathing and the results have been highly variable._!_/
However, it is clear that far less deposition occurs in the head
during mouth breathing than for nose breathing for all particle
sizes.
Deposition in the tracheo-bronchial region is very similar to
that in the head(for both nose and mouth breathers), if deposition
is determined as a fraction, or percent, of particles entering the
tracheo-bronchial region. Deposition approaches 100% around eight
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66
Figure V-l _!/
t i i
a.2 aj aj. 0.7 u>
Aerodynamic Diamvtor—
Ttptal respiratory tract deposition during mouthpiece inhala-
tions as a function of D (aerodynamic diameter in pm) except
belrw 0.5 um, where deposition is plotted vs lirtear diaitater.
-------
'
Figure V-2 2_l
Uppsr resoiratory tract
Anterior nares
Lowrer 'Vf
respiratory 'Si
tract
rachea
Bronchus
Diagrammatic representation of the human upper and lower respiratory tract,
-------
68
_o fifteen micrometers and approaches 10% around one to two micro-
meters .
Deposition in the alveolar region is shown in Figure V-3,
based on the total number of particles entering the mouth or nose,
not on the number of particles entering the alveolar region.\f
Deposition in this region is low above five to seven micrometers
because the larger particles have already been captured by the
nasal passages and the tracheo-bronchial region. Deposition
reaches a relative peak around two to five micrometers. The level
of the peak depends on whether the person is breathing through the
mouth, when deposition reaches 40-50%, or the nose, 20%.
There are two primary reasons why particles deposited in the
alveolar region can have the greatest impact on human health.
First, the alveolar region (where gas-exchange takes place) is the
most sensitive region of the respiratory tract. The second reason
is the significantly longer clearance time required for particles
in the alveolar region. Clearance time is the time it typically
takes for a particle to be removed from the region in question. In
healthy individuals, the clearance of particles deposited in the
nasal passages and the tracheo-bronchial region is usually com-
pleted in less than one day._l_/ Clearance can take somewhat longer
for those people with respiratory ailments. In the alveolar
region, clearance is measured in weeks unless the particle is very
soluble -in body fluid, which diesel particulate is not. While the
results of studies on humans are variable, it appears that a
half-time clearance for relatively insoluble particles is on the
order of five to nine weeks. \J Although particles distributed in
other regions of the body can also affect health, it is those
particles deposited in the alveolar region, which remain in contact
with the most sensitive parts of the lung for the longest periods
of time, which have the greatest potential for affecting human
health.
As a result of a review of the available information on the
effects of particle size on deposition and health, EPA is recom-
mending that future health effects research be conducted on two
size-specific fractions of TSP.2/ One fraction is labeled in-
halable particulate (i.e., particles having a diameter equal to or
less than fifteen micrometers). This fraction includes those
particles which primarily deposit in the conducting airways and the
gas-exchange portions of the respiratory tract. The second frac-
tion is the fine particulate (i.e., particles having a diameter
equal to or less than 2.5 micrometers). This second cutoff was
chosen for two reasons; 1) this fraction includes those particles
which primarily deposit in the gas exchange portion of the lung
(alveolar), and 2) due to the breakdown of ambient particulate by
size and chemical composition, there is a natural break between
fine and coarse (diameter larger than 2.5 micrometers) particles at
this size.
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69
Figure V-3 V
t.o
_o
5 .3
»
o
a
.4
.3
.1 -
-------
70
Diesel particulate is very small in size. Its mass mean
diameter varies between 0.05 and 0.2 micrometers._3/4/ Essentially
all diesel particles fall into the inhalable range and between 94%
and 100% can be characterized as fine particulate._3_M/_5/ Because
of its small size, diesel particulate belongs to that category of
particulate which is most likely to deposit in the alveolar region,
thus remaining in contact with the most sensitive areas of the
respiratory tract for comparatively long periods of time. Clearly,
diesel particulate is of more concern than larger particles which
deposit in the head or tracheo-bronchial regions and which have
much shorter clearance times. Because of this, the control of
diesel particulate and other fine and inhalable particulate is of
high priority.
2. Chemical Composition-Related Effects
In addition to particle size, chemical composition is an
important factor in determining the health effect of a particle.
There are a wide variety of chemicals of particular concern, such
as fibers (e.g., asbestos), toxic elements (e.g., Be, Cd, Pb),
organic matter (e.g., benzo(a)pyrene), carbon, and sulfuric acid.
Diesel particulate is primarily carbonaceous, with between 10
and 50% of the particulate by weight being extractable organic
matter.4/5/6/77 This organic matter is definitely mutagenic in
short-t"erm ~bfoassays,7/ and EPA is currently performing a health
assessment to determine the carcinogenic risk of diesel particulate
to humans.8/ Known human carcinogens are present in diesel par-
ticulate, "such as benzo(a)pyrene, which comprises about 0.0001 to
0.007% by weight of diesel particulate._5/6/ However, most of the
mutagenic response is being caused by substituted polycyclic
organic matter, which does not require metabolic activation.^/
At this time, no definitive statement can be made concerning the
complete effect of diesel particulate on human health. However,
the data available is serious enough to merit caution and diesel
particulate should definitely be numbered among those chemical
types of particulate which require priority control.
C. Current Ambient Levels of TSP
The primary NAAQS for TSP of 75 micrograms per cubic meter
(annual geometric mean) is currently being exceeded in many
areas of the country. While relatively large reductions in ambient
TSP levels occurred between 1971 and 1975,9/ particularly at those
sites which showed high levels of TSP, the next two years have
shown more of a holding pattern than a continued downward trend.10/
Figure V-4 shows the nationwide averages of ambient TSP levels from
1972 through 1977. The ambient TSP level exceeded by 25% of the
sites decreased from 78 to 71 micrograms per cubic meter between
1971 and 1975, while in 1977 it was still 71 micrograms per cubic
-------
71
Figure V-4 10/
.90TH PERCENTILE
-75TH PERCENTILE
•COMPOSITE AVERAGE
•MEDIAN
•25TH PERCENTILE
-10TH PERCENTILE
Figure 3-1. Sample illustration
of plotting conventions for
box plots.
160
u, 140
<
=" 120
11
80
a. •=
V) U>
40
20
1972
BOX PLOT ANNUAL VALUES.
1973
I
1974 1975
YEAR
197S
1977
Nationwide trends in annual mean total suspended
particulate concentrations from 1972 to 1977 at 2,707 sam-
pling sites.
-------
72
meter. The TSP level exceeded by the worst 10% of the sites still
managed to improve, however, through 1977. This level decreased
from 97 to 88 micrograms per cubic meter between 1972 and 1975 and
then decreased to 84 micrograms per cubic meter in 1977.
The high ambient levels of 1976 and 1977 were due at least
partially to very dry weather._1£/_1_1_/ In 1977, some sites recorded
levels of 1000 micrograms per cubic meter for a day or two and this
alone can cause the annual mean to increase 10%.JTO/ Figures V-5
and V-6 show the ambient TSP trends by region for 1972 through
1977. The dust storms of 1976 were primarily located in Regions 8,
9, and 10, while those of 1977 were primarily located in Region 6.
The fraction of the nation's population which is exposed to
TSP levels exceeding the primary NAAQS is shown in Figure V-7.ll/
While the number of people exposed to such levels dropped 9%
between 1972 and 1975, this downward trend stopped in 1976 and 1977
when the number of people exposed remained constant at about 22% of
the nation's population. An identical trend is present for the
nation's metropolitan population. For the last three years
(1975-1977), 27% of the nation's metropolitan population has been
exposed to ambient TSP levels exceeding the primary NAAQS. These
people are living in areas where the quality of the air they
breathe could be harmful to their health.
An even greater percentage of people are living in areas
exceeding the secondary NAAQS for TSP. For example, in 1975 when
49 million people were living in areas exceeding the primary NAAQS;
89 million people were living in areas exceeding the secondary
NAAQS. These people are living in areas where the air quality
could be a hazard to their welfare (i.e., visibility, corrosion of
materials, vegetation, etc.).
To examine the TSP problem in greater detail, ambient TSP
trends are available for five large metropolitan areas.10/11/
These five cities, New York, Chicago, Denver, Cleveland, and St.
Louis, were largely unaffected by the dry weather of 1976 and 1977
(except possibly St. Louis), so this bias should not be present.
The populations exposed to TSP levels exceeding the primary NAAQS
in these five metropolitan areas are shown in Table V-3. The most
significant improvements occurred in the New York metropolitan
area.JjV In 1970, 11.2 million people in metropolitan New York
lived in areas where the annual primary NAAQS was being exceeded.
By 1976, all TSP monitors had registered annual means below this
level. Thus, no one was living in areas exceeding the primary
NAAQS. The average TSP concentration in metropolitan New York
dropped from 78 micrograms per cubic meter in 1970 to 55 micrograms
per cubic meter in 1976.
The results for the other four cities were somewhat different.
Improvements in the number of people exposed to ambient TSP levels
-------
Figure V-5 _10/
US. EPA AIR QUALITY CONTROL REGIONS, EASTERN STATES
160
140
T lm
1=100
5 80
£60,
" 40
20
REGION 1
I i I I I i
REGION 2
t I I I I i
REGION 3
1972 1373 1974 1975 1975 1977
1972 1973 1974 1975 197S 1977
J L__J 1 L
1972 1973 1974 1375 1975 1977
160
140
120
=100
"S 80
a 5D
' 40
20
REGION 4 _
o
I
lt.
1972 1973 1374 1975 1976 1977
REGIONS _
J - 1 - 1
t I
1972 1973 1974 1975 197S 1977
1972- 1977.
Regional trends of annual mean total suspended paniculate concentrations.
-------
Figure Y-6 10/ 74
9 D-
U.S. EPA AIR QUALITY CONTROL REGIONS, WESTERN STATES
160
1401-
120 -
\ SO
40
ZO
REGIONS .
L i : i !
REGION? -
REGIONS -
I ! I I
1972 1973- 1S74-W5-197S 1977 1972 1973 1974 1975 1976 1977 1972 1973 1974 1975 197S 1977
150
140
120
100
- 80
: GO
40
20
0
REGION 9
I
t i i ii i
REGION 10 _
I i
1972 1973 1974 1975 1976 1977
1972 1973 1974 \975 1975 1977
YEAR
trations, 1972- 1977.
Regional trends of annual mean total suspended paniculate concen-
-------
75
Figure V-7 K>/
40
= 30
V Ju
Q
ui
tn
2 20
z
o
-I
=3
o_
£10
METROPOLITAN
NATION
NON-
METROPOLITAN
I
72 73 74 75 76
YEAR OF TSP EXPOSURE
Population exposure to annuaj
mean TSP in excess of NAAQS '~
77
-------
76
Table V-3
Population Exposure to TSP Levels in
Violation of the Primary NAAQS 10/.11/
Population
(millions)*
1970
1972
1973
1974
1975
1976
1977
New York Chicago Denver Cleveland
17 3.4 1.1 3.4
Percentage of Population Exposed to Levels
Exceeding NAAQS
60% 100% 83%
60%
12% 50%
37%
75% 44%
0% 64% 29%
27%
St. Louis
1.9
69%
46%
48%
43%
60%
62%
t- 1_ _
Air Quality Control Region.
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77
in excess of the primary NAAQS have been made, but significant
numbers are still exposed. Denver is probably in the worst situa-
tion.^/ While the percentage of people exposed to TSP levels
exceeding the NAAQS has decreased 9%, a full three-fourths of the
population are still exposed to these excessive levels. Likewise,
for Chicago, 64% of the population are still living in areas where
the TSP levels violate the primary NAAQS.l\J Cleveland has exper-
ienced a steady decrease in population exposure to excessive TSP
levels since 1972, though 27% of the people in the air quality
control region are still exposed.10/
St. Louis is the most interesting case. The population
exposed to excessive TSP levels decreased steadily from 69% to 43%
between 1972 and 1975. After that the exposed population increased
back to nearly the 1972 level. Part of the reason for this in-
crease, which first occurred in 1976, may have been the dry weather
of that year. The precipitation around St. Louis was "slightly
below normal" for 1976.11/ However, nothing is mentioned con-
cerning the weather of 1977 and Region 7 (which includes St. Louis)
in general showed no signs of exceptionally dry weather in 1977
(see Figure V-6). Thus, it would appear that at least some and
perhaps most of the increase of 1977 is due to factors other than
dry weather.
There are two primary reasons why ambient TSP levels have
dropped significantly between 1971 and 1975. Both reasons concern
stationary source particulate emissions. The first reason is the
application of particulate control technology to the stationary
sources of particulate emissions. Since 1970, many of the largest
polluting industries have been required to control particulate
emissions. This has occurred nationwide through attempts by states
and localities to comply with the NAAQS for TSP (e.g., through
equipping existing plants with particulate control devices as
deemed necessary by local TSP levels). The second reason is
that many combustion sources have switched to cleaner fuels which
result in lower particulate emissions. The combustion of coal
produces much more particulate emissions than the combustion of
oil, and the combustion of natural gas produces even less partic-
ulate emissions than the combustion of oil. Thus, many sources in
the early 1970's switched to oil and gas to reduce particulate
emissions, as well as sulfur dioxide emissions.
While these methods have decreased ambient TSP levels over the
last seven to eight years, there are some inherent problems associ-
ated with both of them which limit future reductions. First, most
of the large reductions in particulate emissions possible from
stationary sources have already been raade.9/ The majority of the
largest polluting plants have already come under state and federal
standards, or are under compliance schedules soon to be completed.
The potential for continued emission reductions has diminished, and
future reductions will be even more costly. Since current NSPS
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78
are based on the best system of emission reduction which has been
adequately demonstrated, while taking into account the cost of such
a system, the advent of even greater control of currently con-
trolled industries will not be widespread, barring major techno-
logical breakthroughs.
Second, the trend toward switching to oil and natural gas from
coal has already stopped and even reversed itself due to the
shortage of domestic oil and natural gas. Thus, any gains made in
the past from switching to cleaner fuels will eventually disappear,
and likely reverse themselves as coal usage becomes more and more
prominent.
Finally, growth in production will enter into the situation.
In any industry where emission standards stay at current levels,
every new plant not replacing an obsolete plant will add to the
overall emissions inventory. The ability of the air to clean
itself does not increase with the nation's productive capabilities,
so the end result is dirtier air.
In conclusion, while significant progress was made in the
early 1970's in reducing ambient TSP levels, 22% of the national
population is still exposed to ambient TSP levels in excess of the
primary NAAQS of 75 microgratns per cubic meter (annual geometric
mean). And the two strategies which contributed most to the TSP
reductions of the early 1970's, application of emission controls to
the stationary sources with the largest potential reductions and
fuel-switching from coal to oil and natural gas, clearly will not
be able to provide significant new reductions, expecially since the
fuel-switching process will likely reverse itself and continued
economic growth is expected to provide new sources of particulate
matter. Therefore, heretofore uncontrolled particulate sources and
new major particulate sources will need to be regulated if further
TSP reductions are to be achieved. The next section will show the
environmental benefits to be gained from the control of light-duty
diesel particulate emissions.
n. Impact of Diesel Particulate Emissions
The automotive diesel engine is currently an unregulated
source of particulate in the atmosphere. Three different aspects
Of the diesel's environmental impact will be examined here. First,
the amount of particulate emitted to the atmosphere will be deter-
mined. Second, the diesel's impact on large-scale TSP levels
will be examined. Finally, the diesel's impact in localized
areas where particularly high concentrations could occur will be
examined. All of these impacts will be determined for 1990, as by
that time the environmental benefits of the 1985 standard will be
nearly complete. These environmental impacts in 1990 will be
determined for both light-duty diesels and heavy-duty diesels, even
though these regulations apply only to the former. Both sources
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79
emit in the same areas at the same time, and thus their impacts are
typically combined. Of course, the combined impact cannot be used
to justify control of only one of the sources.
1. Emissions
The determination of total particulate emissions from light-
and heavy-duty diesels in 1990 requires three primary pieces of
information: emission factors (in units of g/mi or g/km), sales
(for each year until 1990), and a breakdown of vehicle miles
travelled (VMT) for both light- and heavy-duty diesels.
The first step needed in this area is to determine the
emission factors for light- and heavy-duty diesels. EPA has tested
every light-duty diesel currently marketed in the U. S ,\2j A
current sales-weighted average of these emission levels (using
Table III-6) is about 0.6 grams per mile (g/mi) or 0.37 grams per
kilometer (g/km). However, the composition of the fleet could
change considerably by 1990. From an analysis of the information
available on future diesel sales, I3_l General Motors, with its
relatively high particulate emitters, is expected to retain a 55-65
percent share of the light-duty diesel market through 1990.
Volkswagen, on the other hand, with its lower emitting diesels, is
expected to lose much of its diesel market share, though increasing
sales on an absolute basis. Ford and Chrysler are both expected to
move toward diesels, together representing 28 percent of the diesel
market in 1990, and nothing can be known about their emissions.
Without the impetus of regulation, it is likely that these newer
entrees to the market would be high emitters, not unlike the
1978-1979 Oldsmobiles.
To this is added the burden of strict NOx control (1.0 g/mi)
by 1985. Up until that date, EPA may grant a waiver to 1.5 g/mi
NOx and this waiver could prevent an increase in particulate
emissions over current levels (see Chapter IV). However, beginning
in 1985, Congress itself has set the NOx standard at 1.0 g/mi (0.62
g/km). Under this NOx standard, it is unlikely that uncontrolled
particulate levels would be much under 1.0 g/mi (0.62 g/kra). In
fact, in their initial comments at the public hearing following the
proposal of this regulation, some manufacturers wanted a 1.0 g/mi
particulate standard even with a NOx waiver to 1.5 g/mi, especially
General Motors which is presently the largest diesel manufacturer
and which is expected to continue to account for a majority of the
diesel market in the foreseeable future._O/,_14/ Others thought
lower levels were possible, but would require further effort. It
is highly unlikely that any of this effort would occur without
regulation. Thus, 1.0 g/mi (0.62 g/kra) will be used as an uncon-
trolled particulate level for light-duty diesels.
The particulate emission factor for heavy-duty diesels will be
estimated to be 2.0 g/mi (1.24 g/km). This factor is currently
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80
difficult to determine accurately since EPA has only recently
developed a transient test for heavy-duty diesels._15/ A transient
test appears necessary to accurately determine in-use particulate
emissions. All historical data was obtained from steady-state
tests and EPA is only now in the midst of its first transient
testing of diesels. Thus, 2.0 g/mi (1.24 g/km), which is an
accepted rough estimate of heavy-duty particulate emissions will be
used._l_6/J._7/_18_/ It should be noted that in the past it has been
believed that 2-stroke heavy-duty diesel engines had greater
particulate emission factors than did 4-stroke engines; preliminary
transient testing has indicated that 2.0 g/mi (1.24 g/km) is a good
estimate for both 2-stroke and 4-stroke heavy-duty diesel partic-
ulate emission factors.
The next step is to determine the number of diesels which will
be on the road in the future. This area has already been examined
for light-duty diesels and the best estimate of future dieseL sales
is shown in Table V-4 ._L3_/ Diesel sales are expected to reach 11%
of. the light-duty market in 1985 and 20% in 1990 where they are
expected to level off. As these projections could under or over-
estimate actual diesel sales, a range consisting of plus and minus
25% of the scenario in Table V-4 will be used for all subsequent
analyses. If these scenarios are coupled with the standard EPA
breakdown of annual vehicle miles travelled by model year,_l_9_/ the
result is that 10.2-17.0% of light-duty travel in 1990 wilT~be by
diesel.
For heavy-duty diesels, the scenarios used here will be taken
from the environmental impact analysis performed by PEDCo Environ-
mental for EPA (based on projections made by Dr.John Johnson,
Michigan Tech University) .JJ3_/ These sales scenarios are shown in
Table V-5. If the standard EPA breakdown of annual heavy-duty
vehicle miles travelled by model year is used.Jj}/ the result is
that 59.7-83.9% of heavy-duty travel in 1990 will be diesel.
The final three items which are needed are an estimate of
nationwide vehicle miles travelled (VKT), a breakdown of VMT by
class, and an urban/rural breakdown of VMT by class. All of these
will be taken from PEDCo (based on DOT data) and are shown in Table
V-6._18/ • .
Using all of these figures, the annual emissions of diesels
can now be calculated. In 1990, uncontrolled particulate emissions
from all diesels nationwide are expected to be 323,000 to 494,000
metric tons per year. Urban emissions would be slightly more than
half this amount, 149,000 to 233,000 metric tons per year. Na-
tionwide emissions from light-duty diesels in 1990 are expected to
be 152,000 to 253,000 metric tons per year without control, while
urban emissions would have been 84,000 to 141,000 metric tons per
year. If no control is placed on heavy-duty diesel particulate
emissions by 1990, they are expected to amount to 171,000 to
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81
Table V-4
Year-by-Year Projections of the Diesel Fraction
of Light-Duty Vehicle Sales 13/
Model Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
Diesel
Fraction (%)
4.7%
7.5%
8.9%
9.5%
11.4%
13.8%
16.5%
17.6%
18.7%
19.7%
20%
20%
20%
20%
20%
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82
Table V-5
Percentage of New Heavy-Duty Vehicle Sales
Powered by Diesel Engines 18/
Model Year
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
Heavy-Duty
Vehicles
Low
28.0
30.0
31.0
31.0
31.0
31.0
31.0
31.0
33.0
39.0
45.0
52,0
58.0
64.0
High
28.0
35.0
36.0
38.0
40.0
48.0
57.0
67.0
78.0
82.0
86.0
90.0
94.0
99.0
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83
Table V-6
Nationwide and Urban VMT and Diesel
Particulate Emissions by Vehicle Class
1.286 trillion miles
1.5% per year
54.1%/45.9%
Nationwide VMT in 1974 18/
Annual Growth Rate
Urban/Rural Split
Breakdown of VMT by Class (1974) \8/
Light-Duty Vehicles
Light-Duty Trucks
Heavy-Duty Vehicles
Diesel Particulate Emissions (1990) (Metric tons per year)
Nationwide
0.788
0.124
0.088
1.000
Urban
0.830
0.108
0.062
1.000
Nationwide
Urban
Light-Duty Diesel
Heavy-Duty Diesel
Total
152,000-253,000 84,000-141,000
171.000-241.000 65.000-92,000
323,000-494,000 149,000-233,000
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84
241,000 metric tons per year, nationwide, and 65,000 to 92,000
metric tons in urban areas. These values are all shown in Table
V-6. To put things into perspective, Table V-7 provides a compari-
son of current annual emissions from several major industrial
source categories with estimates of uncontrolled diesel emissions
in 1990. As can be seen, heavy-duty and light-duty diesels are
projected to be significant sources of particulate emissions by
1990, if left uncontrolled.
During the next decade, as light-duty diesels become a major
source of particulate emissions, there will be a significant
decrease in lead particulate emissions from gasoline-powered
light-duty vehicles and trucks. This trend has already begun and
will continue as the gasoline-powered fleet becomes more and more
dominated by vehicles equipped with catalysts, which require
unleaded fuel and which thus emit little or no lead particulate.
EPA estimates that gasoline-powered light-duty vehicles and trucks
emitted approximately 250,000 metric tons of particulate matter in
1974 (1.173 trillion miles times a lead-salt emission factor of
0.213 g/mi), of which 107,000 metric tons would be classifiable as
^su^pended particulate. By 1990, EPA expects gasoline-powered
light-duty vehicles and trucks to emit only 16,000 metric tons of
particulate matter, of which 7,000 metric tons would be classi-
fiable as suspended particulate. Thus, EPA expects a reduction of
100,000 metric tons of suspended particulate from gasoline-powered
light-duty vehicles and trucks by 1990 as compared to levels in
1974. With the expected increase in diesel particulate (from
uncontrolled diesels) and the expected decrease in lead particulate
(from gasoline-powered vehicles), then by 1990 EPA projects that
total light-duty vehicle and truck particulate emissions will
increase by 52,000 to 153,000 metric tons per year.
In summary, if left uncontrolled light-duty diesels will emit
152,000 to 253,000 metric tons of particulate per year by 1990,
which EPA projects would make them one of the largest sources of
particulate emissions. Lead particulate emissions from gasoline-
powered light-duty vehicles will be reduced by 100,000 metric tons
per year by 1990, thus the net increase of light-duty vehicle and
truck particulate emissions will be 52,000 to 153,000 metric tons
pet 7ear by 1990. These tonnage impacts are significant, both in
terms of the diesel contribution and the overall light-duty con-
tribution. The air quality impacts on various regions will now be
gjtamined in the next sections.
2. Regional Impact
The regional, or large-scale, impact of diesel particulate
emissions is greatest in urban areas. This is no surprise since it
±g in urban areas where the greatest concentration of vehicles
exist. As it is also in urban areas where most of the people of
the nation live and where most of the violations of the NAAQS for
occur ,_10_/ it is appropriate that this section concentrates
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85
Table V-7
1975 Emissions from Selected Major Stationary Source
Categories and Projected 1990 Emissions from Diesel Vehicles
1975 Emissions*
Stationary Sources (tons per year)
Electric Generation Plants 3,000,000
Industrial Boilers 1,000,000
Iron and Steel Industry
Coke Ovens <100,000
Basic Oxygen Furnaces 100,000
Blast Furnaces <100,000
Kraft Pulp Mills 200,000
Aluminum Industry 200,000
1990 Emissions
Diesel Vehicles (tons per year)
Heavy-Duty 171,000-241,000
Light-Duty 152,000-253,000
* Stationary source data extracted from National Emission Data
System, 1975.
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86
primarily on the impact of diesel particulate emissions in urban
areas.
Three studies have attempted to determine the impact of diesel
particulate emissions on urban air. The first was performed by
PEDCo Environmental and focussed on Kansas City.JJ/ An air quality
display model (AQDM) was used to predict ambient diesel particulate
levels throughout the Kansas City metropolitan area within two-
kilometer square grids. A total of 165 grids were modeled (660
square kilometers). The population residing in each grid was also
determined so an estimate of the population exposed to various
ambient levels could also be made.
The second study was also performed by PEDCo Environmental for
EPA, but it used a different approach.2QJ First, three larger
cities were examined, New York, Los Angeles, and Chicago. Second,
che study did not use a dispersion model to calculate ambient
diesel particulate levels. Rather, ambient lead concentrations
coupled with lead emission factors were used to determine the
relationship between emissions and air quality for mobile sources.
Then, ambient concentrations of diesel particulate could be calcu-
lated using this relationship and known diesel particulate emission
factors. Ambient levels of diesel particulate were calculated at
15 actual TSP monitoring sites so the calculated levels could be
directly compared to levels currently being measured at the same
sites.
The third study was conducted by EPA and used essentially the
same methodology as the second PEDCo report. 21/ Ambient diesel
particulate concentrations were estimated in ove~r 35 cities ranging
in population from less than 100,000 to over 5,000,000. The study
also includes similar estimates of ambient diesel particulate
Bevels in Chicago and Toledo which were submitted by General Motors
during the comment period following the proposal of this regula-
tion.^/
Each of these three studies used a different set of input data
for emission factors, VMT growth, diesel penetration, etc. In
order to be comparable, each had to be adjusted to a common set of
input factors. This has already been done under separate cover
for convenience. 2_iy The common set of input factors used was
described in the previous subsection on emissions from uncontrolled
Diesels. The only difference was that growth in VMT was only
assumed to be 1Z per year in the central city areas being examined
by the three studies.
One additional adjustment was also made to the results of the
9econd PEDCo study. From the text of the PEDCo report, it was
determined that an error was made concerning the automobile's
contribution to ambient TSP levels in New York. A referenced
study, which determined the auto's total contribution to ambient
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87
TSP levels included reentrained dust, but was taken to refer only
to automobile exhaust emissions. This error caused the New York
results to be overestimated by a factor of 2.66. Due to the fact
that the Chicago results were partially based on this erroneous
factor, they were overestimated by a factor of 1.62. Any use of
the PEDCo results here will be adjusted by these factors and
a detailed discussion of the adjustments can be found under sepa-
rate cover.21/
The results of the three studies are shown in Tables V-8, V-9,
and V-10. Before drawing conclusions from any of them, it is
helpful to discuss both similarities and differences among the
results of the studies. The EPA study encompasses the cities
contained in both the other two studies, so it can be used as
common measure to compare the results of the two PEDCo methodo-
logies, as well as for direct comparisons between EPA and PEDCo
results.
First, it is evident that the expected Kansas City impact, as
determined from ambient lead levels (Table V-10, EPA) is over twice
that determined by the AQDM (Table V-8, PEDCo). On the other hand,
the expected impacts in New York, Los Angeles and Chicago are about
the same whether determined by EPA (Table V-10) or PEDCo (Table
V-9). This latter finding is not surprising since both studies
used ambient lead measurements as a basis, though slightly dif-
ferent methodologies were used to convert these ambient lead
concentrations into diesel particulate concentrations. The level
found at the first Chicago monitor modeled by PEDCo (Table V-9)
appears quite out of line with all the others and will be excluded
from further reference. It is known that PEDCo assumed that
automotive exhaust particulate was a constant fraction of TSP
throughout the city. If this particular monitor was in a heavily
industrial area showing a very high TSP level due to industrial
sources, of which Chicago has quite a few,_!!_/ then the automotive
portion could be overestimated.
Using the EPA study as a common yardstick, the methodology
applied in the second PEDCo study (Table V-9) yielded higher diesel
particulate impacts than the AQDM even after taking into account
differences in the cities examined. There is independent reason to
believe that the AQDM underestimated the mobile source impact in
Kansas City. A study has been performed which calculates ambient
carbon monoxide (CO) levels using the PEDCo Kansas City results,
and CO emission factors._2_4/ The model appears to estimate ambient
CO levels a factor of four below those determined by monitors
located within the city. This comparison was performed using CO,
because current ambient levels of diesel particulate are difficult
to distinguish from other combustion particles. Also, intuitively,
there should be less error involved in ambient pollutant measure-
ments and emission factors than that involved in regional disper-
sion modeling. From this section it would appear that the greater
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88
Table V-8
Results of PEDCo Environmental's
Kansas City Study 21/
Total Number of Grids (2 x 2km)
Total Population (1970)
Ambient Diesel Particulate Level
(micrograms per cubic meter )
Light -Duty Heavy-Duty
0.7 - 1.2 0.6 - 0.8
0.7 - 1.1 0.5 - 0.8
0.6 - 1.0 0.5 - 0.7
0.6 - 1.0 0.4 - 0.6
0.5 - 0.9 0.4 - 0.6
0.5 - 0.8 0.4 - 0.6
165
756,000
Percentage of Population Exposed
to at Least the Indicated Level
of Diesel Particulate
2.1%
5.9%
13.2%
17.8%
28.6%
32.8%
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89
Table V-9
Estimated Ambient Levels of Diesel Particulate
at 15 TSP Monitoring Sites in Three Cities 21/
Height
City (meters)
New York* 22.9
22.9
18.3
13.7
7.6
Los Angeles 1.2
7.6
27.4
5.5
18.3
Chicago* 9.5
4.6
4.9
39.9
19.2
Distance
from Road
(meters)
91.5
30.5
15.25
30.5
91.5
N/A
1.8
5.0
17.0
N/A
24.4
30.5
21.3
9.15
3.6
Average
Daily
Traffic
12,100
16,500
26,600
17,900
16,800
15,000
15,000
13,500
18,000
N/A
N/A
4,700
9,400
11,600
25,100
Diesel Particulate Levels
(micrograms per cubic meter)
Light-Duty Heavy-Duty
2.1 - 3.5 1.6 - 2.3
2.2 -
2.6 -
2.0 -
2.5 -
5.4 -
5.6 -
6.8 -
5.7 -
6.2 -
9.8 -
4.8 -
5.2 -
5.0 -
4.1 -
3.6
4.3
3.3
4.2
9.1
9.4
11.3
9.5
10.3
16.3
8.0
8.7
8.3
6.9
1.7 -
2.0 -
1.5 -
1.9 -
4.2 -
4.3 -
5.2 -
4.4 -
4.8 -
7.5 -
3.7 -
4.0 -
3.8 -
3.1 -
2.4
2.8
2.2
2.7
5.9
6.1
7.3
6.2
6.7
10.6
5.2
5.7
5.4
4.4
* The levels shown include a reduction by a. factor of 2.66 (New
York) and 1.62 (Chicago) to account for an error in the original
PEDCo analysis. See text for further description.
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90
Table V-10
Estimated Regional Ambient Levels of Diesel
Participate in 39 Cities in 1990 21/*
Particulate Level
Population (micrograms per cubic meter)
Category City
Over 1 .
.... Chicago
million 6
Detroit
Houston
Los Angeles
New York
Philadelphia
Average
500,000 to Boston
1,000,000 Dallas
Denver
Kansas City, MO
New Orleans
Phoenix
Pittsburgh
San Diego
St. Louis
Average
250,000 to Atlanta
500,000 Birmingham, AL
Cincinnati
Jersey City
Louisville
Oklahoma City
Portland
Sacramento
Tucson
Yonkers , NY
Average
100,000 to Baton Rouge
250,000 Jackson, MS
Kansas City, KA
Mobile, AL
New Haven
Salt Lake City
Spokane
Torrance, CA
Trenton, NJ
Waterbury, CT
Average
Under 100,000 Anchorage
Helena, MN
Jackson Co. , MS
Average
Light-Duty
3.0 -
6.3 -
2.1 -
4.4 -
5.7 -
2.2 -
2.8 -
2.6 -
3.6 -
1.9 -
6.4 -
2.0 -
1.5 -
2.2 -
4.4 -
1.8 -
2.4 -
2.5 -
2.8 -
2.2 -
2.6 -
1.7 -
2.2 -
2.0 -
3.5 -
2.1 -
1.7 -
2.2 -
1.6 -
2,4 -
2.2 -
2.0 -
1.7 -
0.9 -
1.3 -
2.0 -
2.4 -
2.1 -
1.2 -
5.0 -
1.9 -
3.8 -
2.2 -
2.1 -
0.6 -
0.9 -
1.2 -
5.1
10.7
3.5
7.5
9.6
3.8
4.8
4.4
6.2
3.3
10.8
3.4
2.5
3.8
7.5
3.0
4.0
4.2
4.7
3.7
4.4
2.9
3.7
3.4
5.9
3.6
2.9
3.8
2.7
4.1
3.7
3.3
2.9
1.5
2.1
3.4
4.1
3.5
2.1
8.4
3.1
6.7
3.7
2.7
0.8
1.7
1.7
Heavy-Duty
2.3 -
4.9 -
1.6 -
3.4 -
4.3 -
1.7-
2.2 -
2.0 -
2.8 -
1.5 -
4.9 -
1.5 -
1.1 -
1.7 -
3.4 -
1.4 -
1.8 -
1.9 -
2.2 -
1.7 -
2.0 -
1.3 -
1.7 -
1.5 -
2.7 -
1.6 -
1.3 -
1.7 -
1.2 -
1.9 -
1,7 -
1.5 -
l."3 -
0.7 -
1.0 -
1.5 -
1.9 -
1.6 -
0.9 -
3.B -
1.4 -
2.9 -
1.7 -
1.6 -
0.5 -
0.7 -
0.9 -
3.3
7.0
2.3
4,9
6.2
2.4
3.1
2.9
4.0
2.1
7.0
2.2
1.6
2.5
4.9
2.0
2.6
2.7
3.1
2.4
2.8
1.9
2.4
2.2
3.9
2.4
1.9
2.4
1.7
2.7
2.3
2.2
1.9
1.0
1.4
2.2
2.7
2.3
1.3
5.5
2.0
4.4
2.4
1.7
0.5
1.1
1.1
Based on data from National Air Surveillance Network (NASN)
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91
emphasis should be placed on the studies based on ambient CO and
lead levels than those using regional dispersion modeling, partic-
ularly when the number of ambient pollutant measurements is
large.
Given this emphasis, the regional impact of uncontrolled
diesel participate emissions in 1990 would be 2-11 micrograms per
cubic meter (light-duty), and 2-7 micrograms per cubic meter
(heavy-duty) in the nation's three largest cities. Together, these
levels represent 5-24% of the NAAQS for TSP. The levels for other
cities are somewhat lower and these levels tend to decrease with
decreasing population, as shown in Table V-10. There are excep-
tions in each population category, such as Dallas and Kansas City.
The impact of all diesel particulate emissions in Dallas is pro-
jected to be 6-11 raicrograms per cubic meter from light-duty
diesels and 5-7 micrograms per cubic meter from heavy-duty diesels.
The impact in Kansas City is only projected to be 1.5-2.5 micro-
grams per cubic meter from light-duty diesels and 1.1-1.6 micro-
grams per cubic meter from heavy-duty diesels. It should be noted
that the regional impacts in Table V-10 are based on National Air
Surveillance Network (NASN) data, which typically involve only one
or two monitors per city. Certainly the small number of monitors
might explain some of the variability between cities. However,
being a part of the NASN system, these monitors have a much greater
likelihood of representing areas at least as large as a neighbor-
hood and not be overly influenced by nearby sources. National
Aerometric Data Bank (NADB) data was not used because these moni-
tors are more likely to be located near large sources of lead and
may not represent larger-scale impacts. Thus, the presence of a
large nearby source should not be a cause of the variability.
Levels such as these would have a significant impact on the
ability of these cities to meet the primary NAAQS for TSP. For
example, in 1976, 64% of the population in the Chicago air quality
control region lived in areas exceeding the primary NAAQS for TSP.
Table V-9 projects the total diesel particulate impact to be 7-14
micrograms per cubic meter, with well over half due to light-duty
diesels, even ignoring the one very high monitoring site. This is
5-12 micrograms per cubic meter higher than the diesel impact in
1976 which was estimated to be 2 micrograms per cubic meter at that
time .20J Ambient lead concentrations in 1975 were approximately
17-27~~percent of the diesel particulate impact in 1990, or about
2.4 micrograms per cubic meter ._2_1_/ Since lead comprises about 52
percent of lead-containing particulate,^!/ this translates into
about 5 micrograms per cubic meter of leaded particulate. Since
use of leaded gasoline should greatly decrease by 1990, a reduction
of about 4 micrograms per cubic meter should occur. The net mobile
source impact would then be 1-8 micrograras per cubic meter city-
wide. If stationary source and fugitive emissions did not de-
crease, then a total of 67-83 percent of the population would
live in areas exceeding the standards, rather than only 64%._1_1/ In
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92
order to comply with the primary NAAQS for TSP with uncontrolled
diesel emissions, an additional 1-7 micrograms per cubic meter of
control would be necessary. This is a large amount of control for
an area already having difficulty meeting the standards for TSP.
The projected impacts of uncontrolled diesels in cities such as St.
Louis, Denver, Dallas, and Los Angeles are similar to those in
Chicago (see Table V-10}»
In summary, EPA finds that the original PEDCo Environmental
analysis (utilizing an air quality display model in Kansas City)
was weak in certain aspects, and that the more recent PEDCo Envir-
onmental and EPA analyses (based on ambient lead levels and lead
and diesel particulate emission factors) more accurately reflect
the regional impacts to be expected from light-duty diesel partic-
ulate emissions. These studies show the regional impacts expected
in 1990 from uncontrolled light-duty diesels to be very signifi-
cant. Moderate increases in mobile source particulate levels
(2-10 micrograms per cubic meter) will add to already excessive
levels of TSP and increase the difficulty of complying with the
primary NAAQS for TSP for practically all of the regions which have
the very worst TSP violations. As discussed in the section on
health effects, all of this additional particulate burden will
involve particles which are inhalable, and nearly all will involve
particles with diameters less than 2.5 micrometers, which are
thought to be the most harmful to human health.
3. Localized Levels
Approximately six studies are available which examine the
localized air quality impact of diesel particulate emissions. Here
localized is defined to include areas on an expressway, beside an
expressway at distances up to approximately 91 meters from its
edge, and in a street canyon. These scenarios represent exposure
co: people while commuting to and from work; persons employed by
roadside businesses such as gasoline stations; families residing
near major thoroughfares; pedestrians on busy streets; and oc-
cupants of offices, apartments, etc. which flank busy streets. As
a survey and analysis of these studies has already been performed,
only the pertinent results along with short descriptions shall be
discussed here.25/
Since each study utilized different diesel penetration rates
and emission factors, these variables were factored from their
respective results and replaced by the standard set of conditions,
described earlier, in order to be comparable. For light-duty
vehicles and trucks, these conditions consist of a diesel emission
factor of 1.0 gram/mile, a low estimate of dieselization equal to
10.2 percent of all light-duty vehicles in 1990, and a high esti-
mate of dieselization corresponding to 17 percent of the light-duty
fleet in 1990. For heavy-duty vehicles, the diesel emission factor
is 2.0 grams/mile. The low and high diesel penetration estimates
are 60 percent and 84 percent of urban miles traveled by heavy-duty
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93
vehicles, respectively. An analysis of urban traffic characteris-
tics reveals that 93.8 percent of accumulated miles are from
light-duty vehicles and trucks, the remainder are, for the purposes
of this study, attributable to heavy-duty vehicles (based on DOT
data, PEDCo).18/
A Southwest Research Institute study evaluated the on-express-
way scenario.J_6/ Positive aspects of this report include: the
choice of dispersion model, GM"s line source model 26/, which
yielded good correlation with tracer gas experiments 28/; the study
site, a portion of 1-45 at Joplin (Houston), where the wind is
oriented roughly parallel to the roadway approximately 15 percent
of the time (from 2,75°-25.25" relative to the road at 2.06-8.3
meters/ second); and the traffic count was well documented at 1494
vehicles/ hour for each of 6 lanes. The results, modified to
comply with the aforementioned standard emission factors and
dieselization rates, can be found in Table V-ll.
From this study it can be seen that commuters on an expressway
with a traffic volume of approximately 9000 vehicles per hour
may expect exposure to diesel particulate at concentrations above
regional levels of diesel particulate ranging from 13.7-65.1
micrograms per cubic meter. These values reflect the low estimate
of dieselization and represent the contribution from both light-
duty, approximately 56% of the total, and heavy-duty diesels. The
high estimate of dieselization yields concentrations ranging from
21.3-100.9 micrograms per cubic meter; 61% of which is from light-
duty vehicles. The wide range in expected levels reflects the
important role of the wind. Higher on-expressway concentrations
result when lower velocity wind approaches a trajectory parallel to
the road. This condition allows cumulative dispersion towards
receptors (people in cars) rather than away from them as would be
the case for steeper road-wind angles.
To characterize the off-expressway impact, the Aerospace
Corporation utilized a number of studies which used monitors
to construct roadside spatial distributions of carbon monoxide
and tracer gases._1_7_/ Carbon monoxide is an especially good sur-
rogate for ambient diesel particulate level projections, since
motor vehicles are the predominant contributors to ambient CO
levels and diesel particulate disperses more like a gas than a
typical large particle. Their approach involved developing a
pollutant concentration index by subtracting background concen-
tration from measured roadside values and dividing the resulting
difference by the appropriate source term. This process was
repeated for various distances from the roadway. A roadside diesel
particulate concentration profile was developed by multiplying the
index values for specific locations by the desired particulate
source term. The 7850 vehicle per hour traffic count was based on
a 24-hour integration of actual traffic flow on an 8 lane urban
freeway in Los Angeles.
This approach should be superior to mathematical modeling
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94
Table V-ll
Expected On-Expressway Concentrations
(micrograms per cubic meter)
Light-Duty
Heavy-Duty
2.
at
36.
28.
06 m/sec
2.75'
7 - 61
4-39
*
.1
.8
2.06 m/sec
at 25.
23.2 -
18.0 -
25*
38.
25.
8
3
8.
at
26.
20.
3 m/sec
2.75°
5 - 44.
6-28.
8.3 m/sec
2
8
at 25.
7.7 -
6.0 -
25*
12.9
8.4
* Wind speed and orientation with road.
Table V-12
Expected Off-Expressway Concentrations
(micrograms per cubic meter)
30 Meters
from Road
9! Meters
from Road
Light-Duty
Heavy-Duty
Light-Duty
Heavy-Duty
24-Hour
Maximum
24.2 - 40.3
18.7 - 26.3
15.8 - 26.3
12.2 - 17.1
Annual Geometric
Mean
8.1 - 13.4
6.2 - 8.8
5.3 - 8.7
4.1 - 5.7
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95
efforts because it is based on measured trends and characteristics
while avoiding such assumptions as constant wind speed and atmos-
pheric stability. The results, found in Table V-12, are given in
terms of a 24-hour maximum concentration during one year and the
corresponding annual geometric mean. In order to obtain 24-hour
maximums, Aerospace chose values of the concentration index which
corresponded to the 99.73 percentile ((1 - 1/365) x 100%). Annual
geometric means were then calculated by dividing the 24-hour
maximum values by 3.
To confirm this relationship between the two sampling times,
the carbon monoxide records of the 8 cities listed in Table 6-1 of
Air Quality Criteria for Carbon Monoxide were examined,2Tj A
slightly different divisor of 3.16 was obtained when the geometric
mean of the ratio of 24-hour maximums to annual geometric means was
calculated. Since the range of individual ratios is 2.44 (Chicago)
to 5.0 (Washington D.C.), it is concluded that the factor used by
Aerospace is reasonable and well within the scatter of the data.
Following this methodology, persons approximately 30 meters
from a roadway carrying 7850 vehicles per hour could be exposed
to annual mean diesel particulate concentrations of 14.3-22.2
micrograms per cubic meter from both light and heavy-duty vehic-
les. Roughly 58 percent of this is the light-duty contribution.
Similarly, concentrations at a distance of about 91 meters from the
roadway fall in the 9.4-14.7 microgram per cubic meter range. As
mentioned above, annual geometric mean values are roughly one-
third of the 24-hour maximum values.
It is important to remember that all these local impacts
consider only one source. The total concentration that people
would be exposed to would, therefore, be the predicted localized
value plus the regional or background value coming from other
roadways nearby which was discussed in the previous section. It is
also important to note that the 91 meter distance used above to
characterize a localized effect is further from the road than many
of the "regional" monitors used to develop the regional impacts
shown in Tables V-9 and V-10. This does not mean that the regional
impacts described in Tables V-9 and V-10 are instead localized
impacts. The regional monitors are located near roadways, but most
are elevated and the roads are not heavily travelled relative to
the expressway examined above. Rather, the large distances (91
meters) at which one can still find single source effects (busy
expressway) is simply an example of the extent of potential local-
ized effects.
Aerospace used the same methodology employed in the off-ex-
pressway study to characterize the street canyon impact.^?/ Data
collected from carbon monoxide monitors at various heights above
the street were used to determine the pollutant concentration
indices. Although it is recognized that mathematical models are
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96
valuable tools when trying to analyze pollutant dispersion, the
Aerospace approach is more appropriate when trying to study general
trends and situations. By not relying on such assumptions as
constant building height and wind velocity this study relates more
directly to everyday conditions. Their results, modified to
reflect the standardizing assumptions mentioned earlier,25/ are in
Table V-13. The traffic count for the street canyon scenario was
936 vehicles per hour.
A special worst case scenario was evaluated to augment the
street canyon study. For this analysis, it was postulated that 100
percent of the taxis in Manhattan (responsible for 40 percent of
the midtown vehicle miles traveled)^/ together with 25 percent of
the remaining light-duty vehicles were powered by dies el engines
emitting particulate at the rate of 1.0 grams per mile. A rush
hour traffic density of 2,400 vehicles per hour was assumed.
Using these inputs to the Aerospace street canyon study, a
predicted yearly 24-hour maximum concentration of 250 micrograms
per cubic meter is obtained for a height of 1.8 meters above the
street. The corresponding annual geometric mean under these
conditions is 83 micrograms per cubic meter. No heavy-duty ve-
hicles were considered in obtaining these concentrations.
General Motors performed a similar Manhattan analysis using a
mathematical simulation of street canyon dispersion.24/ They
assumed a traffic density of 3,000 vehicles per hour, 60 percent of
which were light-duty diesels emitting 1.0 grams per mile. An
expected 1-hour concentration of 127 micrograms per cubic meter and
a 24-hour average of 71 micrograms per cubic meter were reported.
When determining the potential impact of a particular concen-
tration, it is important to consider the length of time people will
be exposed to that level of pollutant. People who live and work in
downtown areas (characterized by the 9.1 and 27.4 meter receptor
heights) will be exposed for longer periods of time than those who
are merely shopping (pedestrians). The impact to those living and
working in the downtown area is, therefore, greater than the
pedestrian impact under the conditions of this study.
In assessing the localized impact from diesels, it is benefi-
cial to compare predicted concentrations to the National Ambient
Air Quality Standards for particulate. The primary standards are
75 micrograms per cubic meter for an annual geometric mean and 260
micrograms per cubic meter for a maximum 24-hour concentration not
to be exceeded more than once a year.
Due to the highly-specialized nature of the on-expressway
study (designed to represent a worst case meteorology), no compar-
isons of its' maximum 65.1-100.9 microgram per cubic meter diesel
particulate levels to the standards will be made. Conditions
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97
Table V-13
Expected Street Canyon Concentrations
(micrograms per cubic meter)
1.8 Meters
Above Street
9.1 Meters
Above Street
27.4 Meters
Above Street
Light-Duty
Heavy-Duty
Light-Duty
Heavy-Duty
Light-Duty
Heavy-Duty
24-hour Max
17.3 - 28.7
13.3 - 18.7
13.9
10.7
8.3
6.4
23.2
15.1
13.9
9.0
Annual Geo. Mean
5.7 - 9.6
4.4 - 6.2
4.6 - 7.7
3.6 - 5.0
2.8 - 4.6
2.1 - 3.0
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98
favorable for such levels will occur less than 15% of the time.
However, it would be useful to note that commuters could be exposed
to these levels for 2 hours per day or more.
Approximately 30 meters from the roadway, diesel particulate
will constitute 16.5-25.6% of the 24-hour standard and 19.1-29.6%
of the annual standard. At the 91 meter distance, diesel contribu-
tions represent 10.8-16.7% of the 24-hour standard and 12.5-19.2%
of the annual standard. It is important to remember that these
numbers reflect the contribution from a single roadway and, there-
fore, do not consider background levels from other nearby streets
and highways.
In the street canyon, at the 1.8 meter height, diesels are
responsible for 11.8-18.2% of the 24-hour maximum and 13.5-21.1% of
the annual standard. At a height of 9.1 meters the percentages are
9.5-14.7% for the 24-hour case and 10.9-16.9% for the annual case.
The worst case Manhattan street canyon projected concentrations for
light-duty diesels exceed the annual geometric mean standard by 11
percent and account for 96 percent of the maximum 24-hour standard.
These analyses clearly indicate that uncontrolled light-duty
diesel particulate emission levels would have significant air
quality impacts on areas surrounding busy streets and expressways.
These localized impacts would be in addition to the regional
impacts analyzed in the previous section and would make it ex-
tremely difficult for some such areas to comply with the NAAQS
standards for TSP. The health effects consequences on persons who
live, work, and travel in such areas would be even greater than
those expected based on TSP impacts, since the small size of diesel
particulate makes it especially hazardous to human health.
E. Air Quality Impact of Regulation
The promulgation of a 0.6 g/mi (0.37 g/km) light-duty diesel
particulate standard in 1982 and the lowering of this standard to
0.2 g/mi (0.12 g/km) in 1985 will markedly reduce both emissions
from these vehicles and their impact on air quality. Beginning in
1982, particulate emissions from new light-duty diesels will
decrease 40% from what would have been the uncontrolled level of
1.0 g/mi (0.62 g/km). Beginning in 1985, emissions from new
diesels will be reduced 80% from uncontrolled levels. However even
after implementation of the 1985 standard, diesel-powered vehicles
will still be emitting approximately 15 times the amount of parti-
culate emitted by gasoline-powered vehicles equipped with cata-
lysts. Thus, even though the proposed reductions are significant,
they do not require the diesel to perform as well as the catalyst-
equipped gasoline engine with respect to particulate emissions.
These reductions are from new vehicles only. Those sold
before 1982 and 1985 that are still operating will continue to emit
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99
particulate at their previous level. ThuSj because this regulation
only affects new vehicles, some time is needed for the in—ase fleet
to change over before the impact of the regulation can reach its
full potential. By 1990, particulate emissions from light-duty
diesels will be reduced 74%, from 152,000-253,000 metric tons per
year nationwide to 40,000-66,000 metric tons per year nationwide.
Urban emissions will similarly be reduced by 74%, from 84,000-
141,000 metric tons per year to 22,000-37,000 metric tons per year.
As was mentioned earlier, uncontrolled light-duty diesels are
projected to be a significant source of particulate emissions by
1990. In terms of projected reduction potential, however, light-
duty diesels may be even more significant. The annual particulate
emission reductions available from light-duty diesels are actually
close to the total annual emissions from some entire industries,
such as the iron and steel industry (see Table V-7). Also, while
further reductions in stationary source emissions can be expected
to mitigate future increases in emissions due to industrial growth,
they cannot be expected to significantly reduce total emissions
from current levels, making reductions from light-duty diesels even
more necessary.
More importantly, the air quality impact of light-duty diesel
particulate emissions will also be reduced by 74% in 1990. Table
V-14 shows the ambient levels both before and after regulation of
15 cities having a population of over 500,000 people. The data
have been taken from Tables V-9 and V-10 and the full range has
been used when more than one estimate is available. These impacts
should be indicative of neighborhood or larger scale impacts in the
cities mentioned. Any monitors modeled by PEDCo (Table V-9) which
did not meet EPA's criteria for the minimum distance from the
roadway were excluded from Table V-14. As can be seen, ambient
particulate levels from light-duty diesels will be reduced by
1.1-1.9 micrograms per cubic meter in Kansas City to 4.0-8.4
micrograms per cubic meter in Los Angeles and Dallas. This reduc-
tion should aid the majority of these cities in meeting the primary
NAAQS for TSP.
The impact of this regulation on particulate levels in local-
ized areas of particularly high concentrations is also signifi-
cant. Table V-15 presents an overview of this impact. (All
concentrations refer to light-duty diesel contributions only.) On
the expressway the diesel particulate level will drop from 36.7-
61.1 micrograms per cubic meter to 9.5-15.9 micrograras per cubic
meter for the 2.06 meter per second wind speed - 2.75° worst case
scenario. At a distance of approximately 30 meters from the
roadway, the maximum 24-hour particulate levels are reduced from
24.2-40.3 to 6.3-10.5 micrograms per cubic meter. This reduction
in the light-duty diesel particulate levels will benefit such
people as service station operators who spend large amounts of time
near roadways. People residing approximately 9 meters above the
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100
Table V-14
Large-Scale Air Quality Impact on Regulation of
Light-Duty Diesel Particulate Emissions
Light-Duty Diesel Ambient
Particulate Level
Population
Category City
Over 1 New York
Million Los Angeles
Chicago
Philadelphia
Houston
Detroit
500,000 to Dallas
1,000,000 New Orleans
Boston
Denver
Pittsburgh
San Diego
Phoenix
St. Louis
Kansas City, MO
micrograms per cubic meter
Uncontrolled Regulated
2.0 -
5.4 -
3.0 -
2.6 -
4.4 -
2.1 -
6.4 -
2.2 -
1.9 -
2.0 -
1.8 -
2.4 -
4.4 -
2.5 -
1.5 -
4.8
11.3
10.7
4.4
7.5
3.5
10.8
3.8
3.3
3.4
3.0
4.0
7.5
4.2
2.5
0.5 -
1.4 -
0.8 -
0.7 -
1.1 -
0.5 -
1.7 -
0.6 -
0.5 -
0.5 -
0.5 -
0..6 -
1.1 -
0.6 -
0.4 -
1.2
2.9
2.8
1.1
1.9
0.9
2.8
1.0
0.9
0.9
0.8
1.0
1.9
1.1
0.6
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101
Table V-15
Light-Duty Diesel Particulate Levels With and
Without Regulation (micrograms per cubic meter)
On-Expressway
2.06 m/sec wind 2.06 m/sec
speed at 2.75"* at 25.25°
Without Control 36.7 - 61.1 23.3 - 38.8
With Control 9.5 - 15.9 6.1 - 10.1
Off-Expressway
30 Meters from Road
8.3 m/sec
at 2.75"
26.5 - 44.2
6.9 - 11.5
8.3 m/sec
at 25.25°
7.7 - 12.9
2.0 - 3.4
91 Meters from Road
24-Hour Max. Annual Geo. Mean 24-Hour Max. Annual Geo. Mean
Without
Control
With
Control
Without
Control
With
Control
24.2 - 40.3 8.1 - 13.4
6.3 -10.5 2.1 -
Street
1-8 Meters Above Street
24-Hour Annual
Max. Geo. Mean
17.3-28.7 5.7-9.6
4.5- 7.5 1.5-2.5
3.5
Canyon
9.1 Meters
24-Hour
Max.
13.9-23.2
3.6- 6.0
15.8 - 26.3 5.3 - 8.7
4.1 - 6.8 1.4 - 2.3
Above Street 27.4 Meters
Annual 24-Hour
Geo. Mean Max.
4.6-7.7 8.3-13.9
1.2-2.0 2.2- 3.6
Above Street
Annual
Geo. Mean
2.8-4.6
0.7-1.2
Worst Case Manhattan Street Canyon**
1.8 Meters Above Street
Without Control
With Control
24-Hour Max.
250
65
Annual Geo. Mean
83
22
* Wind road angle.
**
Diesels comprise 100 percent of the taxi fleet (40 percent of the total
VMT) and comprise 25 percent of the remaining light-duty VMT.
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102
street will witness reductions in the 24-hour maximum diesel
particulate concentration from 13.9-23.2 micrograms per cubic meter
to 3.6-6.0 micrograms per cubic meter. The worst case Manhattan
street canyon scenario concentration will be reduced from 83 to 22
micrograms per cubic meter for the 1.8-meter height on an annual
geometric mean basis. The corresponding 24-hour maximum will be
reduced from 250 to 65 micrograms per cubic meter.
In summary, particulate emissions from light-duty diesels will
be reduced by 74% by 1990, from 152,000-253,000 metric tons per
year to 40,000-66,000 metric tons per year. The air quality
impacts will also be reduced by 74% in 1990, with regional reduc-
tions in large metropolitan areas varying between 1.1 and 8.4
micrograms per cubic meter, and localized reductions near busy
streets and expressways varying between 3.9-6.4 micrograras per
cubic meter (91 meters from expressway, annual geometric mean) to
27.2-45.2 micrograms per cubic meter (on expressway, 2.06 meters
per second wind speed at an angle of 2.75 degrees from the road).
Clearly these reductions are very significant and would greatly
increase the chances of urban air quality regions to comply with
the NAAQS for total suspended particulate.
F. Secondary Environmental Impacts of Regulations
Five potential secondary areas of impact will be discussed:
energy, noise, safety, waste, and water pollution. No significant
impact is expected in any of these areas.
The control technology expected to be used to meet both the
1982 and 1985 standards does not appear to affect fuel economy,
either positively or negatively. Thus, there should be no impact
on the nation's energy resources. Similarly, this control tech-
nology should not significantly affect engine noise.
There are potential safety implications connected with the use
of a trap-oxidizer. It is possible that the trap-oxidizer could be
damaged by extreme temperatures if too much particulate was capture
before burn off. Any design of a device like this will have to
adequately ensure that an accidental occurrence such as this would
not affect vehicle safety. •
It is also possible that these regulations could have an
impact on solid waste and water pollution. While disposable traps
are not envisioned as a likely control technology, if they were
used to collect the particulate emissions, these traps would need
Co be discarded into the garbage, or burned. If discarded into the
garbage and used as land fill, some of the chemical compounds
present in diesel particulate could seep into the ground and
pollute the ground water. This should not be more difficult
to solve than the current problem of disposing of used engine
lubricating oil. Assuming a typical diesel engine oil replacement
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103
period of 3jOOO miles, (4800 km), a 4-liter engine capacity and an
oil having a specific gravity of 0.9, 3.6 kilograms (kg) of oil
must be disposed of every 3000 miles. If a trap collected 0.4 g/mi
(0.25 g/km), this would produce 1.2 kg of particulate plus the trap
every 3000 miles. Since the engine oil actually contains some
particulate from the cylinder and is essentially all organic
matter, while the majority of the particulate matter is carbon, the
traps should be less of an environmental problem than the existing
oil disposal problem.
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104
References
I/ "Airborne Particles," National Academy of Sciences, November
1777, EPA-600/1-77-053.
II Miller, Frederick J., et. al., "Size Considerations for
ETtablishing a Standard for Inhalable Particles," JAPCA, Vol. 29,
No. 6, June 1979, pp. 610-615.
3/ Groblicki, P.J., and C.R. Begeman, "Particle Size Variation
in Diesel Car Exhaust," SAE 790421.
4/ Schreck, Richard M., et.al., "Characterization of Diesel
Exhaust Particulate Under Different Engine Load Conditions,"
Presented at 71st Annual Meeting of APCA, June 25-30, 1978.
5/ Hare, Charles T. and Thomas M. Baines, "Characterization of
pTrticulate and Gaseous Emissions from Two Diesel Automobiles as
Functions of Fuel and Driving Cycle," SAE 790424.
6/ Braddock, James N. and Peter A. Gabele, "Emission Patterns of
DTe s el-Powered Passenger Cars - Part II," SAE 770168.
7/ Huisingh, J., et.al., "Application of Bioassay to the Charac-
tTrization of Diesel Particulate Emissions," presented at the
Symposium on Application of Short-Term Bioassays in the Fraction-
ation and Analysis of Complex Environmental Mixtures, Williamsburg,
VA, February 21-23, 1978.
8/ Barth, D. S., and Blacker, S. M., "EPA's Program to Assess the
Public Health Significance of Diesel Emissions," Presented at the
APCA National Meeting, June 28, 1979.
9/ "National Air Quality and Emissions Trends Report, 1975,"
, OAWM, EPA, November 1976, EPA-450/ 1-76-002.
"National Air Quality, Monitoring, and Emissions Trends
Report, 1977" OAQPS, OAWM, EPA, December 1978, EPA-450/ 2- 78-052.
Hi "National Air Quality and Emissions Trends Report, 1976,"
OAQPS, OAWM, EPA, December 1977, EPA-450/1-77-002.
12 1 Danielson, Eugene, "Particulate Measurement - Light-Duty
pTesel Particulate Baseline Test Results," Technical Support
Deport, EPA, January 1979, SDSB 79-03.
j_3/ "Summary and Analysis of Comments, Light-Duty Diesel Partic-
Regulations," OMSAPC, EPA, October 1979.
Transcript of the Public Hearing on Proposed Particulate
on Standards for Light-Duty Diesel Vehicles, EPA, March
J9-20, 1979.
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157 "Proposed Gaseous Emission Regulations for 1983 and Later
Model Year Heavy-Duty Engines: Draft Regulatory Analysis," OMSAPC,
EPA, December 8, 1978.
16/ "Study of Particulate Emissions from Motor Vehicles," Report
to Congress.
17/ "Assessment of Environmental Impacts of Light-Duty Vehicle
Dieselization," Aerospace Corp. for DOT, March 1979.
18/ "Air Quality Assessment of Particulate Emissions from Diesel-
Powered Vehicles," PEDCo Environmental Inc. for EPA, March 1978,
Contract #68-02-2515, Task #17.
19/ "Mobile Source Emission Factors," EPA, March 1978, EPA-400/9-
78-005.
207 "The Impact of Future Diesel Emissions on the Air Quality of
Large Cities," PEDCo Environmental for the EPA, Contract No.
68-02-2585, February 1979.
21/ Reiser, Daniel, "Regional Air Quality Impacts of Diesel
Particulate Emissions," EPA, November 1979, SDSB 79-30.
22/ "General Motors' Response to EPA NPRM on Particulate Regula-
tion for Light-Duty Diesel Vehicles," April 19, 1979.
237 40 CFR, Part 60, "Standards of Performance for New Stationary
Sources," Appendix C (FRL 907-11).
24/ Rykowski, Richard A., "Relative Impact of CO and Particulate
on Air Quality," EPA Memorandum to Robert E. Maxwell, Chief, SDSB,
November 5, 1979.
257 Atkinson, R. Dwight, "Localized Air Quality Impacts of Diesel
Particulate Emissions," EPA, November 1979, SDSB 79-31.
267 Chock, David P., "A Simple Line-Source Model for Dispersion
Near Roadways," Atmospheric Environment, Vol. 12, pp. 823-829,
1979.
277 "Air Quality Criteria for Carbon Monoxide," Environmental
Health Service, Public Health Service, Dept. of HEW, March 1970,
AP-62.
28/ "Dispersion of Pollutants Near Highways - Data Analysis and
Model Evaluation," Environmental Sciences Research Laboratory, U.S.
EPA, EPA-600/4-79-011, Feb. 1979.
297 Schwartz, Sam, Manhattan Transporation Department, Personal
Communication with R. Dwight Atkinson, ECTD-EPA, September 10,
1979.
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CHAPTER VI
ECONOMIC IMPACT
There is associated with nearly all emission standards a
cost of compliance. In this chapter, the costs necessary for
compliance with these regulations are examined and analyzed.
The primary cost involves the development and installation of
emission control technology and hardware on the diesel vehicles.
Lesser costs are incurred by the emissions testing required for EPA
certification, which include the purchase of new instrumentation
and equipment required for the measurement of particulate emis-
sions. All of these costs are borne by the manufacturer, who, in
turn, passes them on to the consumer. The manufacturer will also
attempt to make a profit on his investment and this will also be
passed on to the consumer. A return on the manufacturer's invest-
ment is necessary, even if the investment is for pollution control
equipment. Finally, the consumer also must bear any additional
operating costs that may result from the proposed standards. All
costs presented in the following sections will be in terms of 1979
dollars.
A. Cost to Vehicle Manufacturers
1. Emission Control System Costs
The technology expected to be used to meet the 1982 and 1985
particulate emission standards was discussed in Chapter IV.
Contrary to EPA's projections in the draft Regulatory Analysis,_!/
vehicle manufacturers are no longer expected to use turbocharging
Co meet the 1982 standard. Instead, it appears that only minor
combustion chamber modifications will be needed to meet this
initial standard. To meet the 1985 standard, all vehicles except
Che Volkswagen Rabbit are expected to require trap-oxidizers.
It is possible that some of these vehicles will be able to use
other techniques to meet the final standard, such as turbocharging
or other engine modifications, but to be conservative, this eco-
nomic analysis will assume that all except the Rabbit will require
crap-oxidizers.
The actual combustion chamber modifications that will be used
co meet the 1982 standard are difficult to identify. The light-
duty diesel manufacturers have been attempting to reduce the
particulate emissions from their vehicles since it became evident
cnat EPA was serious about controlling particulate emissions from
light-duty diesels. Some of the resulting modifications will be
introduced in 1980 with others being introduced in 1981 and 1982.
Complicating matters is the fact that engine modifications have
also been introduced to reduce hydrocarbon and nitrogen oxide
emissions. Some of these modifications have improved particulate
emissions while other have increased particulate emissions.
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To simplify matters, the uncontrolled baseline will be taken
to be the 1978-1979 model years, which followed so closely after
the Clean Air Act Amendments of 1977 that no modifications to
reduce particulate emissions could have been made. From that time
to the 1982 model year, no manufacturer is expected to add any
control hardware to reduce particulate emissions. All that should
be required are modifications to the existing designs of the
engine. As such, the only costs resulting should be those related
to research, development, and retooling. These costs have been
estimated to be $10 per vehicle averaged over all light-duty diesel
sales between 1981 and 1983.2j Due to delaying the standards to
1982 and 1985, the appropriate averaging period would be the
1982-1984 model years. As three model years are involved in
both cases, the $10 per vehicle cost should be appropriate in
either case.
Beginning in 1985, EPA estimates (for economic purposes)
that.all vehicles except the Volkswagen Rabbit will require a
trap-oxidizer. The expected costs of trap-oxidizer systems for
various engine sizes are shown in Table VI-1.2/ The costs decrease
with time because the accumulated production volumes are increasing
with time. A 12 percent learning curve was assumed to apply for
the first five years of trap-oxidizer production, which means that
the cost was reduced by 12 percent each time the accumulated
production doubled. The fleet-wide average costs include the
sales-weighted effect of small producers, whose small production
volumes can lead to very high costs. It was conservatively assumed
that each manufacturer would manufacture its own trap-oxidizers.
As can be seen from Table VI-1, the costs for the smallest manufac-
turer of light-duty diesels could be over two and a half times the
fleet-average cost. With these kinds of economics, it would seem
likely that these small manufacturers would purchase their trap-
oxidizers from an outside supplier to take advantage of lower
production costs. Therefore, these high costs should never occur.
However, they are shown here to indicate what would happen if these
small manufacturers were forced to produce their own control
systems.
The average costs for each year are also shown in Table VI-1.
They were calculated by simply taking the arithmetic mean of the
costs for the three engine sizes. It was assumed that in the
timeframe in question, the production of 4-, 6-, and 8-cylinder
engines would be roughly equal and that this simple averaging would
suffice. 2/ As can be seen, the fleet-wide average cost is ex-
pected to be $189-$224 per vehicle in 1985 and drop to $128-$152
per vehicle by 1989.
The original calculation of these costs assumed that the
second standard would be implemented for the 1984 model year
and covered the five-year period between 1984 and 1988.2J As
we are now interested in the period 1985 tnrough 1989, the original
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Table VI-1
Estimated Costs of Trap-Oxidizer Systems
at Predicted Production Volumes 2/
Largest Smallest
# of Engine Fleetwide Manufacturer Manufacturer
Cylinders Average (GM) (IHC)
1985 4 153-190 133-165
6 184-220 160-191
8 229-263 199-228 469-556
Ave. 189-224 164-195
1986 4 132-164 115-142
6 159-189 139-165
8 197-227 171-197 413-490
Ave. 163-193 142-168
1987 4 119-147 104-129
6 144-170 125-149
8 178-204 156-179 375-444
Ave. 147-174 128-152
1988 4 110-136 96-118
6 131-157 115-138
8 164-188 144-165 348-413
Ave. 135-160 118-140
1989 4 104-128 90-111
6 125-149 109-130
8 155-179 136-155 326-387
Ave. 128-152 112-132
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costs have been simply delayed ne year. For example, what was
originally the fleet-wide average cost in 1984, $189-224, is now
taken to be the same cost in 1985. This is an approximation which
results in marginally higher costs, since the production in every
subsequent year is higher than the preceding year and costs
decrease with increasing production. However, because production
is only increasing 10-25 percent per year during this period, the
costs shown in Table VI-1 should only be around 2-4 percent high,
which is within the general error of cost estimating.
A range of costs is shown in Table VI-1 because the actual
components which will comprise a trap-oxidizer can be variable.
The cost of two different systems have been included in the above
range. The simpler system includes a trap, exhaust insulating
features and a throttle with simple electro-mechanical control to
periodically raise the exhaust temperature. The more complex
system consists of a trap, exhaust insulating features and a
complex electronic-control unit using a number of sensors to
control a throttle on the intake air. A more detailed discussion
of both the systems involved can be found elsewhere.2/
The Volkswagen Rabbits are expected to meet the final standard
with further modifications to the engine at a similar cost to that
of meeting the 1985 standard, $10 per vehicle. All light-duty
diesels built after 1985 are expected to retain the engine modifi-
cations of the earlier years. However, these modifications shall
carry no cost since the research, development, and retooling costs
shall have been paid for during the two previous years.
2. Certification Costs
Certification is the process that a vehicle manufacturer must
go through to demonstrate to EPA that its vehicles are designed to
meet emission standards over a predetermined useful life. A
manufacturer must first submit an application for certification to
EPA. Then the vehicle in question undergoes two types of testing.
The first type of testing is a durability test. This test covers
50,000 miles (80,500 km) of driving during which the vehicle is
tested for emissions every 5,000 miles (8,050 km). The durability
test is used to determine the function between emission levels and
accumulated mileage. The data from a durability test of a single
vehicle type may then be used to characterize the durability of
other slightly different vehicles within that engine family ex-
pected to have similar emission deterioration.
The second type of test, an emission-data test, is performed
to determine the level of emissions from the various vehicles
in each family. This test is performed after each vehicle has
been driven 4,000 miles (6440 km). The emission level at 50,000
miles is then determined by multiplying the emission-data test
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results by the deterioration factor derived from the durability
test vehicle. There will typically be three to five emission-data
tests run for every durability test performed. This allows the
emissions of up to five different vehicles to be determined without
the cost of running five durability tests.
If a manufacturer does not change its engine or vehicle design
significantly from one year to the next, it may request that EPA
"carryover" the emission test results from the year before to the
current year. In this way, the manufacturer can obtain certifica-
tion without repeating the process needlessly, assuming that the
emission standards have not been reduced to a level below the past
year's emission results.
In the case of these particulate regulations the standard will
become effective in the 1982 model year. Normally, this would
prevent any carryover of the previous year's testing because
particulate emissions were not being measured in the previous
year. However, in this case, the option is being made available to
measure particulate emissions during 1981 certification so that
carryover can be a possibility. As the standard for NOx is being
reduced in 1981, most vehicles are expected to have to recertify in
1981. Certification to the 1982 particulate standard in 1981 is a
real possibility since all manufacturers were expected to be able
to meet the 0.6 g/mi (0.37 g/km) standard in 1981. A one-year
delay was made because the promulgation date of the standard was
too late to require all manufacturers to certify all of their
vehicles in time for the start of the 1981 model year. However,
there should be time for manufacturers to certify most of their
vehicles for particulate emissions in 1981, if they so choose. It
is possible that this regulation will require very few additional
certification tests in 1982, or that it will require all that
normally would be required by a new standard, because no one was
able to take advantage of the option of certifying in 1981. The
first situation would result in nearly no 1982 certification costs
being due to this regulation. The second would result in nearly
all 1982 certification costs of light-duty diesels being due to
this regulation. However, there are always new models being
introduced and significant changes occurring with others that
require recertif ication regardless of emission standards changing.
This will be particularly true for light-duty diesels, because the
growth in sales expected during this timeframe will include many
new models. Thus, it will be estimated that 30 percent of the 1982
certification costs will result from new or modified models and at
70 percent will be due to this regulation.
It is estimated that a durability test will cost about
$168,000 to perform while an emission-data test will cost $23,000.
3/ Of these costs, 3.5% result from actual testing while the
•r"est is due to vehicle use and mileage accumulation. Table VI-2
shows the number of successful tests each manufacturer is expected
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Table VI-2
Light-Duty Diesel Certification
Test Costs for MY 1982
Estimated Number Estimated Number
Manufacturer of Durability Vehicles \J of Emission Data Vehicles
General Motors 6 18
Volkswagen 3 8
Daimler-Benz 3 9
Peugeot 1 3
International Harvester 1 3
Others _8 _23_
22 64
Cost per Vehicle Tested 2/ $ 169,000 $ 23,000
Total Cost 2/ $3,790,000 $1,500,000
Cost Due to Particu-
late Regulation
Maximum V $2,653,000 $1,050,000
Minimum 5/ $0 SO
_!/ Approximately equal to number of Engine Families.
2J Hardin, Daniel P., Jr., "Light-Duty Vehicle Certification
Cost", EPA Memorandum to Edmund J. Brune, March 13, 1975.
Adjusted to 1979 dollars using an annual inflation rate of 8%.
_3_/ A factor of 1.55 has been applied to 3.5% of the test costs,
which is due to actual emission testing, to account for voided
tests and retests.
_4/ Includes a factor of 0.7 to account for those tests which
would have occurred without these regulations on new models and
models which were significantly modified.
5/ Assumes all vehicles were able to certify in 1981 and obtain
carryover.
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to perfor on light-duty diesels and the associated costs. All of
the costs in this section are stated in 1979 dollars. Based on
current EPA experience in testing light-duty diesels for gaseous
emissions, a void rate of 20% on such tests is typical. This
rate is expected to decrease in the future as experience with the
diesel procedure increases. When other disqualifiers are included
(e.g., manufacturer and administrative errors, lack of correlation
with previous tests, etc.), the overall retest rate becomes about
50%. The addition of a particulate measurement system is expected
to increase this retest rate by 5%, or to an overall rate of 55%.
This factor has been included in calculating the total costs shown
in Table VI-2.
The total cost of 1982 certification due to these regulations
is estimated to be $0-3.7 million. No additional costs due to an
inability to carryover should occur in 1983 and 1984 because the
particulate standard will not change. Certification costs in 1983
and 1984 will increase slightly, though, due to the need for
increased personnel requirements and the increased number of void
tests due to particulate testing. It is estimated that the
additional requirement of particulate measurement will require one
additional technician to be present for three hours per test. This
time period includes the weighing of the particulate filter.
Assuming the number of tests decreases 30%, due to a carryover of
50% o£ the 1982 models plus 20% additional new engines and model
lines, and a cost of $25 per hour for technicians, the additional
cost in 1983 and 1984 is $23,000 per year for the entire industry.
The 5% increase in retest rate amounts to about 15 extra emission
tests per year or about $6,000 per year.^/ Thus, the total cost of
1983 and 1984 certification due to these regulations is $29,000 per
year.
The result for the 1985 standard is slightly different than
that for the 1982 standard. The presence of a reduced particulate
standard will prevent carryover for most light-duty diesels where
it might have taken place since federal gaseous standards are not
expected to change in 1985 for these vehicles. It would be reason-
able to expect the number of engine families and models to increase
about 30% between 1982 and 1985, since total diesel production is
expected to increase in that timeframe. One-third of .these new
models should arrive in 1983, one-third in 1984, and one-third in
1985. Those that arrive in 1985 would not have been able to
carryover from 1984, even without particulate regulations, because
they will be brand new models. Thus, the cost of 1985 certifica-
tion of the new models in 1985 should not be counted against these
regulations. To account for the new models of 1983 and 1984, the
maximum 1982 certification costs should be increased by 20%. It is
also expected that with increased experience, the basic void rate
Of light-duty diesel emissions testing (before particulate testing)
should decrease. This decrease is assumed to be about 10%, re-
ducing the overall retest rate to 45% from 55%. It is assumed that
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this will occur in time for 1984 testing. Taking these factors
into account, 1985 certification costs due to these regulations
will be about $4.4 million. The additional costs of certification
in future years due to the 1985 standard should be about $34,000
per year.
The addition of particulate standards is not expected to
increase the number of Selective Enforcement Audit (SEA) tests
performed on light-duty diesels. These vehicles can already be
audited for compliance with gaseous emission standards. There will
be an increase in the cost of these tests, however, due to both an
increase in the number of voided tests and an increase in number of
personnel needed to perform each test. Currently about 40 light-
duty engine families are audited each year, with about ten vehicles
being tested in each audit._4/ Each test is expected to cost
about $400 (1979).2/ Roughly assuming that 10% of these engine
families will be diesels and using the above estimates for the
increase in voided tests and test personnel due to particulate
measurement, the increased cost of SEA testing due to diesels will
be $4,000 per year.
3. Test Facility Modifications
The light-duty diesel particulate regulations will require
that manufacturers purchase new equipment to modify existing
emission test cells to allow the measurement of particulate emis-
sions. EPA estimates that it will cost approximately $55,000 plus
$30,000 for a filter weighing system to modify each test cell._2/
A breakdown of this cost is shown in Table VI-3. Using this
estimate, the total cost to industry will be $4,065,000. The
distribution of this cost among the various manufacturers is shown
in Table VI-4. The estimated number of test cells and facilities
includes those required for SEA testing.
B. Costs to Users of Light-Duty Diesels
Purchasers of light-duty diesels initially will have to pay
for the costs of any emission control equipment used to meet the
particulate emission standards plus the cost of certification and
SEA which includes the cost of new particulate measurement equip-
ment. The vehicle manufacturers pass on these costs to the pur-
chaser by increasing the "first cost" or sticker price of the
vehic le.
To calculate these costs, an estimate of the number of light-
duty diesels which will be sold each year is needed. EPA's best
estimate of diesel penetration can be found in the Summary and
Analysis of Comments to the proposed regulation.^/ This estimate
is reproduced here in Table VI-5. The estimates of total light-
duty sales were determined by taking 1978 sales of light-duty
vehicles and light-dut-y trucks, and using a 2% per year growth
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Table VI-3
Costs of Modifying an Emissions Test Cell for the
Measurement of Particulate Emissions
Item
600 CFM PDP-CVS
18" Dilution Tunnel
Particulate Sample System
Cost Per Cell:
Microgram Balance
Weighing Chamber
Additional Cost Per Test Facility:
Table VI-4
Certification and SEA Test-Equipment Modification
Costs by Manufacturer
Estimated Number Estimated Number
Manufacturer of Modified Cells of Facilities
General Motors 24 13
Volkswagen 8 4
Daimler-Benz 6 3
Peugeot 2 2
International Harvester 2 1
Others 15 8
Total: 57 31
Cost
$38,000
10,000
7,000
$55,000
$10,000
20,000
$30,000
Total Cost I/
$1,710,000
560,000
420,000
170,000
140,000
1,065,000
$4,065,000
\l Based on $55,000 per cell modification and $30,000 per laboratory.
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Table VI-5
Year-by-Year Projections of the Diesel Fraction
of Light-Duty Vehicle Sales 2/
Model Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
Diesel
Fraction (%)
4.7%
7.5%
8.9%
9.5%
11.4%
13.8%
16.5%
17.6%
18.7%
19.7%
20%
20%
20%
20%
20%
Total Light-Duty
Diesel Sales
732,000
1,192,000
1,443,000
1,571,000
1,923,000
2,374,000
2,895,000
3,150,000
3,414,000
3,668,000
3,799,000
3,874,000
3,952,000
4,031,000
4,112,000
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rate. The 1978 breakdown sales by manufacturer was assumed to
stay constant through 1990. Diesel penetration rates were then
estimated for each manufacturer and combined to yield the diesel
fraction of total sales.
The costs of this regulation to users of light-duty diesels
can now be calculated and are shown in Table VI-6. The cost of
test equipment modifications were assumed to occur in 1981 and all
certification costs were assumed to occur during the year prior to
that model year. A 10 percent discount rate was used to determine
the present value of all expenditures in 1979. These costs were
then amortized over future diesel production to yield a constant
cost per vehicle (again using a 10 percent discount rate). All
costs incurred through 1983 were amortized over 1982-1984 pro-
duction, which are the model years for which the first standard is
effective. All later costs were amortized over the next five years
of production (1985-1989).
The costs of vehicle modifications are shown next in Table
VI-6; for 1982-1984 ($10 per vehicle) and for 1985 and on ($138-
$164 per vehicle). The latter value is a sales-weighted average of
the cost for Volkswagen Rabbits ($10 per vehicle) and the cost for
all other vehicles ($147-$174 per vehicle averaged over 1985-1989).
The users of light-duty diesels will also have to pay for any
increases in the costs of maintenance or fuel that occur because of
this regulation. No increases in maintenance or fuel costs are
expected due to the engine modifications occuring in 1982. The
trap-oxidizer is expected to require about $30 worth of maintenance
after the vehicle is 5 years old._2_/ The addition of a trap-oxidizer
system is also expected to reduce maintenance in two ways. One,
the system will include a stainless steel exhaust pipe which will
eliminate the normal need to replace it.2/ This is expected to
save an average of $36 once during the life"of the vehicle (at five
years). Two, the trap itself should eliminate the need for either
Che muffler or the resonator.2/ This also eliminates the need to
replace the muffler or resonator, which again occurs once when the
vehicle is five years old and typically costs $44. Altogether, the
addition of a trap-oxidizer should reduce operating costs by $50,
which would typically have occurred in the fifth year of "operation.
Discounting back to the year of purchase reduces this savings to
$31 per vehicle. No fuel penalty is expected from the use of a
trap-oxidizer.
The total cost to the consumer can now be simply added up.
For the 1982-1984 models, the users' cost should increase $11-$12
per vehicle. For the 1985 models, the cost of owning and using a
light-duty diesel should increase $107-$133 per vehicle. The range
of the latter cost is due to the possibility of different trap-oxi-
dizer systems being used on different models. The actual cost paid
by consumers will fall somewhere between these two costs, depending
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Table VI-6
Cost to the Consumer of Light-Duty Diesel
Particulate Regulations
Pre-Manufacturing Costs
Test Equipment - 1981
Certification and SEA - 1981
- 1982-1983
- 1984
- 1985 and on
Total 1981-1983 \J
Amortized over 1982-1984 Production "If
Total 1984-1988 _!_/
Amortized over 1985-1989 Product ion _2/
Control Hardware Costs
1982-1984
1985 and on (VW Rabbit)
(All others) 1985
1986
1987
1988
1989
(Sales-weighted average)
(Sales-weighted average
1984-88)
Operating Costs
1982-1984
1985 and on
(discounted to year of model)
Net Cost to Consumer
1982-1984
1985 and on
$4,065,000
$0 - 3,707,000
$33,000
$4,400,000
$38,000
$3,407,000 - 6,471,000
$1-2 per vehicle
$2,807,000
$0 per vehicle 3/
$10 per vehicle
$10 per vehicle
$189-224 per vehicle
$163-193 per vehicle
$147-174 per vehicle
$135-160 per vehicle
$128-152 per vehicle
$147-174 per vehicle
$138-164 per vehicle 4/
$0
-$50
-$31
$11-$12 per vehicle
$107-133 per vehicle
JY Discount rate of 10%, present value in 1979 dollars.
2j Amortization weighted to result in an equal cost per vehicle
over the years of production cited. Discount rate assumed to
be 10%. Expenses are assumed to occur on January 1 of the
given year and revenues are assumed to be received on December
31 of the given year.
_3_/ Less than $0.45 per vehicle.
kj Based on 80% of VW1 s diesel production being Rabbits, 42% of
VW's production being diesel, 11.4% of fleet sales being
diesels (1985), VW representing 2,17, of light-duty sales and
he total diesel sales projections for 1985-89 shown in
Table VI-5.
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on the complexity of the t rap-oxidizer syst.em used on a given
mode 1.
C. Aggregate Costs—1982-1989
The aggregate cost to the nation of complying with the 1982
and 1985 light-duty diesel particulate standards consists of the
sum of increased costs for new emission control devices, new test
equipment, additional certification costs, and changes in vehicle
fuel consumption and maintenance requirements. These costs will be
calculated for two periods. First, the aggregate cost of the 1982
standard will be calculated for the years for which that standard
will be effective, 1982-1984. Second, the cost of the 1985 stan-
dard will be calculated over a period of five years, 1985-1989.
Both aggregate costs will be presented in terms of 1979 dollars,
present value in 1985. The year 1985 was chosen as the present
value reference point to coincide with the implementation date of
the second standard, since most of the costs of the regulation are
associated with this standard. The aggregate cost of the 1982
standard was also calculated using 1985 as the present value
reference point so that the two costs could be additive.
The aggregate cost to the nation is dependent on the number of
light-duty diesels sold during these time periods. Any projection
of this type will by nature be rough, due to the many social and
economic factors involved. The sales projections used will be
those shown in Table VI-5, plus and minus 25%. The aggregate cost
to the nation based on these sales projections are shown in Table
Vl-7. The per vehicle costs of the two emission standards were
taken from Table VI-6.
As shown in Table VI-7, the aggregate cost of the 1982 stan-
dard between 1982 and 1984 will be $42-76 million (present value in
1985, 1979 dollars). The five-year aggregate cost of the 1985
standard will be $897-1857 million (present value in 1985, 1979
dollars) between 1985 and 1989.
D. Socio-Economic Impact:
1. Impact on Light-Duty Vehicle Manufacturers
These regulations will affect diesel manufacturers in two
ways. First, the manufacturers will be required to modify their
current test cells to allow for particulate measurements and to
certify their vehicles in 1982 and 1985 when otherwise they would
have been able to obtain carryover. Secondly, the addition of
particulate control hardware including R & D expense will raise the
initial price of the vehicle and may affect sales.
Overall, diesel manufacturers may have to spend $7.7 million
(1979 dollars) by 1982 to modify their emission test cells and
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Table VI-7
Aggregate Cost to the Nation of Light-Duty
Diesel Participate Regulations
Per Vehicle
Cost Sales Aggregate Cost _!_/
1982 Standard $11-12 3.2-5.3 million $42 to 76 million
1982-1984 Model Years
1985 Standard $107-133 10.3-17.2 million $897 to 1857 million
1985-1989 Model Years
1982-1989 Total: $939 to 1933 million
I/ Present value in 1985, 1979 dollars, 10% discount rate used.
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certify 1982 model year vehicles. A breakdown of these, costs by
manufacturer is shown in Table VI-8 (taken from Tables VI-2 and
VI-4). General Motors could bear the largest portion of this, $2.7
million. This should not prove to be a problem for a company with
over $35 billion in annual sales and $2.2 billion in capital
expenditures (1975). 5J Volkswagen may have to spend $1.0 million,
which again is not troublesome for a manufacturer of 2.1 million
vehicles worldwide (1976).5/ Daimler-Benz may have to spend $0.9
million in 1981, but even if all of this was added to the price of
their 1982 U.S. diesel models, it would only amount to $32 per
vehicle, which is only about 0.2% of their sticker price (10%
discount rate). If Daimler-Benz would spread the cost over 5
years, the per vehicle cost including 1985 certification would only
be $10. Peugeot and International Harvester may have to spend more
than the others, when compared on a per vehicle basis, because of
their relatively small sales. On an absolute basis, though,
neither would be expected to have a problem raising the capital
involved. Thus, while there is a real cost involved in this area,
no manufacturer is expected to be adversely affected.
The second area of impact of these regulations on manufac-
turers occurs in the area of increased vehicle prices due to
emission control hardware. Cash flow problems should not be
significant since the money invested in control devices is re-
covered soon after from the sale of controlled vehicles. The
sticker price increase due to these devices, though, could poten-
tially affect sales. In 1982, sticker prices of light-duty diesels
are expected to increase $11-312 per vehicle. With current vehicle
prices ranging between $5,000 and $23,000, this increase represents
less than 0.3% of the initial vehicle price and sales should not be
affected.
Between 1985 and 1989 projected price increases are expected
to average between $138 and $164 per vehicle. This represents
about 1-6% of initial vehicle prices. This real price increase
could affect sales in two ways. Purchasers of diesel-powered
vehicles might switch to gasoline-powered vehicles. Or some
purchasers may decide to wait an additional year before buying a
new diesel.
It should be realized that the price of a gasoline-powered
vehicle will also increase by 1985 due in part to the new gaseous
emission standards being implemented in 1980 and 1981. Using the
same cost methodology as that used for trap-oxidizers, a three-way
catalyst system with its larger production volumes is expected to
cost $226._2_/ This, plus the cost of exhaust gas recirculation
(EGR) and evaporative hydrocarbon control would place the total
cost of pollution control equipment on gasoline-fueled vehicles
around $240. The cost for a diesel to meet these gaseous emission
standards should be less than $30 per vehicle based on current
designs of exhaust gas recirculation systems. Even with the
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Table VI-8
Initial Investment Required by
Light-Duty Diesel Participate Regulation
Manufacturer
General Motors
Volkswagen
Daimler-Benz
Peugeot
International Harvester
Others 2/
Cost for Test Cell
Modification and 1981 Certification _!_/
$2,710,000
1,044,000
920,000
337,000
307,000
2,450,000
TOTAL: $7,768,000
_!/ Present value in 1981, 1979 dollars.
21 Could include Ford, Chrysler, AMC, BMW, Volvo, Fiat, etc.
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particulate regulations, the overall cost of pollution control
from diesels should be less than that from gasoline engines. It is
true that between now and 1985, the price of light-duty diesels
will rise more than that of gasoline-fueled vehicles, but this is
only because gasoline-fueled vehicles are currently paying a larger
price for pollution control than diesels. Light-duty diesels will
lose most of their advantage (with respect to the cost of pollution
control) in 1985 due to this regulation, but it will be an advan-
tage that was gained from previous environmental regulation.
Gaseous pollutants such as hydrocarbons, carbon monoxide, and
oxides of nitrogen simply came under control before particulate
emissions. It appears, then, that diesel sales should not decrease
at the expense of gasoline sales due to aggregate emissions regula-
tions. Second, any absolute decrease in diesel sales should be
less than any decrease in sales of gasoline-powered vehicles and
this particulate standard should be no less acceptable than the
Congressiona1ly-raandated gaseous emission standards from this
standpoint.
Thus, these regulations should not adversely affect the
light-duty diesel industry, either through employment or productiv-
ity. Though a small decrease in diesel sales may occur due to the
1985 standard, this decrease should not be greater than any experi-
enced by the gasoline-powered vehicle industry due to gaseous
emission standards.
2. Impact on Users of Light-Duty Diesels
Users of light-duty diesels will be affected through higher
initial vehicle costs averaging $11-$12 for 1982-84 and $138-$164
for 1985 and on. The average retail price of a new car in 1978 was
estimated to be $6,940 or $7,495 in 1979 using an 8 percent infla-
tion rate.kj This means that the average vehicle sticker price
will increase 0.2 percent between 1982 and 1984 and 1.9-2.2 percent
in 1985 and beyond. Users of light-duty diesels will actually save
$50 through reduced maintenance costs beginning in 1985. The
lifetime cost of owning a vehicle was $12,600-17,900 in 1976
(undiscounted) .]_/ Inflating this to 1979 prices using an 8 percent
inflation rate yields $15,900-22,500. When the increased cost of
this regulation are compared to lifetime vehicle costs, the in-
creases represent only 6.1 percent (1982-84) and 0.5-0.9 percent
(1985 on) (undiscounted) of lifetime vehicle costs. Thus, this
regulation should not have an adverse impact on the users of
light-duty diesels.
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References
_!_/ "Draft Regulatory Analysis - Light-Duty Diesel Particulate
~ Regulations," MSAPC, OANR, EPA, December 22, 1978.
_2/ "Summary and Analysis of Comments - Light-Duty Diesel Particu-
late Regulations," MSAPC, OANR, EPA, October 1979.
_3/ Hardin, Daniel P., Jr., "Light-Duty Vehicle Certification
Cost," EPA Memorandum to Edmund J. Brune, March 13, 1975.
_4/ Personal communication with Frank SLaveter, Mobile Source
Enforcement Division, EPA, July 10, 1979.
_5_/ Automotive News - 1977 Market Data Book Issue, April 27,
1977.
_6_/ Personal communication with Tom Alexander, Economic Analysis
~ Division, OPE, EPA, August 21, 1976.
l_l "Cost of Owning and Operating an Automobile - 1976," FHA, DOT,
1977.
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CHAPTER VII
COST EFFECTIVENESS
Intuitively, cost effectiveness is a measure of the economic
efficiency of an action towards achieving a goal. Historically
however, the cost effectiveness of emission control regulations has
been expressed in such terms as "dollars per ton of pollutant
controlled." This expression is a measure of the cost of the
regulation, not necessarily its efficiency. The presence of this
conflict makes it awkward to speak in relative terras about cost
effectiveness since a low cost-effectiveness value implies a highly
effective regulation. To escape this conflict here, and still
follow the precedent of placing cost in the numerator, the measure
of cost effectiveness will be referred to as the cost-effective-
ness ratio, or C/E ratio.
Furthermore, air pollution control regulations have multiple
and frequently differing goals and, therefore, do not easily lend
themselves to direct comparison of C/E measures. In the past, the
principal application of comparing C/E measures has been the
evaluation of alternative control strategies applicable to the same
source, in the same time frame, and with the same objective. This
markedly simplifies the analysis and, as will be seen below, avoids
many problems. Nevertheless, a rough measure of one aspect of the
relative merit of the light-duty diesel rules can be achieved by
comparing the C/E measures of alternative diesel standards with
other strategies designed to control particulate emissions. One
area where EPA has adopted regulations to limit particulate emis-
sions is the New Source Performance Standards (NSPS) for Stationary
Sources called for by Section 111 of the Clean Air Act. While the
statutory purposes and tests in Section 111 are different from
those applicable to this diesel particulate standard, a rough
comparison has been made which indicates that this decision is not
inconsistent with other decisions the Agency has made to control
particulate emissions.
In this chapter, the C/E measures for the two levels of
diesel particulate control will be calculated and- compared to
those from other control strategies. As will be seen, it is
not possible to take into account all of the environmental factors
such as meteorological conditions, location, population exposures,
etc., due to a lack of data. However, as many of the factors for
which data are available will be incorporated.
A. 1982 Light-Duty Diesel Particulate Standard
The calculation of the C/E ratio for light-duty diesel par-
ticulate control can be performed using input data already pre-
sented in past chapters. The uncontrolled emission level is 1.0
g/mi (0.62 g/km), and the standard is 0.6 g/mi (0.37 g/km). If
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125
these levels are assumed to occur over me entire life of the
vehicle, the improvement due to regulation is O.A g/mi (0.25 g/km).
If the life of a light-duty diesel is taken to be 100,000 miles
(160,900 km), then the lifetime emission reduction is 0.04 metric
tons. The cost of control has been calculated in Chapter VI to be
$11-12 per vehicle. Thus, the C/E ratio is $11-12 divided by 0.04
metric tons, or $275-300 per metric ton of particulate controlled.
This procedure of dividing lifetime costs by lifetime emission
reduction does have the effect of underestimating the C/E ratio
somewhat compared to the C/E ratios of stationary source controls
to be presented later. However, as this procedure has been used
for all past mobile source regulations, its use will be continued
here.
B. 1985 Light-Duty Diesel Particulate Standard
For this standard, two C/E ratios should be calculated. The
first is an overall C/E ratio which represents the cost of the 1985
standard compared to no control. The second is the incremental C/E
ratio which expresses the cost of the 1985 standard over that of
the 1982 standard. It is this latter ratio which should be com-
pared to the C/E ratios of other control strategies.
The overall cost per vehicle of the 1985 standard is $107-133
(Chapter VI, Section B). The overall emission reduction is 0.8 g/mi
or 0.08 metric tons over the life of the vehicle. The overall C/E
ratio is then $1,337-1,662 per metric ton of particulate con-
trolled .
To determine the incremental C/E ratio, both the incremental
cost and the incremental effect of the 1985 standard, over that of
the 1982 standard, must be determined. The incremental cost is
$107-133 minus $11-12, or $96-121. The incremental control is 0.08
minus 0.04 metric tons, or 0.04 metric tons of particulate con-
trolled. The incremental C/E ratio is then $2,400-3,025 per metric
ton of particulate controlled.
C. Comparison of Strategies
The purpose of this section is to determine the C/E ratios of
other particulate control strategies and demonstrate that the C/E
ratio of the light-duty diesel regulations is not inconsistent with
those of past strategies. All comparisons will be made against the
higher incremental C/E ratio of the 1985 standard. If the 1985
standard is consistent with the incremental C/E ratios of other
strategies, then the 1982 standard will also be consistent. All of
the C/E ratios examined should be marginal in nature. This is
necessary because the comparison must be made between the cost of
the last level of control and cannot be influenced by the costs
at less stringent control levels.
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126
The incremental C/E ratios for several stationary sources are
shown in Table VII-1. Except for the industrial boiler category,
all of the C/E measures shown represent the costs and emission
reductions of a Federal New Source Performance Standard over
the less stringent alternative rejected by the Agency in selecting
the level of the standard. The C/E ratio for the industrial boiler
category represents the costs and effectiveness of two alternative
control devices which are available.
As mentioned earlier, the most direct and easiest use of a
cost-effectiveness measure is to compare various levels of control
of a single source. In this case, most of the factors pertinent to
the environmental impact, such as source location, dispersion
characteristics, and pollutant characteristics, are the same for
all the levels considered and the 'dollar per ton1 measure is a
good relative measure of the cost effectivenesss of the various
strategies. Given enough knowledge and data, there is no reason
that this same kind of analysis cannot be used to compare various
strategies for controlling different sources. The problem is, of
course, that the necessary data is usually very difficult to obtain
and not available. The comparisons being made in this section are
not true comparisons of the cost effectiveness of any of the
strategies being examined. The necessary data is simply not
available. However, comparisons such as these are being made
elsewhere and will be made in the future. The goal here will be to
make the comparisons, while at the same time stating clearly the
limitations involved, insuring that any use of the results of this
section is accompanied by full knowledge of their meaning.
The strategies being examined here all address particulate
emissions on a nationwide scale. The light-duty diesel regulations
will apply to every new light-duty diesel sold in the U.S. begin-
ning in 1982, regardless of where the vehicle is bought or used.
Likewise, the New Source Performance Standards (NSPS) for sta-
tionary sources also apply to all new or significantly modified
plants of a certain type nationwide. No comparison of the diesel
regulations will be made to other mobile source strategies because
these diesel regulations are the first to control the emission of
particulate matter from motor vehicles.
While both the mobile source and stationary source strategies
being examined control particulate emissions into the atmosphere,
there are differences in their primary purposes. An examination of
Title II of the Clean Air Act, particularly section 202, shows that
the primary purpose of mobile source regulations is to protect the
public health and welfare. The primary purpose of the NSPS's, on
the other hand, is to reduce inequities in interstate competition
for economic growth, while minimizing emissions through the nation-
wide use of the best available control technology. A nationwide
NSPS prevents those states and Loca1ities.without severe air
pollution problems from having an unreasonable advantage in drawing
new plants from areas where strict controls are required.
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Table VII-1
Incremental Cost Per Ton of Particulate Removed
for Selected New Stationary Sources (1979 Dollars)
Cost-$/Metric Ton for
Particulate Collected
Source in Incremental Range Reference
Medium Sized Industrial
Boilers_l_/ $900 1
Electric Utility Coal-
Fired Steam Generator^/ $800-$900 2
Kraft Recovery Furnace3_/ $1300-$1700 3
Kraft Smelt Tank_4/ $150-$200 3
Rotary Lime Kiln5_/ $1100-$1200 4,5
Electric Arc Furnaces
- Steel6/ $600 6
Baghouse (0.03 lb/10 BTU) versus cyclone (0.3 lb/10 BTU).
2] fi
High efficiency ESP (0.03 lb/10 BTU) versus lower efficiency
ESP (0.1 lb/10 BTU).
I/
High efficiency ESP (99.5 percent) versus lower efficiency ESP
(99.0 percent).
4/
Venturi scrubber versus Demister (80 percent efficiency).
51
High efficiency ESP (0.3 Ib/ton limestone) versus lower
efficiency ESP (0.6 Ib/ton limestone) for 500 TPD plant; baghouse
(0.3 Ib/ton) versus lower efficiency ESP for 125 TPD plant.
A/
Direct evacuation with 90 percent efficient canopy hood versus
direct evacuation with open roof.
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While the priory purposes of the two types of strategies
differ, the levels of control they represent do have a common
purpose, that of protecting the public health and welfare. The
NSPS's exist because some states and localities require at least
this level of control to protect the public health and welfare in
their areas. There are factors that affect the relative stringency
of the two types of standards. For example, economics may be a
more critical parameter for NSPS's than mobile source standards and
the requirements for the demonstration of technology are stricter
for NSPS's than mobile source standards. In a rough sense, how-
ever, both represent control levels implemented to protect the
public health and welfare.
To take one rough step toward making the measure of cost
effectiveness more relevant to health and welfare impacts, the
basis of the previously cited 'dollar per ton' figures shall be
modified to reflect the cost of controlling inhalable and fine
particulate. In Chapter V, it was shown that it is these par-
ticles that have the greatest potential for adverse health impact.
Thus, it is appropriate to emphasize the control of these par-
ticles. Also, it is these smaller particles (inhalable particles
have diameters of Less than 15 micrometers and fine particles have
diameters of less than 2.5 micrometers) which have the greatest
effect on visibility, which is likely one of the largest welfare
effects of diesel particulate emissions.
Particle size data currently available for these sources
are limited and the figures presented below should only be con-
sidered to be rough approximations. The size of diesel particulate
has already been discussed in Chapter V. All of the uncontrolled
diesel particulate is inhalable (diameter less than 15 micrometers)
and between 94 and 100% is fine (less than 2.5 micrometers). It
will be assumed that these size fractions will remain constant
after the first level of particulate control in 1981 and the
necessary levels of NOx control needed to meet the 1981-1984 NOx
standards. This is a reasonable assumption since there is no reason
to believe that the size should change drastically with the ad-
dition of EGR. The trap oxidizer, however, may be more efficient
in trapping large particles than small ones. To be -conservative,
it will be assumed that all coarse particles (diameter greater than
2.5 micrometers) are captured and burned and that only that amount
of fine particles necessary to meet the 1985 standard are also
captured and burned. Using these assumptions, the result is that
100% (by weight) of the additional particulate controlled by the
1985 standard is inhalable and 91-100% is fine. An average value
of 96 percent will be used for the latter figure.
Power plants (large steam generators) tend to emit larger
particles^than diesel engines. EPA has measured the particle size
distribution of electrostatic precipitator effluent at both the
previous emission standard of 0.1 pounds per million BTU (43
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129
nanograms per joule) and the revised standard of 0.03 pounds per
million BTU (13 nanograms per joule). Of the additional paj—
ticulate collected at the revised standard, 90-100 percent (by
weight) is inhalable and 20-40 percent is fine._6_/
Medium sized boilers are commonly spreader stoker-type boilers
which emit coarser particles than pulverized coal-fired boilers.
As an approximation, it is estimated that 70 percent of the par-
ticulate collected in the incremental range between a cyclone and
baghouse is inhalable and 25 percent is fine. For electric arc
furnaces, the particulate removed by a baghouse installed with a
canopy hood is about 90 percent inhalable and 60 percent fine.67
For a kraft recovery furnace the incremental particulate collected
by an ESP in the range from 99.5 to 99.0 percent is about 100
percent inhalable and 70 percent fine. The differential quantity
of entrainment collected by a venturi scrubber in comparison with a
demister on a kraft mill smelt tank is about 85 percent inhalable
and 55 percent fine. High efficiency collection versus medium
efficiency collection of particulate from a rotary lime kiln
captures particulate that is about 80 percent inhalable and 50
percent fine.
Using these approximations, the C/E ratios for these six
source.s can now be placed on an inhalable and a fine particulate
basis. The results are shown in Table VII-2. As can be seen, the
cost effectiveness of the 1985 light-duty diesel standard is not
inconsistent with those of past Agency actions or with a possible
future Agency action (medium-size industrial boilers).
It is important to emphasize a point made earlier, i.e., that
in some respects the mobile and stationary source strategies for
particulate control have certain differences in their primary
purposes. Therefore, selection of a measure of effectiveness for
comparison purposes has inherent limitations. In spite of these,
however, a comparison may still be useful to the degree that it
focuses on one of their common purposes, protection of public
health and welfare.
Up to this point, however, we have only incorporated one
factor which may improve the comparability of the cost-effective-
ness measures for different source strategies. There are many
other factors which would need to be accounted for before a truly
valid comparison could be made, such as emission dispersion char-
acteristics, source location, chemical composition (and resulting
health effects) of the particulate, etc. As these factors cannot
be incorporated at this time due to lack of data, even the com-
parison performed in Table VII-2 must be taken cautiously. The
incorporation of the factors mentioned above could change the
results drastically.
To indicate this possibility, one rough calculation will be
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Table VII-2
Incremental Cost-Effectiveness Ratios of Particulate
Control Strategies Using Three Measures of
Effectiveness (1979 Dollars per Metric Ton)
Total Particu-
Controlled Source
Light-Duty Diesel
1982 Standard
Light-Duty Diesel -
1985 Standard
Utility Steam Gen-
erators
Medium-Size Industrial
Boilers
Electric Arc Furnaces
Steel
Lime Kilns
Kraft Pump Mills
Recovery Furnaces
Smelt Tank
late Basis
275-300
2400-3025
800-900
900
600
1100-1200
1300-1700
150-200
Inhalable Particu-
late Basis
275-300
2400-3025
800-1000
1300
700
1400-1500
1300-1700
180-240
Fine Particu-
late Basis
286-312
2500-3150
2000-4500
3800
1000
2200-2300
1900-2400
270-360
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made comparing the air quality impact of a given rate of emission
for both diesels and power plants. Only rough large-scale impacts
will be considered, so this will not b
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Table VII-3
Air Quality Impact of Three Steam Generators
at Ground Level 4/*
Annual Emission Rate
(metric tons per year)
Plant Size (Megawatts)
25 300 1000
71
854
2847
Typical Stack Height (meters)
75
175
275
Maximum Ground Level Concentration
(micrograms per cubic meter):
Annual Mean
24-Hour Maximum
0.1
1.3
0.1
1.3
1.3
Ratio of Maximum Ground Level Concen-
tration to Annual Emission Rate (micro-
grams per cubic meter/metric tons
per year)
Annua 1
24-Hour Maximum
.0014
.0183
0.00011
0.0015
<0.000035
0.00046
* Numbers bracketed (_/) indicate references at the end of this
chapter.
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be by light-duty diesel in 1990. At a particulate emission rate of
1.0 gram per mile, light-duty diesels would emit 321 metric tons
per year. Using this scenario) the ambient concentration at a
typical TSP monitor would be 1.5 micrograms per cubic meter (Table
V-7). The ratio of ambient concentration to the annual emission
rate would be 0.0047 microgram per cubic meter (per) metric ton per
year. The maximum 24-hour impact for light-duty diesels is about
3.16 times the annual geometric mean (see Chapter V). Thus, the
ratio of the 24-hour ambient concentration to annual emission rate
would be 0.0149 microgram per cubic meter (per) metric ton per
year. These results are summarized in Table VII-4. A comparison
of these values with those in Table VII-3 shows that the ambient
concentrations per unit emission rate of light-duty diesels is 3.4
and 134 times that for small and large steam generators on an
annual basis, respectively. On a 24-hour basis, the ambient
concentration per unit emission rate for small power plants is
actually 1.2 times larger than that for light-duty diesels. For the
large plants, however, light-duty diesels still have the larger
relative impact by a factor of 32.
As mentioned earlier, the above ratios are only an extremely
rough estimate of the relative air quality impacts of diesels and
power plants. Many simplifications were necessary to be able
to make this comparison at all. However, the results do indicate
the size of the factors which may occur if an extensive analysis
were performed and how the results of Table VII-2 might change if
other factors were incorporated. Finally, the results also indi-
cate clearly that the control of diesel particulate is no less cost
effective than certain other cost-effective control measures
adopted by EPA using the measures of effectiveness discussed above.
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Table VI1-4
Air Quality Impact of Light-Duty Diesels in the
Kansas City Metropolitan Area - 1990
Total vehicle miles traveled in area
Fraction of travel by light-duty diesel
(low estimate of dieselization)
Emission factor
Annual emissions
3.34 x 10 miles per year
0.094
1.0 gram per mile
314 metric tons per year
Maximum regional air quality impact 1.5
(micrograms per cubic meter)
Maximum 24-hour average per year 4.7
(micrograms per cubic meter)
Ratio of maximum ground level concen-
tration to annual emission rate
(micrograms per cubic meter (per) metric
tons per year):
Annual 0.0047
24-Hour 0.0149
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References
_!_/ "Particulate Emission Control Costs for Intermediate-Sized
Boilers," Industrial Cleaning Institute for EPA, February
1977.
2J "Electric Utility Steam Generating Units - Background Informa-
tion for Proposed Particulate Matter Emission Standards,"
OAQPS, EPA, July 1978, EPA 450/2-78-006a.
_3_/ "Standards Support and Environmental Impact Statement, Volume
1: Proposed Standards of Performance for Kraft Pulp Mills,"
OAQPS OAWM, EPA, September 1976.
kj "Standards Support and Environmental Impact Statement, Volume
1: Proposed Standards of Performance for Lime Manufacturing
Plants," OAQPS, OAWM, EPA, April 1977, EPA 450/2-77-007a.
5J Compilation of Air Pollutant Emission Factors, AP-42, Sup-
plement No. 7, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina, April, 1977.
6_f "Background Information for Standards of Performance: Electric
Arc Furnaces in the Steel Industry Volume 1: Proposed Stan-
dards," OAQPS, OAWM, EPA, October 1974, EPA-450/2-74-017a.
TJ Personal communication with Jim Abbot, Industrial Emissions
Research Laboratory Studies, ORD, EPA, January 10, 1980,
unpublished emission control test results.
_8_/ "Air Quality Assessment of Particulate Emissions from Diesel-
. Powered Vehicles," PEDCo Environmental for EPA, March 1978,
EPA-450/3-78-038.
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CHAPTER VIII
ALTERNATIVE ACTIONS
These particulate regulations for light-duty diesels were
required by Congress in the 1977 Amendments to the Clean Air
Act. Nonetheless, possible control of other sources of particulate
emissions were examined to ensure that these regulations were
consistent with EPA's program to improve the nation's air quality.
Also, Congress left it to EPA to determine the actual level of the
emission standard, so many alternatives were available in this
area. In the following chapter these alternative actions will be
presented and discussed. In the first two sections, those actions
which would preclude control of light-duty diesels will be pre-
sented. These would include 1) further control of stationary
sources, and 2) the control of mobile sources other than light-duty
diesels. Strategies for controlling fugitive dust or reentrained
dust have been discussed previously and will not be repeated
here._l_/* Next, alternatives to the traditional individual vehicle
emission standards will be presented and discussed. These alter-
native approaches include averaging the emission standard over all
corporate sales, or over all corporate diesel sales. Finally,
specific alternative emission standards to the 0.6 g/mi (0.37 g/km)
standards for 1982 and the 0.2 g/mi (0.12 g/km) and 0.26 g/mi (0.16
g/km) standards for 1985 will be presented and discussed.
A. Control of Stationary Sources
The majority of major urban areas have severe particulate
non-attainment problems. The need for reductions in particulate
emissions from some source or sources is clear. However, these
areas have also demonstrated that attainment is not feasible even
after adoption of all reasonable stationary source controls. While
new source performance standards can definitely help to mitigate
increased emissions and ambient impacts due to industrial growth,
they cannot be expected to reduce TSP concentrations in urban areas
from current levels. (See Chapter V.JYJ/) Thus, it is concluded
that further control of stationary sources is not.a viable alter-
native to these light-duty diesel regulations.
B. Control of Other Mobile Sources
In addition to considering further control of stationary
sources of particulate emissions as an alternative to controlling
light-duty diesels, the control of other mobile sources was also
considered. These alternative mobile sources include gasoline-
powered light- and heavy-duty vehicles, diesel-powered heavy-duty
vehicles, locomotives and aircraft.
Light-duty vehicles and trucks powered by the gasoline engine
and using leaded fuel were once a very significant source of
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partriculate emissions. In 1974, it is estimated that exhaust
emissions from these vehicles totalled 250,000 metric tons of
participate, with 107,000 metric tons classifiable as suspended
par t i cu 1 a t e ._3/ The great majority of this particulate matter
consisted of particles related to the lead and lead scavengers used
in the fuel. Since 1975 though, the majority of new vehicles
have required the use of unleaded fuel in order to prevent pre-
mature catalyst degradation. With unleaded fuel and catalysts,
these vehicles produce less than 3% of the particulate emissions of
a diesel-powered vehicle. By 1981, when more stringent gaseous
emission standards for light-duty vehicles will have come into
effect, it is expected that almost all manufacturers will require
the use of unleaded fuel in their vehicles. Thus, by 1982, when
these light-duty diesel particulate regulations come into effect,
new gasoline-powered light-duty vehicles and trucks will be pro-
ducing very low levels of particulate emissions. Thus, control of
these vehicles does not present an alternative to controlling
light-duty diesel particulate emissions.
Heavy-duty diesel vehicles, like their light-duty counter-
parts, are a significant source of particulate emissions. It is
estimated that by 1990, particulate emissions from uncontrolled
heavy-duty diesels will reach 171,000-241,000 metric tons per year
(Chapter V). This emission level is as large as the estimated
emissions from uncontrolled light-duty diesels mentioned earlier.
Also, much of the control technology available to light-duty
diesels should be equally applicable to heavy-duty diesels.
The Clean Air Act requires heavy-duty diesel particulate regula-
tions and EPA is in the process of formulating an NPRM in this
area. The control of heavy-duty diesel emissions does not reduce
the need for regulations for light-duty diesels. Tne rationale for
the level of the proposed light-duty standards has been based only
on the projected impact of light-duty emissions. The light-duty
standards have not been set at a level to alleviate the total
diesel contribution to ambient TSP levels. Reductions will be
required from heavy-duty diesels and have been assumed in the
process of determining the light-duty standards. Also, these
reductions from heavy-duty diesels are necessary from an air
quality standpoint if the contribution of diesel particulate
to ambient TSP levels is to be reduced as far as technology and
economics permit. Thus, controlling particulate emissions from
heavy-duty diesels is not an alternative to these light-duty
regulations, but is a necessary complement to the overall mobile
source scheme for reducing particulate emissions.
New regulations for heavy-duty diesel particulate emissions
have not yet been proposed because of changes currently planned for
the standards and test procedures for heavy-duty diesel gaseous
emissions. The current heavy-duty diesel gaseous emission test
procedure is a 13-mode steady-state test. There is an additional
transient test to measure smoke, since smoke levels typical of
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in-use driving do not appear during Che 13-mode cycle. A new
transient test procedure, which will replace the steady-state test
procedure, is being developed for use beginning in 1985. It has
been determined that this new transient test procedure is necessary
to adequately measure particulate emissions from heavy-duty
diesels. Thus, regulations governing particulate emissions from
heavy-duty diesels are currently being planned to come into effect
in 1985 when the transient test procedure becomes available for
diesels.
The contribution of heavy-duty vehicles powered by gasoline
engines to total particulate emissions was also examined. In 1975,
heavy-duty vehicles (gasoline) emitted about 51,000 metric tons of
part iculate ._4/ Because today's heavy-duty trucks (gasoline) are
still being built for operation on leaded fuel, this figure would
still be a rough estimate of emissions in 1978. While the par-
ticulate emission level o£ heavy-duty vehicles (gasoline) does not
compare with the particulate emission level of light- and heavy-
duty diesels, it is still significant. By 1984 though, it is
predicted that most new heavy-duty vehicles (gasoline) will be
equipped with catalysts due to new emission standards which will
come into effect that year. This will require unleaded fuel, and
the particulate emissions from these vehicles will decrease dras-
tically, as in the light-duty case. Thus, it appears that particu-
late emissions will be low from the new vehicles of this class by
1984, and no further control will be required.
Locomotives' are another source of particulate emissions in the
U.S. In 1975, locomotives emitted nearly 45,000 metric tons of
particulate.kj While this is not insignificant, a complete removal
of all locomotive particulate emissions would only be a fraction of
the necessary reductions of emissions from light-duty diesels.
Also, reductions in locomotive emissions will not decrease the
effect of automotive diesels near the roadway, where the largest
impacts will occur. Thus, while locomotive particulate emissions
may merit control at some time in the future, such control is not a
feasible alternative to the proposed light-duty diesel regulations,
either in magnitude or locality of emissions.
Finally, the control of particulate emissions from aircraft
was examined as a possible alternative to the proposed regula-
tions. In 1975, civil and commercial aircraft emitted 18,000
metric tons of part icula te._4/ This emission level is even less
than that from locomotives and amounts to only 7-12% of the pro-
jected light-duty diesel emissions in 1990. Thus, control of
aircraft particulate emissions is not a viable alternative to the
proposed standards for light-duty diesels.
C. Averaging Approaches
In the Notice of Proposed Rulemaking (NPRM), EPA invited
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interested parties to comment: on alternative regulatory approaches.
One alternative approach generated considerable discussion during
the public hearing and comment period — the development of an
average particulate standard. Presently, all mo tor vehicle
emissions standards are per vehicle standards, that is, each
manufacturer is required to certify every engine family at or below
each emission standard to receive certificates of conformity for
every engine family. Under an average emission standard, each
manufacturer would only have to insure that its average, fleet-wide
emission level was at or below the appropriate emission standard.
There are two primary advantages of an average emission standard as
opposed to a per vehicle emission standard. The first is the
increased flexibility that a manufacturer has in determining how it
is going to comply with the emission standard. Instead of being
required to design each engine family such that it can certify at
or below the emission standard, the manufacturer has more flexi-
bility as it must only conform to the requirement that its sales-
weighted average emission level be equal to or less than the
emission standard. Tne second advantage of an averaging approach,
a result of the added flexibility, is that the manufacturer is
better able to optimize its control technology strategies with
respect to economics. It may quite likely be more cost-effective
for a manufacturer to control one engine family to a very low
emission level and a second engine family correspondingly less,
than to control every engine family to the very same level. Two
distinct averaging approaches were proposed during the comment
period. General Motors (GM) proposed a plan whereby the sales-
weighted average particulate level of a manufacturer's entire
light-duty vehicle fleet would have to be equal to or less than the
Corporate Average Particulate Standard (CAPS). Volkswagen (VW)
suggested that the particulate emission levels from diesel vehicles
only be averaged, and that each manufacturer's sales-weighted
average be required to comply with the Diesel Average Particulate
Standard (DAPS). Both of these proposals have been evaluated by
the technical staff and will be discussed below, not only in the
specific terms as proposed by GM and VW, but also with modifica-
tions that have been suggested by the technical staff to make the
proposals more acceptable to EPA.
1. Corporate Average Particulate Standard (CAPS)
The following is an abbreviated description by GM of their
CAPS proposal:
"[I]n response to the EPA invitation to address alternate
particulate standard concepts, General Motors has developed a
Corporate Average Particulate Standard (CAPS) concept. We
believe this concept has the potential for providing the
benefits of the diesel engine, reasonably controlling diesel
particulate emissions, and being responsive to the legislative
and regulatory requirements while properly considering techno-
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logical feasibility and manufacturer capabilities. This CAPS
results in a sequence of participate standards based on the
average level of particulate emissions of a manufacturer's
total--both gasoline and diesel-powered—light-duty car and
truck production. Although this standard-setting concept is
markedly different than that proposed by EPA, such a concept
is currently used in establishing fuel economy standards,
so it is not new to government regulation... [T]he basic
objective of the particulate standards is to prevent any
deterioration in the mobile source contribution to total
suspended particulates... The resulting CAPS levels are
shown below:
Year CAPS Level
1981 0.2 gpra
1983 0.1 gpm
1985 0.07 gpra
1987 0.05 gpm
In addition to these CAPS levels, a maximum permissible
particulate emission level of 1 gpm from any individual
diesel engine was also made a part of the CAPS requirements.
In summary, the CAPS concept provides a number of major
benefits. First, the air quality impacts would be reliably
controlled, since the CAPS level would limit the total par-
ticulate emission levels to the atmosphere. This is a dis-
tinct improvement in long-term performance of the standard
over the individual engine standards proposed by EPA. Second,
CAPS would provide each manufacturer flexibility in deter-
mining what mix of diesel engine sizes can be produced, as
well as what percentage of total production can be diesel
engines....Third, CAPS provides a strong incentive for
diesel manufacturers to develop better particulate emission
controls, since successful development would allow increased
sales of diesels with the resulting increase in fuel effi-
ciency. Fourth, the CAPS concept is enforceable utilizing the
basic structure of EPA enforcement regulations now in place.
Only minor administrative modifications would be required to
perform the enforcement operations in an effective manner. "_5_/
As was mentioned earlier in this chapter, we agree with
GM that the promulgation of an average particulate standard would
provide more flexibility to the manufacturers. We also agree
with GM that CAPS would put a "lid" on diesel particulate emis-
sions. Once a manufacturer reached approximate equilibrium with
the CAPS level, any increase in the number of diesels sold by that
manufacturer would have to be accompanied by a corresponding
reduction in particulate levels (assuming constant total sales by
the manufacturer). Thus, the total diesel particulate loading to
the atmosphere would be relatively constant, except for small
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increases due to increasing total sales by the industry. While we
agree with GM that CAPS provides these two benefits, we take issue
with the remaining two benefits which GM claims, and extensive
analysis has found many problems which have compelled EPA to reject
both GM's specific proposal and the CAPS concept in general. These
issues will be examined in detail.
One basic tenet of EPA's motor vehicle emissions program has
been to utilize uniform individual vehicle standards within a class
of vehicles, i.e., to promulgate uniform standards within each
class of vehicles that each individual vehicle must comply with.
There are two primary reasons for this policy. One is simply the
structure of Title II of the Clean Air Act, which assumes individ-
ual vehicle standards (see, for example. Sections 202 and 207). It
is true that the current SEA assembly-line program is based on a
quasi-averaging approach, but this was implemented so as not to be
"unreasonably burdensome to the auto companies" in the short-term,
and may be only temporary._6/ EPA's position is that the Clean Air
Act requires every vehicle to meet the emission s tanda rds . _7_/
Certification averaging would clearly be inconsistent with this
position. The second reason for individual vehicle standards
concerns vehicle/vehicle equity. It has been determined that
vehicles of the same general utility should be required to comply
with the same emissions standards; that it would be inequitable to
legally allow vehicle A to emit more than vehicle B is allowed to,
when both vehicles perform the same general function. CAPS, and
any other averaging approach, is inconsistent with both the Clean
Air Act and the vehicle/vehicle equity considerations which are the
bases for individual vehicle standards.
Another serious drawback of CAPS involves manufacturer equity.
Since the CAPS concept averages diesel and gasoline-powered vehicle
particulate levels, and since the latter are typically very low, a
manufacturer's corporate average particulate level would be depen-
dent not only on its diesel vehicle particulate levels but also on
its relative proportion of diesel to gasoline-powered vehicles. A
manufacturer which produced a small percentage of diesels could
tolerate much higher particulate levels on its diesels, and still
comply with a specific CAPS, than could a manufacturer which
marketed a much higher percentage of diesels. In effect, manufac-
turers which produce higher percentages of diesels would have to
meet more stringent diesel particulate levels than manufacturers
which market lower percentages of diesels. Thus, manufacturer A
would be allowed to market "dirtier" diesels than manufacturer B,
only because A produced more gasoline-powered vehicles (with both
manufacturers having the same total diesel sales) or fewer diesels
(with equivalent total vehicle sales). Of the present light-duty
diesel manufacturers, GM would be the primary beneficiary of such
an approach since diesels comprise such a small percentage of their
overall sales. Daimler-Benz and Peugeot would be the manufacturers
most negatively affected by CAPS. In fact, given their present
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diaseI/gasoline vehicle mixes (approximately 65 percent diesel),
CAPS would be much more stringent for both Daimler-Benz and Peugeot
than the per vehicle standards of 0.6 g/mi (0.37 g/kra) in 1982 and
0.2 g/mi (0.12 g/kra) in 1985. Under GM's suggested numerical
standards and assuming that gasoline-powered vehicle emissions are
negligible, Daimler-Benz and Peugeot would have to average 0.31
g/mi (0.19 g/km) in 1982 and 0.11 g/mi (0.07 g/km) in 1985 on their
diesel vehicles. Alternatively, GM has estimated that its 1982
diesels would average approximately 1.0 g/mi (0.62 g/km) and its
1985 diesels 0.50 g/mi (0.31 g/km) under CAPS.8/ This analysis
indicates that under CAPS, GM would be allowed to market diesels
which would be approximately 3 times "dirtier" in 1982 and 5 times
"dirtier" in 1985 than diesels sold by Daimler-Benz and Peugeot,
while marketing more diesels than either of these manufacturers)
simply because it sells many more gasoline-powered vehicles. In
effect, CAPS licenses a manufacturer to market greater quantities
of and progressively "dirtier" diesels based on its gasoline-
powered vehicle production and EPA considers such an approach to be
unacceptable.
CAPS might also act to restrain competition in the industry as
a firm which wanted to produce only light-duty diesel vehicles
would likely find it impossible (or nearly so) to comply with CAPS
without also producing similar quantities of gasoline-powered
vehicles, which might make the necessary capital investment
prohibitive. GM proposed two possible solutions to the manufac-
turer equity problems of CAPS.9/ One was that EPA could provide a
temporary period of exemption from CAPS for certain manufacturers.
The second was that a "regulatory administrative process could be
developed that would allow a manufacturer to obtain an additional
particulate emission tonnage from another manufacturer which was
not using its particulate emission tonnage for a specific year,"
i.e., that particulate tonnage could be sold or traded between
manufacturers. Temporary exemption is simplistic and unacceptable,
but in any case does not solve the problem of manufacturer inequity
in the long term. The selling and/or trading of particulate
tonnage would be an administrative nightmare, and would simply
magnify the equity discrepancies even more in favor of low-percen-
tage diesel manufacturers. Neither of these "solutions" is accept-
able to EPA.
EPA has determined that adoption of the CAPS concept would be
inconsistent with the statutory authority for the diesel par-
ticulate regulations provided in Section 202 (a)(3)(A)(iii) of the
Clean Air Act. As discussed in Chapter IV, EPA is convinced that
"the greatest degree of emission reduction achievable" mandate of
that section requires best available control technology which, in
turn, necessitates standards based on that technology. This
mandate is impossible to fulfill with the CAPS approach since the
particulate emission levels that a manufacturer's diesel models
would be required to meet are dependent upon that manufacturer's
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diesel/gasoline vehicle mix and the manufacturer would be able to
adjust that mix to whatever extent desired. A manufacturer could
clearly avoid using best available control technology, or, in many
cases, any particulate control technologies at all, by simply
producing only a very small percentage of diesels. CAPS would then
serve predominantly as a sales-mix forcing concept rather than a
technology-forcing concept. In fact, CAPS implicitly establishes
an upper limit on light-duty diesel sales. It is very unlikely
that any manufacturer could sell more than 50 percent diesels under
GM's CAPS, and as pointed out previously two manufacturers already
exceed that figure. Adoption of CAPS would restrict those manu-
facturers to fewer diesel sales than the market demand; these
manufacturers so affected might very well market diesels which emit
lower levels of particulate than the cars sold by other manufac-
turers not so restricted. EPA has consistently held that Section
202(a)(3)(A)(iii) of the Clean Air Act was not meant to restrict
light-duty diesel production, but rather was designed to encourage
"clean" diesel production. The CAPS approach does not necessarily
motivate low particulate levels, because of the possibility of low
diese 1/gaso line-powered vehicle mixes, and actually restricts
diesel sales at high diesel/gaso line-powered vehicle mixes. This
latter problem could be alleviated somewhat by offering CAPS as an
option to those manufacturers which might prefer it to the indi-
vidual vehicle standards. There would still be an equity problem,
however, as low-percentage diesel manufacturers would have a real
choice between the two types of standards, while the high-percen-
tage diesel manufacturers would be compelled to certify under the
individual vehicle standards.
Analysis has shown that there are difficulties associated with
ensuring compliance under an average particulate standard approach.
One approach that has received considerable attention adheres
closely to the present philosophy of enforcement on an engine
family basis. Each engine family would have a particulate enforce-
ment level which would be the product of its certification level
and the manufacturer's "safety factor," defined as the ratio of
CAPS to the manufacturer's projected corporate average particulate
level. Thus, if CAPS was 0.05 g/mi (0.031 g/km), and the manufac-
turer's projected corporate average particulate level was 0.04 g/mi
(0.025 g/km), that manufacturer would have a safety factor of 1.25,
and each of its engine families would have an enforcement level 25
percent greater than its certification value. Any engine family
with an SEA particulate value in excess of its particulate en-
forcement level would then be subject to an order of corrective
act ion.
The primary difficulties associated with this type of enforce-
ment arise due to the fact that while the fleet-wide standard that
must be met by the manufacturers would remain constant throughout
the model year, the enforcement levels for the engine families
would be subject to change. This is because the enforcement levels
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are dependent on the manufacturer's safety factor, and thus on the
sales distribution (which could fluctuate throughout the model
year) as well. During the certification process, the safety factor
would be calculated based on the manufaturer's projected sales.
Yet any final determination of the safety factor would not be
possible until the end of the model year, when the final produc-
tion figures would be known. This could lead to several possible
problems.
For example, it can be shown that it is possible, 'due to a
change in production distributions, for all of a manufacturer's
engine families to be in compliance with their respective enforce-
ment levels (as calculated during certification) while its cor-
porate average particulate level could actually be exceeding CAPS.
This is illustrated by the scenario shown in Table VIII-1 of a
manufacturer with three diesel engine families. Based on its
certification levels and sales projections, the manufacturer has a
projected corporate average particulate level of 0.040 g/mi (0.025
g/km), and assuming a CAPS of 0.05 g/mi (0.031 g/ktn), a projected
safety factor of 1.235. Its enforcement levels were as shown in
Table VIII-1. The table shows that even though the actual SEA
levels were less than the corresponding enforcement levels, the
manufacturer was in noncompliance because its corporate average
particulate level was 0.051 g/mi (0.032 g/km). In this case, the
manufacturer did not produce any more diesels than it had pro-
jected, but simply produced more of engine family Z and less of
engine family X. This resulted in a smaller safety margin, and
permitted fleet-wide noncompliance simultaneously with engine
family compliance. The magnitude of this problem could be much
worse if a manufacturer actually produced a higher percentage of
diesels than projected, or if a much more marked sales shift from
the "cleaner" diesel engine family to the "dirtier" diesel engine
family occurred. Obviously this scenario could not be tolerated in
an enforcement program. EPA could attempt to ameliorate this
problem by constantly recalculating the safety factor throughout
the model year. This precaution would not exclude the problem
entirely, only make it less likely, as there is an inherent time
interval between when a manufacturer changes production and EPA can
recalculate its safety factor.
A second major drawback of this approach it that it would
allow the scenario where an engine family would be declared to be
in compliance immediately following an SEA test, but could actually
be in noncompliance later in the model year. This could arise due
to a changing production distribution resulting in a smaller safety
factor and smaller enforcement levels. For example, in Table
VIII-1, engine family X certified at 0.25 g/mi (0.16 g/km) and had
a projected enforcement level of 0.31 g/mi (0.19 g/km). Assume
that an SEA test was performed early in the model year and the mean
particulate level was found to be 0.29 g/mi (0.18 g/km); the engine
family would clearly be in compliance at that time. It could be
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quite possible that later in the model year, again due to a dif-
ferent production mix, chat same engine family could have a revised
enforcement level of 0.28 g/mi (0.17 g/km); at that point the
engine family would be in noncompliance. This scenario raises the
issue of how EPA would respond to such a discovery, especially at
the end of a model year, when the only corrective action available
is recall. The manufacturer would be forced to recall an entire
engine family after it had been allowed to produce it for an entire
model year. This also indicates the necessity of determining the
mean particulate level for each SEA test, when enforcing on an
engine family basis, since otherwise EPA would never know when the
enforcement level might drop below the SEA mean particulate level
for an engine family.
A third major difficulty with the engine family enforcement
approach would arise when one engine family of a manufacturer
exceeded its enforcement level, while an engine family which
emitted more particulate did not exceed its enforcement level. For
example, if SEA testing showed engine families X and Y (see Table
VIII-1) to have mean particulate levels of 0.32 and 0.42 g/mi (0.20
and 0.26 g/km), respectively, the former would be in noncompliance
while the latter would not. If this was discovered at the end of a
model year, and recall action was instigated, that manufacturer
would have to recall vehicles from the "cleaner" engine family
while the "dirtier" engine family would be unaffected. This hardly
seems logical or equitable, least of all to the consumer who may
have purchased the former vehicle partly because of its lower
particulate emission level.
The Council on Wage and Price Stability (CWPS) suggested a
similar but slightly different compliance mechanism (though pro-
posed as part of a diesel-only average approach, it could also be
part of a corporate average approach) ._10/ The manufacturer or EPA
would set a limited number of categories, each with a separate,
fixed particulate standard. Each engine family would have to
certify under one of these distinct category standards; the cate-
gory would presumably be chosen by the manufacturer based on the
certification emission level of the emission-data vehicle for each
engine family and any safety-margin deemed necessary. At the
beginning of a model year, the category standards and projected
sales for each category would be used to determine whether a
manufacturer would be issued a certificate of conformity. During
and at the end of a model year, the actual production (or sales)
figures and the category standards would be averaged to determine
fleet-wide compliance. The category standards would also be used
for SEA and recall testing. The advantage of this approach is that
the SEA enforcement levels are fixed, and are not dependent on the
manufacturer's sales distribution or safety margin. This compli-
ance approach would avoid the aforementioned scenario where an
engine family would be in compliance immediately following an SEA
test, but would be in noncompliance later when the enforcement
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Table VIII-1
Hypothetical Particulate Enforcement Scenario
Certification Projected Enforcement Actual SEA Actual
Engine Level Sales Level Level Sales
Family (g/mi) (%) (g/mi) (g/mi) (%)
0.25 4.5 0.31 0.30 3.5
0.35 4.5 0.43 0.42 4.5
0.45 3.0 0.56 0.54 4.0
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Level changed. The other major problems could still occur—all of
a manufacturer's engine families could be in compliance with their
respective category standards though, due to a changing sales
distribution, its fleet-wide average particulate level could be
exceeding CAPS, and "cleaner" cars could be faced with corrective
action even while "dirtier" cars sold by the same manufacturer
remain unaffected. Thus, the CWPS suggestion eliminates one of the
uncertainties involved in the engine family compliance approach
(the changing enforcement level), but does not resolve the other
problems inherent in such a compliance approach.
Finally, EPA could abandon the engine family compliance
approach and enforce on a fleet-wide basis only. EPA would still
test emission-data vehicles from each engine family for particulate
emissions. The manufacturers would be required to submit their
sales projections, on an engine family basis, for the model year.
With the particulate emission levels and sales projections it would
be possible for EPA to calculate the projected corporate average
particulate level for each manufacturer. If this projected level
is less than, or equal to, CAPS, and no engine family exceeded the
maximum particulate level allowed (and assuming all other emissions
requirements were fulfilled), EPA would grant the manufacturer a
conditional certificate of conformity. The certificate would be
conditioned on the manufacturer keeping its actual corporate
average particulate level (at any time, based on production up to
that time) under CAPS throughout the model year.
SEA would still be used by' the Agency to ensure that produc-
tion vehicles were in compliance with CAPS. Whenever the SEA
particulate value exceeded that engine family's certification
particulate value, the former would replace the latter in the
calculation of the manufacturer's actual corporate average partic-
ulate level. The SEA test, however, would no Longer indicate
noncompliance on an engine famiLy basis, but wouLd be a contribut-
ing factor in indicating noncompliance on a fleet-wide basis. At
regular intervals throughout the model year, and whenever an SEA
resulted in the substitution of a higher particulate value for an
engine family, each manufacturer would be required to report its
actual and projected production figures and actual and projected
corporate average particulate levels. As long as these levels
remained at or below CAPS, the manufacturer would be in compliance.
If, at any time during the model year, a manufacturer's actual or
projected corporate average particulate level exceeded CAPS, due
either to an SEA test or a shift in the sales distribution, the
manufacturer would be required to notify EPA immediately and to
take corrective action. The central enforcement tenet of this
approach is that at no time is a manufacturer "allowed" to exceed
CAPS.
Because this compliance approach is on a fleet-wide basis
only, it avoids the problems of engine family enforcement discussed
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above. This approach would necessitate a whole new compliance
apparatus, however. Whereas SEA is now designed to indicate
whether a certain percentage of vehicles pass an emission standard,
under this fleet-wide compliance approach SEA would have to be
designed to determine the mean particulate level of the engine
family tested. More SEA would likely be necessary in order to
ensure that EPA does not underestimate a manufacturer's actual
corporate average particulate level by relying heavily on certifi-
cation emission levels. This approach would also commit EPA to
much more monitoring and paperwork, as EPA would have to be contin-
ually monitoring actual and projected sales for each manufacturer,
and recalculating actual and projected corporate average partic-
ulate levels.
In conclusion, while EPA considers engine family enforcement
to entail many difficulties, we have determined that fleet-wide
compliance could probably be made workable, although it would
involve such structural changes in motor vehicle enforcement
procedures as to make it uninviting unless other concerns compel
its acceptance. As noted elsewhere in this section, we do not find
such compelling factors.
Another question concerning CAPS is how to quantify the
particulate emissions from gasoline-powered vehicles. There are
three ways to incorporate gasoline-powered vehicles into CAPS:
require them to certify and subject them to enforcement just like
diesel vehicles, assume their particulate emissions to be zero, or
exempt them completely from the average particulate standard.
Requiring gasoline-powered vehicles to certify and subjecting them
to enforcement would greatly increase the certification and en-
forcement workload both for EPA and for the industry. This does
not seem justified in light of the low particulate levels exhibited
by light-duty gasoline-powered vehicles. Assuming these emissions
to be zero is not justifiable either, since for those manufacturers
marketing 90 to 100 percent gasoline-powered vehicles gasoline
exhaust particulate would be a major, and possibly a majority,
contribution to the total corporate particulate tonnage. Finally,
exempting gasoline-powered vehicles would violate the very basis of
a corporate average particulate standard. We see no easy solution
to this problem. It should be noted that there are no such prob-
lems with the per vehicle particulate standards, as EPA has deter-
mined that gasoline-powered vehicles emit far less particulate than
even the 1985 standard. There is no need to certify gasoline-
powered vehicles under per vehicle particulate standards.
Under GM's CAPS proposal, the maximum particulate level
allowed would remain at the relatively high 1.0 g/rai (0.62 g/km)
level even though the average values would be progressively tight-
ened. This would allow the possibility of localized particulate
impact problems in the future in certain cities, neighborhoods, or
roadways which might have an unusually high concentration of
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diesels emitting at or near the 1.0 g/rai (0.62 g/km) particulate
ceiling. One likely possibility would be the dieselization of the
New York City taxi fleet. The magnitude of this problem could be
alleviated by reducing the maximum particulate level allowed, but
this would diminish the flexibility so desired by the manufacturers
and which is a cornerstone of the averaging concept.
A final difficulty with GM's CAPS is simply the high particu-
late levels that it would allow manufacturers who market small
percentages of diesel vehicles. GM provided to EPA "an indication
of the average diesel emission performance required" of GM should
CAPS be adopted as proposed. These data are given in Table VIII-2.
The level of control that EPA has determined to be technologically
feasible by 1982 (0.60 g/mi, 0.37 g/km) for all vehicles would not
be reached by the average GM diesel until 1985. The level of
control we expect by 1985 (0.20 g/mi, 0.12 g/km) would not be
necessary for GM, under CAPS, until 1990. This despite the fact
that GM is expected to be the largest light-duty diesel manufac-
turer (by far), producing nearly 1,000,000 light-duty diesels by
1985 and possibly twice as many by 1990 (see Tables III-3 and V-4).
GM would need to do absolutely no more additional particulate
control work until the mid-1980's and would not need to do any
major work until the late 1980's. This phenomenal leniency for the
manufacturer which is expected to dominate the light-duty diesel
market in the 1980's would be irresponsible public policy. It
would be possible to make CAPS more stringent, of course, which
would have the beneficial impact of forcing low-percentage diesel
manufacturers (Like GM) to recognize that particulate control must
be a consideration of their diesel designs. But a more stringent
CAPS would reduce the flexibility available to the manufacturers
and, more critically, would only exascerbate the manufacturer
inequity problems discussed earlier.
The multitude of serious problems discussed in this section
have convinced EPA that the corporate average particulate standard
proposed by GM is inferior to the per vehicle standards that are
being finalized. Had the evaluation of CAPS been more promising,
other questions would have to be considered, such as whether a
completely new rulemaking would have to be initiated to allow for
public comment. The possibility of giving manufacturers an option
of choosing either per vehicle standards or an average standard was
also rejected for the same environmental, equity) statutory, and
enforcement reasons cited above. The increased flexibility avail-
able to the manufacturers clearly cannot justify the numerous
difficulties inherent in the CAPS approach.
2. Diesel Average Particulate Standard (DAPS)
The second averaging approach proposed to EPA was conceptual-
ized by VW:
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Table VIII-2
CM Participate Emissions Under CAPS 6/
Model Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
CAPS
0.20
0.20
0.10
0.10
0.07
0.07
0.05
0.05
0.05
0.05
% Diesel
Projected
4
9
10
12.5
14
17.5
19
21
23
25
Average Diesel
Particulate Level (g/mi)
1.00
1.00
1.00
0.80
0.50
0.40
0.26
0.24
0.22
0.20
-------
"DAPS limits the sales weighted mean of the particulate
emissions of all diesel vehicles sold by a manufacturer during
a model year [and] would allow manufacturers to mix the diesel
models sold on the market in such manner so that their diesel
fleets comply with DAPS. Compliance with DAPS is determined
by calculating the Diesel Average Particulate Emissions (DAPE)
for each manufacturer from the certification data and the
Projected Sales Figures. Whenever the DAPE for a manufacturer
is smaller than or equal to DAPS the Administrator shall issue
a certificate of conformity with DAPS. Such certificate of
conformity v.ay provide that the sales mix may not be altered
to such an extent that the manufacturer's DAPE exceeds DAPS at
the end of the model year. In order to make the DAPS concept
work with respect to the SEA, emission warranty, and recall
provisions of the Act, it is necessary to establish individual
control limits in addition to DAPS. Such control limits for
individual vehicles and individual engine families could be
called Diesel Individual Particulate Standards (DIPS). They
would be used solely to determine compliance with the enforce-
ment provisions of the Ac t. . . .Reasoning for introduction of
DAPS and DIPS: a) Contrary to the CAPS concept, the approach
suggested here is consistent with the Clean Air Act as it can
be implemented immediately upon introduction [without] having
to amend the Clean Air Act; b) Contrary to CAPS concept, there
is no negative impact on competition if the DIPS/DAPS concept
is compared with a traditional standard concept; c) The
DAPS/DIPS concept specifically regulates particulate emissions
from all light-duty diesel vehicles. Therefore, such partic-
ulate standards are still technology-forcing, while standards
under a CAPS concept are mainly sales-mix-forcing; d) The
DAPS/DIPS concept would allow manufacturers to make use of
diesel technology as a contribution to the effort of the U.S.
to conserve energy. Because large diesel cars with relatively
high particulate emissions could be offset by small diesel
cars, the use of diesel technology is not restricted to small
diesel cars....Under a diese 1-bubble concept, DAPS of not
lower than 0.6 g/mi for model years 1981 and 1982, 0.4 g/mi
for model years 1983 and 1984, and 0.3 g/mi for model year
1985 and subsequent model years could be established." 111
The primary difference between GM's CAPS proposal and VW1 s
DAPS proposal is that the latter averages particulate emission
levels from diesel vehicles only. Like CAPS, DAPS gives the
manufacturer increased flexibility and the opportunity to optimize
its diesel particulate control technologies with respect to econom-
ics. DAPS also avoids some of the serious problems inherent in the
CAPS concept. DAPS is more equitable to those manufacturers who
produce significant percentages of diesels. Regardless of how many
gasoline-powered or diesel vehicles a manufacturer produces, each
manufacturer would have to comply with the same average diesel
particulate level. DAPS also satisfactorily resolves the dilemma
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152
concerning gasoline-powered vehicles since, by definition, it
excludes them completely, Finally, EPA has concluded that DAPS
could be designed to be consistent with Section 202(a)(3) (A) (i ii)
of Che Clean Air Act. 3v levering the DAPS values below chose
proposed by VW, we are convinced that DAPS could satisfy the
"greatest degree of emission reduction achievable" mandate of that
section. Under a stringent DAPS, it would be impossible for a
manufacturer to market high part iculate-etaitt ing diesels since they
could only be "balanced out" by very low particulate-eraitting
diesels (and riot by gasoline-powered vehicles) and there is a limit
to the extent to which this balancing can work. In any case, the
low average diesel particulate level would have to be maintained.
Tnus, DAPS could be designed to require best available control
technology and to accommodate the technology-forcing concept.
Also DAPS does net implicitly limit diesel sales.
DAPS does share many of the drawbacks of the CAPS concept
which were delineated above. It violates both of the primary bases
for individual vehicle standards—the structure of Title II of the
Clean Air Act and vehicle/vehicle equity. DAPS involves the
same enforcement dilemma as CAPS—basing compliance and enforcement
on an engine family basis involves too many difficulties, basing
compliance and enforcement on a fleet-wide basis only would neces-
sitate major administrative changes. EPA has Che same localized
irapacC concern with DAPS; VW did not propose any maximum allowable
level, but one would be necessary. An averaging approach is not
inviting to the manufacturers unless EPA. allows maximum levels
greater than the 0.60 and 0.20 g/mi (0.37 and 0.12 g/km) standards
chat would otherwise apply. Yet any incremental increase in the
maximum levels allowed increases our concern for those urban
areas which might be subjected to an atypically high concentration
of high particulate diesel vehicles.
EPA considers the VW proposal of 0.60 g/mi (0.37 g/km) in
1981, 0.40 g/mi (0.25 g/kai) in 1983, and 0.30 g/mi (0.19 g/km) in
1985 to be too lenient. Levels which would be more consistent with
feasible technology would likely be opposed by the industry.
Obviously, it becomes progressively more difficult to" ".balance out"
a high part iculate-etnicting engine family as the average standard
decreases. Under a DAPS, it is impossible to "balance out" high
emitters by simply producing gasoline-powered vehicles. Thus,
lower DAPS levels would remove much of the flexibility that is the
primary motivation behind the averaging proposals.
One other discinction must be made between the CAPS and DAPS
proposals. CAPS implicitly establishes a ceiling on total Light-
duty diesel particulate emissions--once a manufacturer reaches
approximate equilibrium with the CAPS levels, any increase in the
nuraber of diesels produced would have to be accompanied by a
reduction in the average diesei particulate level. DAPS does not
perform this function as it constrains only the average dieseL
particulate level, and not the total corporate particulate tonnage.
-------
In conclusion, DAPS is inconsistent wich legal and regulatory
policy, shares many of the environmental and enforcement difficul-
ties of CAPS, and results in less flexibility to the manufacturers.
Thus, we rejec: ic3 use as a regulatory approach for parciculate
control, both as a replacement for the individual vehicle standards
and as an option for those manufacturers who might choose it.
D. Alternative Individual Vehicle Standards
Now that it has been shown that an individual vehicle standard
for light-duty diesels is necessary (i.e., no other alternatives
are preferable), the timing and stringency of this standard is all
that remains to be discussed. The following discussion will first
examine the initial level of control and then examine the second
and final level of control. Within each discussion, the standard
for diesal-powersd Light-duty vehicles (LDV-D's) will be examined
first and chen :hsc for diesai-?owered light-duty trucks (LDT-D's).
1. Initial Level of Control
The first level of control for LDV-D's is 0.5 g/mi (0.37 g/km)
beginning in 1932. This standard could be more or less stringent
and could.be implemented earlier or later. From the analysis of
the lead-time available before che 1981 modal year contained in
Chapter IV, there is enough time available for the manufacturers to
implement the necessary technology. However, unless they had
started their 1981 certification process before the final promul-
gation of this regulation, there would not be enough time for
manufacturers to complete a certification program for all or their
vehicles. Thus, the earliest year of mandatory certification is
1982.* The discussion of available technology in Chapter IV also
makes it quire clear that a standard more stringent than 0.5 g/mi
(0.37 g/km) would result in the elimination of the diesal engine
fron some code! lines. This would clearly be in violation of EPA's
stated approach of setting the standard based on the worse-case
vehicle. 127 Thus, it is not possible to promulgate a standard
more stringent than 0.6 g/mi (0.37 g/km).
It would be possible to delay the implementation of the first
standard by one year. The benefit of such a decision would be to
give the manufacturers one more year to meet the standard. Tne
control technology would not be expected to be any different so the
cost of meecing the standard should be the same as in 1982.
* In an effort to reduce costs, manufacturers are being allowed
the option of certifying to tha particulate standard in 1981 and
obtaining carryover for 1982. As the MOx standard is being reduced
in 1931, most vehicles will have to be certified in 1981 regard-
less. With ehe option, it is hoped that most manufacturers will
be able co avoid recertification in 1982.
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154
Overall light-duty diesel emissions in 1990 would increase by 0.5X
or by 173-288 metric tons per year.
Ambient levels of light-duty diesel particulate would also
increase by 0.5%, but this would be less than 0.05 micrograms per
cubic meter in any of the 15 cities shown in Table V-14. This
increase would be difficult to measure. Thus, the benefit of a
delay would be to allow the manufacturers another year to implement
control and the detriment would be a very slight increase in
ambient particulate levels. This is often the case for a one-year
delay in any emission standard and often leads to the argument that
the standard should be delayed. However, extending this argument
one year at a time could lead to the conclusion that a Longer delay
would also have only a slight detrimental affect on the environ-
ment, while the effect would indeed be significant.
As outlined in Chapter IV, the manufacturers should actually
be able to meet a 0.6 g/mi (0.37 g/km) standard in 1981. Because
there would not be enough tine available to assure that all ve-
hicles could be certified before the normal start of the model
year, the standard was postponed a year to 1982. To delay the
standard another year would simply allow manufacturers to move
ahead even more slowly than was possible. As this extra time is
not necessary and no significant cost reductions are foreseens
there appears to be no compelling reason to delay the 1982 stan-
dard.
The last issue is whether or not the 1982 standard should be
any less stringent than 0.6 g/mi (0.37 g/ku). Reasonable alter-
natives would be 0.8 g/mi (0.5 g/km), as suggested by the Depart-
ment of Energy J7 , or 1.0 g/aii (0.62 g/km), as suggested by a
number of manufacturers.^/ Again, the primary benefit would be
accrued by the manufacturers. Less work would be required of them
in meeting the standard. The 1.0 g/mi (0.62 g/km) level should be
high enough to preclude any real control, while the 0.8 g/cai (0.5
g/km) level would require some control from one manufacturer. It
is difficult to calculate any cost savings from these higher levels
since much of the costs involved with meeting the 0.6 g/rai standard
are amortized research and development costs which have already
been incurred. With the 0.8 g/mi standard, light-duty diesel
particulate levels in 1990 would increase 9%, or 0.04-0.3 micro-
grams per cubic meter in the 15 cities of Table V-14. With Che 1.0
g/mi standard, light-duty diesel particulate levels in 1990 would
increase by 19% or 0.08-0.6 micrograms per cubic meter. These
calculations assume a 1985 standard of 0.2 g/mi (0.12 g/km).
The real question again is whether or not the 0.6 g/mi (0.37
g/km) level can be met in 1982. The cost savings involved with
less stringent standards are small, less than 910 per vehicle
(Chapter VI). The air quality impacts of the higher standards are
small, but now measurable, if a 1985 standard of 0.2 g/mi (0.12
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155
g/kn) is assumed. As shown in Chapter VII, the cost effectiveness
of the 0.6 g/mi standard is excellent. Its cost effectiveness
ratio is about one-tenth that for the 0.2 g/mi standardj which
itself is in the same range as those from stationary sources. The
only reason the 0.6 g/mi standard should not be promulgated is
if it couldn't be met. As outlined in Chapter IV, this is not the
case. Thus, the 1982 standard for LDV-D's should be 0.6 g/mi.
The arguments outlined above for implementing the initial
standard in 1932 are essentially the same for diesel-powered
light-duty trucks (LDT-D's). However, the choice of level of this
LDT-D standard deserves some attention. It was shown in Chapter IV
that the difference in weight and size of LDT-D's vs LDV-D's could
cause particulate emissions to increase 20%. On the other hand,
the NOx standard for LDT-D's through 19 S4 will be 2.3 g/mi (1.43
g/kni) . This standard was set to be equally stringent to a 2.0 g/mi
(1.24 g/krr.) NOx standard for LDV-D's. The beneficial effect on
particulate emissions of raising the NOx standard to 2.0 g/mi from
1.5 g/mi (LDV-D waiver Isvel) appears much greater than 20* (Chap-
ter IV). The net result of the two differences between LDV-D's and
LDT-D's is that it should actually be easier for LDT-D's to meet a
0.6 g/mi (0.35 g/km) standard than for LDV-D's to meet the stan-
dard. To raise the standard for LDT-D's above 0.6 g/mi would
aggravate this difference. This would encourage the dieselization
of light-duty trucks over that of light-duty vehicles since less
control would be required. This would result in inefficient use of
control technology since more advanced technology would have to be
used on LDV-D's than LDT-D's at a conceivably poorer cost effec-
tiveness. It would also result in worse air quality than would
occur if the same technology was used on both classes of vehicles.
Thus, for these two reasons, a standard higher than 0.6 g/mi for
1982 is unacceptable for LDT-D's.
If the effect or a higher MOx standard does more than overcome
the weight and size penalty of light-duty trucks, then an equally
stringent standard for LDT-D's could be less than 0.6 g/mi (0.37
g/km). However, this lower standard would not be much below 0.6
g/mi and could only stay in effect through 1984, since the NOx
standard for LDT-D's will decrease in 1985. For example, if the
standard would be lowered to 0.5 g/mi (0.31 g/km), light-duty
diesel particulate emissions would only decrease by 0.4£ and the
ambient levels in the cities in Table V-14 would improve at most
0.02 micrograms per cubic meter. It is also likely that many
people would be confused and believe that EPA was controlling
light-duty trucks more stringently then passenger cars. Given the
minimal, air quality benefit, the small magnitude and temporary
nature of any inequality, and the potential confusion of the
public, it appears to be in the best interest of all to not pro-
mulgate a standard any lower than 0.6 g/mi for LDT-D's.
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2. Second Level of Centre I
The second level of control is expected to
of the introduction of trap-oxidizer technology. As such, alter-
natives to the 0.2 g/ai (0.12 g/ka) standard in 1935 involve 1) the
levels which can be achieved with and wichout this new level of
control technology and 2) the data that trap-oxidLzer technology
can be available. As EPA knows of no viable control technology at
this time which would allow the expected LDV-D fleet to meet a
standard more stringent than 0.2 g/'rai (Chapter IV), no standard
below 0.2 g/mi will be discussed bars.
The first alternative to examine is trap-oxidizer technology
vs. no crap-oxidizer technology in 1985. As outlined in Chapter
IV, with trap-oxidizers LDV-D's are expected to be able to meet a
0.2 g/mi (0.12 g/ka) standard. Without crap-oxidizers LDV-D's
would be expected to be able to meet a 0.5 g/mi (0.31 g/kas) stan-
dard. .s Both of these determinations include the need to meet a 1.0
g/mi (0.52 g/km) N0:< standard, which will be in place no later than
1935. Using the methodology of Chapter V, the 0.5 g/mi standard
would causa 1990 light-duty diesel part ic'-ils ta emissions to in-
crease 97% over emissions occurring under a 0.2 f/tni standard.
(For the purpose of this discussion a similar increase in the LDT-D
standard will be assumed.) This would cause ambient levels o:
particulate from light-duty diesels to increase similarly by 97%.
The absolute effect on ambient levels is shown in Table VIII-3 :or
: -itias. As can be seen, the effect of che higher standard is
•"asurahle. In Chicago, ambient regional levels of light-
_esel oarticulata would increase by 0.8-2.7 micro grams per
.Loic meter over whac they would be under a 0.2 g/mi (0.12 g/ka)
standard. Regional levels in Dallas would increase by 1.5-2.7
nicrograras per cubic meter. Localized impacts would similarly
increase by 973.
VJhile the higher standard would increase ambienc parciculate
levels, it would also reduce costs. From Chapter VI, "he removal
of Che trsp-oxidiser would reduce the overall cost of the standard
by 3107-133. Using che methodology of Chapcer VI, Section C, this
would reduce the 5-year aggregate cost of the 1985 standard (1985-
39) by 5897-1357 million (present value cakan in 1985, 1979 dol-
lars). Using the methodology of Chapter VII, the incremental
cost-effectiveness ratio (C/S ratio) of adding the Crap-oxidiser
would be 33,567-4,433 per metric ton {$107 to S133 divided by 0.03
metric tons lifetime reduction). On an inhaLable particulace
basis, Che C/E racio would remain 33,567-4,433 per mecric Con. On
a fine parciculace b.a.sis chs C/E ratio would increase Co $3,7i6-
4,618 per metric Con.
It is evident chat boch significant air quality and economic
effaces resulc from che addition of trap-oxidizers to light.-ducy
dies els. An indication. o£ whether che increased effectiveness is
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157
Table VIII-3
Large-Scale Air Quality Impact of Light-Duty
Diesels Under Two Different Emissions Standards in 1985
Pop ul at ion
Category City
Over 1 ail lion New York
Los Angeles
Ch icago
Philade Iph ia
Houston
De troi t
500,000 to Dallas
1,000,000 New Orleans
Bos Con
Denver
Pittsburgh
San Diego
Phoenix
St. Louis
Kansas City, MO
0
1
2
1
1
2
1
3
1
1
1
1
1
2
1
0
Light-Duty Diesel Ambient
Particulate Level
(micrograms per cubic meter)
.5 g/mi I/ 0.2 g/mi 2/
.0
.8
,6
.4
.2
.0
.3
.2
.0
.0
.0
.2
. 2
.2
.8
- 2
- 5
- 5
- 2
- 3
- 1
- 5
- 2
- 1
- 1
- 1
- 2
- 3
_ 2
- 1
.4
.7
.5
.2
.7
.8
.5
.0
.8
.8
.6
.0
.7
.2
.2
0
1
0
0
1
0
1
0
0
0
0
0
1
0
0
.5
.4
.8
.7
.1
.5
.7
.6
.5
.5
.5
.6
.1
.6
.4
- 1
•• 9
- 2
- 1
_ i
- 0
- 2
- 1
- 0
- 0
- 0
- 1
- 1
- 1
- 0
.2
.9
.8
i
• J.
.9
.9
.8
.0
.9
.9
.8
.0
.9
.1
.6
I/ Emission standard for LDV-D's (0.31 g/ktn). Assumes LDT-D standard of 0.6 g/mi
TO.37 g/km).
1] Emission standard for LDV-D's (0.12 g/km). Assumes LDT-D standard of 0.26 g/mi
(0.16 g/km).
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worch the increased coses car. be found from comparing "he in-
cremental cos- effectiveness to those from other control strategies
(See Chapter VII). Unfortunately, the data necessary to truly
perform such a comparison is not available and any comparisons must
be made using very rough measures of effectiveness. This was done
in Chapter VII and Che incremental cost effectiveness of a number
of nationwide stationary source strategies were estimated and shown
in Table VII-2. Placing greatest emphasis on the fine and in-
halab'.a particulars bases, the C/E ratios calculated in the pre-
vious paragraph for the addition of trap-oxidizers are not incon-
sistent with those from stationary source strategies. Given chat
further control of particulata emissions is needed (See Chapter V),
the addition of trap-oxidizers appears to be a reasonable strategy.
Some caution should be placed on the use of any comparison
such as the one perforated in the previous paragraph. While the
estimates of the cost effectiveness of the various strategies
represent c'r.e best available, the cost-effectiveness measures used
do not represent the true effectiveness of any of the strategies.
Factors such as source Location, population exposures, particle
composition, etc., have not bean taken into account due to a lack
of data. Any one of these factors could have a major effect on the
outcome of any cost-effectiveness comparison.
For example, motor vehicle emissions occur at ground level
and tend to be concentrated in urban areas. This would increase
the relative ambient impact and population exposure to diesel
particulate emissions compared to a source with a tall stack
located in a rural area. In Chapter VII, it was very roughly
estimated that emissions from light-duty diesals have between 0.8
and 13^ times the ambient impact as an equivalent amount of emis-
sions from electric utility steam generators. The range and the
absolute size of Che above estimate indicate the potential effect
that factors such as this one can have on any cost effectiveness
comparison. Thus, while this regulation appears reasonable with
respect to cost effectiveness, it should be remembered that any
such comparison performed at this tirae is lacking in completeness
and only a minimum amount of weight can be given to -the comparison.
The final set of alternatives now revolves around the imple-
mentation year of che second standard, which is directly tied to
the availability of trap-oxidizer technology. Since our technical
analysis (sae Chapter IV) indicated a strong likelihood of suc-
cassful trap-oxidirer application by 198i, one alternative would be
to promulgate the 0.2 g/tai (0.12 g/km) standard for 1984. The
Agency has seriously considered doing exactly that. It was a
difficult decision, but because of the uncertainty that exists with
regard to trap-oxidizer durability and vehicle application EPA has
decided to minimize the economic-risk of this' rulemaking-by delay-
ing the implementation of the 0.2 g/rai (0.12 g/kin) standard until
1985. This delay will increase light-duty diesal parciculata
-------
emissions in 1990 by 9 percent:, but will ensure "hat the manufac-
turers will have "he ability Co optimize trap-oxidizar application.
Since i: is alvays possible to delay che implementation of a
standard, a second alternative would be to promulgate the 0.2 g/mi
(0.12 g/km) standard for 1986. This delay from 1935 to 1936 would
increase light-duty diesel part iculata emissions in. 1990 by 12
percent. It would also give the manufacturers additional Lead cine
for trap-oxidizer optimization. 3ut sines we have determined tha:
trap-oxidizers sight very well be feasible by 1984, and are delay-
ing implementation of the 0.2 g/mi (0.12 g/km) standard to 1985 in
order to ensure optimum trap-oxidizer development, there is no
reason to delay implementation until 1935. Thus wg are rejecting
this latter alternative as well.
Concerning LDT-D's, the rationale for implementing a 0.25 g/mi
(0.15 g/km) standard in 1935 and rejecting all other alternatives
is analogous to chat described above for LDV-D's. The only area
noc dealt with above is that of setting the LDT-D s.ancard at the
same technological stringency as the LDV-D standard. As the data
in Chapter IV shows that a 30% increase in particuiate emissions
cculd result from the greater size and weight of LDT-D's, a 30%
cushion over the 0.2 g/mi (0.12 g/ka) LDV-D standard should resale
in equally stringent standards. A lower or higher standard for
LDT-D's would result in an artificial bias toward the dieseLization
or one of the two vehicle classes. This would have negative
effects on air quality since tha bias would be toward the worst
polluting class. For this reason, any standard for LDT-D's other
than 0.25 g/mi (0.16 g/km) should be rejected.
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160
References
I/ "Summary and Analysis of Commencs Co Proposed Particulate
~ Regulations for Light-Duty Diesels," MSAPC, EPA, October,
1979.
2/ ' "Impact of New Source Performance Standards on 1985 National
~~ Emissions from Stationary Sources," EPA-45G/3-76-017, April
1977.
3/ Chapter V.
4_/ "1975 National Emissions Re port," OAQPS, EPA, May 1978,
EPA 450/2-78-020.
_5_/ "General Motors Response to EPA Notice of Proposed Rulemaking
on Particulate Regulation for Light-Duty Diesel Vehicles,"
April 19, 1979, Attachment 2.
6_/ "Selective Enforcement Auditing Procedures," Federal Register,
Vol. 41, No. 146, Wednesday, July 28, 1976, p. 31474.
]_/ Ibid., p. 31480.
$_/ "General Motors Reponse...," Attachment 2, Figure 5.
9/ Ibid., Attachment 6.
_1_0/ "Comments of the Council on Wage and Price Stability on the
Particulate Regulation for Light-Duty Diesel Vehicles," p.
44.
Ii/ "Supplementary Information to the Record of the EPA Hearing on
March 19, 1979, Concerning Proposed Particulate Emission
Standards for Light-Duty Diesel Vehicles" submitted by Volks-
wagen in April 1979, Section 4.
12/ "Particulate Regulation for Light-Duty Di-esel Vehicles,"
Federal Register, Vol. 44, No. 23, Thursday, February 1, 1979,
pp. 6650-6671.
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